Hi to all,

I just want to make a album for 15 songs time over 16 minutes. It's simple. Each user has to copy and paste adding only one song to the album so in the end it's 12 songs, one per user, and each album has to have a different theme.

Whoever adds the last song of the album gets to say what the the theme for the next album will be and it starts all over again.

Songs over 16 minutes:

1. Pink Floyd - Echoes (23:31)
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.

Has anybody built a set up for KT88/6550, 300B, or 845 who could share experiences and ideally, a BOM and what you did for supply voltages? I think there was talk of tailored BOMs, but it looks to me like the thread never got that far, even for the KT88/6550.

Paul

Started looking on line for this transformer for the Elliot P05. Power supply.... Does Hammond make one. My principal source might be Quebec, Canada. but if not in the US. Does anyone have a link. Found some on Ebay but they are from China

What is the meaning of Life?
To me it seems life has no real meaning.

What do you think?
What are your goals here in life?
Other than surfing diyaudio.com 😀

I just downloaded a file from there; it's the first time is about a year I've been able to. Might want to check yours as well?

I know I might be close to "being in over my head" ....

But that level of challenge is what keeps me going 😀.

The design goals -

PCB 1 = analog

-Analog regulated power supplies.
-IC / discrete class A buffers.

PCB 2/3 = digital

- DAC / clock

- PGA2311 /arduino /LCD display

- of course .... the analog 3.3 , 5V digital supplies.

PS - the PCB being split will allow just a line stage builder
to also take part in the project.

(below 1/2) - the line stage.
10ppb/1k diamond based buffer - 7X gain.

Also , the .asc ...

OS

I'm really interested in building a clone or at least a speaker inspired by the Devore Fidelity Orangutan o/93. Has anyone tried this before? I'd be using the Seas A26 kit from madisound presumably, though I'm open to buying each part separately. I've never built a non-kit speaker so I'm a bit over my head but have the woodworking and electronics skills just not the speaker design skills. Any recommendations on how to approach this? I see that several others here have tried something similar so hoping to hear some expertise or experience. Specifically I'm also interested in how to adapt the kit I referenced into a larger cabinet. Can that be accomplished with changing the crossover? Does it stay the same? Any advice is greatly appreciated.

Hi!

Since several months I have to wait say 3 to 6-7 seconds for an answer from the site.

Also, many times, when doing a quote, it will time out and noting happens - so I have to redo it - sometimes up to 3 times before it works. It just ends up without any action done and without any fault indication. It can vary from quite OK during shorter periods but is generally bad.

Macbook pro M3 on fiber-> Wifi.... other sites OK.

Why could this be?

//

Lately, I've been seeing a lot of discussions about slew rate in various media, and frankly, it pisses me off...
A guy says "the old model of this amplifier had a 90v/μs slew rate, the new model has reduced it to 45.. so the amplifier is slower than the old one"...
If you are using your amplifier as an FM transmitter, this can be considered an argument.. Of course, if your transmitter/amp is not transmitting square waves... Bu no, it is still not a logical argument.
Let's do a little math; if an amplifier can handle a rising edge of 45v on the μs scale, it means it can output a signal of at least 500khz at a peak level of 45v. If we reduce the signal to 20khz, the peak value will be 1125v....
Hypothetically, let's say your amplifier is "extremely slow" and only has a slew rate of 5v/μs. + You are listening to heavy metal at extremely high volume, for example 500w rms power (whatever kind of ears you have) and there is such a transition in the song that the signal comes out from 0 to 500w with a 20khz transition.. Can your amplifier respond to this? 500w@8r is ~ 63.5v rms. Even if your amplifier has a weak slew rate of 5v/μs, it reaches this value in about 18μs. This is about 60khz. And if you calculate a rising and a falling edge, we divide this into two and reach a square wave bandwidth of 30khz.
And don't forget that your dear extremely high end speaker will convert this signal to the sine with great pleasure.
So it is meaningless... Even if your amplifier's slew rate is 3v/μs, it is still meaningless.
I would like to draw your attention to the values we used as reference: You are listening to 500w and the dynamics of the music increases with a 20khz, i.e. 50μs, transition from 0 to 500w. I leave it to you to comment on what kind of audiophile (or human) can listen in this way.

Hi everyone!

I just received my Behringer DCX2496 digital X-over!

It looks great :



The specs are ok too.

This will be part of my 3-way active loudspeaker system.

I am very impressed by the flexibility with which you can configure the system and setup x-over parameters (using the PC interface - Serial RS232), which for me was the decisive factor for buying this unit......

Anybody else on this forum who has experience with this unit?

I built a modded Marshall 2203 guitar amp a few years back and ended up needing to do some prototyping on it to get it right.
Basically its the same schematic but with different B+ voltages and using 807 tubes (based on the advice of an old fella who has now since passed away.)
Looking back now I would have just built a pure replica with EL34 tubes, but hey this thing is unique!
My main concerns are around Bias voltages, plate voltages on preamp tubes and poor presence control.
The amplifier seems to sound OK, but I felt it did not put out as much power on the low sensitive input as the high did.
Not too sure if this is normal for this design or not, but its still pretty damn loud when cranked up full, from memory im getting closer to 200W on the high sensitivity input when overdriven.
This thing is a beast for sure.

So the mods are as follows:
B+ 400V
807 output tubes
12AT7 phase inverter
everything before the phase inverter is the same as the marshall design, I have highlighted my changes in red on the schematic.

When taking measurements, i got the feeling that the plate voltages on the preamp tubes might be high, the old guy also told me to change the resistor values on the power supply at the top (highlighted in red) changing the original 10K value didnt seem to reduce the plate voltages much, so i just left at 4.7K and 1K respectively.

Voltages measure as follows:
V1A anode to ground 280V
V1B anode to ground 335V
V2A cathode to ground 1.5V, anode to ground 191V
V2B cathode to ground 190V, anode to ground 383V, across anode to cathode 189V
Phase inverter, anode to ground 265V, across anode and cathode 168V

Do any of these voltages look too high? 335V on V1B seemed a bit too high to me.
As far as presence control goes, even the original marshalls had poor response and little to no difference in sound is observed, I dropped it down to 4.7K from 100K and it makes more of a difference to the negative feedback received, the difference in the phase inverter may also have a role to play.
As far as bias voltage goes, i think ive got it sitting around -50V from memory, Im not sure ive got this right, as a rule 10% of plate voltage should be applied, I think i went by ear mostly and left it where I felt it sounded right, but I should revisit this.
Any other feedback is appreciated, largely the amp seems to run sweet, but I just want to tidy this thing up and order some new resistors to replace the ones ive tacked on while prototyping it.

See schematic attached, modded values are marked in red.

I have been rebuilding a pair of Quad ESL-63s and am getting close to finishing. By rebuild, I mean I have reglued stators, and replaced diaphragms in all eight drivers.

I used Gorilla clear polyurethane glue to glue the stators of only one speaker- the other stators were bonded well and would probably have broken if I tried to break them loose.

I used 3 um mylar film, stretched using a pneumatic stretcher, with resonance tuned while the film was on the stretcher to about 92Hz. The diaphragms are glued using 4693H contact cement that unlike the factory glue, actually bonds to the grid and the diaphragm.

I applied Licron Crystal to the diaphragms and tested resistivity and resonance before and after applying the Licron. Resistivities all came out at either 10^8 or 10^9 Ohms/square. Resonance dropped by about 1 Hz with the added mass of the Licron Crystal. For those who might be concerned about longevity, I have some old drivers that I worked on in the early 90s that used 4693H and Licron coating, and they are still in good shape.







You can see details of my failed and successful methods on my blog page, here.

I'll be installing the drivers back into the speakers and testing with full bias applied over the next couple days.

After visiting @Audio Elite in 2017 I knew I wanted to build speakers like that. Slowly but surely I gathered parts. 2nd hand or discounted. Since Stuart was not allowed to share the crossover schematic I had to find something else. But I saw something that was similar to the frequencies I "needed" to cover. I copied that and did a mod for the different tap on the Crites 3636 autoformer. I've posted the crossover pic but here is the complete system schematic..

PS...there is still some work to do on the crossover.

I also decided on open baffle mid-bass. Because I could go active/dsp. And because wood is very expensive.

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What is the use of ground on dual rails devices.

I installed SB Acoustics 8" Fullrange(SB20FRPC30-8) in TQWT.

Well-extended bass.
Natural mid and high range with little grating.
High quality throughout the all range, and the performance is above the price.

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I've no idea why the shape of a cabinet would affect bass response. Volume is the only significant factor, right?
I ask this question because I've spent a lot of time trying fashion a subwoofer to fit under a bed. I think I'm currently embarking of MK VI.
Cabinet making is not my forte. So it's easier for to use a floor-standing tower cabinet as a base (25 litres). But on reflection I've never met a skinny floor-stander with an impressive bass response.
Has the shape got anything to do with it?

Hey all, getting ready to make another pair of CLS panels...

Planning on using a Spring Scale to set vertical tension, just need to know value....

From specsheet, the Dupont Mylar C 6 micron should shrink 2% in Machine Direction, and 1.2% in Traverse Direction with 300F heat applied for 30 minutes...but we only want vertical tension, so heat shrink not an option ("barreling" of mylar over spars - yup did it)

Sooooo....Mechanically...

Elongation = F*L/A*E

F= force (what we are looking for)
L= Length
A= Cross sectional area mylar
E= Modulus of elasticity (using Mylar 710kpsi, cannot find Mylar C value)

So plugging numbers, tensioning 36 pounds should get 1% elongation.

I still think this is too high.......anyone know if this is correct, or able to check my calc?

​

I started a new project to re-home a pair of OPTs from an old Scott 299 amplifier and am looking for PI circuit opinions/ideas. Ultralinear isn't an option with those transformers so I decided to experiment with a really stiff screen supply. It's an all-tube design except for the rectifiers but I'm really impressed with the performance of the regulator and anxious to hear it. I'm going to be using the 6P14P as the output tubes (the Scott 299 used 7189s originally) and it idles right at 500 volts on the anodes. There's lots of room for screen V adjustment within a range that still provides excellent regulation so I'll be doing lot of tinkering.

