Hello everyone,can anyone identify me this GZ34,the tube has no code.I am interested in who is the manufacturer of this tube,the factory,and if anyone knows year.Here are the pictures.Thanks

Maybe this is the correct forum (and not the Pass one).
I'm a very newby in electronics but I would like to try to build a Pass F5.
Only the F5 board and not the PSU, so I need a built PSU.
Best trafo than switching type...
Output should be +/-24 V plus the Ground with about 300W.

Please help me to choos the right one!!


Danilo

Good day.

I would like to build a good DAC.

I want to use the AK4493 DAC or 4495 even 4497 will do with LT3042.
Where can be find good layout for 4-layer PCB?

Thx.

Hi Guys,
I've built a set of Pensil cabinets out of Birch ply, not Baltic Birch alas. I need to mount the drivers on the wide side of the cabinet not the skinny as the instructions specify. Several years ago I recall one of the gurus (Scott or Dave or?) blessing this driver location. I've made the backs and bottoms removable so internal stuffing or lining will be easy. The Pensil specs call for some level of stuffing. I'm happy to use poly-fill or some other variant but am curious of the intent. Are we stuffing the cabinet to dampen cabinet vibrations to reduce unwanted coloration, slowing or speeding up the air flow to the terminus or something else? Also, should I still put the port on the same face as the driver? My plan is to have them painted by a car shop that painted my Fried subwoofers which have held up really well.
Thanks for any and all input.
Mark

Hello!

I've searched the last 2 weeks for Audio Players for my Raspberry Pi, but yet haven't found one that fits my purpose.
In theory its really simple:
My hardware includes a Pi (2 or 3) and a cheap amplifier plus speakers, there is no need for a good hifi experience.
I just want an offline player, that starts very quickly (because no special modules/services) and auto play all audio data on the USB stick I insert. Its headless and should work without any command, just like switching music CD's.

I tried PiCorePlayer because of its merit to poweroff without harm, but couldn't get it to work. Forum members said the player has to be online and can't autoplay.
MoOde, Volumio and RuneAudio should be similar and have way more features I don't want. MoOde ought to have many configurations, but the same problem as PiCorePlayer I estimate?

My next steps would be trying Archlinuxarm and then pygame, but I also don't know if it works there.
What would be the best solution for my task?

If it has to be online, I will accept that, but USB autoplay on boot and switching USB stick has to work!


Thanks in advance!

I have a dc audio 7k that pops when it shuts down. Any ideas what is causing this?

Also known as the "Death Of the Staircase". My previous design was called "The Staircase", so I thought of putting it to an end. 😀 This is the 3rd reconstruction of the amplifier with mostly the same parts, but a new chassis. The reason for rebuilding the old and not making a new is because it's cheaper - not having to buy entirely new parts. Afterwards it's my first and it will always be my amplifier for learning and practicing.

This version has improved chassis - rigid, very thick pine wood; coupling - interstage transformer 1:1; power supply - RIFA PEH169 high grade capacitors.

It is not completed yet. I have to build transformer housings, put black plate screws, tube top cap insulation and... I'm also winding hi-fi low Cp and low DCR psu chokes and maybe I'll do a higher grade power transformer. I'm very tempted to try regulation, maybe salas SSHV for the driver stage and "something else"for the output stage.

Every component is described in the schematic right here! It says it all.

I'm very happy with the result - smooth, liquid, live sound that makes you go into extasy right away 😀. The bass is a little slow and I guess the high PSU DCR is to blame, this is why I'm tempted for the regulation. Ideas never stop.

The power output is 11W. There are no power switches. The power cords are Neotech 3PS25 terminated with Valab rhodium IEC and plug. There is a separate power cord for the heaters.

Enjoy the pics. I'll shoot some more in a more thorough way these days.

Hi @all,

i work the last days on a broken amp. One fet in channel 4 was broken.

3 channels run fine. If i replace the broken, the new one gets in a few seconds really hot and the amp goes in protect.

I see that between gate and source was a difference of 6V DC. None of the other channel has it.

I replaced all the green marked fets, transistors, diodes, OP amp too.

but it will not work.

Anyone any idea?

Dropbox - IMG_20200630_211903.jpg - Simplify your life

Thanks

Hi,

I'm curious about the impedance curve of my new esl panels. I have REW installed on my laptop, but my laptop has only a mic out jack, no line inputs. I would like to use this scheme:

https://www.roomeqwizard.com/help/images/impedancesetup.jpg

I'm wondering what would be a good way to make a impedance plot with my laptop + REW: would an external USB soundcard with line input and mic output work? Something like this soundcard:

Product

Greetings, all. First post; retired lifelong police officer, turbine helicopter geek, as likely to go necrotic as quickly as this thread will.

I hope it helps somebody, somewhere, in whatever your future allows. The following is my way of giving back, to this group, especially.
Thank All Ya'll Very Much, DIYAudionerds. Your existence only enhances life quality.

A Gut, Hack, Mod and Polish Turd-Treat Especial*. A Moldie Oldie, but Goldie.
An Ambitiously Absurd Tale of Transforming Surplus into Slightly Better Surplus.
For Dummies, by a Dummy. *AvE

VICTIM
Anchor Audio Xtreme XTR6000CU1 Sound Reinforcement System, aka Anchor's obsolete, disowned millenial era bas_ard child, a Kitchen Sink Combo Cab, sans batterias.

SITREP:
-2016. Purely ignorant, infatuous impulse purchase. Lubbock TX pawn shop, $100. History unknown. "Very good knick", my Brit brothers might say.
-Clueless (Anchor Audio who?) but absolutely intrigued by its MILSPEC-like construction/design, etc; in a word, outstanding.
-Made in the State of Degeneration nee California in the late '90's, apparently. In spite of this, clearly built to be as indestructible as a Smyrna Glockenspiel.

-**Turns out, Anchor only markets to, essentially, "wedding rentals" alongside their corporate/conference/commercial venue et.al. demograph. Hidden secret in plain sight, hence my highly educated, yet total, ignorance of them.

NERDISTRY:
(representative internal pics will follow, precise photos upon forum request.)
The public marketing-wank brochure specs are readily available, but almost nothing else. Surprisingly scant info. Webwashed.

-The bi-amped thing is bi-bi-amped, QUAD-amped, essentially.
"Proprietary", through-hole mother-daughtercard mezzanine design, aviation-quality assembly. Every PCB crisply marked with pinouts & traces. Impressive and Unusual. HackNmod Freedom Bonus Points=Anchor, Inc.

-An apocryphal tale references a "passive companion speaker", its existence known by few, and seen by fewer....The 6001, allegedly born to suckle from a then-obscure oddity, 4-pole biamplified Speakon Socket. Professional Prescience Bonus Point=Anchor, Inc.
-properly and precisely shielded & separated ERFI noisy-bits.

