I've built a bunch of Paralines*, but I wasn't satisfied with the sound. A lot of dips in the response, and a character that was generally harsh.

I believe the problem is that the sound radiated from the diaphragm hits the bends in the Paraline and is reflected back to the throat. The reflected wave is a higher order mode. HOMs make a horn sound harsh.

So...

I wanted to use some of the same tricks that we use with waveguides to reduce higher order modes. I wanted to use gentle curves to reduce reflections back into the throat.



The first thing I do is draw that familiar 'eye' shape. The point of this shape is to take a spherical wavefront and flatten it into a ribbon shaped wavefront...

* For more info on how Paralines work, read my threads here:

http://www.diyaudio.com/forums/multi-way/133745-i-dont-understand.html

and here: http://www.diyaudio.com/forums/multi-way/217298-square-pegs.html

and here: http://www.diyaudio.com/forums/multi-way/225832-stargate.html

Those are in chronological order, but the real 'eureka' moment was the second thread. Danley has comments in all three, which are valuable insight into the devices.

Evening all, I am going to play a trick on a friend who says he can pick a direct drive turntable blindfolded.

I have disguised a cheap Stanton DD but there is one giveaway I need help with. It’s the instant start up - is there a way to ramp the speed up somehow? I know this is usually considered a feature of DD turntables but for this scenario it isn’t.
Regards, sp

I’ve had these speakers for about 20 years.

I found them abandoned in a audio repair shop after they had the surrounds replaced on the woofers.

Had to make my own grills.

They’re not perfect, have some scuffs etc, but presentable.

Haven’t used them in a while…last time was a few years back (2020?). Still sounded good then and the woofer surrounds were still in good condition.

They are from the early to mid 90s.

A bit of info on here and the web about renewing them if you really want to i.e. ferrifluid clean and replacement in tweeters, recapping crossovers etc.

They’ve been covered and stored in my dry basement fir a bit now.

I’m moving soon and feel like I have way too much stuff in general.

They are located in central Connecticut on the outskirts of Waterbury.

Offer what your conscious feels good with…better they go to someone that will use and enjoy them.

Hi. I am currently repairing 2x Mackie SRM450 V3 for a friend. Both speakers have the bass driver amplifier sections blown.
I discovered that on the TDA8954 amplifier chips that one of the output legs was shorted to the corresponding bootstrap leg.
I find it strange how there is a lack of people talking about these or this repair. He used them at a wedding in a bar and i was also there. We borrowed a sub so i guess he never noticed when the bass from the Mackies stopped working. He took them to another event not knowing and had to cancel on site when he found out.
I am not a huge fan of these tda chips. 420W bridged in such a small chip with such a small heat-sink. Perhaps these need a PCF circuit to make the most of them but if both can blow during a fairly normal night that's not too reliable.
Anyway. I have ordered the parts and will ty to post here if the repair is that simple.
Notes:
Mackie seem to be gluing the speaker cable and led connector to the amp module making it quite difficult to separate. I 1/2 removed the silver cover and worked as much as i could around the gap in the connector with a knife and a flat blade screwdriver taking care not to destroy anything. Eventually i manged to separate them.
Take care when removing the TDA chips as i did lift one track slightly. I will try hot air station on the 2nd one. On the 1st one i removed i took some solid copper wire the length of the chip and i flooded it and the legs with solder taking care not to remove the smd cap closest. I could then lift one side and then work on the adjacent side.
There is no under-chip central pad, just the legs.
It was the exact same short on both TDA modules. I think it was pin 21 and 22 shorted together where the opposite pins (15 and 16) were not shorted.
Other things i noticed were that many of the nuts and bolts were not too tight including those that hold the drivers in place. One of the silver covers was more difficult to remove as some adhesive had stuck it down in places, you have to get a blade under there. Also when removing the main board from it's heat-sink you may find you need to cut some adhesive away from the heat-sink plate to separate everything.
Also, here is a V1 aside a V3. Many people still prefer the V1 as Mackie was originally made or owned by RCF The weight difference is huge!

Good day folks,
Anyone got schematics or similar for these old school amplifiers?
The chassis is written Zeus, on the pcb it’s silk screened Zeus/mars.
I got this in, I haven’t torn into it as yet, but looking at the unit, it has alot of NTE parts. And a lot of “additional parts,” I’m not sure if these were factory add ons or it was modded at some point in its life.
One power transformer is burnt, seems like it took out the pre amp and power supply FETs with it. The secondaries on the transformers appear to be connected in series.

Hi! I recently purchased a Pioneer SX-680. When I purchased it the stereo light worked when we jumped from FM station to another (if it came thru well), well at least that’s what I thought. When I got home, the light no longer works even if the FM station comes in clear. Also I can’t tell whether the stereo functionality is working properly, like when certain notes comes out of one speaker and not the other. To me right now both speakers sound the same. What am I doing wrong? Any input would be appreciated. Thank you!

AMRG Dual Mono Attenuator parts stripped out of faulty preamp - the two AMRG attenuators work fine and can be reused, you might also find use for the rear panel hardware, but realistically it’s only the attenuators that are worth keeping.

No other details available, make me an offer.

Thanks

NOS, unopened, unused Schitt Mani phono stage. $100. Will split shipping in CONUS.

Hi All,

I recently had the joy of listening to a zero FB SET amplifier and have decided to have a go at building one. I am contemplating something like the attached schematic, which is I understand is reasonably tried and tested. I'll add a few of my own flourishes such as SS regulated supplies, but was otherwise hoping to copy the actual amplifier section more or less as published (with appropriate changes for the regulated supply). I understand it's pretty conventional but I am looking for an honest SET experience.

I'm interested to know if there's any reason to avoid this design or any other shortfalls? I note the absence of grid stoppers and seemingly conservative current in the driver tubes, any issues or suggestions here?

Appreciate any thoughts or suggestions or even alternative all triode designs to consider.

Many thanks,

Greg

Well, while we're at it (https://www.diyaudio.com/community/...stige-ca22rny-and-27tffc.410983/#post-7649811), I also introduce you my little Classic 15, implemented with first order crossovers. And… wow!
It's a shame that the mono recording doesn't do justice to the tonal beauty of this speaker. The other day, while we were listening to music from YouTube, my nephew said to me: "Zio, but the advertising is fantastic with these speakers!" 😂 (see for example the filming of the “THUN Christmas 2012 Commercial” with the voice of Ciro Imparato).
The test amplifier is a Breeze Mini Dual TPA3116 costing 30 euros, just to go a little outside the audiophile canons.

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So wondering if it's best to:

1) use a 1:1 IT and a 1:2 step up at input
2) use a 1:2 IT and no step up at input
3) use a choke load and cap and a 1:2 step up at input

Will be for a triode 6V6 input stage for a SS amp.

Looking for gain if 15- 20 ish.

Concerned about how to maximize bandwidth and also minimize noise and microphonics.

I already have a choke that will work with the 6V6 (EP 30mA 100H choke)

Thanks!

Thanks!

Not quite a PASS amp yet but will hopefully be part of it.