Anyway, the 299 used an ECF80 phase inverter and I've re-drawn the circuit (attached) but am wondering if anyone else has used this design and how it compares to some of the others. Chassis constraints limit me to a single 9 pin miniature tube so I guess I'm not "married" to the ECF80 if there's something that is a lot better, but I've read a lot of great stuff about the tube and I have a bunch so I planned to at least start out with it. What I don't know though is how the original Scott circuit design might compare sonically to some of the others. Yes, I know, opinions and tastes vary from person to person but having never heard a working Scott 299, I thought I'd ask the guys that play with this stuff more than I do. I've been into lots of guitar amp projects and amateur radio stuff but this is probably my first "hi fi" audio project so in that regard opinions are worthwhile to me.

Enough blabber. PI schematic attached. Many thanks in advance for your opinions, ideas, suggestions etc.

https://www.ebay.com/itm/195785024138

This uses k1058/j162, the circuit diagram looks like a goldmund clone.
But why does this kit have a vbe multiplier? Does it work?
I'm new to vbe multiplier on an amplifier using lateral MOSFET.

MM PHONO RIAA Preamplifier - KIT - A very good preamplifier that sounds very good compared to many transistor preamplifiers. Much discussed on many forums and built by many of our colleagues.

Kit for building PHONO RIAA Preaplifier with tubes russian 6N3P-E (high quality audio grade, 5000+hours life). Is a stereo variant - for two channels one single board.

Variants:

• complete - all components and tubes - assembly - 65EURO + 15 Euro shipping to EU.

I am sending to EU only.
Note: NO power transformer, NO case.

https://postimg.cc/SJJbCJP0



Attention, electronic tube mounts work with dangerous voltages that can cause death if you are not careful and do not know how to use them.

For more details, please send me PM.

PCF 802 KIT - PHONO RIAA Preamplifier

Kit for building PHONO RIAA Preaplifier with tubes. Is a stereo variant - for two channels one single boards

Variants:

• only tubes - 25EURO + 15 Euro shipping to EU. I am sending to EU only.
• PCB - tubes - sockets - 50EURO + 15 Euro shipping to EU. I am sending to EU only.
• complete - all components and tubes - assembly - 65EURO + 15 Euro shipping to EU. I am sending to EU only.

Note: NO power transformer, NO soft start function, no power supply module

Attention, electronic tube mounts work with dangerous voltages that can cause death if you are not careful and do not know how to use them.

For more details, please send me PM.

Link with photos: https://postimg.cc/gallery/yHGGGJB

It seems the Calpamos is not being sold as a kit speaker any more and there are no more built crossovers being sold.
Does anybody have the crossover schematic and values please?
The schematic is available on the site but the component values are not provided.Although the type/make of components is.

Can one reliably hear any difference between this amplifier and a lower THD amplifier. A really good amplifier. As you can see no capacitor is used for stability compensation
https://www.pcbway.com/project/shareproject/mosfet_amplifier_f17685a0.html

Finally bitten the bullet building my first open baffle. Using Dayton 2x PHT1-6 ribbon tweeter and 2x vintage Saba 10” alnico 6 ohm (dc reading 5.2 ohm for both) I will be mounting them on a live edge hardwood baffle of similar size to this.
Unfortunately I don’t have any TS Parameters for the Saba. I’m told they are very efficient full range. I will be using a dedicated subwoofer driven with class d plate amp. My question is how do I go about designing a crossover without any specs on the Saba’s. I will be driving them with a single ended set tube amp of up to 8w.

So i have four 6.5" woofers that came out of some yamaha ns-300 towers. I want to fit them in place of stock speakers in my ford ranger front and rear doors and maybe fit an amp that gives 180watts at 2 ohms. The issue i have, is that the yamaha drivers are 12ohm impedance, which is too high. The doors have tweeters in them which as far as i can make out from researching, are 4ohm with capacitor added for crossover.
If i wire the woofer and tweeter in parallel, according to parallel speaker calculator i will get total impedance of 3 ohms which is great and 120watts total power from amp, but the issue is, that it says the power will be shared at 30watts to woofer and 90 watts to tweeter. So either will blow tweeter or at least will have very weak woofer output and massive top end.

Does anyone know a way around this?
Ive seen it is possible to put high power resistor across woofer but would lose sound quality. I wondered if it may be possible to remove voice coil from some old 100wat 8ohm speakers i have and put it across the woofer? That would give me 2.18ohms total imp and share power at 75woofer 90tweeter which is better.
Dont know if its possible to do that.

Does anyone in the know have any ideas?

Ideally i want to get a 4 channel amp and have a woofer and tweeter on each channel. Any help would be gratefully accepted. Cheers

Hi there,

I am actually by designing a multichannel DAC (form my active speaker system) with the newest ESS chips, the 9017 and the pin compatible 9027. I'd like to make it DIY friendly, and as flexibel as possible/practicable. If you have any ideas what all should be considered, please let me know! Perhaps we could develope and realize it together...😉

Some main aspect of this chips:

• they have solder legs, so easy to DIY
• they have hardware mode, so a controllel is not absolutely necessary
• they have the newest Hyperstream IV architecture
• performance is quiet good: 110-114 / 120-124dB (THD+N / DNR)
• they are pin compatible, the smaller one is quiet cheap (but without ASRC and SPDIF input)

The design is almost ready, but the output filter pcb, that will be placed beneath the DAC pcb must be finalized yet.

Cheers,
Bela

There has to be a way to get that 90 degrees on a stylus without the damn air pump!!


I don't want to go off track in other tonearm threads so I decided to start a new thread focusing on the discussion and design ideas for pivot style tonearms that can attain tangential tracking, a pivot linear tracker if you will. Sounds like an oxymoron but it can be done.

To be brief, most tangential tracking tonearms are typically air-bearing tonearms that allows the stylus glide across the radius in almost frictionless manner to simulate how a record is cut on a lathe. Other means of this gliding action can be also achieve via linear bearings like rollers on a rod or bushing on a rod, etc... Some concept arms even suggest using floating opposing magnets. The flaw of such tonearm is that the horizontal mass is enormous regardless of bearing quality, low friction or no friction. It limits the choices of stylus, depending on its compliance. And the use of an air pump is not for everyone to say the least - a personal pet peeve of mine. The genre of electronic servo detection pseudo-tangential trackers like the Rabco tracking across the record in tiny little arcs constantly self correcting its way to the end of the record is not part of this discussion here. Anyway, this thread is NOT about the above tonearms. We want to talk about pivot tonearms that can track tangentially by changing stylus angle simultaneously.

The best examples are actually currently available in production. By now, many people have heard of the Thales tonearm from Switzerland. It is a pivot style tonearm with an extra pivot at the headshell area right above the stylus. The changing angle is always 90 degree to the radius because it is part of a triangle that is inside a semi-circle that adheres to the Thales theorem, that is, "Thales discovered that the circumferential angle subtended by a triangle in a semicircle is always a right angle. As a result, the half circle above the hypotenuse of a right-angled triangle is called the Thales Circle."

http://www.tonarm.ch/kommentare/thaleskreis_e.html

6moons industryfeatures: Thales

.



.

With the basis of the Thales Circle, the designer Micha Huber devised a tonearm that can track any point inside the semi-circle always 90 degrees to the center of the record, voila a linear tracking tonearm that pivots without any linear motion. Genius! The tonearm appears to be executed with quality construction and precise worthy of a Swiss watch. So far it is the ONLY tonearm on the market that is capable of 100% geometric accuracy in maintaining tangency, at a price,of course, as it sells for, I believe, 6000 €.

.



.

Visually, it has the look of a Rube Goldberg device but looking closely, everything seems to have its specific function for good reason. I don't want to write a white paper on the Thales design but for those who are interested in examining it more closely, feel free to explore its website. But this tonearm does give a good example of the objective here.

.

Thales will introduce a new tonearm named "Simplicity" that looks simpler and elegant and even though it is not 100% accurate in geometry but it reduces the tracking error to a maximum of 0.008°! Pretty damn good in my book.

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.

There are historical predecessors of such design and one can find that in the classic Garrard Zero 100.

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.

And the Burne-Jones arms.

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.

One can also find examples in contemporary designs like the RS Labs RS-A1 arm with a pivoting headshell.

.



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.

"Prototype of the 'Bajulaz' tonearm on a TD-124. It was designed by Ing. Bajulaz to overcome the geometry problems of the conventional tonearms, but allegedly it wasn't so good for the new stereo cartridges and therefore never went in production."

.



.

I will continue to upload more pictures and present ideas to stimulate discussions and, hopefully, inspire the DIY spirit.


.

Here's a bunch of tweaked BJT (both "vintage" and current) LTSpice models for your perusal, see attached and see this thread for details on the method I used. After posting it, I continued measuring and tweaking models for pretty much all the small signal and VAS/driver transistors I have in stock. At one point or another I've used all the models at least once and they seem to work fine, but the usual disclaimers apply: provided as-is, no express or implied warranty, no liability, etc.

These are the models included:

Small signal:
2N5088
2SC1775 / 2SA872
2SC1815
2SA1016
2SC2240 / 2SA970
2SC2291
BC183C
BC183L
BC547 / BC557
KSC945C / KSA733
KSC1845 / KSA992
LM394
MPS8099 / MPS8599
MPSA06 / MPSA56
MPSA18
MPSA42 / MPSA92
ZTX384 / ZTX214
ZTX653 / ZTX753

VAS/driver:
2SC1941
2SC2910
2SC3116 / 2SA1248
2SC3788
2SD600 / 2SB631
BD139 / BD140 (both Fairchild and STM)
/ KSA1142
KSC2690 / KSA1220
KSC3503 / KSA1381
MJE243 / MJE253
MJE340 / MJE350
TTC004B / TTA004B

Some random notes:

- The Peak Atlas DCA Pro provides a maximum Ic of about 10 mA and I don't really know how much you can extrapolate the accuracy of the model to higher currents. Bear this in mind especially for the VAS/driver models.