-"DIVERSITY" UHF wireless RX module, 1-channel. For the tinker bits bin; unneeded, obsolete & unsupported, but a fascinating little RF device, and 12VDC...[more on that later.]
Conjoined to its plate-steel housing, (was) a then-high-end, Belgian Samsung DAC'd, 12VDC OEM CDR used in a few BMWs. Combined, they fill a single DIN or 1/2U space, with intriguing possibilities, as will follow.

GOAL:
Meh. Learning experience, heckuva lot of fun. Flying OClamps fitted, repurposed PDU PCB, etcetcetc. Maximum overdrive mods, because if worth doing, its worth overdoing. No rabbit hole too deep.

Anybody interested in specific details from here, I'll do my best to cover it with specificity. Otherwise, I'll gradually post the processes & pieces I used in coming days.

Eric

Found an old NAD T760 which needed a little TLC, clean it up, straighten the case etc. The only issue it had was a hum in the rear channels.

Initially using the optical input the noise was horrendous but calmed down after a few minutes but was still quite audible. If you just use the analog inputs things improve in all channels and if you use the pre-out RCA connectors the sound is again clean.

This led me to the belief the hum must be isolated to the surround board and changing the caps to newer ones would clean up the signal, so fitted some Elna Silmic II. I double checked the connections after I did each one and validated the caps were the same way round as before.

Put everything back together and while the rear channels sounds better the original hum is worse than before, not horrendous and when you watch a film it isn't very noticiable but I would like to resolve the issue if I can.

A visual inspection of the board looks fine and when I plugged it back in nothing I could reach got hot nor did the heatsink the transistors are attached to.

I do have some initial thoughts but would really appreciate any suggestions on what I could do to resolve this. I am no expert, not even at an intermediate level but I am trying to learn and happy to have a go.

A few thoughts I had:

Wondered it a shielded power supply would help.

The board has empty junction connectors marked A and B thought of connecting them with a separate wire

Could there be interference from the power supply which is right next to the board

Could there be interference from the AC3 board which has a random wire running to the surround board. NB. There are a few extra wires connecting boards together which I think is factory as I saw this in pictures of another T760 just a bit bizarre.

As I said, your suggestions would be appreciated

Happy Independence Day to all the USA members here! Have a good one and enjoy! 🙂

I had posed a question in the Aleph J thread a number of months ago to see if there was any reason I shouldn't try the following, and not receiving any negative feedback, I went ahead and made the changes this past week.

I had built an M2 and an Aleph J a while back. I've always loved the stereo imaging and sound-stage depth I get from mono-blocks, so I wanted to convert my amps to mono-blocks - but the expense for the extra chassis and power supplies kept me from doing so.

Since the Aleph J and the M2 use the same power supply, I decided to swap an Aleph J channel for an M2 channel between amps, so each amp has one Aleph J and one M2 board. I installed a heavy duty DPDT switch on the back of each amp, unhooked the V+ and V- from the power supply to the boards, and instead ran the V+ and V- to the center pole of the switch, and then ran lines from the switch to the V+ and V- of the audio boards. I didn't do anything with the ground lines.

The power supply in each amp now only powers one board depending on the position of the switch, and I change the RCA input, speaker outputs and switch position depending on whether I want to hear M2 mono-blocks or Aleph J mono-blocks.

How did it turn out? Really well. I always had a bit of a ground loop that I could hear in my Aleph J if my ears were close to the speakers. Beyond the increase in separation that mono-blocks bring, now both the M2 and the Aleph J are totally silent with my ears right next to the drivers.

Both amps were built with Antek 18V 300 VAC transformers. As a stereo amp with this transformer, the M2 sounded very pretty for jazz, and folk type music, but wouldn't really rock to satisfaction. Dedicating the power supply to a single audio board has given the M2 much more bass drive and punch. I was actually shocked at the difference, as I wasn't expecting it. Now the amp can rock as well.

Hear are a few not-so-great pictures that demonstrate the change.

P.S. Not that there would be any reason to, but as 6L6 pointed out when I asked about the idea earlier, you would never want to flip the switch while the amp is running.

I have 2 OPPO Sonica DAC's. In general, I really like the DAC and she plays beautifully w/DSF files from the hard drive.


Background: One of the Sonica's suddenly sound's slightly muddy or more like listening through a veil, lacking authority or punch. Frankly if I heard this DAC standalone for the first time, I would have assumed "meh, nice but not that impressed".


Performing an A-B swap out of one Sonica for the other, clearly demonstrates it's the DAC.


Question: Any idea what to check?

Thanks for any guidance.

HQ-Audio ESS9018 Reference DAC for sale, 500$ O.B.O.

Hi. Selling my great HQ-Audio (quanghao forum member). This is a great dac and it was my best dac before I upgraded to quanghao latest ESS9038/Tube I/V DAC. So Mine is for sale. It has the solid-state dula mono I/V converter and high current Class-A output stage. Full discrete low noise regulators for each DAC section, I/V section inspired by dCs apparently. Each I/V channel has +/- low noise shunt regulators. Excellent design and implementation, Sounds great!

Mine as these mods:
-Replaced the MELF stock I/V resistors with Nude Vishay resistors for best sound. A substancial upgrade!
-Installed a rear mounted 1/4'' headphone jack. The output section is powerfull enough to drive an headphone with ease.

It has the Amanero USB input that works great with my music server.
It has also coaxial, AES/EBU and optical SPDIF.
Everything is working perfectly.
Silver color, comes with remote. Accept up to 24bits/384Khz and DSD as well.

Asking 650U$ (O.B.O.) + Paypal fee + Shipping.

You won't find a better dac at this price...

Thanks for looking
SB

Hello Phreax !

I´m confused. I want to build my own High-End-CD-Player.
For the CD-Transport-Unit i want use an expensive Philips-VAU 1252 with the "I2S" Output. This is very good ,because i´m not use a Digital-Interface-receiver (like CS8412,CS8414..).
The Digital-Filter (DF17xx,..) i don´t use, too !
It´s very minimal: Only 2 piece ob Burr-Browns "PCM63" direct coupled to the Philips !
There is only one problem : The PCM63 is not "Stereo", I need
2 piece for a Stereo-DAC. But is there a way to "divide" or seperate the "I2S"-Signals for the "Left"- and the "Right"-Channel.

Then i thougt, i can take the "PCM69" because it´s a Monolithic-Chip "Stereo-DAC", but i cannot get this Type here in Germany.