Chances upon this (not that I was looking for an arc welder) 70 years old, beautifully designed and extremely well constructed 9KVA arc welder. The last picture us a steel insert in the aluminium cap, a well thought out design detail, hardly found in the Made-in-China products these days.

The top and the base are made of cast aluminium. Centre is 1.5mm thick sheet aluminium, finished in hammerite green.

It is a 3-phase only arc welder, on the label it says 130A@20V output, 9.2KVA, either I have to re-attend my secondary school physics class on ohm’s law or the man who did the calculation failed his maths.

I was looking at the Pass Amp 20 years ago, so this looks like a perfect low cost entry 🤣

When I hooked it up to the 3-phase supply it didn’t blow the apartment to pieces. The output measured 65Vac. Opening it up revealed that the transformer was wired to 2 phases, 450Vac across the primary, neutral not connected, 3rd phase omitted.

So I re-wired it to single phase, L1-N, 230Vac and the output fell to 41Vac. With that if I add a bridge rectifier and some electrolytic capacitors I should be able to get +-25Vdc.
So I ordered a Pass A5 clone today, with the +-25 Vdc I should be able to get 40W @8 ohm? to drive my Sonus Faber Concertino with 86dB sensitivity.

The reason why I chose not to build an A2 instead was that I may buy a “proper” toroidal transformer later if I cannot get rid of the transformer hum later.

Found an old thread by John Biles that someone suggested that the EMF emitted by the transformer would cause Leukaemia, this is in a grounded and fully enclosed aluminium case and perhaps that itself is a Faraday’s cage? Just to be on the safe side I am going to buy a EMF tester.

Wish me luck!

View attachment 1297311View attachment 1297311

Wanted 8 off Dale metal film 221k 1/4 watt 1%, or any other quality none magnetic resistor of this value.

There is this collector of stereos in Melbourne who tried to replace belts in his Marantz CD-95 and failed.
He then sent it to me with a note saying that other than the belts, he wanted me to fix the display which "used to work fine, but with all this handling of the player during the belt replacement attempt - it no longer does. All the segments are now lit". He does not recall doing anything specific that might have caused it.
it looks like this:

I have replaced the belts and the player now works OK but the display is still stuffed.
I am afraid to keep the player on for too long, because I have no idea if I will not blow it completely, given it has 30% more voltage supply than it should.
In addition, it is very hard to work on, because there is this "Feature Board" in front of the display and all the cables are short, so it is hard to measure anything.
Anyone has any experience with this or any ideas what went wrong?

The only manual for it I could find was CD-95DR which only shows differences between it, and the Marantz CD-12.
The display circuits in both CD-95DR and CD-12 are similar to what is inside of this player, but marginally different nonetheless.
I soldered some wires and have been able to measure some voltages.
The 3.2V AC heater is OK (connector JF10 pin 3 & 5 on the bottom of pic)
The 20V AC is on the pins 1 & 2 of the same connector.
The negative -20V is in fact -27.
The 5V and the 12V rails are both OK.
Resistor RF-51 measures as it should - 6.8k
DF-50 is IN-4002, DF-51 is a 5.6V Zener and the 1 Ohm resistor RF-50 are all OK.
I know, because I managed to blow the last two trying to measure voltages, so they are brand new and the display still behaves as it was before.
Any ideas why I have the -27V instead of -20V supply?


The service manual warns about the display issues and suggests... resetting it by turning it on and off and checking oscillator frequencies (all appear to be OK).

I'm looking to do some simulations from script only from AKABAK-3. I get error during processing:

ERRORS ------------------------
All sources muted (provide LE-network or enable Fixed Driving)

Repro Steps:
- New Project
- BEM -> New Component -> Script
- Specify text file with the following:

>>>>

Click to expand...

Def_Driver 'SimpleSpeaker'
Sd=150;
Re=8;
End

Def_Signal 'SimpleSignal'
Amp=1;
Freq=1000;
FixedDriving=Yes;
End

Network
Node=1
Driver='SimpleSpeaker', Node=1, Signal='SimpleSignal'
End
<<<<<

- Processing -> Calculate All

Any ideas how to accomplish running script only simulations?

Regards

I'm unable to reach Rod Elliott's site for more than a week now on a Win10 PC.
Tried different browsers: Firefox, Chrome, Edge with the following error: DNS_PROBE_FINISHED_NXDOMAIN
I restarted the PC, all updates are in place, no other sites are affected.

Causes:

You typed the site name incorrectly into the search bar. I clicked the links in Google so no typing errors.
There is an internet connection error preventing your access. All other sites work.
Your firewall is blocking access to the website. Disabling it doesn't help.
An antivirus or a VPN is interfering with your network settings. AV= standard Windows defender, I do not use VPN
The domain has expired or is not registered. ??? I believe others can access the site.
Your DNS settings are not configured the right way.

I tried all options here: https://kinsta.com/knowledgebase/dns_probe_finished_nxdomain/

I'm out of ideas, reaching out to the smart(er) guys.

Hugo

Good day
Dear gents

Which project is better for DIY?
Original 47lab or Audiosector?

Aidiosector design in attachment

RIP Dr. Alan E. Hill, September 4, 1939 – May 29, 2023.

Alan developed his plasma tweeter while working at the Air Force Weapons Laboratory and after he left there to form Plasmatronics Inc., in Albuquerque, N.M. He first showed the Hill Type 1 plasma speaker system at the Winter CES in January of 1978 to great acclaim (nothing like it exists to this day).

Alan's health had been deteriorating for some time and he was recently diagnosed with late stage Parkinson's. He did manage to attend AXPONA 2023 where his fantastic tweeters were back on display after 40 years out of public view. I owe Alan a tremendous debt of gratitude for the more than twelve years of knowledge he generously passed on to me.

[As of 3/20/24, this post is still a draft in work. I'll update this first post with additional "lessons learned" over the course of a few days. -birdbox]

Somehow I found myself to be blessed to reach out to the right person at the right time (just after Christmas) and was given the gift to be an early builder of the Firstwatt Aleph J, Zen Mod edition. @ItsAllInMyHead was looking for some lucky folks to build the kits he’s working on for the store. I think his goal was to get a couple folks to verify the kits are complete, provide feedback on the to be released build guide, and share lessons learned along the way.

After eagerly accepting Patrick’s offer, I soon had the kit in hand and began the process of “asking Patrick a thousand questions”. Man is this guy patient and kind! I wanted to build it as fast possible, however, I learned along the way that “slow is smooth, and smooth is fast”. The build guide is top notch and certainly is on par with the quality build guides 6L6 provides the diyaudio community. This is going to be a fantastic kit for “new-ish” folks like myself, who have built some store kits in the past with SMPS power supplies, and are now interested into wandering into the Firstwatt amp designs with linear power supplies.