- Where I had a bunch of them, I measured beta and Vbe for the lot and based the model on the one closest to the median, but for some I only had one or two, so the model may not be as representative. Also, even where I had a bunch, the model will be representative of that particular bunch, the ones you have / buy may well be different, so ymmv. They were all pulled out of vintage equipment or bought from reliable suppliers (Mouser, Farnell, etc.). I'm not going to list all my stock, so if you have questions about a specific model, please ask.

- I have measured vs. simulated curves (Ic-Vce, hFE-Ic, Ic-Vbe and reverse) for all of them. Those are the direct measurements I've based the models on. I've also tweaked to match other things like beta droop, ft, Rb, temperature effects, etc. where those were available from the datasheet or elsewhere, which isn't always the case. If they weren't, I've left those parameters as they were in the model I tweaked or at their default value. If you're interested in the curves and/or details of a particular model, again please ask.

- This has been discussed before but it bears repeating: it's amazing how outrageously bad some of the models provided by the manufacturers are. Take for example the Toshiba TTC004B / TTA004B: it looks like they've tried to model the quasi-saturation apparent from the Ic-Vce curves in the datasheet by giving them a ridiculously bad VAF, when in fact they are excellent in that respect.

- On that note, given the difficulties with simulating quasi-saturation (see the thread above), I've only bothered with it where it was apparent in my measurements, but not where it appears only in the datasheet at voltages / currents where I don't envisage using that particular transistor, as in those Toshibas.

Can't think of anything else to say right now, comments and questions always welcome!

Cheers,

Cabirio

Update 14-Mar-25: Revision B attached, see post #8.

WITH THIS >

Male / Female
Up / Down
Left / Right
White / Black
On / Off
Yes / No
In / Out
High /Low
Day / Night

I can't help but think about Polarity.
Another thing about polarity is that it gave us ONES & ZEROS. That is the 'language' of a Computer.
A Silicon switch on or off.

Perhaps the miracle is that if it wasn't for the grains of sand we see on the beach, that is Si = Silicon, todays computers wouldn't exist.

so WHITH THAT ... what do you think?

I’m just questioning on the tweaking tweeter’s high-pass filter. Assume we have a 0.75” (19mm.) tweeter. Its high-pass filter is a standard 2nd-order configuration comprising a series capacitor and a shunt inductor with C = 6.8uF and L = 0.2mH. The first question is does this filter cut so low frequency off for the 0.75” tweeter?

I know the correct way to answer this question could be achieved by a “measurement”. But I just ask if there’s an experienced DIYer who could answer this by his “sense” from his “experiences”.

Well, the second question is what if I change the values of C = 7.5uF and L = 0.18mH, will it introduce any cons to the (0.75”) tweeters?

An experienced friend of mine suggested me both scenarios (6.8uF and 7.5uF cases) gave too low cut-off frequencies for those little tweeters. These should be more widely found in midrange drivers instead of highs. Is this true?

Edit: the impedance of the tweeter is 4 Ohms, DCR = 3.2 Ohms.

I want to build a bass horn a la scala. But with the 15pr400 like Volti audio.

It (15pr400) mostly needs a bigger doghouse. So I was thinking 20 percent bigger la scala all round. Perhaps also with a bass reflex mod as well. As is now 'standard' on the AL6 model.

I guess I have to learn to use hornresp?

Moderation Edit: For updated information and new links regarding this project, please refer to post #2386.

New Links and Information

My latest audiophile approach named Q17.
So far the best sounding amplifier I ever made. Harmonic reach with exceptional bass response and 3d soundstage.
Archive contain everything. Full amplifier description and operation. Ltspice asc file for simulation. KiCad source for Q17 and his power supply. Gerbers zipped, so you may pick and drop on your favourite PCB manufacture. BOM with current active parts for Q17 and power supply.
Detailed description on how I made the PCB inductor and more, is also incuded in zip.
Inside zip:
LTSpice - contain asc file
ps - power supply KiCad source files
Q17 - amplifier KiCad source files
Spiki - inductor generator - python script to generate inductors in KiCad
Q17project_presentation.pdf - detailed presentation - bill of materials included
Q17 is on GitHub under GPL3 - Q17 is an open-source hardware project
ngspice simulation
Measurements
How to order your transformer
How to order your own PCB from JLCPCB, or click & order your Q17 with dual output pair PCB @
You have extra money and wanna buy directly from me, subscribe to this GB list.
Purchase parts for one channel with one click from mouser.
Purchase parts for active power supply from mouser. Does not include synchronous rectifiers and optional decoupling MKP.

Enjoy !


Edit 23.July.2021 If you build this amplifier, please give him a serious burn-in. All these mosfet's will start to sing after 200-300 hours.
You may download latest KiCad for your OS from >>> KiCad Downloads

Edit 25.July.2021 GerberQ17.zip is for amplifier pcb and gerberPS.zip for power supply.
Upload each zip file separately to jlcpcb. Jlcpcb will process one file at a time as separate orders.

Edit 26.July.2021 There is an error on output connector on GerberQ17.zip. Don't use this file until I correct this.

Edit 27.July.2021 Output connector issue is cleared. See this post for latest archive > Q17 - an audiophile approach to perfect sound

Edit 12.Aug.2021 Mounting holes have been added to power supply pcb. Gerbers available here >> Q17 - an audiophile approach to perfect sound

Hi, I am trying to fix the amp board on REL q201e subwoofer. The transistor BF469 and zener diode got completely burned off. The transistor BF469 and BF470 are no longer available. What other equipment part can be substituted for this??

-Max

Just recently got back into listening to music after a 20 year break, so am on a steep learning curve and I expect to be learning for some time yet. This site looks like great for me going forward.

Hi guys,
I have one phoenix gold ZX350 with buzzing problem. I have this noise only with gain set to max (0,2V), and source connected. Without source no buzzing/noise. I have tryed different sources, but the problem is still present.
Can be normal this buzzing? For understand, is like high setting level on the guitar amplifiers.

Have made a TPA3255 board thinking it would be super easy to get working 🙄

But it will not start up, and I'm a bit stuck .....

There is oscillation on OSC_IOM/IOP, see oscilloscope picture.
Had made some stupid mistakes with the reset circuit, but have replaced it with just a blue LED and the 5.6k to 12V which was already there. This means I get 2.6V on reset which should be ok. When I short the LED, bringing RESET to GND and let go again, there is short action on the output surely trying to start up, but it stops right away.
I have put red numbers on the Schematics, for the measured voltages.

Fault is low, and Clip_OTW is high.
This should mean "Overload (OLP) or undervoltage (UVP). Junction temperature lower than 125°C" .... but where is the Under voltage?
Nothing is hot.

When reset is set to GND Fault goes high.

Any suggestions?

Thanks

thread index at the end of this post!

When planning, simulating, building and measuring bass reflex enclosures for 2-way speakers one difficulty is dealing with port resonances in the midwoofer’s passband.

I thought it should be possible to absorb resonances with Helmholtz resonators in/at the bass reflex port.
Obviously I am not the first to come up with this idea, but I also didn’t find very much about it on the internet.
Thus I decided to make my own measurements, see the following posts!

some web references:​

Short thread about this issue on diyaudio. note that the thread starter wrongly refers to the "1/4 wavelength resonance" of a port. This is not correct! The fundamental resonance of an open tube happens at the frequency that has a wavelength equal double the tube length.

A german thread about port tube resonators.


various web references for resonance of open tubes and helmholtz resonators:

https://en.wikipedia.org/wiki/Helmholtz_resonance

https://en.wikipedia.org/wiki/Acoustic_resonance#Open_at_both_ends

https://www.physicsclassroom.com/class/sound/Lesson-5/Open-End-Air-Columns

https://en.wikipedia.org/wiki/End_correction

http://troelsgravesen.dk/vent_tuning.htm (including end correction values!)

calculating resonance of bass-reflex port (open tube resonance):​

occurs at frequency that has half wavelength equal to end corrected reflex port length and respective frequency multiples.
Oscillation node (pressure maximum) is at center of port (or further divisions for multiples).
pressure absorber works best at the respective node.

Option 1: tube absorber​

Simple tube, one end closed, it should thus have roughly half the length of port for absorbing resonance of port fundamental; can either be parallel (and inside) the port or 90° perpendicularly mounted at port. Open end should be located at half port length.

Option 2: Helmholtz absorber​

Mounted at half bass reflex port length, connected by its own small Helmholtz port to the bass reflex port

-------------------------------------------------------------------------------------------------