Is there anybody there with a little Tip for me and my problem ...?

greetings from Obelix

I was wondering if anyone had done anything in the area of detecting shorts on power amp speaker outputs while the amp has its output muted by SSR.

What I mean is using some way to sense possible shorts on the speaker side while the speaker is disconnected from the amp by the SSR.

It's not difficult to do with electromechanical relays, using the other side of the switch that would normally not be used, to pickup the lead from the speaker while it's not physically linked to the amp's output, and when the relay is energized to unmute, the speaker is connected while the short sensing circuit no longer is...

The thing is, it's a bit different with SSRs, with no physical contacts being used, and there would be no way to disconnect the short sensing circuitry from the speaker once the amp is unmuted.

So far I haven't found any way to do this with SSRs, but perhaps some have given some thoughts and may have come up with something usable?

Do you think this is enough heatsink for two DLH amps? I think I pulled it off of a powered sub so not new and no spec's. ( No idea why it flipped the picts ).

Hey everyone.

So I've made my 3 way cabs and dicided to go active and my setup is 1x 2 channel amp for the 12" subs and 1x 4ch amp for the tweeters and mids and an active crossover unit to separate the frequencies.

I was in the studio the other night giving them a first test and managed to set everything up nicely and they sounded great but when it got to a live gig they really under performance in the sense of I could hardly get any volume out of them before feedback occurring!

My main question is do all amp channels need to clip at the same time as the mixer?

I ask this because all amps channels are just about registering a signal according to their displays while the mixer is at optimum levels. Obviously I haven't set the amps correctly but I just wanted to know if they all need to clip at the same time?

Hope this makes sense!
Sal

(delete)

Sorry, thought my post was gone and wrote it again.
How to delete this thread?

Dwm0608X_V20
any way to get these board somewhere,
its installed on a Ground zero gzua 1.1000dx.
Or if someone sits on scematic on this board. ?

I overheated the pads on the to ics so pretty much destroyed the copperlines around.
i reflowed the u2 an u3 too many times ,
i assume u2 was tl072 and u3 is lm311 or 211..

so it got this board messed up.

best regards
Niklas .

I am working on a OTL headphone amplifier where noise and hum is essential. I can't help being nervous about having AC on my heaters for the 6AS7 output tubes and 6SN7 small signal tubes.
I have done some reading about maybe applying DC to the heaters to eliminate the risk of 50hz noise. I can see that DC on the heaters is not something you do without side effects. My idea however is to mount the heaters in a MOSFET H-bridge so I can switch the current direction with 1Hz or so.
Would this idea give me the best or the worst of both worlds?
For the power supply itself I'm thinking of using a toroid transformer with the heaters in parallel if I go with the pure AC option. If I go for the switched DC I am planning on something like a Mean Well LRS-75-12 with the tubes in series of pairs.

Hello,


I have a Rotel RCD-971 CD player that I would like to modify so it can accept I2S signal from an external digital inputs receiver switch that has a I2S output.
In this way I will be able to connect external digital sources and use the Rotel's PCM63 DAC chip and have the anlalog output from the Rotel's analog outputs.
I need your help to understand where should I connect the DATA, BCK, LRCK, MCK outputs from my digital input selector to the PMD100 in the Rotel.


I'll appreciate any suggestions.


Thanks

what is a simple way to provide short citcuit protection ?
i have an sony amp that has and it works nicely as the music cuts out for like 20 secs of shorted

Hi just posted a new thread - a message popped up and before I could read it fully it disappeared ............ at a glance it mentioned thet the posting would not appear...........and I missed the rest. Are postings fully moderated then approved and then displayed............how long does this take??

Hello,

I got a good deal on 2 Mach5 IXL-18 with a Behringer NX6000D amp and I am keen to build my first DIY sub box (I have moderate wood working ability, and live in Canada, so buying flat packs will not be a great option).

But I am wondering what I should build.

For background info:
Use will be 75% music, 25% HT
Room is ~ 16ft x 10ft
The way the room is laid out, one sub will most likely go right behind the main listening position and one directly in front / center.

Priorities for me would be (in order):
#1 Accuracy and musicality, so I was looking into a sealed box. But then I was playing with WinISD and noted that I may not be able to get as deep as I would like without extreme DSP (which I am ok with) but also extreme cone excursion (which I don't want to blow these subs).

#2 Low extension, the lower the better (although this is my first proper sub, so we shall see how addicting that low end really is), so then I was maybe thinking about a large EBS build. Would a full or mini marty be a good fit?

Thankfully space will not be an issue, so really any box size I would make work.
Also, I typically listen below reference, so will not need them to hit crazy high levels.
I just want it clean and then deep.

Super keen for any recommendations.
Also, since this is my first build, if there are any recommended sites for designs (mostly if ported is the way to go) that would be great!

Sub specs if that helps:
Mach5 IXL-18
T/S Parameters
Fs = 17.7 Hz
Re = 3.4 Ohms
Qes = 0.39
Qms = 5.59
Qts = 0.37
Mms = 434.3 grams
Rms = 8.69 kg/s
Cms = 0.184 mm/N
VAS = 274.1 litres
Sd = 1029.2 cm2
Xmax = 22 mm
Cone Diameter = 36.2 cm
Le = 6.09 mH
Bl = 20.51 Tm
Power Handling: 800 Watts SPL (2.83v/1m): 89.2 db
Ported: 200 litres (7 cu.ft.) 19hz tuning
EBS: 365 litres (12.88 cu.ft.) 15hz tuning

Thanks!

Hi,

i am selling my tube amp TU-879S as i have recently changed the setup completely:

the amp is in very good condition, the circuit is modified with several audio grade Mundorf coupling capacitors, the tubes are new 1 x JJ ECC83, 2 x JJ 6L6 GC.

( currently it incl 230V Power supply, but i can also ship original 100V Transformer NOS Kitamura Kiden PT-877 ( K6C1SK )

let me know if anybody is interested
cheers
Michael

Hi all, I have on my bench work a Musical Fidelity xa2 with power transistor fault and I'm waiting for a new pair of SAP15PY and SAP15NY for replace.
The problem will be the setting of bias.
Anyone can help me to fix the bias point? I can't found the service manual.

Thanks very much

Sergio

Hi



Got the amp for £23 as spares or repair. Fancied a go as I had a spare SVI2004A chip which I did not need from China. Seller said it was working until it started going into protection from time to time but now full time.


Burned a cap C523 as soon as I plugged it in > replaced it > OK

Checked the pre drive transistors OK
Checked votages on SVI2004A Pin 1 and 16 at around 50v. Others not in spec either so I presume both channels affected.