Up until this point I had built a pair of mono Amp Camp Amp’s, a couple Korg B1s, an Amp Camp Preamp+, WHAMMY, ACA-Mini, and the Zenductor (at BAF ’23). So although I wasn’t a tadpole anymore, I was still pretty much a minnow in a giant ocean. It was attending BAF in October of 2023 that had me catch whatever "bug" it is we call diyaudio. Before that event I was diyaudio-curious, afterwards, I was diyaudio-obsessed. Antibiotics did nothing, antivirals did nothing, the only cure was more amps! So I started to research and read regularly about what are some next options I could jump on. Iron Pre sounded like a fun project, but the store was sold out. My thinking was F5 would be a good first build, then I bumped into ItsAllInMyHead via a post and PM, and the rest was fate.

Ok, enough backstory, that’s not all that interesting really. Let’s talk this wonderful amp kit...

The boards are very well laid out, great fabrication with lots of shinny gold, and compact. They fit the universal mounting system (UMS), so I went with the chassis I had on hand from Modushop’s Black Friday sale, a 4U Deluxe. The kit provided had all the parts necessary to stuff the boards. I had already started to acquire some basic parts I knew I would need regardless of what Firstwatt design I’d try and build, so I had an Antek AS-3218 on hand as well as a AS-4220.

I also needed:

• PSU Filter Board V3 from the store
• Rectifiers – Monolithic using rhthatchers boards
• CL60 Inrush limiter – using rhthatcher boards
• Wiring
  • For AC & DC power & speaker out I used 16Ga – BNTECHGO Silicone Kits on Amazon
  • For signal I used Mogami W2330 from Markertek
• Back connectors (Neutrik RCA & Speaker Terminals) – Back Parts Kit from store
• Keratherm Insulator Pads – diyaudio store
• Heat shrink – Amazon cheap variety kit
• Crimpers – Haisstronica Crimping Kit on Amazon
• Faston spade connectors (sorry ZM) – Mouser/Digikey
• Power Entry Module – Back Parts Kit from store
• M3 bolts - variety kit from Amazon
• Standoffs - nylon spacers & brass hex variety kits from Amazon
• ??

I did my very best to practice patience and go slow to ensure I did it right the first time. That wasn't easy, but I kept telling myself "Follow the process". I followed the build guide and asked Patrick lots of questions allong the way that he graciously answered with enthusiasm.

So, enough with all the words….time for some pics.

Here's @rhthatcher 's insrush and rectifier boards all populated with components.


All the parts in the kit (I wasn't supposed to open it all at once, so don't do what I did)


Crossing off components as they are installed on the schematic.


Crossing off components as they are installed on the PCB layout.


I loved the "verify" / "install" / "inspected" approach. This sets the stage for a really good quality process.


Patrick shared the value and "tricks" he had for cleaning the board (99% Isop, Acid Brush, Kimwipes). I went one step further and got a cheap sonic toothbrush.


I cleaned up the top and bottome with 99% Isop and sonic toothbrush. I would "rinse" the board with Isop after a scrub, then repeated 2 more times. 3rd Times a Charm.


Oooooo, shiny!


Extra large fender washer (1/8" ID x 3/4" OD), lock washer, and M3 boltholds MOSFET on Keratherm pad.

Finished board mounted and torqued to 0.9 N-m.


Laying out the linear power supply components.


Twisted all the wires and mounted the AS-3218 on a fancy little seat so I could use "lip up" on chassis plate and still have transformer really close to front panel.


For space reasons, I used the Modushop "riser" to go vertical with the PSU filter board.


Power supply checkout. Don't forget to wait plenty of time for caps to discharge. I would measure voltage with multimeter to be sure they were discharged.


Don't forget the chassis thermister. I did at first. I slide it into the soft silicone insulation and use a little solder to secure it in place.


@rhthatcher rectifier boards with snubber resistors & capacitors per Quasimodo link suggestions. You'll notice the R values are different here than the picture above. Well, I ran into a really bad transformer hum issue. I tried every possible solution. It took me 3 days to figure it out. In the end, the problem was my recessed LED dimmable lights on a triac autodimmer. If the lights were set at 40-60%, transformer hummed crazy loud. Any other setting on the dimmer, dead silent. [Insert "The Far Side - We should write that down somewhere" comic.]


Setting the bias connections using the little "grabbers".


Bias setting heat soak. [0.46V across 0.27ohm yeilds a bias of 1.7amps]


Trying to clean up the wiring with zipties after getting the DC offset down to pretty much 0.0V



So how does it sound? I’m not very good at describing the “sound” of an amp with eloquent descriptions, personifications, and analogies, so I’ll just quote what I told Patrick after spending a few hours listening to it….



By far the best sounding amplifier I own and punches well above anything I could have expected. This amp is not just a winner, it dominates. I love it. I’ll probably name it and keep it close to me for the rest of my life as my “first Firstwatt". What a wonderful experience.





Now, what's next?

Hey just wondering what would be a good sealed enclosure size for the Rosso-6MW150D crossover is 500hz - to around 3khz might use stuffing might not use it I have 34l of sealed space in my 3 way towers just for the tweeter and midrange separate enclosure I want to divide up the space so it’s enough but not too big or small for the midrange speaker can anyone help please

Thank you

Here is a Urei 6150. Another low feedback, wide open loop design. Leach inspired?. This has a bit of buzz on both channels through headphones or speakers. I believe its the layout design that causes this. All components test fine. Filter capacitors are also fine.

Buzz might be caused by this..

-There is some EMC shielding around the transformer but transformer will radiate still.
- Input shielded cables run very close next to mains wire input.

Apart from tthe buzz it actually sounds quite good. THD average..0.02% across full audio range. Bass full bodied.

Hi all.
Could you please give me some guide line for making a preamp with variable gain (60db or if possible 100db) with relatively accessible parts?
I was able to achieve a fixed 60db preamp with simple parts and dual 12v supply (with +-12v) and inspired with this project. sorry if it seems noob.




Now the problem is i now have a single 5v supply instead of dual ±12v.

It's been shown in several measurements by different people that Quad ESL63 can have very low distortion. Final ESLs have a reputation of having poor harmonic distortion either because they use an unusual drive configuration (inverted electrostat) or because they used to use high conductivity membranes. The example of a more recent Final ESL I found a review of pretty good, though:

https://www.diyaudio.com/community/threads/inverted-electrostat-inferior-in-distortion.409322/
Just one picture (ignore the 0.5% THD which is probably THD+N, the important thing is that the HD2 is 60 dB down = 0.1% HD2)


I also had a chance to measure an Acoustat 1+1 recently. I just did a quick test at 200 Hz at rougly 85 dB / 1 m and got HD2 about 55 dB down, so not bad at all.

There were also measurements of pre-production Capaciti panels in Klang+Ton and HobbyHifi magazines which were in the 50 dB+ range.

Well, I came across this review of the purity which has a Gen 2 CSL panel (same reviewer & magazine as the Final review, but different equipment and parameters):

https://hometheaterhifi.com/reviews/speaker/floor-standing/a-secrets-speaker-review15/

1 kHz distortion at (guessing from full FR sweep further down in the articla 87 dB / 1m ) is poor at 1.36%, this time stated as THD+N. More importantly, the HD2 is only about 37 dB down.


https://hometheaterhifi.com/wp-content/uploads/2015/08/martin-logan-purity-speakers-1-khz-large.gif

That number, however, is not consistent with THD+N sweep which should be higher because of the noise included and reads more like 0.6% at 1 kHz:

Even at 10 kHz, still 0.24% which is high for an ESL

Even the integrated ICE-T amp can't be that bad. So is anyone aware of reviews or other published measurements of Martin Logan ESLs? Is there a chance the Gen. 2 with their metallic coating and clear plexiglass spacers / dampers perform worse than the Gen. 1 with graphite coating, heavier foil and foam dampers?