Thread index​

#3 - first resonance absorber tests with tube test setup
#5 - decay plots of test bass reflex box
#8 - resonance absorber results by @augerpro
#11 - link to a relating message by @rdf including link to roozen/philips-paper
#19 - new parallel 6th order bandpass test box for further investigations
#22 - dealing with enclosure resonances
#25 - chuffing audibility test
#42 - particle photos (using water sprayer)
#48 - port 2 variants and measurement results
#50 - port stalling test
#54+55 - influence of smoothed port flange
#56 - port 2 impedance results
#58 - port resonance absorber test
#81 - link to bryce doll paper by @Hearinspace
#103 - port 2 variants resulting in the same tuning frequency, with geometry drawing
#104 - photo of port 1 variants
#141 - port wall stiffening influence
#157 - port 1 variants response measurements
#159 - chuffing RTA measurement of straight port 1
#161 - chuffing RTA measurement of rectangular curved wall port and big 3d printed port
#165 - chuffing RTA measurement of flat port and small straight port
#166 - resonance absorber setup
#167 - measurment of resonance absorber lenght variations
#202 - resonance absorber filled with melamine foam
#206 - chuffing RTA measurement of 3d printed port with resonance absorber
#214 - influence of port diameter/dimension for enclosure resonance transmission
#228 - small 3d printed port drawing and measurments
#230 - testing noise of roughened port surface
#236 - port with resonance absorber documentation by @Kwesi
#249 - chuffing RTA measurements in singe dB steps (small 3d printed port)
#251 - separating resonance absorber from the port with latex membrane
#288 - link to salvatti devatier button paper
#302 - explanation of boundary layer thickness by @andy19191
#310 - impedance measurements for port 1 variants at different input levels
#320 - "progressive port geometry" concept
#324 - progressive geometry port measurements
#328 - progressive geometry port length correction
#329 - progressive geometry port impedance measurements at different levels
#330 - progressive geometry port response
#331 - progressive geometry port chuffing RTA measurement at 100 Hz
#341 - output level measurement / comparison
#349 - is airspeed the main chuffing factor? progressive port chuffing RTA measurement at 50 Hz
#350 - new particle photos
#352 - explanation of turbulent air motion by @andy19191
#363 - relating chuffing to particle displacement
#367 - first GIF-excepts of 120 fps particle videos
#390 - port variants with sound recordings by @Tenson
#391 - correct port particle displacement calculation formula by @David McBean
#395 - (1) first slow motion video: hard edge port
#407 - (2) second slow motion video: flared port
#434 - flange variant video
#438 - (3) third slow motion video: progressive geometry port
#448 - influence of air particle displacement for the excitement of low frequency noise
#449 - differences of a big and small (optimized) port for a small 2-way midwoofer
#460 - (4) fourth slow motion video: small straight hard-edge port
#468 - small very flat port - checking for boundary layer flow resistance
#503 - how to calculate the strouhal number using max port air velocity data, CORRECTION see #591
#504 - water tank simulation
#522 - @Dmitrij_S Karlson couple port
#526 - flared port geometry definition
#529 - 2 way speaeker test ports to be measured ...
#531 - ... response measurements ...
#546 - ... chuffing measurements (RTA) ...
#591 - correct calculation of strouhal number, related to peak-displacement instead of p-p- displacement (thanks to by david mc bean)
#595 - how to find a suitable port exit diameter using the Strouhal number (corrected version!)
#616 - first beta version of a simple excel sheet for tuning calculation of NFR=0.5 ports
#621 - relating the strouhal number to compression and distorsion
#624 - parametric fusion 360 model for a NFR=0.5 port by @augerpro
#627 - augerport with resonance absorber by @augerpro
#646 - parametric NFR=0.5 port model for freeCAD, including STEP and STL model
#652 - announcement by @David McBean: stouhal curve included in the port exit air velcity graph.
#654 - how I make my 3d printed ports
#680 - chuffing/noise audibility comparison: straight and flared port
#704 - big collection and evaluation of 3 speaker and 14 port variants - proposed MID PORT STROUHAL NUMBER (MPSN) parameter
#747 - updated excel calculation tool with correction and variable NFR ...
#748 - ... and the imperial version of the same calculator
#753 - comparison ports vs passive radiators
#811 - compressing the optimum geometry definition to two relevant parameters
#812 - The breakthrough: Finding compression behaviour patterns
#847 - Iterative port geometry optimizer tool


(will be updated)

Today I bought 🙂 (pics are not mine)

Harman Kardon Citation 11


Yamaha B-2


Nakamichi 480


Philips CD-104


Yamaha CT-610


Philips CDR-765


CEC DD-8200 with Shure V15 type IV


Grundig Fine Arts T-903 MKII


Next 😀

Oops! Almost forgot yesterdays goodie 🙂

At 27g, the B&C 320K/C-A has some of the lowest Mms you will find in a currently available 12" driver not marketed as a "guitar driver", outside of some boutique Supravox offerings.
"guitar drivers" would be of interest but I'm after an FR.

My only experience with ultra low mms driver was the Sica 10D1CS, another FR with slightly lower mms/sd ratio spoiled by a very weak magnet.
With a Qts of 1.56 it was unusable as a sealed FR but provided some insight, this driver has an airy and liquid midrange tone that I quite like however peaks in the upper end were particularly pronounced.
How much of that is down to the unsually low mms or the overall characteristics of the drivers is not known.

"liquid" is a term associated with low mass planar headphones (versus the "granular" sound of dynamic headphones) and that is sorta what it reminded me of

You can tell the cone is light just by touching it, it flexes like an A4 sheet of card and I am presuming the B&C cone would have to be similar enough.

With regard to damping, break up behaviour, LF/HF performance etc. what are the potential compromises and gains with a very light cone?

The only glaring difference you can glean from the spec sheets is much reduced power handling spec compared to pro drivers in the same size class, which suggests that distortion rises quickly with power... that is a good trade off for home users pushing only a handful of watts into them.

This thread is intended to be a place to discuss the balanced and unbalanced output versions of the stereo phono preamps as well as the Devinyliser designed by Doug Self and sold as boards only via The Signal Transfer Company website.
Website description: “The Signal Transfer Stereo Phono Preamplifier is a stand-alone version of the phono system used in the Precision Preamplifier. It offers both moving-magnet and moving-coil inputs, the latter with two gain options for optimal performance. It gives extremely accurate RIAA equalisation, a noise performance that approaches the theoretical limits, and superb linearity.”
No parts kits are currently available, according to recent correspondence with Mr Self.
Balanced output version: http://www.signaltransfer.freeuk.com/RIAAbal.htm
Unbalanced output version: http://www.signaltransfer.freeuk.com/RIAAunbal.htm
Devinyliser: http://www.signaltransfer.freeuk.com/devinyl.htm
Mr Self has taken over managing the website and fulfilling orders. He has been very responsive and the boards were received quickly.
I’m impressed with the build quality of the boards. Most of the parts are easily sourced using the BOM provided in printed documentation (or perhaps you will get a pdf) with the boards by searching for the values needed at your preferred supplier and verifying the part you choose has the correct lead spacing to match the board.
He does have a supply of the 2SB737 low noise transistors that he sells, tests each first and ships.
It took some digging and help from other diyaudio members to source a few of the parts.

Pending:
BOM with parts numbers from Digikey, Mouser, etc
Instructions to bypass Phono Preamplifier onboard subsonic filtering to leave that for Devinyliser to handle
Suggestions for some hard to source parts or their alternatives

Thank you to Kimmo Saunisto for this wonderfull software😛, very very gratefull.
it is very complete and powerfull, but you need to know well loudspeaker design.
Software

thank you again.

I've been repairing/restoring/rehabilitating a great 30-year old pair of speakers and I have some questions stemming from my novice inexperience.

1) In the woofer part of the crossover, the schematic shows a "100uF 100V bi-polar" in parallel with the woofer. My existing crossover, spare crossover that I purchases, and in every photo that I've seen of the crossover, they use two 47uF caps instead of one 100uF cap. Why?

Why not two 50uF caps (which certainly appear to be available)? I understand that two smaller value caps might perform better than one large value cap (correct me if that understanding is wrong), but why use 47uF caps?
I will certainly re-build this cross over with some type of Metalized Polypropylene cap. But do I use two 47uF (maybe with an added higher-quality bypass cap) or two 50uF caps?

2) In the midrange section of the crossover, it has two 10uF caps in parallel wire in series with the midrange drivers. See attached snippet from the schematic:

As with the woofer circuit, I will probably replace these with Metalized Polypropylene caps. I assume I can use one 20uF poly cap rather than two 10uf poly caps without any significant difference in quality. Or will two 10uF actually be much better?

3) In the tweeter circuit there are 3 inductors. The first in series with the tweeters is a very small 0.011uH ferrite core inductor with a Rdc of 0.1 ohm (the other 2 are 0.5mH and 1.3mH inductors wired in parallel with the tweeters). Following the concept that ferrite core inductors are problematic, particularly in series with tweeters, I am considering replacing it.

None of the speaker parts sellers (Madisound, Parts-express, Parts-connexion) have any inductor that small. Is that possibly a typo? (I will have to see if I can measure the inductor) 0.011uH = 0.000011mH = 11nH. Does a value that small make any sense to any of you? I would like to replace it with an air core (for obvious reasons) and I can find air core inductors in roughly that size (0.010 uH) on digikey.com. But the size does seem strange to me. Further, if it is correct, the Rdc of the inductor will almost certainly be different. Do I need to compensate for the different resistance in the circuit, and if so how or where would I do that? This is what the 11nH inductor looks like:

Hello everyone.
I can't get the RPI to recognize via Wi-Fi.
I have a Raspberry Pi Zero W, with no Ethernet port for configuration.
I followed the installation instructions with the Raspberry Pi Imager, and after several attempts, I couldn't get Moode to appear on the network. I tried creating a wpa_supplicant.conf file on the root of the SD card, but nothing worked; this file systematically disappears.
Any help would be helpful.
Thank you.

The Saturn Project (7/4/2025)

The finished speaker is a 3-way active system designed to be used with stereo subwoofers. Towards the end of construction I decided the name of this speaker would be Saturn. The drivers are:

ScanSpeak 26W-4867T00 260 mm (10”) aluminum cone woofer

Bliesma M74A 74 mm (3”) aluminum dome midrange

Bliesma T25A aluminum dome tweeter

Hypex FA253 3 channel DSP amp located in the speaker stand.



Thread Index

Woofer evaluations Post#102 link 102

Twin woofer concepts Post 127 link 127

Reconsidering the twin woofer concept Post #171 link 171, #325 link 325

Concepts for stand mounted 3-way Post #198 link 198 , #205 link 205

Prototype M74A baffle measurements Post #216 link 216, #257 link 257, #264 link 264

Tweeter selection process Post #276 link 276, #309 link 309

Final driver selection Post #318 link 318

@Fluid’s T25A waveguide concept Post #332 Link 332
T25A simple waveguide profile

Decision to not use a waveguide Post #410 link 410

Midrange-tweeter baffle Post #451 link 451

Cabinet structural damping – my approach Post #499 link 499

Cabinet construction Post #515 link 515

Polar scans of each driver Post #559 link 559

Completed speaker Post #576 link 576

======== ========= ========

Original starting post:

Many people say that dome midrange drivers have a sound quality which is unique and desirable. I have heard systems with dome mids that sounded very good, and others which were very ordinary. This thread discusses this topic in detail....link

For the past year, I have been thinking about the Bliesma M74A-6 driver, and simulating various options to use it effectively. To me, this driver offers an excellent way to experience the power and potential of a good dome mid in a high performance application. I like that it operates pistonically over its full range, and the first mode resonance is more than an octave above its likely pass band. This feature sets it apart from its silk and paper dome sisters. I like that it has high sensitivity and high SPL capability. I like that @HiFiCompass has measured very low harmonic and modulation distortion at high SPL. I like that the “A” aluminum dome version is considerably less expensive than the beryllium and textreme versions.

