Does anyone have a schematic, (or sell a PCB), for a circuit that can monitor the voltage drop across a 1 ohm sense resistor and output a latched high output if the voltage goes over the pre determined set point? Whereby if the voltage rises over a set point it will output a latched high that can then be used to energize a relay that cuts mains power via its NC contacts. For example your amplifier loses its bias for some reason, your four 300B tubes worth $1,000 start to melt down and you want the whole amp to simply turn itself off. I see that the INA300 chip does exactly what I need, but I don't want to start from scratch on that.

SilentSwitcher - mains-free +/-15V and 6.5/5/3.3V power

Well, I did it! My SilentSwitcher is now live at Kickstarter!
Looking forward to getting this on the road!

https://www.kickstarter.com/projects/1684029908/the-silentswitcher-mains-free-low-noise-15v-and-5v

Jan

I have been designing another small MEH.

So far I have been designing it around the Faital Pro 2fe24 however from doing measurements the distortion is mega high at 10% THD at 10W around 600hz. It's still mega high on less power minimum 2% or 3% THD

Edit: thought I would add that this distortion is even just with a small rear chamber and no front chamber/ports/horn



This is the rear chamber I made for it: (I got the 3d file from Faital Pro and seal it with a small o ring at the top)
It is fully sealed, you can tell because the cone is harder to move than when it's free.



I'm going to borrow some peerless 830970 to try which look a bit more suitable

Does anyone know of any other good drivers that could be used in a MEH that are 2" or 2.5"?

I'm trying to push the mid up to 2.5khz at least so I need a 2" really

Hi all
some years ago I built a couple of 2 way speakers based on mid-woofer SB17NRXC35-8 and a tweeter SB26STC-C000-4.
The cabinet was sealed with a volume of 15L
I enjoyed a lot them, but I feel that bass are too poor. So I decided to realize a new project 3 way that is an extension of that one.
I'm evaluating 2 sub-woofer: SB26SFCL38-8 or dayton sd270a-88 (the first one to be preferred bcause it is 8 ohm).

I designed the cabninet, all SPL response and the crossover. My only problem is that the final impedence seems too low (about 2 ohm expecially at high freq) and I'm not able to adjust it. I tried with LPAD, but I'm not so familiar and I was not able to reach good result.

Can someone help me?

For Sale, pair Acoustic Elegance TD-12M midbass drivers in good contition with boxes.
Price 800 Euros, plus shipping. Only EU please.
https://aespeakers.com/shop/td/td12m/

Dear DiYA members, I have been fomenting this speaker project for the last month and submit the premilinary XO for anyone enjoyment and constructive/destructive comments. Thank you.

Announcement: Audio Widget project

The Audio Widget project is open-source code and schematics for
USB based digital audio. It has functional firmware and software. And
it sounds good!

Cool? You bet! Here you can get started with USB audio without
worrying too much about the USB part of things.

Or you can contribute to a great open-source coding project. The
most important contribution we could need right now is coders for
USB Audio Class 2 drivers on Windows. But other efforts are needed
too. See below.

The code is written in C for the Atmel AT32UC3A3256 32-bit MCU. It
supports USB Audio Class 1.0 and 2.0 (UAC2). On Windows / UAC1 it
works with 24/44.1 and 24/48 with sample skip/insert. Asynchronous
USB is in progress, and we could use your help.

On Linux (>2.6.37) and OS X, using asynchronous USB, it also
supports 24/88.2, 24/96, 24/176.4 and 24/192. The open-source
firmware is in a git repository. It can be selectively compiled to run
on the three different boards. The firmware includes several UI and
display options.

There are three hardware options. The hardware is in a beta state. It
plays music very well, but there is still tweak potential.


1) A stand-alone USB-DAC with stereo audio playback functions only.
This board uses the ES9022 DAC chip. Contact
george.boudreau@YoyodyneConsulting.ca for info on how to obtain
one. More information on the this and other audio designs visit
Yoyodyne Consulting/Audio Hardware

2) USB-I2S module + Analog Board. The module has all the pinouts you
need for digital audio, GPIO, I2C, SPI, LCD display and UART debug.
The module uses 2.0mm pitch pin rows. The Analog Board uses the
module to do stereo playback with an ES9022 DAC and low-noise
VBUS-LDO based power. AB-1 is a straightforward design to begin with,
and if you're into analog tweaking we challenge you to make your own
versions! Schematics and BOM are on
Downloads - sdr-widget - Audio and Control Interface for Amateur Radio SDR and Audiophile USB-DAC - Google Project Hosting.
Go to Q N K T C USB-I2S Module and Analog Board 1 for more information. Contact
borge.strand@gmail.com to obtain a kit.