My name is Ivan from Bulgaria.
Professionally, I repair the electronics of sewing machines in a sewing factory.
Audio engineering is my new hobby.
My English is not perfect!

Hi all,

I am currently working on implementing LM1876 based amp and ran into the issue with the mute and standby pins.

From the datasheet, if a logic high (1.5 to 5V) is applied to the MUTE pin, the amp will be muted.

The goal is to mute the amp during the turn on (and turn off).
For that a logic high needs to be applied to the MUTE pin when amp is turned on, but after 1 or 2 seconds wait time the MUTE pin should be pulled low (< 1.5V).

I have come up with a simple simulation circuit that consists of :

• 5V zener regulator
• RC time delay
• NOT logic gate

Power is taken from the positive rail of the amp's power supply that is 20V to 25V.

Zener regulator resistor is selected at 1K, and it pulls about 20mA of current.

Any suggestions on improvement will be appreciated.

HI
Any have picture of DM1500 DD amplifier ?
I need value of cap C15 in area of the power supply

24V output LV-Regulator kit from Glassware Audio Design/John Broskie. New, unassembled.
$45 includes postage in CONUS.

Every now and then I must go and look at this F7 magic thing. I mean, mouser etc. must hate this amp it has so few part! I think this is just plain incredible! Wish I could give an ear to it...

Hello,
Does any one know what are all the reasons an AVR would blink a red light for? I'm not talking about obvious reasons here like an output short, I need to know all the causes because seems like my AVR has some issues going on so I want to check every possible reason (A guide to which pins to check is appreciable)
It worked awesome for the last 10 years but a week ago it burned a capacitor (which I changed) and problems started cascading. I did everything I could do but now I'm stuck with the blinking light
Here is a list of things I tried:
Checking spk output for short
Resetting the AVR
Checking supply rails (all of regulators are within a tolerance of 5% or less)

Hi guys

I would like to experiment with open baffle speakers on the cheap and was thinking of building one using the SB20FRPC30-8 which I have installed in my car and was really impressed by it.

The plan is to have the speakers eq'ed (if needed) to reach moderate levels below 80hz and then crossed them to by subs.

Would you be able to offer any guidance regarding driver selection, baffle size (if possible to be minimal and short) and expected bass response based on xmax? I don't know how to properly simulate this.

Thanks!

I'm looking for some insulated turrets, preferably with inside thread mounting like this one:

https://eu.mouser.com/ProductDetail/Keystone-Electronics/11512?qs=do/%2B0R7m72eYwljRf/eNuA==

Mouser wants $ 15 for each which is more than I want to pay. Someone has a bunch laying around they no longer need?
I need about 2 dozen.

Jan

Hi! I had a lucky find at Seattle Goodwill - Oppo BDP-103 for $24.99.

When I plug it in the tiny light on the far left of the front panel glows red but other than that the unit is completely unresponsive. No other lights come on, no sounds of moving parts. Pressing power button does nothing.

I opened it up to look for obvious signs of damage and didn't see any...no bulging or leaking capacitors, no water damage, no scorch marks etc.

Any ideas on what might be going on? Thanks in advance! -Joe

All SOLD

This year I thought I was going to build something I was trying to for a long time, a multi amplifier with lateral mosfets, so I bought a buch of lateral amplifiers in the forum.... but the fact is that I don't have time to build a nice amplifier. i have tested them and they sound awesome. In a direct comparison to Goldmund Job I have to say there is just a subtle difference... if any, but the friend who let me the Goldmund Job will sell it to me at a ridiculous price and it will save me very much time to buy a finished amplifier than building it, so they will go for sale priced to be sold trying to recover part of my investment. All of the amps has been tested, adjusted and in perfect working condition.

2x Holton Precision HPA NXV200L 4.1 with 1 pair EXICON mosfets each: Asking 200€ for both. (Priced each at 165€ at Holton web)
150 Watts RMS 8 Ω at +/-63VDC rails
270 Watts RMS 4 Ω at +/-63VDC rails
Driver stage can be feed regulatd or unregulated

2x SIGMA reference class audio amplifier with 2 pairs of 2Sj1058/2Sk162 each board. Asking 260€ for both.
180 Watts RMS 8 Ω at +/-68VDC rails
220 Watts RMS 4 Ω at +/-68VDC rails

2x PeeCeeBee V1.1 amplifier with 1 pair of 2Sj1058/2Sk162 each board. Asking 60€ for both.
80 Watts RMS continuous sine wave into 8 Ω can be run from +/-15V up to +/-35V
100 Watts RMS continuous sine wave into 4 Ω can be run from +/-15V up to +/-35V

Prices + PP fee + Shipping.

Any question, offer or whatever, PM me.



Holton Precision HPA NXV200L



SIGMA reference class audio amplifier



PeeCeeBee V1.1 amplifier

Does anyone have hands on experience with the DCX50 driver and is there a proven WG and crossover design for use in a studio monitor type speaker setup?

This looks like a very nice driver but I can't find any existing designs that employ it.

Hi all,

first off I would like to say that DIY Audio is really great filled with many great people. I’ve spent the last few weeks reading about how I should approach doing my own BLH.

it started with auditioning a pair of acousta 115s….then going through the Alfredo horn threads. I thought I was set on building the Alfredo horn with Tang band W8-1772 only to learn that the bass rolls off at around 60Hz. While the Acousta would reach 40Hz.

I’m not a big fan of Lowther drivers…..so I thought of replacing it with the W8-1808.

Could anyone give their opinion on this?

price check RA3000

I designed a TO-3 to TO-252 adapter PCB to upgrade an amplifier I have from obsolete MOSFETs. I wanted to post it here to gauge interest from the community. I'm willing to sell these as a kit with pins or pre-soldered. Price TBD but will be reasonable.

The board has thermal vias under the TO-252 tab for heat transfer to the bottom ground plane which is exposed copper with no soldermask.

Edit: gone!

HI would anyone happen to know the correct replacement part for the volume control for a plinius iib preamp? And where to source one?

Cheers

So I maybe found an easter egg, or at least an undocumented feature of my XP-10. Fiddling with buttons while listening to my usual 90's proto-grunge trash, I found this setting called "gain", and turned it on. It made the almost-clone-of-the-ACA-Mini I was using for amp duties sound quite wonderfully chunky and thrusty. What even is this?? 😍

I am trying to build a wifi airplay module for Airplay as of now. Though the Linkplay modules can do much more and can possibly replace Moode / Volumio / PCP on Raspberry pi.
So my challenges are the PCB design and selection of DAC chip. I still do not know if the Linkplay board will play the game or not as PE does not share much info on it. But since the cost was $10, I could not help picking one up.