Thus, I started this project with just one primary requirement, that it use the M74A driver.

Hello--

I return once again in need of help. My buddy reached out to me about his amp not working (power light not turning on). Quote " i was beating the crap out of it to be honest. But once i smelt a small amount of burning wires I cut all power and turned it on once since them. I had to tap it to come on.". Not sure what "it" is or where...he also sent me a picture of an exploded mosfet, Q707, IRF3205 (? based off the one next to it, not sure that is the correct number).

Now, i know blind part replacement is bad, but, if there are no other visibly damaged parts on the board, would it be a good place to start by replacing the exploded one, and maybe the two on either side of it and seeing if it works?

If that doesnt fix it, I will probably buy Perry's amp repair guide, and go from there.

Which are the interesting tubes available in mesh plate versions? I'd nominate the 27 and AZ1 or AZ11 as ones I've used and liked for instance.

Any explanation why mesh plates sound good?

Hi,

I have been wondering about this thing.

In a normal 2 channel stereo, mono sound comes from a phantom center. However compared to a mono speaker it doesn't sound the same. So in some sense sometimes mono might sound a bit more realistic especially if the music source is essentially mono. Example a guitar, piano or cello. Tilting the speaker inwards tend to improve on the imaging giving it a more robust phantom but still not as good as a mono speaker.

My purpose is not to do a DSP or mess around the signal chain but just to improve on the presence of the phantom center to be as close as possible as a mono speaker in front. I am wondering if an additional speaker connected to the left and an additional speaker connected to the right placed right in the center together, so acoustically mixed, at much lower volume, say -10dB compared to the side will produce a more robust phantom center?

Has anybody tried such an experiment? Or come across some work on it.

Thanks in advance.

Oon

Hi Guys,

Just seen a recent press release on the new Hypex Fusion plate amps. Look like game changers for active speaker technology. I can't wait to try these babies out. Press release here:

Hypex Electronics Introduces New NCAS500MP Active Speaker Amplifier Module

Single Ended Tokin SIT THF-51S Common Drain Mu Follower Amplifier , 45W?

Edit: 70W Version added:https://www.diyaudio.com/community/...mu-follower-amplifier-45w.371187/post-7855849

Edit: Stereo Version to suit 4U 400mm Chassis, 44VDC Power Supply, added: https://www.diyaudio.com/community/...mu-follower-amplifier-45w.371187/post-7928760
This version has very limited Iq adjustment. Iq is approximately 1.9A

Edit: 44VDC Power Supply Version with wider range of Iq adjustment: https://www.diyaudio.com/community/...mu-follower-amplifier-45w.371187/post-8046556

I used to be a huge fan of single ended common source SIT amplifiers. I had a 2SJ28 version of Michael Rothacher's Hammond 193V choked loaded L'Amp and I also have a THF-51S version of Mr. Pass's BAF2015 2SK77 amplifier (Zen Mod's version is the Singing Bush). I took the 193V out of the L'Amp and tried it in a higher Watt 2SK180 L'Amp. Unfortunately that did not work out as well as I had hoped in that it had thermal runaway issues. However that turned from bad to good when I tried the 2SK180 in common drain mode with the 193V as load, and I was pleasantly surprised:

https://www.diyaudio.com/forums/pas...93v-choke-loaded-2sk180-lamp-post6601437.html

So now I am a huge fan of SITs in follower mode. I suppose I shouldn't be surprised as Mr. Pass's recent DIY Sony VFET Part 1 is also a follower amplifier, and Mr. Pass has impeccable taste. So I got to thinking that my THF-51S BAF2015 monoblocks are good candidates for conversion to common drain follower (inverted BAF2015 THF-51S?).

For the CCS/mu follower I needed to find a suitable P-Channel enhancement mode Mosfet. Unfortunately they are not in great supply, especially when I was thinking power dissipation of about 100W. So with a safety factor/derating factor of say four, I was looking for a device rated at a minimum of 400W. After some searching the internet I found the IXTQ26P20P. However it was only rated at 300W. I was willing to give that a try though. Its datasheet had a Safe Operating Area chart showing DC parameters at Tc=70C, Tj=150C and it looked very feasible. Then I found an even better device that was used by diyAudio member Lynn Quam in his SIT3X amplifier design: the IXTN40P50P. It is rated at 890W, so plenty of headroom, and it is also the same form factor as the IXFN140N20P in the BAF2015 amp. Also Lynn had the Spice model posted so I didn't need to search for it. Thank you, Lynn.

Since my plan is to repurpose my BAF2015 THF-51S build, I will be using the existing chassis and power supply. The power supply was designed to comfortably output 60VDC at 3.0A. It is currently running at about 2.3A and 62.5VDC. The chassis has a fan cooled heatsink and temperature is not an issue.

So I started out with some LTSpice simulations and decided to go with the mu follower and not just straight CCS, as the mu follower's additional power output was enticing. I found 62VDC and 3.0A was a good operating point. Simulations showed 45W into 8 Ohms was feasible. In reality, to be determined.

EDIT:
New - PCB Available: Start of PCB Design at post #173

Looking for a good sounding pre amp .
Needs good price quality ratio , good sounding , big soundstage and has to reproduce lots of details in the music .
Already build the Korg Nu tube and also the Wayne line stage .
The Wayne pre does sound pleasant in my ears bud soundstage is too narrow and cause of that a lot of details in the music is hidden or pushed away .

I spotted some amusing videos on youtube on the audio designer Angela-Gilbert Yeung. I would like your input on the products she/he puts in the market.
Ans can someone give me an explanations for the massive amount of silicone that is randomly sprayed in the audio builds?

Hi everyone! I'm a retired electrical engineer, and after getting into hifi audio several years ago, recently discovered DIY and Nelson Pass. I've built up two ACAs in April, and now just finished an F5M. The sound quality of both are outstanding!

This thread is for people to discuss their builds, build issues, and parts for the DIY Class A/B "Wolverine" Power Amplifier.
The boards are currently available through group buy's when they are held.
@jjs is servicing the USA and Canada regions.
@stuartmp is servicing the other regions.

Main Thread:

Wolverine 57v & 64v Schematic:
Please see the attached PDF files. These schematic show.
The Wolverine IPS - V3.7 (1st Group Buy) & V3.8 (2nd Group Buy)
The Precision EF3 - Both

BOM and Build Guide documentation:
Currently only available to group buy members.
In time will all be posted publicly once the group buy members have had time to order parts.

YouTube Build Link

Google Photos - Wolverine Build Album

Review Attached by @fireanimal 30-06-22
Review Attached by @richbandit 05-08-23 or at post #2,493

Posts of Interest
#

There is also a distortion sweep plot of the Wolverine below with the values listed for 1K, 10K and 20K.
A big thank you to Andy for taking this measurement for us. 🙏

17-3-23
we finally have 20k distortion measurements.
0.000095% THD 80 watts 8 ohm load.
Thanks again Andy for providing these amazing results
More test results can be found at the end of the build guide.

-------------------------------------------------------------------------------------

Announcing the Wolverine 5th Group Buy - Pre Order Open Now!​

Register for the Wolverine 5th group buy

This thread is for discussions about the F5 clone boards. For more information on this product, please see the product page below.

• Product Page
• Build Guide
• Schematic (V2 boards)
• Bill of Materials (V2 boards)
• Dimensions (V2 boards)
• V3 board schematic

Threads on diyAudio that relate to this product (If we have missed one, please post it in this thread and we will add it to the list):

• Build Thread: http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier.html
• Build Thread: http://www.diyaudio.com/forums/pass-labs/182723-how-build-f5.html
• Build Thread: http://www.diyaudio.com/forums/pass-labs/188691-illustrated-guide-building-f5.html
• Build Thread: http://www.diyaudio.com/forums/pass-labs/185154-initial-setting-f5-bias-help-please.html
• Listening Impressions: http://www.diyaudio.com/forums/pass-labs/155599-f5-listening-impressions-discussion.html
• Modifications: http://www.diyaudio.com/forums/pass...building-quartet-amps-search-ultimate-f5.html
• Modifications: http://www.diyaudio.com/forums/pass-labs/168040-f5-2sk2013-2sj313.html
• Modifications: http://www.diyaudio.com/forums/pass-labs/182966-f5-low-z-loads.html
• Review: 6moons.com - industry features: Swansong for an ugly duckling

Friday evening chez Weldon:

Start with a warm winter evening and a bit of a sunset
Add a glass of red, a shot of hooch
and a couple Dungeness

Gentlemen,

Thanks for the help over the years I have recently wanted to revisit an old idea. The J2 but with substitute J-FET outputs.
I have two 20pcs boxes of United SIC Power JFETS I bought a few years ago. I never got around to building any jig due to my mothers passing and lifes difficult duties so I dug the boxes out again. The devices in the boxes are:

UJ3N120065K3S
UJ3N065080K3S

is any of these any good to try anymore for a 10-15 watt SE design? How can I mod the circuit to work? I am a SMT technician; not an engineer.

You might laugh but I asked ChatGPT and Google Gemini on deepmode for possible subs and maybe I didn't ask the question right it sounds too optomistic!

"Find replacement for SemiSouth SJEP120R100 for use in First Watt J2 see schematic attached."

Depletion-Mode SiC Devices​

The First Watt J2 amplifier’s Q5/Q6 stage originally used SemiSouth SJEP120R100 SiC JFETs (now discontinued). We surveyed active, true depletion-mode (normally-on) JFETs in Silicon Carbide (SiC) to identify suitable substitutes. The table below summarizes each candidate’s key specs; further details and application notes follow.

Silicon Carbide (SiC) JFETs​

onsemi (formerly SemiSouth/Soitec) offers a line of “EliteSiC” normally-on JFETs (650–1700V)mouser.com. Key parameters are extracted from their datasheets. All devices require a negative gate bias to set conduction, and exhibit positive temperature coefficient (ease of paralleling).