3) SDR-Widget Beta 2.0. This is the original fork of the project,
open-source HAM radio. The hardware supports both playback and
record. Contact george.boudreau@YoyodyneConsultingl.com for info
on how to obtain one. Visit
Yoyodyne Consulting/SDR-Widget
for more information of pricing and availability.

For more information, go to sdr-widget - Audio and Control Interface for Amateur Radio SDR and Audiophile USB-DAC - Google Project Hosting
and
https://groups.google.com/group/audio-widget?hl=en
This announcement is cross-posted. Please join the mailing lists of
both SDR-Widget and Audio-Widget to continue the discussion there.

SDR-Widget is the original branch, where most of the firmware
discussions take place.

Feel like contributing? We'd always like to see more hands. There's
quite a few tasks planned:

- Firmware for Asynchronous UAC1 / Windows for 44.1 and 48ksps.

- Analog tweaks. Ideas are welcome for PSU, DAC, IVC, preamp etc.
Feel free to make suggestions, or even better, your own Analog
Board for the USB-I2S module.

- Windows open-source drivers for USB Audio Class 2.0. This
protocol is supported in Linux and OS X kernels, but not yet
in Windows.

- Adding more IO control to the firmware


Cheers,
Børge

Rather than muddy my other speaker post I'll ask for answers here.
If I want to play "Mix&Match" with different boxes as Jeff talked about I'll want to put the XO in a separate enclosure and either use it as a base or as a divider and sit the second box on top.

Would the components get warm enough to need a ventilated box?
I've made standalone crossovers before but I've made those in old amplifier cases so I've never had to think about heat issues

안녕하세요 여러분.
이 놀라운 커뮤니티에 가입하게 되어 매우 기쁩니다!


저는 하이엔드 오디오 디자인, 특히 DIY 스피커와 크로스오버 네트워크에 깊은 열정을 가지고 있습니다.


최근에 Accuton 드라이버(C25-6-158, C90-6-079, C173-6-191E x2)를 사용하여 4방향 스피커 시스템을 설계하고 맞춤형 패시브 크로스오버를 신중하게 만들었습니다.
AI(ChatGPT)와 철저한 계산을 통해 부드럽고 자연스러운 소리를 위해 주파수 응답과 위상 정렬을 조정했습니다.


이 멋진 취미를 계속 발전시키고 즐기면서 여기 계신 모든 훌륭한 전문가분들께 배우고 제 프로젝트를 공유할 수 있기를 기대합니다.


환영해 주셔서 감사합니다!

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

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

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

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

When reset is set to GND Fault goes high.

Any suggestions?

Thanks

Ive had my hsu VTF2 Mk3 forever and I kinda wanted something new. Bringing a whole subwoofer from the US (live in Brazil) checked in on the plane is a huge hassle. I know, cause thats how I brought my hsu sub back home. After online dating with Speedwoofers I've decided that it's easier and better to just buy the driver, amp (not sure if plate or external) and assemble it here in Brazil.

I was thinking. If I get a 150ish liters box (not counting the area of the driver itself, potential amp or braces might take), would that be enough for a good response? I live in an apartment, even my hsu sub never ever reached anywhere near its potential, so I'm really not looking to reach some crazy output. My goal is to have an agile that performs very well for music and can deal with a good range (20hz+) for movies and videogames. 18 inches may sound a bit overkill, but since I can't just swap the driver cause I have to fly to America to get another one, I just don't wanna waste the trip.... does that make sense?

I cant get my hands on 0,25mm MDF here, which is pretty much equivalent to one inch thick. I was thinking maybe using the 1 inch thick MDF would make me require less bracing making the build a lot easier?
Also maybe using a external amp could make my life easier too for the assembly and maybe I could save money with a used external amp... I use a Denon 3313 CI. Do I need anything else? Or is it just the amp, woofer and enclosure?

Any thoughts? The Ultimax II 18" measurements made me really excited!!!
Help me out, and if you think something you might wanna point out is too obvious: don't. I'm stupid, go ahead and say it. I'm just an ******* with a dream here.