So Far I have been able to connect the link play module to my local wifi and have my iPhone play connect to it like an Airplay Device and the phone transfer's the audio to it.
I am also able to send API get-command to it check what is playing on it and change volume - this works.

LinkPlay Module has I2S audio out of about 24bit / 192kHz.

Also, the I2S pins are BCLK, LRCLK, and DATA_OUT. Only MCLK is not provided.

The Biggest Question that arises is which DAC and how to connect

PCM5102
ESS9023
?

this is the schematic i have built so far - the Resistor the output of the Regulators is going to be chokes and not resistor, its a place holder

I have 5 or 6...DigiKey, Mouser, Allied etc. I was just using the last Mouser from March 2012 -- amazing how useful a "Table of Contents" is compared to a search engine.

Good evening.

I'm working on a Rockford Power T600.4. The repair seems to be good. Biasing is done... only problem is, the front and rear left channel is 4.5db louder than the front and rear right channel.

I haven't messaged Rockford about a schematic yet. Was wondering if anyone else has had this issue before?

Hi folks,

I've been sorting through my caps and came across these- Sprague Vitamin Q caps with a prefix "L". The code is L96P.

I have never seen that "L" prefix before, nor can I find any info about it.

I'm familiar with most Sprague codes (91P, 96P, 191P, 196P, CP08, 260P 118P, 160P, etc...) But this has me stumped.

96P is inserted tab construction; 196P is extended foil construction. Ultimately, I'm trying to identify the construction of L96P.

Hope someone can help! 🙂

Thanks, Kent

Hi Folks
I am looking for a reference level speaker to build for a small room and I am interested in the Zaphaudio ZD5 floorstanding vented enclosure.
Since it is an old design and most of the info I find it's also old I wonder if it is still a good choice or I should be considering other options.
I also checked the Troels Revelator-51 and Ellam 9800 but I am not sure if the bass response is on pair to ZD5.
Please, I would appreciate some advice!

If I decide to build the ZD5 I would like to make the enclosure less deep using part of the sand filled chamber at the bottom. Total volume and front baffle would remain unchanged. Approximately something like this:

Internal dimensions inch(cm): Width x Deep x Height
ORIGINAL: 5.5(13.97) x 12(30.48) x 23(58.42)
MOD: 5.5(13.97) x 9(22.86) x 30.5(77.5)

Is this a bad idea? Other dimensions would work better? Port can remain in the same position?
I read that lots of additional damping will be required at the bottom
Please I need guidance from expert guys!! Thanks!!

Hi guys,
I have a pair of 3301 with JBL 2226HPL 12-inch woofers but my issue is that the 3301 are too loud compared to the woofers. I tried applying an EQ on my master out from the console but this isn't the best solution. Could be too loud because of the crossover design? As far as I remember the crossover PCB I have inside the speaker is extracted from another speaker with different specifications. Can anyone give any suggestions? Should I replace the crossover PCB with something different to reduce the volume or do I need a resistor in series to achieve this?
best regards

WTB: OPA 654AM metal can.

My (former) mains PA uses rather small horn top cabinets, only 26.5 inch wide. The sealed conical expansion FLH (front loaded horn) response drops below 200 Hz, but using fourteen 8" drivers per side makes the response OK to around 70 Hz. When I need a bit more low end and directivity I use wave-guides in front of the stack, it gives the low end of the horn a 3 dB boost down to around 70 Hz, and maintains the 90 degree pattern down pretty low.

In front of the Keystone TH (tapped horn) cabinet, the wave-guide increases SPL (sound pressure level) by an average of 3 dB over the entire sub-woofer pass-band from 36 to 100Hz.

The wave-guide adds SPL to any LF (low frequency) enclosure by increasing forward directivity.

The wave-guides in the photos below are constructed from four pieces (top and bottom, left and right sides), and break down to a package about 6" (inches) x 20" x 54.75". Ratchet straps are used to attach the four parts, and to attach the wave-guides to the mains cabinets. There are no rattles even at the full peak power of around 6600 watts per stack. Since the wave-guides couple a larger area/volume of air in front of the stack, SPL in the immediate vicinity directly in front of the stack is actually lower than without the wave guide.

The wave-guides take a few minutes extra time to set up, but considering the cost to output level increase they afford in a small cargo space, the equivalent of doubling speaker cabinets without paying for the second set is quite worth it on gigs that need a lot of SPL using the minimum amount of power.

To sum up, the advantages of horn extensions and wave-guides ("barn-doors") are several:
1) Some venues are simply too small to use a really large horn in.
2) Horn extensions can be made to nest like Dixie cups, as did the Community "Leviathan" horns from the 1970s, or can be made in four parts, like my 1977 (or 1978?) exponential FLH "Collapsable Crunchers", or the wave-guides described from this century. Any of those approaches can reduce the transport volume by as much as 90% compared to a single horn of equal size, but do require more set up time, construction is more difficult, and some extra hardware is required.
3) The two "tunings" (Fb or Fc) afforded allow a horn extension to be left off if program material does not require the extra LF (low frequency) extension. That said, a cabinet designed for horn extensions may be a compromise in either configuration, especially in TH compared to FLH designs.
4) Wave-guides can add 3-6 dB forward gain with no power compression, drastically reducing power demands for a given SPL compared to the same cabinets without, and require no special design consideration regardless of cabinet design- they work equally well on BR (bass-reflex), TH, or FLH. The bigger the wave-guide, the better, for more forward gain and reduced rear "wash", while also reducing SPL in the immediate near-field directly in front of the cabinets.

Some wave-guide construction details are in post #40.
An example of a rather ineffective TH extension is in post #9, and a far more effective TH in post #49.

Art

I put together a little test box which is a two channel inverse-RIAA network / attenuator including a simulated MM cartridge to give more realistic noise response:



The actual unit has the inverse RIAA network switchable so a flat response can also be obtained. At 1kHz the MM output attenuation is 40dB, the MC output attenuation 60dB.



The inverse RIAA response for the two outputs:




Slight peaking from the inductors is evident. I didn't quite meet my design values of 40dB and 60dB attenuation at 1kHz but its close 🙂

When used to test one of my phono preamp designs I measured the THD against level of the combined system:



I was worried the inductors might be adding distortion but it seems to be noise limited until the headroom runs out.

I've not seen the concept of including a model of the cartridge in such a network - I mean to graph the noise spectrum at some point (its best to do this far away from mains electricity for a cleaner trace).

The sort of plot I expect is this: (from another breadboarded test circuit)



as opposed to the more commonly seen:

Would this help LTSpice beginners?

Just got one. Looks fine. Manual is really thin on detail. Not sure if this thing is working or not. Powers up but can't see how to adjust parameters like plate and grid voltages. It's like this is a guick-start guide, but no, it's the manual. It says to make adjustments for set-up, but where do they appear? The LED is only operative in Hold mode, but initial settings are done in Sweep. One good thing--it is talking to the scope. Appreciate any help.

I am currently reworking my ATS2. Since I haven't found an official calibration procedure I'm starting this thread, maybe someone is interested in exchanging ideas.