Checked for cold solder joints > nothing yet
Replaced SVI2004A > no change (wanted to have a go at this - original probably ok and looks as if it is a genuine svi2004a)

Input selector does not work properly as it does not show red led selection. Only the yellow tape source selection.
Track on circuit board had been previously repaired. Cheked it



Any ideas / help would be appreciated ?


Thanks

I need some help with my minidsp. My old laptop bit the dust a few days ago and I bought a new one today, and I didn't get the chance to transfer a saved minidsp program from the old pc to the new one. The program is saved onto a a minidsp kit built into my speaker though. Is there an easy way to just plug my new pc into the minidsp and extract the program saved on there? Or do I have to get my old computer back online and export the program?

I checked the forum, and most of the hits were in the chip-amp forum and was dedicated to the "how to" of wiring existing chip-amps. That's nice, bit it doesn't help me understand how to set up the design parameters to get the desired output power from the partially designed mono-blocks. If this specific issue HAS been addressed and I missed it, a pointer to the thread would be greatly appreciated.

The situation :
I will have two mono-blocks per channel in an amp I'm working on (in simulation and a single rough prototype). They will be driving an 8 ohm speaker/crossover. I'm looking to get about 50W/ch, and rough math says I should have about half that power in each mono-block, but I'm getting confused with the math, and could use some help.

Rough math says to get 25w into an 8 ohm speaker, each mono-block will have to put in about 1.75A driven by 14Vrms, or roughly 40Vpp.

What I think the solution space looks like :
If I understand Bridged Mode correctly, while we get twice the voltage swing, each amp sees half the resistance, so we're now trying to drive 25w into 4 ohms, which results 2.5A at 10Vrms or roughly 28Vpp. Each mono-block provides that much voltage, at the same current, so that's 20v (total) swing at 2.5A, for 50w of power to the speaker.

If I understand Parallel Mode correctly, it is the opposite, each mono-block sees twice the resistance, but contributes to the total current, so you get twice the current you'd expect for the (doubled) resistance. In this case, 25w into 16 ohms results in 1.25A at 20Vrms, or roughly 56Vpp. But each mono-block provides that much current at the same voltage, so it's 20v at 2.5A (total), for 50w of power to the speaker.

The BIG question:
Is my math correct, and did I get the two circuit topologies right?

If so, bridged looks to be the way to go, from ease of setting up the power supply and modifying the circuit. Getting a clean 56Vpp signal sounds like a bit of a pain...

Next up will be to get to the output voltage of 10Vrms... from line level input. That will take a total of 30dB in gain (31x gain from 0.32v, consumer line-in levels, to the final output voltage of 10v).

Presently, the amp design gives about 12dB of gain, and I hope to get a fair bit more out of it, but I doubt I'll get all the way to 30dB gain out of such a simple amp design.

So, if I understand this part of the problem correctly, I'm looking at a pre-amp that can punch it up part way. The preamp will have to add (30dB-PowerAmpdB) worth of gain to get from consumer line-out level to 10v, and achieve 50w/ch, correct?

Hello!

I'm planning to build an amp with tha power of a 300b amp but with DHT 845 tubes.. I hope they are more economical and indistructible at this low voltages! Someone have build this amp?
I have some other low voltage schematics with845 to discuss...

Thanks in advance

Max ;o))

I've built a Subwoofer using TPA3118. It makes a big thump noise when I turn it on. Then this Thump Noise repeat after every 5 seconds. But when I turn my volume potentiometer at "0" and let it make a thump then slowly increase the pot meter, then the thumping noise disappears.

What's the problem here ??

[I'm completely new into DIY stuff]

I am trying to generate audio signals using LM386. But the problem is the impedance is not matching with the loud speaker.
I have given a supply voltage of 10 volts.

Got a message from steve about MEF

My Internet connection has gone down and it will take a service call with new equipment installation to get it going again. I don’t know yet how long that will take, but it’s looking like several days at least.


Thanks,
nosaj

Hello all,

I`m thinking of buying a new dac board. I have my music on a htpc(flac) and also use Spotify 😉

Today i use a Soekris 1021 v2 dac, but i need to try a new dac, mostly for fun and also to hear a new delta sigma (right?) dac.

What to buy?
This one and build a regulated dc supply will be cheaper...

ES9038 Q2M DAC DSD Decoder Support IIS DSD 384KHz Coaxial Fiber DOP | eBay

Or is it better to go for a eBay board with a 9038 pro chip? Cost alot more..

ES9038PRO Ulitmate DSD DAC OELD Display Successor of ES9028 DAC / XMOS XU208 USB | eBay

Maybe a stupied question 🙄 . But will i hear any diffrent when i play from Spotify?

BR //Daniel

Hi all !!

Is enough one 6S45P to drive (180vpp ) one 300B tube ?

Hi all. I am stuck with a thorny problem and I'm hoping someone out there can help.

I'm restoring a really early 1968 Silvertone 1422/Sears 40XL combo amp. I've got both channels of the amp up and running and sounding really good (just replaced all the electrolytics and several resistors that were out of spec). However, I was not surprised to find that the reverb was not working. I took the reverb unit apart hoping the problem was just a wire that had come loose. Instead I found a very primitive reverb using a couple of piezoelectric tabs. Apparently this was a common early reverb used on Danelectro amps made for Sears. I've attached a copy of a photo of the disassembled unit. Anyway a tab on one of the piezo units is disconnected at the base and not able to be fixed.

I would like to replace it with an Accutronics or other modern transducer reverb tank, but I don't know if the drive and recovery circuits are up to the task. One of the great frustrations of working on these amps is that there is no schematic available anywhere on the web. So, in order to begin the restoration process I made a detailed layout of the PCB, components and wiring to suss out the power circuit and other amp modules. I've attached a copy of the layout that I did. I don't have the ability to convert this to a schematic, bit I think I have figured out that the reverb drive is the output of one-half of the first 12AX7 (identified as V1 on the layout) coming off the plate (pinout 7) and traveling up to the reverb unit through a simple capacitor coupling. As best I can tell, the return is from the green wire on the center tab of the reverb pot which is connected to the right hand terminal strip and then back to the amp through the volume and tone networks via the red wire that connects to pin 7 of V3 (another 12AX7) through another simple capacitor coupling.

If anyone can help me figure whether a transducer replacement is possible it would be much appreciated.

For several reasons, I have selected the S5 Electronics preamp as my first valve project.
It's just about the simplest tube preamp schematic you can imagine. There's a cathode and plate resistor, cap on input and output.
Uses a 5670 twin triode. Tiny thing. Doesn't include a power supply.

So I'm looking to find anyone who's built this kit, like to know their experience and if there's any simple improvements without crazy modifications.
There could be others out there that have built similar simple preamps.
Like to hear their thoughts as well.