Recommendation:

• Primary Choice: onsemi UF3N120007K4S. This 1200V, 120A, 11mΩ, 789W device in a TO-247-4 package is an exceptional performer. It offers immense headroom in all critical parameters, ensuring the amplifier operates with greater stability and potentially cooler temperatures. The 4-pin package with Kelvin source connection provides an opportunity for improved high-frequency performance, though it would require a minor modification to the PCB layout for the fourth pin.
• Alternative (Direct 3-pin Drop-in): onsemi UJ3N065025K3S. This 650V, 85A, 33mΩ, 441W device in a TO-247-3 package is an excellent choice for a direct physical and functional replacement. While its voltage rating is lower than the original, it is still more than adequate for the J2 amplifier's +/-23V rails, and its current, on-resistance, and power dissipation capabilities are significantly superior to the SJEP120R100.

Conclusions and Recommendations​

The obsolescence of the original SemiSouth SJEP120R100 necessitates the selection of modern SiC alternatives for the FirstWatt J2 DIY Clone amplifier. The analysis of currently available "normally-on" devices reveals a clear path for replacement, with options that not only meet but significantly exceed the original component's specifications. This improvement is a direct result of the rapid advancements in wide-bandgap semiconductor technology since the original JFET's introduction.

For the Q5 and Q6 positions, the following conclusions and recommendations are provided:

1. Direct "Normally-On" SiC JFET Replacement (Minimal Circuit Modification):
   • Conclusion: Modern discrete SiC JFETs from onsemi are the most straightforward replacements for the original SJEP120R100. They are inherently "normally-on" (depletion-mode) devices, aligning perfectly with the existing J2 amplifier's design philosophy and gate drive requirements. These devices offer vastly superior current handling, significantly lower on-resistance, and substantially higher power dissipation ratings, leading to improved efficiency, reduced thermal stress, and enhanced long-term reliability for the amplifier.
   • Recommendation:
     • Primary Choice: onsemi UJ3N120065K3S. This 1200V, 34A device in a TO-247-3L package is an excellent choice for a direct physical and functional replacement. Its voltage rating perfectly matches the original, and its current handling is significantly superior.
     • Alternative: onsemi UJ3N065080K3S. This 650V, 24A (at 100°C), 80mΩ, 190W device in a TO-247-3 package is another strong candidate. While its voltage rating is lower than the original, it is still more than adequate for the J2 amplifier's +/-23V rails, and its current, on-resistance, and power dissipation capabilities are superior to the SJEP120R100.

In summary, while the original SemiSouth SJEP120R100 is no longer available, the market offers a robust selection of "normally-on" SiC alternatives, particularly from onsemi, that can significantly enhance the performance and reliability of the FirstWatt J2 DIY Clone amplifier.

✅ Recommendation​

Both UJ3N120065K3S and UJ3N065080K3S are suitable replacements for the SJEP120R100 in the First Watt J2:

• UJ3N120065K3S is closer in voltage rating and offers a lower R_DS(on) than the original SemiSouth device. However, it has higher gate cutoff voltage (~–6.6 V), so ensure your gate bias circuit accommodates this.
• UJ3N065080K3S is slightly closer in capacitance to the SJEP120R100 and is better suited for high-frequency audio performance, but its 650 V rating (still >8× expected voltage swing) is perfectly safe for the J2 topology.

If audio transparency and closest behavior to the original J2 are top priority, UJ3N065080K3S may be slightly better.

If thermal headroom and lower R_DS(on) are important, especially at higher idle currents, UJ3N120065K3S is the better choice.

Let me know if you want SPICE models, bias calculations, or help simulating these parts in the J2 circuit.

is any of this true and/or accurate?

Thanks,

Jeff

I recently stumbled upon a pair of Aurasound MR-12.4 subwoofers on eBay, new in box, for $300 including shipping. A fantastic price, I thought, for the NS12-794-4A's flamboyantly dressed twin.

I bought them, received them, and as promised, they were new in box. Unfortunately, all was not well with the subs.

Their coils were rubbing.

I removed the magnets and found that the plating on the neodymium magnets was bubbled on one, and bubbled/flaking on the other. I was able to remove the bad plating, but this left me with two problems:

1.) The magnets are neodymium/iron alloy. Without the plating, they will corrode/rust over time.

2.) The voice coil in one driver was scratched in several places by the flaking plating, resulting in shorting. Its coil reads 2.6 ohms instead of 3.5.

The seller was excellent about this, refunded me my money, and let me keep the subs. Needless to say, I want to try to repair them. So, I was hoping to do a little brainstorming with you all.

My initial ideas are to:

1.) Coat the exposed sides of the magnets with a high-heat primer, or maybe even a dielectric varnish to take care of any possible corrosion.

2.) Gently sand away the scratches on the damaged voice coil, and recoat it with varnish.

Anyone have any thoughts, concerns, or ideas? What would you try?

I'm looking to design a bandpass filter using OP-AMPs that is unity gain and will approximate the following filter curve.





I've got +/- 12V to work with and will either use a DPDT relay or switch to bypass the filter when it is not needed.

I wonder if high Q drivers could profit from a more damped TML than usually constructed.

The aim would be a low resonance frequency and lowering the Q at the expense of output from the line.

Did anyone try this out? Or is there no benefit of a damped TML against other designs for putting Q down like Variovents (resistive damping techniques).

If the principle of a damped TML would keep resonance frequency low and lower the Q at the same time would it be better than a closed box with a variovent of same size?

I never built TMLs and have no simulation programs but maybe there are already analysis on this.

Would simulation programs simulate correctly the properties of damping material and the grade of damping inside the line like 60 / 80 / 90 / 100 per cent?

Like Hornresp or

I made the following receiver to pick up the signal from my part 15 AM transmitter to monitor the audio.





If I increase the RF gain any using the RF gain control or I move the receiver closer to the transmitter (sits about 4' from it now) I get the following demodulated audio with the transmitter being fed a 400Hz sinewave.





With no modulation I can increase the RF gain or move the receiver closer to the transmitter and the RF waveform still looks good.

If I use my scope on the RF output with no modulation I get 8.1Vpp at 1MHz with the RF gain set to minimum which based on calculations is 1.77.

It seems like to me like it may be a problem with the detector circuit which is the 1N5711 given the RF waveform based on the +/- supply voltage can go up to 26Vpp minus how close the output can come to the rail voltages of the LM118 and going much above the 8.1Vpp at the output of the LM118 causes the issue.

One thing I cannot remember is what the 27k resistor is for.

I need the schematic for JBL pro 5191 phono/tape head preamp plug in.
No luck finding it on line.

Art

I have only studied tube amplifiers, but I am interested in transistor amplifiers this time, and I want to study them. The problem is that I know nothing about transistors. I want to buy a kit for under $50 from AliExpress and make it as a beginner. Currently, I am looking at the TDA7293 kit and the Quad405 kit. Which one sounds sweeter? Or is there a kit that you recommend for under $50?

G'day Guys,

I've been working through this one for a while now and I have nailed down enough of the design details to do a board layout.

Firstly a bit of background as this is not my first rodeo with the Aikido.
My first was a Tubes4hifi.com SP14 kit which I have absolutely loved the sound of since it first fired up something like a decade ago.
http://www.tubes4hifi.com/SP14.htm

I've also built one using Broskie's 12vac Aikido pcb.
New Aikido 12Vac PCB and part kits
I built the 18vac version using 12AU7 tubes. This is testing in my system. It's an amazingly elegant solution with a great sound but it was made for another project.

This brings us back to the SP14.
I chose to use a custom chassis instead of the stock one and this has created quite a headache. I simply cannot make the 254mm x 150mm pcb fit properly into my chassis without fouling on some other component.
It has been upgraded and rebuilt several times over the years but I've never been satisfied with the chassis layout.
Last time the SP14 ended up on my healing bench I decided I was sick of battling the blasted thing. It was time for a new solution. Time to salvage the components and find some new boards that fit.

I spent a lot of time looking at Broskies Mono Aikido board
Aikido Octal Dual-Mono PCB

But after much mocking up I discovered that it is just a weeny bit too large to work in my chassis. I also don't like where his ins and outs are located.

Thus I came to the point where I have to make my own boards.

Now, the design outline:
1) Mono board for maximum flexibility in chassis layout.
2) Within 100x100mm to take advantage of the JLCpcb special.
3) Separate PSU for maximum flexibility in chassis layout, also the JLCpcb thing.
4) A textbook 6SN7 aikido like the old SP14
5) At least 50mm spacing for coupling caps for flexibility. I've always wanted to try some NOS Soviet caps but they never fit.
6) 12v heater supply to take advantage of Eba with a series/parallel selector switch so that I might try 12SN7s
7) Signal I/O and PSU I/O on opposite sides of the board for chassis layout purposes.
8) Fastons for PSU connections, Screw terminals for signal connections.

So here is what I have come up with so far.




I've separated the signal ground from the onboard decoupling.
I managed to get 58mm between the widest pads on the decoupling caps.
May I please ask for some feedback?


Does it pass muster?

Does anybody see any flaws?
Any suggestions for where things could be done better?
Insults are fine as long as they are witty.

So the TPA325x series of chip amps came out about a decade ago, yes really that long! My datasheets for the TPA3251D2 are dated June 2015 and that's where we happen to be now only 10 years later, so, happy birthday TPA325x series. 🥳🎂

Over the years I've seen it mentioned a couple of times that one could go composite with the TPA325x using an ncore style integrator only I'd never seen it actually done. Now my main amplifiers, for my active speakers, have been based on a PFFB implementation of the TPA3251. The performance is more than acceptable but I'd always wanted to try and go that bit further so figured I'd give the integrator a go. It wasn't my plan for this to coincide with the chips ten year anniversary but there you go.

As you can imagine it took a considerable amount of trial and error, plus simulation time, to get things working correctly. This is especially so as there are no models provided for any of the TPA325x series so everything required a large dose of guestimation.



4 layer PCB from China with the TPA mounted on the bottom side of the board. The PCB being bolted to a bar of aluminium to get the heat out. The bar then being bolted to a case panel once 6 channels have been built.

So some performance graphs.

First up frequency response into no load, 9.4 ohms, 4.7 ohms, and 2.35 ohms.



Next as ASR has made popular 1kHz 5 watts into 4.7 ohm load 48kHz bandwidth unweighted.