The first thing I did was to replace some faulty AD797 opamps (got incredibly hot and caused very high THD values). I have also replaced some caps. Now all values are okay. Nevertheless, generator B produces much higher THD values than generator A when the system gets warm, but they remain just below the specs.

I was able to identify the effect of most of the trim pots by trial and error, I will try to summarize the results here later. Does anyone have any idea what the pots circled in red in the picture are tuning

I hope someone is interested as well.

Best regards

Hey Folks,

I have been a happy user of my custom made TPA3255 boards for years now and still am, despite a recent incident at high volumes🙂

I have a MCU in the front end that detects clipping/error conditions and lowers the volume when clipping or any kind of overload occurs. I am using them with two 20V 170W Lenovo power supplies that are stacked up for 40V DC output. The amp is configured to run in stereo BTL mode, which is meant for loads from 4-8ohm. PVDD capacitors are two 1000uF 50V Panasonic FMs.

When testing the amp at a friend's place on his B&W 703 S3 I finally pushed it a bit harder and it did overload at some point - clipping was detected and volume was lowered as expected by MCU. However, on few occasions and before clipping was detected a loud cracking sound occurred, like there was a hard cutoff at the output - not a very pleasant thing to hear as you can imagine. I was not expecting this, as I was hoping that any error conditions would be caught by internal circuitry and errors raised to be handled by MCU.

Now, I know that according to specs, 8ohm 703S3 can go as low as 3.1ohm at some frequencies, so I am wondering if this was maybe the culprit? Or maybe the PVDD capacitor bank is not big enough, seeing that eval board is using 2x4700uF? According to the datasheet, if OC protection kicks in, the device will go into error state which needs to be cleared by _RESET.

Any ideas what could be causing this kind of behavior?

What should a DIY-Audio novice build first. The WWW has suggested the famous CMoy headphone amp as a good novice project but I think we should construct a few projects that are easier and more robust for the novice. The following is my effort to offer such a project which I hope the novice will find buildable or interesting.

(Newbie, newb, noob, noobie, n00b is a slang term for a novice)

Legacy Projects: CMoy is a portmanteau of Pow Chu Moy who created a minimilist headphone amplifier that people could build with parts from Radio Shack. The original was in a plastic box with an opamp and a battery. It had a high-low switch for volume control. The HeadWize site showed many variants especially the Altoid Tin version. Mr Moy has passed away and HeadWize is gone but someone created a memorial site without the lost forums. [Memorial]

Next, there is the comprehensive tutorial provided by Tangentsoft [Audiologica]. It suggests that the CMoy pocket amp is an excellent choice for your first DIY audio project. I agree except that the tin can enclosures and rail-splitter power supply are not required for a desktop unit.

Prerequisites: You need to do soldering, drilling, and multimeter measurements. You need to have keen interest in doing it.

Shopping: You need to satisfy the Bill of Materials (BOM). Most parts are from Mouser. There are a few items from Amazon.

System: Here are two images showing the completed system recently tested. The front panel 1/4 jack connects AKG K702 headphones. The K702 demands more drive for it's 62 ohm impedance. It is not a problem for this single opamp JRC4556AD in single-supply mode. The power supply is Triad 15vdc. I did not test with 24vdc which is not required. The back panel has a DC jack and two single RCA jacks for input from the FiiO line output.




Enclosure: The enclosure is a Hammond Box with standoffs for 2 BusBoard Systems size1 PCBs. This box has removable front and rear panels for easy drilling. This project uses panel mount jacks and volume pots. Panel mounting requires a bigger box but does not require the precise panel measurements of an integrated PCB.

The selected Hammond Box has room for two size1 PCBs or 1 PCB which can be in 3 positions ... front, center, or back. With one PCB only, the box has more room for panel mounts. There are six standoffs in the base and 4 more in the cover.

PCBs: Busboard has 3 types of size1 (80x50mm) PCB. There is stripboard, proto board, and PadBoard. PadBoard is best since it is double-sided with plated-thru holes. Solder flows into the thru-hole such that a good connection can be made without solder blobs. And it is easy to desolder cleanly. Only the PadBoard has a square pad every 5th hole for easy placement of parts in 31x19 holes. I provide a layout plan to visualize the end result before starting installation.

Top View: Here is the Amp with the top cover removed. It reveals a few flaws caused by all the standoffs. The PCB is in rear position to leave more room for the front panel wires. The PCB can be in the center positon if smaller wiring is installed. The volume pot needs to be installed closer to center so that it can be rotated to feed shorter wires along the side. The phone jack needs to be closer to center because the cover has standoffs for a size2 PCB. The cover can close but it rubs the phone jack a bit.

My build has flaws or bugs but the plan is updated to resolve them.

Schematic: This first build does not include an integrated power supply. Instead it is biased for single-supply operation so that a 15vdc wall adapter can be used. D1 protects against accidental reverse-voltage. D2 indicates when the unit is active. R2 and R3 provides 7.2vdc for opamp bias. C7 and C8 protects the headphones against DC voltages. There is a special power-on procedure to prevent noises from capacitor charging. Wait a few seconds before connecting headphones. The caps will charge through R10 and R11.

Mr Moy advised CMoy builders to use disposable headphones since they are not protected in the minimalist rail-splitter (virtual-ground?) design. TangentSoft has a whole page explaining virtual ground variations. Given all the explaining, there is no way to make it robust. And novice projects need to be robust.



PCB Plan: The PCB is modelled with VeroRoute (VR) as a 1-sided unit. The connections are routed automatically but constrained. For example, VR Tracks cannot cross each other but VR Wires can. IC1-1 connects to C7 and R9 via a purple VR Track, which is a bare wire on the PCB underside. IC1-2 connects to R9 via a pink VR Wire which crosses the IC1-1 VR Track (an insulated wire on the top side). There are no tracks on the PadBoard, connections are physical wires between the component pins.

Sometimes VR will take an awkward route as it recursively searches for a good path. In that case, I add labelled pads or VR wires to guide it to a preferred path. At other times, the autoroute is too complex making the plan hard to read. For example, IC1-5 needs to connect to C6-R5. There is no connection in the PCB model, just U5 labelled pads. The connection is completed by adding a top-side insulated wire U5 to U5. It's easier to use this hybrid approach.

There are gaps between components for ease of soldering without creating short circuits. The circle-X symbols are non functional. I use them to mark pads that should be reserved.



Stuffing: Components are added to the PCB in phases. Phase 1 includes soldering the resistors and other components in their planned location. They should be lightly soldered on the under-side such that resistor leads are straight and cut short less than 5mm. These short leads are posts for the connecting wires. The PCB supports are 5mm. So install all the components to complete phase 1.

Phase 2: The under wires are installed in phase 2 where the component pins are wired according to the plan. Since the DIP socket has short pins for installation on a fabricated PCB. the PadBoard requires a custom procedure for the DIP. Insert a bare wire top-side, switch to the under-side and bend the wire to form an "L". Next, retract the wire until the end is flat on the PCB and touching the DIP pin. Solder gently. If this seems strange, you can try making a hook around the pin instead.

Use a temporary wire twist to hold the DIP in place for soldering.