I don't know a lot about tubes, but I see many designs with a cathode resistor bypass cap.
I suppose I could just try it, but I'd rather ask than break the thing out of the gate. Are there any recommended values for the bypass cap?
The Cathode Bypass Capacitor Explained - DIY AUDIO BLOG, AUDIO WORKSHOP

For $25 more, I purchased slightly "better" resistors and caps: Clarity caps and PRR resistors as opposed to orange drops and carbon resistors.

Untitled

I repair the PS on this amp.Amp is producing audio but the high side FETs heating up more than the low side.Is that normal for this amp?

The output has been worked on befor.Drive signals looks good.

Hey guys, first time DIY here.

A small backstory and goals for my project..

I currently own a pair of B&W 705 s2 bookshelfs, they do sound good (very revealing and transparent) but I'd want something else and that something
is dynamics and midbass presence. I recognize that these bookshelvs do sound very good on reference material music, but older music, they just sound very tamed with little dynamics to it. Like if you hit up ACDC the bassdrum just sounds abit "lame", the guitars sounds quite abit meh aswell
(I can describe the guitar as the sound comes from a pair of audiophilespeakers rather than an actual guitar cabinet).
So I'd like something thats quite accurate but can deliver good punch in less bassheavy music like older mixed music without it being "bassy". (If thats even possible) Currently running the bookshelvs with a Hegel H90, also tried with h190 which is quiteabit beefier, however it's still lacks that presence.

The idea of the build was NOT to build myself a bass-monster, but rather get the definition in these critical mid bass area and midrange that makes music so much fun and engaging.
Like when you hear a cello you just get that presence of the full body of it, it pops the heck out delivering depth to the touch of the instrument.

Ive been messing with VituixCAD for quiteawhile now, however I have no previous experience at all building speakers. And with that lack of experience i do not know wether
I completely messed up anything very basic. I have never built a crossover but tought myself
the basics(from what I know in speaker-design and crossover design). Im more worried about the stuff that I don't currently know of which might be plenty.

My initial design goals:

• Good horizontal off axis.
• Fun engaging/dynamic and natural presence to instruments.
• Can play orchestral music and bigger pieces without sounding "flat".
• Reasonable easy to drive impedance and sensitivity wise.

My initial design:

• Timealligned woofers tweeter.
• 4way with a 6,5inch midbass coupler woofer.
• 70-85litre cab(empty)

Current elements in the design…

1. (TBD) Tweeter (1inch) Seas Excel E0011-06 T25CF002 Millenium -> https://www.hifikit.se/media/attachment/file/e/0/e0011_t25cf002_millennium_datasheet.pdf
2. High-mid (4,5inch) Scan-Speak Illuminator 12MU/8731T00 -> https://www.hifikit.se/media/attachment/file/1/2/12mu-8731t00.pdf
3. Mid-bass (6,5inch) Scan-Speak Revelator 18W/8531G00-> https://www.hifikit.se/media/attachment/file/1/8/18w-8531g00.pdf
4. (TBD) Bass (8inch) Scan-Speak Revelator 22W/8851T00 -> https://www.hifikit.se/media/attachment/file/2/2/22w-8851t00.pdf

Currently I have two setups one more classic:

Setup1:

• Tweeter 1inch
• Upper mid woof 4,5inch
• Midbass woof 6,5inch
• bass woof 8inch +

Setup2:

• Upper midwoof 4,5inch
• Tweeter 1inch
• Midbass woof 6,5inch
• bass woof 8inch +

Ill attatch a picture or two of the basic ideas..(not 100% to scale..)

These two depends quiteabit on the height of the speaker, my thought on the latter was that the tweeter and the midwoofers would "theoretically"
be more aligned given that the seating position is in a more narrow sweetspot vertically(aka ears by the tweeter).. (my logic is that both woofers shares the same distance to the listeners ears since tweeter is in the middle yielding more precise phase)

Extra:
The idea was scan-speak drivers using their revelator series and ive simumlated in this example a seas millenium tweeter. While the woofers im pretty sure i like the combination (except maybe the "sub woof" which depends on exactly how large i make my cabsize)
the tweeter is abit work in progress aswell (might checkout the satori berylium tweeter).

The "easiest/working" simulation of a crossiver ive found so far was using 2nd orders using VituixCAD.
It currently has not baffle-step compensation to it, nor any simulations towards baffle-diffraction(so keep that in-mind).
The elements are 8ohm , but the speaker seems to act more of a 6ohm rated using this specific crossover due to some overlap which i deem as worthy sacrifice.

Ported or passive rad is yet to be decided..
Questions:

1. Does anything of this make any sense?
2. I recognize that the crossover due to baffle-diffraction and time alignment have to be remoddeled and tweaked extensivly after the fact, do you guys use in-room measurments for that? Like do you start with the manufacturs given ZMA FRD or do you start with your own measurments in-cab?
3. The crossover i attatched is there anything wrong with it? or can i use that as a base?

Servicing a model 15 amplifier. Q113 and Q112 need replacements. Marantz part numbers DTM13 and DTM11 for these parts.

Any idea what these are in terms of industry standard part numbers?

Hi there,

any experience with the current Audax production?
Proraum does not offer the Z0 anymore, because
of being different to the older ones.
Anyway, I try to decide between HM170Z0 and HM170Z16
for an 3-way MTM project. It is active and DSP controlled.
The bass-mid drivers range would be about 90-1100 Hz.
For the purpose I am using Visaton W17E at the moment.
These are quite good for the money, but I would buy the
Audax drivers if there would be an improvement.
One reason for choosing them is that I don't need to build
new baffles. Also I am curious about them for a long time.
My goal is that they fit well to my Stage Accompany ribbon
tweeters.

I got these data from AARV:
Paramètres haut-parleur de THIELE et SMALL, sans filtre ni ampli
Paramètres haut-parleur de THIELE et SMALL, sans filtre ni ampli

It seems the parameters are the same. Confusing....

I would appreciate any help or insights 🙂

Kind regards,
Christian

The Accuphase E-305 was manufactured from 1987-1991. I have owned this amp for about 2 years, Years before the E-305 I owned an E-303. In between I owned several other amps, tube, SE tube, PP tube, several vintage Sansui solid state amps, vintage Marantz, Luxman and DIY solid state amps I built following threads on DIYAudio. To my ears nothing gives the balanced and detailed presentation like the Accuphase amplifiers.

The amp is nearly 30 years old So when I first received it I replaced all the electrolytic capacitors on all boards. The capacitors were replaced with the same values except in a few cases the voltage rating has been increased.

The E-305 has a phono section, 2 speaker outputs and tone controls.

The amplifier power transformer has a multi-voltage primary that can be wired for 100v, 117v, 220v, 240v. It is currently wire for 117v.