Next the same thing but 51 watts.



Here's a two tone 18500Hz + 19500Hz, as Bruno liked to show off with the Ncore amps, at 5 watts into the 4.7 ohm load.



And now at 51 watts.



Next up is a distortion sweep at 5 watts into the 4.7 ohm load 96kHz bandwidth just so we can see what the 3rd harmonic really does towards 10kHz.



And finally a distortion sweep at 51 watts 96kHz bandwidth.



Anyone who is familiar with the TPA325x will immediately notice the significant improvement in high frequency distortion. The main area the TPA325x has issues is at the high frequencies. I'm assuming that, for stability, TI needed to start compensating the amplifier pretty low down in frequency as can be seen from distortion Vs frequency sweeps of the standard implementation.

Here's the datasheet distortion at 80kHz bandwidth.



At higher power levels it can be seen that the distortion starts to rise as low as 100Hz! The composite version completely does away with that and reduces the overall magnitude significantly. So happy 10th year TPA325x and enjoy some higher performance.

Now I wonder when Chi-Fi will come up with something similar. Complete schematics not shown for obvious reasons (at least yet). If China want to copy it they are welcome to, and possibly improve upon it, however they will at least have to figure it out for themselves! Just knowing it can be done should be enough encouragement for them to try. Topping are you there? 🤣

I need to build 4 more channels and then I finally get to listen to something.

By the way TI hurry up and come out with a replacement for the TPA325x series using GaN FETs. You've already done an integrated GaN motor driver gimme some class D. I want the improvement in efficiency and idle power consumption. Not to mention that the ability to switch faster should reduce the needed deadtime and improve performance.

As to the clipping of the TPA325x composite. The usual ncore clipping detector and limiter is used although I haven't tried to really fine tune things. Nothing, so far, has blown up. The TPA325x amps are very good at shutting themselves down if anything untoward happens, and that happened a lot when trying to get this stable. The window of stability being quite narrow. Not enough feedback and you oscillate, too much feedback and you also oscillate. You need to find the Goldilocks zone of stability. One nice thing about the TPA chips is they have a clipping detector so should it be necessary you can shut the amplifier down at the onset of clipping.

I’ll go first. Which one of you guys did this?

I'm a beginner when it comes to TL's and horns. What are some good threads, guides, videos, you recommend that cut straight to the useful facts about these enclosures and designing them with Hornresp, which I have not yet downloaded.

I have seen a few different configurations, and am curious how they generally compare and the pros and cons of each: the driver having a sealed back, a ported back, one side open to the outside of the enclosure, one side exposed near the rear of the inside of the TL, and one side exposed toward the front of the inside TL. It would be interesting to see a phase comparison of the opening of the TL vs the other side of the driver of these different configurations over the usable frequency range and a little beyond, if anyone has done some of those tests.

Also, are there any general rules of thumb regarding the way it is folded to save space: expanding opening (which I assume would increase sensitivity and harmonics), constant size, decreasing area (which I assume would decrease harmonics), smooth bends vs hard right or even acute angle bends? I assume right angle bends would set up harmonic resonances, while acute angles may trap them and prevent their escape while decreasing efficiency.

I realize the potential complexity involved, but I'm trying to just learn the basics.

Image 1 contains four drawings.
1 and two are basically the same thing but with the mouth on the side or what should be the top (that should be flipped upside down). In either case the mouth is the same distance from the back driver tap within a few mm, and the back driver tap is about as close to the mouth as you can get.
The 3rd drawing is almost the same thing with an extra fold to put the back side driver tap a bit further back from the mouth.
The 4th is a random pic of the XOC TH18 google grabbed from one of the threads, showing the driver as close to the mouth as you can get.

A lot of early diy tapped horns were like the first two examples, It's easy to fold and build, very forgiving if you place the middle baffle at an angle that's not quite right and it's a good shape for domestic use, a large volume with a tiny footprint.

The problem with these is the dip in the response right before the big peak can be nasty. And I don't know how people that built these feel about it or deal with it. Personally I now have an amp with Audyssey so that's my only eq. I don't think any pre programmed eq system is going to touch a 10 db dip with a ten foot pole. I think they look at it like a black hole, no matter what you throw at it you can't fill it so there's no point in even trying. And that thing is always right at the edge or right outside the passband where even a steep low pass crossover isn't going to hide it.

There's a bunch of things you can do to fill it a bit. You can move the driver back a bit from the mouth but then folding complexity skyrockets.
You can make the horn bigger. Somewhere on the way to the size of a garden shed the frequency will even out at a level around the top of the harmonic peaks.
You can do dual or even triple different flare rates the the XOC TH18 to move the resonances causing that dip in a way that lessens the issue, but folding complexity skyrockets.
You can increase the compression ratio. A very high compression ratio can fix that dip right up, at about 4:1 the dip fills in completely in this example horn but the entire response looks overdamped if you do that, kind of what it looks like with a weak magnet.

Image 2 contains 4 Hornresp screen grabs.

1. Light trace - A single PAR flare rate 470 liter tapped horn, 18TBW100 at about 27 cm from both the throat and mouth, this corresponds to Image 1 drawing 1 or 2.
Dark trace - Same thing with the mouth side tap moved back to 68 cm. This reduces the big dip from about 7 db down to maybe 1.5 db.

2. Top row right - This shows group delay for the same examples described above. Notice group delay is better on the one with the worse response dip.

3. Bottom left - Hornresp suggest that putting these horns in a corner or using them in multiples fills in the dip on the left side of 100 hz spike a bit but makes the dip on the right side of the peak worse. This is good information because I will be using a tapped horn in a corner so it's something to keep an eye on but for the tapped horn with the driver side tap close to the mouth, the dip only filled in a couple db. It's still a gaping 5 db hole.

4. Bottom right - That's the XOC TH18 (it's one of the iterations, I don't know which one) with the same driver I used in the other sims shown here just to keep it apples to apples. Despite having the driver so close to the mouth it almost looks like it's trying to escape, that tiny little dip is the result of the dual flare rate in that horn. If you change it to a single flare rate it turns into a 5 db hole, which isn't as bad as the 7 db hole shown in the other example here but that's probably because it's tuned much much higher and the impedance peaks in different places.

Does anybody know how Audyssey handles big dips?
How big is too big in your opinion? At what point is the fold complexity and group delay worth the trade off of a smaller dip?
I don't like to go too far below 2:1 compression ratio, the XOC TH18 sim I found doesn't, generally Danley doesn't, although he famously did in the actual TH118. What are your thoughts on that?
Any other general thoughts on anything?

I got an itch to build something. I was going to do a dirt simple single fold tapped horn like the first example in image 1, something quick to shake the rust off because it's been a long time. Then because of the dip I was going to do example 3. And now I figure if I'm going to have to live with the damn thing maybe I need to a a much larger lower tuned version of the TH18. (That doesn't already exist by the way, does it? I haven't been around for awhile. I need 25 hz or lower tuning.)

Thanks.

Hi everyone,
I'm new to the DIY audio world, but I'm really interested in getting started and building some exciting projects. I’ve just completed my first DAC setup and I'm looking forward to learning more and improving my skills along the way.
Looking forward to sharing ideas and getting advice from the community!
Alberto

Hi everyone, my name is Darek and I am a Software Engineer from Poland. I always wanted to get into electronics and I thought that DIY audio might be a good start while also getting (hopefully) a nice set of speakers and gaining necessary knowledge on how to build them if I ever wanted to upgrade in the future.

Good afternoon,

I'm a complete electronics newbie here. Due to a strange set of circumstances, I have started collecting some vintage solid state audio equipment and I have questions ... lots of questions. I will post those elsewhere. Interested are high end car audio, home audio, race cars, going fast, bourbon & family (in no particular order).

Jeff S

If you don't know, BOFU is a speaker driver from Pioneer with those letters in the model number. They were inexpensive but surprisingly nice and quite popular with DIY folks. These are the original Pioneers. Well, it's time to pass these on to someone else. I built them back around 2015 or so and I've used them for most of that time and was quite happy with them. Then a pair of B&W speakers followed me home from the dump and I was impressed by the speed and resolution over the BOFUs (top end needs help but that's another story).

The BOFUs aren't the last word in resolution, and while the bass goes relatively deep (good output down to 40Hz or lower), and is reasonably punchy and not bloated, it still isn't as tight as the B&Ws. These are transmission line boxes and are basically quite nice. The look isn't too bad for a living room too, though there are plenty of mistakes and issues (mostly not visible from the listening position). The original design didn't use a tweeter, and I tried it that way at first, but found it was a bit lacking in the treble regions. So I put in a cheap 3/4" tweeter with a 4.7uF cap for high pass. This tweeter could use some padding down to my ears, but that's for you to decide. Much of the time I had the tweeters disconnected and used a pair of JBL 2402H bullet tweeters (not positive of the JBL model #).

I recently re-foamed the BOFUs (6 months ago or so) so they should be in good shape for a while. I am in New England (coastal NH) and these are probably for pickup only. They are quite large and heavy. I can provide more pics if you like, showing all the warts. I'd like to recoup some costs and they just are too good to give away. Not sure what is a reasonable price for them so I'd take suggestions. I'll be thinking about price too and post if I come up with something. At some point I'll post them elsewhere but for now they are just here.

Video here: Login to view embedded media Just my phone, and compression won't help them shine, but it might give a little sense of how they sound.

Full meaning the whole thing.....

I last listenend to my BEST OF MOUNTAIN record 🙂

Hi eveyone,

I'm trying to design & build a pair of 3-way speakers, using the AJ Sealed cabinet calculator program (based on the Golden Ratio). (www.ajdesigner.com)

It asks for the Qts, Qes, Fs, Vas, PMax, diameter and Xmax of the speaker driver, leaving the Qtc for you to choose (I've read 0.707 is a good number).

For my Monacor bass drivers, it comes up with an interesting size, which I'm happy with.
But for the mid driver (which can also be used as a bass driver in a 2-way bookshelf speaker), the cabinet size it comes up with is very small, only marginally bigger than the actual driver unit!

I have all the parameters it wants from the Monacor data sheet, so I can only think that this driver needs an incredibly small cabinet.
But it seems very odd for it to be so small.