Phase 3: The top-side insulated wires are installed in phase 3. These
are not shown in the plan. Here is a list.

U3: F5 ~ D14
U5: L4 ~ B14
U8: M8 ~ J21
!U4: J9 ~ R17
U4: C8 ~ H23
H1: H13 ~ C21
H2: I17 ~ C23



The BOM is attached. It is in Open Data Format.

My listening room is 10 x 20'. It will be for high-end, 2-channel listening and for home theater with a 65" screen. The speakers and screen will be on the 10' wall. I am considering open baffle speakers, preferably a full-range driver or co-ax point source. Is this room too small for open baffle? Am I better off with a single, point-source driver in a small cabinet? I will be using three subs.

Really struggling with this one. I've read Radio Designers 4, Wolpert, Poppovitch and other source material, non the wiser. Could someone tell me what is the equation I need & what are the various parameters I need to know please?

So far I've figured out Vpri & Ipri, Vsec & Isec and Lpri of a 25W PP OPT with a Zpri of 4k & Zsec of 8r. I figured I'd need an L of 63.69 for a 3dB loss or 127.38 for 1dB. I then pulled a load of spec sheets for "typical" laminations. This is where it gets tricky. I have 4 sets of laminations with bobbins, one set I know is Goss, the others, Bog knows. All lams are about 0.3mm thick. The only other spec I can find for a UK supplier of Cores is "thickness 0,35 mm, 50 Hz, 17.000 Gauss" or 1.7T: not much to go on.

So how the hell does one work out how many turns one needs on the pri to get L whatever with laminations of Bog knows what type of steel? Is there a rule of thumb?

Andy.

Looking for 100 pcs of NE5532 ONSEMI DIP8 for reasonable price. Europe.

Hi All
I'm very dissapointed I can not access the Rod Elliot website anymore (new website The Audio Pages) Someone experiencing the same problem?

It’s visudo not nanosudo! I’m old, I don’t have any more space to learn a new editor and I’m tired of setting my EDITOR each time. That’s all, thank you.

I'm heading towards my next build for a pair of stereo desktop speakers. Crossover points will be established through testing, but there is a fair chance that the final decision would be considered a wide-range assisted design. At least, I'm intending to use a "full-range" driver as a wide mid-range, or beyond. So in the absence of clairvoyancy I'm posting here.

The drivers I've chosen after some testing are the Alpair 7ms and SB23MFCL45. The former will go to below 80hz at -6db in a 5L sealed box - though I intend to high-pass them as part of an (active) crossover, and might also try a tapered aperiodic design. The latter are technically called subwoofers but only have a 6.5" effective cone diameter and will go up towards 200hz, which seems high enough for woofer assistance (my aim is stereo, not a sub+sats). They'll reach down to about 37hz at -6db in a 23L box, which is pretty much what I want (though they could go lower with EQ if wished; I'm listening at less than 1m, so am not needing massive SPL/excursion).

These 'may' be joined by a pair of 19mm SB tweeters crossed at several khz or more, but I've not decided yet. I'm not against tweeter-assistance, and in testing I do slightly prefer their contribution. However I have old enough ears that their benefits are fairly small over the 7ms alone, so I might not bother with tweeters at all. We aren't very sensitive to a lot of subtleties at very high frequencies but even so, achieving properly good integration (including stuff like controlled directivity) would be reasonably involved.

Please send me a message if you know of one available. Thank you!

Hello,this is original cowen horn folded for 12 inch,,,


I own two C/E/X pa flat to 30Hz with 18inch eighteen sound 18NLW9000 which i like soundwise ,but i found i don`t need the headroom in my hifi system,,,

So eventually i made a test cowen horn and modified bit to fit eighteen sound 15sw 115,yes i did calculations in hornresp but more for

backing up my thoughts,mainly i pushed some wood around and made measurements,,,,

I`M listening the modified sub for half year now and for me it plays well,deep,and enough power for home use 🙂


Maybee someone can use this info...

so here modified version,,,



yes





Yes I´m german so only metric 🙂

here measure of FT30




s
brown is 0-meter 20-50Hz (mic direkt horn exit)

blue is 0-meter 20-100Hz ""

cyan is 1-meter 20-50Hz mic 1-meter from horn mouth ground plane


lets see what 15inch cowen modified does



same measure

red 20-50Hz 0-meter mic at horn mouth

blue 20-100 0-meter

green 20-50Hz 1-meter mic one meter ground plane


lets compare





brown is ft30,red modcowen 20-50Hz mic direkt horn mouth









cyan is ft30,green is modcowen mic 1-meter grond plane,yes room modes but comparabel,,,,,







test box modcowen is 18mm chipboard vibrating like hell ft30 is well build lots braces from plywood

so should improve when build right

modcowen is prx:370Liter

ft30 is :595Liter

mod cowen not so bad compared and lud enough for home use,,,

measurements are not spl calibrated,,,

have a nice day

I am currently restoring my SB-6 cabinets - sanded and filled the corners with filter - then a primer spray and black satin finish

Taking the speakers, they were quite set in their place - my previous paint job ( wasnt pleased with it)

I took the plastic surround off one woofer without issues and then damaged the other as per photos.

The material looks like cardboard or some compressed paper onto metal.

What would be the best adhesive glue? assume one with flex?

Thank you Sam

To save making another thread, I noticed Rust-Oleum paints have a paint/ primer. I am thinking though being particle board, its best to use a primer and maybe their 5in1 Satin black, as ive used the 5in1 and it has a nice low output setting etc. I worry using spray paint as dont want another bad finish lol.

https://www.bunnings.com.au/rust-ol...-ultra-cover-paint-prime-spray-paint_p1580677
Rust-Oleum 340g Canyon Black Satin 2X Ultra Cover Paint+Prime Spray Paint

https://www.bunnings.com.au/rust-oleum-340g-grey-flat-2x-ultra-cover-primer-spray-paint_p1580683
Rust-Oleum 340g Grey Flat 2X Ultra Cover Primer Spray Paint


https://www.bunnings.com.au/rust-ol...rust-custom-spray-5-in-1-spray-paint_p0489935
Rust-Oleum 340g Satin Black Stops Rust Custom Spray 5 In 1 Spray Paint




above lighter shade where it ripped up some of the surround - note the right hand corner of some of the surround

below - the plastic surround was glued to the surround - other woofer it came off without damaging the surround.


its lifted as per photo

New to DIY audio but, experienced in "HIFI" in general. My question is, does anyone make a premade board with DIP8 opamp sockets?
I would like to build a RPi based DAC with a swappable opamp. Anyone with experience with this?
Thanks in advance for any suggestions.

https://www.ticketsales.com/beat-king-crimson-tribute-tickets
Taking my wife.

For starters, thoughts on price performance things. I find that decent PR units can cost more than the active driver, in some cases. One that I am messing with is a $100 driver and the PRs come in at $65 each with 2x needed. Is nailing the targets justification enough to spend so much on "ports" or is that money better spent on optimising a dual active driver design? Such are today's pondering while perusing online shopping carts on what to pull the triggers on 🙂

I had a search around, and while.i found a lot on birch/poplar/fir ply, and MDF, I didn't see much mention at all of OSB.