$1950 shipped

Thought this was a nice compilation, which came across my LinkedIn feed:

DIY – Scan-Speak A/S

Best,

E

Hi diyAudio,
I have a Musical Fidelity A3.2cr pre amp and amplifier separates. They are about 17 years old (2003 manufacture). They have never been serviced and I am currently not experiencing any issues (that I am aware of). They get a lot of use ~3 hours listening a day, and I leave them on all the time. They are class A/B and biased about 3watts in A and warm to the touch at idle.

A. is there any point in doing anything before there is a problem? No caps are bulging or leaking.

B. If recapping is suggested, how difficult is it for someone with limited electronics/soldiering experience. I own a Weller soldiering station for the occasional fixing of things

C. If recapping is suggested and I have someone else do it, can anyone recommend a shop in the Chicago area? I am in the NW suburbs but also can deliver downtown.

From my searching, I do not believe there are schematics available for the Musical Fidelity amplifiers. I only know of one shop in the UK that does rehabs of these units and the owner is a former Musical Fidelity technician that opened his own shop. I don't really want to ship 40lbs of amplifier to the UK and back.

Thanks for any suggestions.
Andy

I built two rev 1 LM3875 amps back in the day and was gifted a pair of rev 2 boards that I never built. I have most of the parts necessary to build these save for the transformer and I need an extra amp so I'm looking at building these.

Looking at chipamp.com on the Wayback Machine I came across the rev 3 / carlosfm unregulated PSU. I've come across a few variations of the schematic. Is this rev 3 PSU still the way to go?

My rev 1 builds are using 330VA 25+25V transformers. I don't currently have particularly difficult speakers to drive but would it make sense to use a lower voltage transformer for this build? With Avel Lindberg through parts-express, it seems my only other option would be 250VA 18+18V. Searching Digikey gives basically the same result.

Thanks.

Played around with the FIR Designer M beta

Nice new "Supplementary responses window" option

Fir Designer M beta : “Supplementary responses” window | Timo's World all around the globe

I built a Millett Hybrid Max headphone amp about a decade ago and used a bunch of Black Gate caps. It's been a great amp but I'm ready to move on to other things...I just built the Whammy, and may also build the NuTube headphone amp.

Is there any reason not to desolder the Black Gates from my old amp and use them in new projects? They still function fine, apparently, and regardless of the hype I think they sound great. I know electrolytics can dry up, but I also have a 40-year-old Yamaha receiver that still works great, so I take that with a grain of salt.

When it comes to wave guides on tweeters, I have very little knowledge. I would like to know more.

What is the typical profile of a wave guide? Parabolic? elliptical? exponential?

Do most people fabricate their own, or do they buy them?

Is there a thread on this site which covers the basics? or perhaps on another website?

I've been modifying a cheap commercial 3-transistor phono stage as a little hobby project to see how good it can sound. I've been messing with the RIAA filter lately, but this is a bit hit or miss without having an accurate way of measuring the response. I tried generating a RIAA equalized frequency sweep using Audacity and then playing it back through the phono stage making a recording and doing a spectrum analysis on the resulting recording. The results were not good, they weren't precise enough to really be able to use them for finetuning the response. The best they could do was confirm what my ears were telling me - that there was a slight rise happening from 10kHz onwards and that there was some bass rolloff. But that treble rise for example could've been +0.2dB or +0.7dB for all I could gather from the spectral analysis.

So I'm looking for a way to get more accurate recordings and analysis - basically I'd like to feed the phono stage something (pink noise? frequency sweep?), record that and analyze it in a way that gives me a nice, precise line from 20-20kHz where I can see it's down 0.1dB at 200Hz and up 0.2dB at 2kHz etc.

I'd think this should be relative easy to accomplish using the right tools, but I'm not sure what those might be, so I'm asking if anyone has been through this road (with Linux software hopefully) and to share their experience and what tools they used. Thanks!

Selling the pcb with the transformer and komponents (I think all the komponents on the main ocb)output transisitors .
Sommeone wants to take over this build,inkcluded is the smd protection pcb.

I think a fair price is 55$ + shipping.

Having trouble with this unit and need some help ( schematic is available )

All voltage are present the unit is in mint condition and i trace the problem around TC 9173P and TC 9174P problem is that these seem to be very obsolete plus that it seems that i cannot get any datasheet for them in order to start checking a few things around .


Any ideas ???

Kind Regards
Sakis

Hello is it safe to order capacitors from Justradios.com? And is it true that miec capacitors are good?

Good evening and I hope all of you are staying safe and healthy. I have a few questions that I hope have not been answered already? I am looking to build full range speaker for T.V. duties and low back round music. So here are the drivers am looking at?

1. Alpair 7 and 7MS and 7p and pluvia seven HD 4's and the sevens PHD 4's.

2. Alpair 11MS and pluvia 11's.

I know there is a lot between these drivers as I could guess not all drivers sound the same. I did have a pair of 3 inch blue cone driver years ago. It sound awesome in the mid-range but the highs sounded like it was missing sparkle on top and the bass well it's a 3 inch driver. I have never heard anything new from Mark Audio in years. I am looking at all of these drivers I listed. I need help with the sound and characteristics of his driver's like the M11 means Mono suspension. Does it really make a difference in sound to the other newer metal cones used by mark audio? Also are they bright sounding like other metal cones I have in the past sound like tin cans? Well please let me know? Am kinda excited to start a new project for my bed room and the T.V. Also how are the new paper drivers sound? Thanks Jeff

Hi,

Dual 6J5GT can be directly replaced 6SN7?

So if project use 2 6J5GT, can I use 1 6SN7 instead?

After ditching the idea of using a my higher voltage transformer for a Class A build, a friend of mine has kindly given me a toroidal 300VA 18+18VAC transformer which he no longer needs.

I was planning on starting by building a low noise regulated power supply while sourcing the transistors and other bits for the amp.

Can anyone suggest some options for a Class A design which will match a transformer of this size and output? Primary focus is on the best quality sound, but also preferably something reasonable simple and without really hard to source matched transistors.

Hirage Le Monstre usually calls for 12-14V I think. Would this be too high?

JLH?

Hiraga Le Classe A 20W?

One of the Pass Labs designs?

I am currently an electronics engineering student and doing a project at the moment. My proposed project is this, "Cry Detection System". To detect if a sound is a cry or not, I have already used the neural network in Matlab. Now, the problem is to be able to process the real time recording of a baby (i.e. if the baby is sleeping, I will place a microphone connected to a laptop and leave it there). My solution for this is to divide the input sound recorded by the microphone every 10 seconds so my neural network can process it, but I have no idea how to do it. Any suggestions on how to do this? What software can I use? Or have you guys thought any other way on how to process the input sound? Thanks in advance.

i have for sale my IAN CANADA LIFEPO4 MKI Batteries Power Supply.
batteries are included.
price: 320€ included shipping in Europe.