I'm going to have the mid cabinet built separately and attached to the top of the bass cabinet, and employ time alignment by having it receeded slightly (c.1 5/8 inch) back from the edge of the bass cabinet.

I used to own a pair of B&W DM-6 speakers (the 'pregnant droid' speakers!), and loved the fact that it had the mid driver recessed back from the bass, and the tweeter recessed back again from the mid driver, to achieve correct time alignment.

I thought I'd try and incorporate the same idea in my speakers. It won't do any harm in trying.
I'm using the measurements from the very back of each driver, as it's the closest I can see to measuring to the centre of the magnet, which I believe is the actual axis I should be basing such calculations on.

I've read that each side panel should be internally braced to avoid resonances.
What exactly does this look like?

Do I just glue diagonal strips of wood on each internal side?

I'm thinking of using oak plywood, as it's readily available from a local DIY store.
I've read birch veneer cabinet grade plywood is preferable, for which I'll look.

I was considering getting a brad nailer to assdist in the construction, but have read of people using wood / deck screws.
I built 2 GhettoBlasters a few years ago using the Golden Ratio, 1/2 inch oak plywood & MDF (one each), old car radio units, 6x9 speakers and car subwoofer amps & drivers.
I used deck screws for the construction, along with carpenter's glue, but found it very time consuming drilling all the pilot then clearance holes, and thought that if professionally built cabinets are constructed using staples / nails, then surely it must be just as good as screws and much faster..?

They sound great, by the way, which is why I'm attempting this speaker build.

The speakers with be 3-way, and will be matched to a Bassworks 2x12 front ported car subwoofer cabinet featuring 2 x 12 inch SSL "1000w" speaker drivers.
I had this running via a QSC amp recently, via a Clean Box Pro -10 to +4 dB converter, from my 2.1 stereo amp, and it sounds incredible!

So, it'll be a 4-way actively crossed over system, using a dbx DriveRack 260 speaker management system, feeding into 3 Yamaha Natural Sound stereo amps plus the QSC sub amp.
The dbx will give me stereo top & stereo mid, then mono-summed bass and mono-summed sub-bass at line level.
The Yamaha amps and Monacor drivers (all the tweeters, squakers & woofers are Monacor, to keep the sound consistent) are matched for power output / input, and all the Yamaha amps are identical (to keep the sound consistent).

My aim is to combine my experience of working with PA sound rigs, studio monitor sound systems, car and home audio Hi-Fi speaker technology and create a hybrid sound system.
I want, not just a 3-way speaker (which is a rarity in domestic Hi-Fi, and why I loved my DM-6s so much), but an ACTIVELY crossed-over time-aligned 3-way speaker, using the advantages of PA technology, then adding it to a deep and powerful sub-bass speaker unit.

The potential is quite breathtaking.

My very own personal Hi-Fi PA theatre studio monitor system.
If nothing else, it'll be a fascinating experiment into all of the fields mentioned.
And judging from my GhettoBlasters, there's every chance the system will sound pretty impressive.

Going for sealed cabinet / infinate baffle seems to give a big margin of error, and hopefully a nice, warm quality bass sound.
The Bassworks sub-bass cabinet has dealt with the ported aspect, so I don't have to consider it for the main speakers.

I know there's a lot going on here, and probably many areas of concern / issue for many of you out there.
Don't worry. I know it's a totally mad idea. But why not? It'll be a laugh! And could sound great!

I just need a bit of advice in the design of the mid cabinets and the general construction of the bass & mid cabs (the tweeters will reside above the mids in the same cabinet, but sealed off so their internal volumes don't affect each other).

I've found my Canadian Tire mitre & table saws aren't very accurate, so cutting consistently is a bit hard.
I've tried using my circular saw using a metal ruler clamped down as a straight edge guide, but this too has its issues with accuracy.

I've had no wood-working / carpentry training, and have taught myself the skills so far. Maybe not very well..!

Any advice is greatly appreciated!
Many thanks in advance - Dave

Hello I have a JL AUDIO HD 750 that I'm trying to repair Maybe you could assist? Do you have a schematic you could send me ? The green light was flashing. I found 2 bad rectifiers and replaced them. The light was solid green and I got audio for a short time. There was some popping distortion...
It intermittently plays audio with a solid green light then switches to no audio with a flashing green light.

The caps and resistors and fets are testing good

Hello !

This thread is dedicated for discussion of methods of generating stereo sound in a small room acoustic space by using a single DIY loudspeaker !

Encouraged by the results achieved in the Stereolith thread I explored the concept of single speaker stereo further:

http://elias.altervista.org/html/SingleSpeakerStereo.html

The general principle I'm using is this:


Interesting is the selection of parameter x !
When x = 0, the speaker is bipolar sideways projection (Stereolith).
When x = 1, the speaker is MS stereo.

I think the optimal value is about x = 0.5, which I'm using at the moment.


The Cardboard is back, but now totally different since enhanced with psychoacoustic vector steering !

I've been listening to this for about a week now, and results are very positive ! There is a great potential !

Experimenting recommended ! 🙂


*************

EDIT 2017:
Dropbox has deceived their customers and eliminated public folders. Thus the pictures linked herein are not visible any longer.

Go to http://elias.altervista.org/html/SingleSpeakerStereo.html to see the pictures


- Elias

My Prodigy sometimes makes a clicking sound:

MartinLogan Prodigy clicking sound - YouTube

After consulting with ML I replaced the power supply and then the transformer with new replacements and it still didn't completely fix the issue (though it seemed to happen less frequently).

After a few months it largely went away, I may get a few clicks every month or so.

Lately it's starting to happen more frequently again (maybe once a week, and when it happens it does that on and off for minutes).

Any idea what causes that? It's not the panels, those were replaced and I also swapped them between the two speakers and it stayed with the same speaker. Vacuuming didn't help.

Hi Guys.
I was planning a speaker project and wondered if anyone could help me with the calculation for a dual-woofer transmission line design.
I can find online calculators for single woofers but not dual, so I'm thinking I need some advice from your expertise 🙂
Many thanks for considering my request.

Hello everyone, long time lurker and admirer.

I picked up a functional S500 optical Bias with some cosmetic challenges. She lived a tough life in a car collectors shop. A lot of paint overspray and grime. Inside is not bad though. So I have been reading up on everything I can find concerning operating and servicing these babies. I have repaired a lot of Sansui, McIntosh and the like but this is my first class. A A/B amp. I know they run warm, 40-50c. My particular unit runs about 54c on the left and 50c on the right after idling for 30 min no load. I have only run it for 30 min a few times until I can give it a proper check up and maybe change the smaller caps where needed. I would like to get the units bias balanced as well as I can

I’m not quite sure on the biasing procedures, I know the pot for the bias adjustment is a turd to get to. I see on some schematics you set the bias cold to 90mV across one emitter where some have 20-40 mV as optimal. What temp would be best to bias it too? I’ve read some run cool and some run hot.

Can anyone enlighten me as to the proper procedure for the S500 with optical bias? Also has anyone recapped this model? I’m sure some are due to be changed out by now.

Thanks for any help.
Vince.

Now midrange I'll usually do mirror imaged and off-set but I'm about to make a start on another big OB with a 15" and several 12" woofers.
The panel I bought to use is 600mm wide and I had planned to do short wings on the sides, I've always had trouble using "The Edge" and it doesn't seem to be working on my new W11 upgrade anyway

Thread Index
Please go to posts #2500-2502 see the latest version of this project.
There you will find the current baffle plans and crossover schematics.
For explanations of how the crossover works, see post #1388
https://www.diyaudio.com/community/threads/fast-fun-inexpensive-ob-project.110583/post-4573958
For ideas on doing an active crossover see post #3006
https://www.diyaudio.com/community/threads/fast-fun-inexpensive-ob-project.110583/post-7033913

---

100Some time ago last year a speaker building buddy of mine in California decided to see what he could do in a simple, inexpensive, open baffle project. He came up with a 2 way passive system on a medium size baffle. He has been trotting them out at shows across the country and baffling a lot of folks who would never have thought so simple a concept could sound so good.

For your pleasure, here are the build specs on the Manzanita 12s:
To build each speaker you will need:

• Peerless SLS 830669 - 12" Woofer
• Seas 27TDFC tweeter
• Sledgehammer 12mH 15 gauge inductor
• 0.8 mH aircore inductor
• 12uF film capacitor
• 25 ohm 5W resistor
• Binding posts
• 3/4 wood for baffle, base and side wings. MDF or plywood, chipboard, etc.

Total project parts cost is under $150 US per side, excluding wood. Or less than $300 for the pair. The drivers and parts are easy to find in the US, and should be as easy to find in Europe. As long as you keep the crossover values the same, feel free to substitute your favorite brands. Obviously, you will use the same drivers!

There may be plenty of forum denizens who will poke holes in this design without ever building it. No worries, that’s part of the DIY sport. Those who do build it will enjoy it, holes or not.

Why build this speaker? A few reasons:

1. It sounds good.
2. It’s simple and easy to build.
3. It plays well in an average size living room.
4. It does not cost arm and a leg.
5. Works well with most types of music.
6. Very wide and deep soundstage.
7. Easy to listen to – low fatigue.
8. You’ve always wanted to try an open baffle design.

Why NOT build this speaker?

1. Too simple. You need more of a challenge.
2. Too cheap, you need to impress your friends.
3. You like a hot midrange.
4. You need ultimate finesse and flattest response.
5. Your listening room is huge – or tiny.
6. Your amp is a 2 watt SET-DHT job.
7. You would rather go to the beach. (I understand…)

Really, this project is so easy you can start after lunch and be finished in time to kick back, and enjoy the blues and some brews before dinner. The speakers throw a large soundstage, don’t suffer typical box coloration and have good tonal balance. The recessed midrange makes them very easy to listen to. But the midrange fills in nicely in the typical living room that is often a little over bright. With a good solid state or tube amp of 20 watts or more, you’ll have plenty of power. Even an AMP6 10 watt T-Amp runs these speakers to quite respectable volumes. A 20 watt tube amps has no trouble, despite the low sensitivity.


Continued in next post.....