Aesthetics to one side, is there any reason OSB isn't a good material for cabinet building?

It all started out with my making a pair of Tannoy GRF replicas and liking that sort of sound.

It ended up with a full 5 way horn system, evolving and my learning lots along the way.
A long way from Tannoy Dual Concentrics in scale, dynamics and detail.

Pictured in 2023



2015



The journey was From big conicals to a mixture of Le Cléac'h, Tractrix, Exponential, and of course the thunderous yet tuneful Tapped sub bass horns.

It all started when I first heard I_Should_Coco's (yes, he has a lot to be thanked and cursed for🙂 ), AH-300 conical horns with Vitavox S2 drivers and my making a pair of conical horns.. and crossing them at 1000Hz using Tannoy HPD's as bass in my birch plywood GRF cabs.

Under construction.



Then complete.

I used JBL2435Be's.
1.5" Beryllium diaphragm modern compression drivers.

I'd heard good things about them and they were not that expensive... Sounded pretty good to be honest!
I had to import them from the USA. They were not directly for sale, used as tweeters in JBL Vertec arrays.



this 2 way set up then had a cheap Eminence tweeter added and progressed to using Emience Kappa Pro LFII's instead of the Tannoys and my own 2nd order 12dB / oct crossovers.

After a while fingers started itching and I got a pair of JBL2482's 4" diaphragm, 2" throat, alnico compression drivers in good sounding condition.

Big mid horns for them world cross at 330Hz... The JBL2435's played up to around 1250Hz.

Once made they looked like this



So far that's 48 tapered compound angled petals cut out for the mid and upper mid horns.

Suddenly mid range was clear and fantastic. Piano OMG, clarinet!! Asking a paper cone to do that sort of thing just cannot compete with decent compression drivers...

Then of course a mid bass conical.

Read up and had some excellent advice...
Petals on the go...



Driver back box



Strengthening


Nice scale to these

Driver chamber



Kappa 15-A chosen after modelling in Hornresp - excellent proj/tool - respect and many thanks for use of it




First test


Using GRF;s as low bass bins



mid bass horns cross at 90hz

Rearranged - sounded better



Now for some deep bass - tapped horns

Thanks to Volvotreter and Cowanaudio and the Colborative taped horn sub project thread - excellent stuff.

I chose to use my Eminence Kappa PRO LFRII's, they had been in the Tannoy GRF cabs before - nice drivers and they modelled well in Hornresp.











First side done




Now to relax. listen, already tuned the upper / mid horns to work nicely with the md and tapped horns.

Really sounds good. Horns are the way to go. 5 way is the ultimate I think..
'Normal' music sound great with accurate fast bass and then ask it to do some sub stuff and oh yes you hear / feel that.
Makes lower listening levels enjoyable as you get full range without terribly loud. High WAF!

Loved this project and the results. Will do some fine tuning / measuring but my ears tell me it is close...

What next. Not sure about 5 way amping or fully active tbh...

I am currently working on a Marantz PM48 amplifier. I can’t find any service manual or circuit diagram for this product, and it would be a great help to me if I had some information about it.



If anyone can supply a copy of the manual or diagram I would be most grateful.



TIA!

Hey guys, I am totally new to the game and I've been looking for a while to try and find information to help me build a class D amp to power some speakers 4ohm rated at 45watts I have at home.
My requirements for the system are 30w x2 channels using a 12v DC supply and a 3.5mm audio jack. I would like to use readily available parts and since its my first time I am not too phased about over complicating it and having extremely good quality but I don't want it to sound like a tin can😆😆. If anyone has previously posted a thread that could help or would like some more information from my side and is willing to share their knowledge, Please let me know and I look forward to joining this community!!

I've seen it stated categorically that foils of these drivers last only 10 - 15 years. On the other hand, I have come across listings for Aerius i, SL3, ReQuest, ES100R, ES200RS whose owners say they are still running the original foils and they are fine. Should I believe this?

Hi everyone, I am importing Denon avr x4500h from Japan to India. Japan is on 100v and India is on 220-230v. I referred to the service manual and found the relevant SMPS pcb diagrams (pdf attached). These diagrams show the "option" to change certain components and keep certain lines "open". I just wanted to know if anyone has done this and how difficult it would be or should I just opt for a step down transformer (and quality could be an issue).
Any kind of help would be much appreaciated. Thanks.

I have been sending emails to this company and have not received any replies at all. Anybody know if they are not conducting any business anymore?

i "need" to build a headphone amplifier and im limited to these active components, the headphones(iem's) i want to drive are the kinera celest gumiho, the issue i have with them is that theyre 8ohms and my dongle cant keep up current wise during the bass notes.

is this a dust collector dome ?

Hi friends,

is there some of you that recognize this amp?

https://it.aliexpress.com/item/1005001337470583.html

in the bottom there is this label: AUDIO MD A5-AMP

I'm in serching of schematic for understand how to correctly power it

Thanks

Peter Higgs, Nobelist Who Predicted the ‘God Particle,’ Dies at 94​

The Higgs boson was named for him. It was a key element of the Standard Model, which encapsulated all human knowledge so far about elementary particles.

Peter Higgs, who predicted the existence of a new particle that came to be named after him (as well as God) and sparked a half-century, worldwide, billion-dollar search for it culminating in champagne in 2012 and a Nobel Prize a year later, died on Monday at home in Edinburgh, Scotland. He was 94.

The cause was a blood disorder, said Alan Walker, his close friend and fellow physicist at the University of Edinburgh, where Dr. Higgs was an emeritus professor.

Dr. Higgs was a 35-year-old assistant professor at the university in 1964 when he suggested the existence of a new particle that would explain how other particles acquire mass. The Higgs boson, also known as “the God particle,” would become the keystone of a suite of theories known as the Standard Model, which encapsulated all human knowledge so far about elementary particles and the forces by which they shaped nature and the universe.

I'm thinking to build a line array - I remember years ago, people were happy to try certain parts express close out drivers in arrays. Is there a present favorite in the very cheap surplus line array driver category?

I'm planning to introduce (preferably a pair) of subwoofer into my current 2 channels setup. I've 2 units of Hypex plate amp from the past project years back hence I'll be reusing this and looking through the option, i am really interested with the Madisound kit of the SB34SWNRX (https://www.madisoundspeakerstore.c...-sb34-12-subwoofer-kit-with-passive-radiator/)

It seems in a reasonably sized box (~2.0-2.5cubic), the SB34SWNRX with a single passive radiator will have a F3 of <30hz, and I've the Hypex plateamp that can boost it further if required. All in all, the size and the combination sounds like a good use-case.

I've a question hopefully will get some feedbacks:

• There's another driver which is SB34SWPL, it has a beefier cone surround and looks more like a subwoofer driver to me, and it seems it fits into an smaller box well enough, anyone tried this driver and how does it compares to SB34SWNRX?
• anyone has build a sub based on either the SB34SWNRX or SB34SWPL drivers, and what's your experience?

Many thanks