Hi guys

I am contemplating building a subs using both ports and a passive radiator. The box will be big (circa 480 liter nett.) and my idea is to use dual length ports tuned to both 25Hz and 20Hz. But, since the sub will be capable of it, I want to add a PR, tuned low, for extension below 20Hz. Ports of any decent size for frequencies below 20Hz gets very long. My thinking is that with the ports in the box the PR will be lossy, which is OK, but there will be some additional extension. I might also experiment putting some wool in the ports to see what the effect will be on the PR. My question is just- will it work? My thinking is that this will be like multi-length ports, albeit more lossy in the very low frequencies than ports would be. Any thoughts?

Deon

I formed a simple amplifier to test these compensations. Most of the distortion measured is noise.Output 30Vp
posted order TMC Miller Cherry and mine bellow.




Hayk

So I built this boombox a little while ago and I've been trying to implement a minidsp to get it to sound better. The thing is, whenever I try to eq it I make it sound like crap. For whatever reason, I haven't had this problem with the speakers inside my house, but for this one, since it is portable, I've been taking it outside to measure and eq it. I sit it on a desk and push it to the edge so the desk doesn't reflect, and make sure it's far away from anything outside that can interfere with my measurements. I use a umik 1 mic with a proper stand now and set it up four feet or so behind the right channel of the speaker. I have the mic aimed right at the tweeter where my ear would be while I'm listening. (This is a typical woofer + tweeter arrangement so the tweeter is on top just like a bookshelf speaker) I have the left channel disconnected so it doesn't interfere with the measurements. I can eq it so that it reads within +- 2 db on a graph but it sounds awful, it doesn't sound faithful at all. When I do a frequency sweep manually and listen for how flat the speaker is it's very obvious to me that it's far from flat even though that's what the graph shows. My handheld spl meter confirms this. I'm not sure what exactly I'm doing wrong, I've done this several times and I'm on the verge of giving up and not using any eq at all but I hate leaving performance on the table, especially when I already have the minidsp. I will add that it might be a factor that my enclosures for the drivers are a little strange, the enclosure for the tweeter is separated from the woofer. I'm not sure how much of a difference it makes. So what am I doing wrong? Is there a book somewhere telling me how to properly do something like this?

Hi All,

With a previous speaker project finished and out of the way now, it's time to start on the next project - a large floor standing three way system which has been on the boil conceptually for many years which I now have all the drivers for.

While I wait for a chance to start on building cabinet etc and get more detailed (in box) measurements, I've been spending a bit of time doing some preliminary crossover design experimentation and have run into a bit of a hurdle with the woofer crossover suffering from excessive peaking.

The Woofer is a Visaton W300S 8 ohm, (12") and the intention is to put it into a large bass reflex box of approx 110-120 litres tuned to 25Hz. The woofer will be close to the floor for optimal mid/upper bass performance. Here's a basic box sim in Vituixcad:



I'd describe this as an early gradual roll off response, which is 3dB down at about 35Hz and 6dB down at about 29Hz.

The original intention was to passively cross it over at 250Hz with a L/R 4th order accoustic roll off, but this is proving a real challenge due to the interaction of the woofer impedance.

Here is the current circuit:



The issue I'm seeing is a huge 4dB peak in the filter response centered around 80Hz, along with a minimum input impedance of about 4 ohms centered slightly above this:



This is presumably a combination of the capacitive reactance of the woofer between 50-150Hz, and the low pass filter acting as a resonant impedance transformer - by causing the input impedance to go well below the woofers actual impedance (6.8 ohms DCR, about 8 ohms above resonance) it is effectively "boosting" the filters output 4dB above the input, and obviously this is undesirable.

I was still able to manually tune the response of the filter to get a spot on 4th order L/R accoustic low pass filter response (theoretical target is the purple curve) including predicted baffle step loss, and also a flat summed resonse from about 80Hz up with good phase tracking to the midrange driver, however I'm still not happy about this situation for a number of reasons:

1) I don't like the impedance dipping down to 4 ohms in the bass. Yes a lot of speakers do this (although usually by being a 2 1/2 way or similar) but it's an unnecessary strain on the amplifier and also makes the impedance variation across the spectrum greater thus making the tonal balance of the speaker more sensitive to speaker cable resistance / amplifier output impedance variations, something I'd like to minimise.

2) While my midrange and tweeters are quite sensitive (95 / 96dB respectively) this artificial and unwanted voltage sensitivity boost in the upper bass region of the woofer doesn't leave me with much attenuator wiggle room for the mid/treble networks to get the tonal balance correct, especially when the near floor mounting of the woofer will give it about another 2dB of gain vs the high mounted midrange.

3) The artificial peak near 80Hz completely changes the low frequency roll off shape of the bass, changing it from an early gradual rolloff with a smooth gradual curve to a sharper more abrupt rolloff which is now 3dB down at 56Hz and 6dB down at 44Hz - a far cry from the un-modified driver response of 35Hz and 29Hz respectively. 🙁

So what can be done about it ? In a passive network, not a lot it seems, although I'm hoping someone has an idea I haven't thought of...

A few thoughts:

1) I could in theory add a series tuned trap to notch out the 42Hz impedance peak, however that is totally infeasible as the capacitor and coil values would be humoungous and expensive, with the resistor dissipating a huge amount of power.

2) I could shunt the woofer with say 33 ohms to flatten the impedance curve out a bit near resonance. Despite adding a shunt the minimum input impedance actually increases to about 4.6 ohms due to the impedance transformation effect. This also avoids a capacitor and coil and does give some improvement, however the resistor still disspiates a lot of power at the frequencies where the woofer impedance is high, for relatively minimal gain in the response. (The peak is reduced by about 1dB)

3) I could increase the crossover frequency a bit to get further away from the impedance peak - if I increase it from 250Hz to 300Hz the peak drops by 1dB or so but I'd hardly call that fixed, and I don't want to go any higher than 300Hz.

Other than that I'm out of ideas..... anyone else have any ? And no, "use an active crossover" isn't an option. 😛

It seems that this must be a fairly common problem with passive woofer crossovers ? On my last 2 way design the baffle step correction did interact a little bit with the woofer's impedance resulting in a broad 1.5dB peak around 100Hz, however this wasn't harmful in that design as the woofer was high mounted (being a 2 way) so would usually have a suppressed output in the upper bass due to room interactions anyway.

But in this design I deliberately want the woofer close to the floor for increased mid/upper bass response, so I don't want to add an additional big peak in the midbass due to the crossover itself, and I can't seem to tune out this 4dB peak without destroying the accoustic low pass function.

I just replaced my preamp with a nanoDigi 2x8 so now my Modi 3 is connected directly to a vintage BrianGT LM3875 amp.

When I turn off the amp, I now get a brief pop/buzz sound out of my speakers. I've used this amp with several preamps and have never had this issue.

Yesterday, I swapped the Modi 3 with a Khadas Tone Board and the problem has gone away.

Other than the power off noise, the Modi 3 is normally quiet and well behaved.

Any ideas on why this occurring and how I can prevent it?

Hi all,

I got this above mentioned subject loudspeaker for repair.when I drive 100hz sine wave only upper part of it shows in the output. But when I heat the area near drivers I am getting good sinewave output. I checked all the transistors and resistors and everything seems good. I also checked if vias is trouble and I did not see any broken trace. What could be the reason and how to solve this. Thank you.

Unsure if this is the right place to ask but I have had a few PCB's lying around for years now. Looking to finally pull the trigger and get a build under way but I my electronic knowledge is 0. I can solder, that is all.


Is there some in Australia, preferably Brisbane that can assist with the build. I would of course pay you for your time.


I have the PSU PCBs, Red Baron PCB and Tube-i-zator PCB. I don't have the Salas shunt PCB's but I believe they are easily available.

Hey all,

Its been a while since I've posted here... Life, marriage, moves, dogs, kids, jobs, kid with cancer, covid.... Anyhow, all is well bow and I'm interested in getting my 2 channel system back up and running.

I have ProAc D15s at 88db. I built a 12b4a linestage that was feeding an AR VT100 MKIIs. Sold the VT100 and was using a PP EL34 kit for a while but that is now gone. I have a 10 year old breadboard of a 6sn7>300B>845 but I don't want to work on that now as the voltage scared me back then, and well, its been a while since I've used the solder iron.

What I would like to build is a solid, clean amp to power the ProACs. 35 Watts is decent but for big transitions, having more headroom would be ideal.

As I mentioned its been a while since I've been here. My old brain would tell me 6550 in PPP? What are other options that would suit my needs? What's changed in the past 8 years?

I listen to classic rock, piano, bluegrass, jazz etc.

All help and guidance is appreciated.

Many Thanks,

Bryan

Focal Aria 5 kits from way back in the day, good drivers and crossover, really nice sounding, but now replaced by Focal 936/CC900/SR900. Cabinets are in nice shape; black woodgrain not so exciting methinks. What would a fair price be between friends?

Hello to all,

I have a question: may I replace:
KTC3911S-GR
KTC3911S datasheet

with
2SC2713-BLLF
2SC2713-BL,LF Toshiba | Mouser

Honestly, I don't know too much about transistors.
I checked datasheets and it looks OK, but I am not so sure, so I have to ask.
KTC3911S-GR is SMD version, I will appreciate also standard version through hole.

Thank you for reading and have a nice evening/day 🙂

I'm in the process of servicing this (massive) amp - but I sorely miss a schematic/service manual. - Does anyboby know if it's "out there" - or even better: Does anybody have a copy they could share?

Of course, I have searched the net, but hardly anything turns up, so I'd be glad to get any information what-so-ever.

These are custom machined by Luciano @ Jakeband ( in Italy ).
Google up Jakeband sockets to find his website.
At least as good as Yamamoto. I think a little better.
I have four. These have the gold plated pins. Gorgeous sockets.
$ 95.00 for all four. Shipping included for US only.
International shipping and insurance is on the buyer.
Thanks for looking.

Quiet a few years back I bought as part of a group buy here the Maxxon motor, motor pod pulley, pcb for dc power and 12v battery charger combined
Also have a hifi club acrylic platter and bearing. All are up for sale if anyone is interested. Usual story, never got around to completing project.

Or maybe he says 50Hz, it's hard to tell on this laptop.

YouTube

I’m having a hard time determining the outer foil side of Mundorf 0,47 µF Mcap SUPREME Classic capacitors.

The trick with the oscilloscope (10 mV scale) doesn’t show any difference between connections and the 50 Hz. hum is hardly noticeable when touching the capacitor’s body.

I’m not sure what to do now. Leave it undetermined and just pick a side?

Regards, Gerrit

15"
8ohm

Perfect working order. In VGC.

Was thinking £200 the pair, plus shipping within the UK.
Sending them to the US would be coals to Newcastle [emoji846]

If there's no interest eBay looms!

Regards,
SteveView attachment 858218View attachment 858219View attachment 858220View attachment 858221View attachment 858222View attachment 858223

so i found this obscure buffer while back https://www.diyaudio.com/forums/analog-line-level/26846-simple-discrete-unity-gain-buffer-post316511.html
And have been using it where ever i can with great success. In comparison i find it to sound even better than a jlh buffer and in fact its the best sounding low part count buffer i have tried.

Now id like to scale it up to drive headphones much like the way the dao buffer is used and would like to know how id do that.

Simply tweak the resistor values and use medium power bjts on heatsink? Hmm

Hello,

I’m searching for drawings or advices about how to calculate for a synergy horn fitting two 10” fane sovereign 10-300 and one 1” Sica 120.44/640 Poly. The enclosure should be 660mm wide, it’s the only demand I’ve got since it must fit my subs underneath. Otherwise I’m totally open for suggestions regarding shape or technique.

Anyone got something fun in the drawers? 🙂

Hi Folks,

i have been using Robert McLean's excellent "TransformerModels Rev4.xls" utility from this site to generate output transformer models for LTspice.

Does anybody know how i can modify a model generated (Ham1645) from Mr McLean's data set to provide two separate secondaries ?

i'm trying to simulate the Drake output transformer found in the TVA-1 valve amp from the late '70's/early '80's which has a 0-4-8 ohm speaker secondary and a 0-16 ohm secondary connected oddly to provide negative feedback.

Please see attached circuit diagram.

Thank you for reading this post,

xx.

Vifa P13-WH-00-08 out of spec/not for sale

No longer for sale. Tested Fs, out of range due to aging of surrounds.
Moderators, if possible, please delete posting.

Hi,

I just came across the service manual for the a family of Kenwood CD-Changers

kenwood_1060cd_1070cd_d-r350_dp-r6090_7090_sm.pdf

which is available for download at electrotanya.

It seems they have a chip to compute the bitstream and then two 74HC373 per channel, directly followed by the opamps.

What are the advantages of using external logic gates for output switches and downsides? Why would they use D-flipflops? One would assume it is the preceding chip's business to get the timing right, so if they wanted to get the switches off the substrate, a HC04 or HCU04 should have done the job.