First, you should know:
I am a seafarer and I spend fully half of my adult life out at sea. I'd like to say it's just a job, but it really does qualify as a life.

Second thing: I built a powered speaker system to suit my job and I'll tell you the things it needed to achieve in order to even make it aboard a ship with me.

1. Minimum weight: check in luggage has weight limits if you aren't filthy rich. I think the whole setup (2 speakers, MiniDSP Flex & cables) is around 25lbs.
2. Small box dimensions: keeping things small is actually a good way to keep weight down as well...less wood, less weight...and Small box means small suitcase witch might also weigh less.
3. Nothing stands proud of the box: it's soo much easier to protect the drive units if the surrounds or domes aren't sticking out into harms way. Just tape a protective piece of cardboard over delicate drivers and done!
4. Wide bandwidth at the expense of SPL: staterooms aboard ship are tiny so no need to get crazy loud....but I still like bass.

The completed package.

More later.

Hi,

To make a long story short, I'm working on a SET design with a slightly complex PSU design (200, 270 and 380Vdc from three separate transformer windings).
I plan to use 2x 6AU4GTA in a hybrid bridge for the 380V rail (@140mA) and I also wish to use vacuum diodes for the other two (20mA and 100mA respectively).
To keep the costs down I've been looking at russian dampers (6D14P and 6D20P) for the input and driver tube supply rails but I can't quite figure out how to interpret the heater-cathode insulation ratings in the datasheets:


Would it be safe (in long terms) to use these tubes as rectifiers up to less than 300Vdc with the heaters referenced to ground?
I could connect the heaters to the cathodes but would prefer not to if possible, no other tubes will be powered by the same heater windings though.

I'm trying to decide on a push-pull amp to start building. I have most of the parts required, including transformers, and a couple of hand-me-down chassis I can use. I was thumbing through one of my old copies of the RCA Receiving Tubes manuals and found this in RC-19:



R18 and R19 (100k) take signal off the 6V6 plates to the 6AU6 driver cathodes for NFB.

R9 and R10 (330k) are a mystery to me. Simulation shows they increase the NFB a little. But how? I guess they feed a little output signal from the cathodes to the grids of the 6AU6s. That would create a little positive feedback, no?

Otherwise the design is straightforward.

I don't have a 9k or 10k OPT, but I do have a pair of 8k:VC OPTs.

The capacitor values introduce high pass filters in a couple of places that result in an infrasonic peak closed loop. I'd increase the values of C3, C4, C7, C8 to smooth that out. Otherwise the design looks well behaved, as the OPT is not within the feedback loop.

I would also improve the power supply; make it stiffer by using UF4007 diodes and bigger reservoir and first smoothing caps, and try to stabilize or regulate the 6V6 screen supply.

QUESTIONS:

• Would it be better to use plate-grid FB around the 6V6 outputs, or is the 6V6-plate to 6AU6-cathode FB basically the same thing done a little differently?
• Is the addition of R9 and R10 a good idea? I've never seen that done in any other amp designs I've looked at.
• I assume using a 6FQ7 or 6CG7 in place of the 12AU7 would be an improvement and would not require much in the way of changes. Good idea?
• I might also try this with EL84 or even 6P15P outputs instead of 6V6s. Thoughts on that? I think it would be an improvement, and they'd be easier to drive as well.

???

A thread to discuss how well a compression driver matches the profile of a particular horn, and how to determine that match - or mismatch.
When choosing a compression driver to go with a particular horn, what is important to know so that the two work well together? Can any driver be used with any horn? Or do some compression drivers work well certain horns and not well with others?

EDIT: April 19, 2023
Attached to this post you will find a spreadsheet, kindly provided by @marco_gea, that allows you to calculate and see the match between a given horn and driver. The spreadsheet takes the parameters of the compression driver throat and calculates an exponential horn that has an equivalent flare rate to the driver throat. With that information you can calculate and see how well a certain expo or hypex horn will match the driver's initial flare rate.
Instructions are included in the spreadsheet.

Obviously the first thing we would look at when choosing a compression driver for a horn is "are they the same size?" In other words, is it a 1", 1.4", 1.4" or 2" entrance to the horn? We normally choose a driver of the exit size as the horn throat. Also to be considered would be the mounting style, such as screw or bolts and the bolt pattern. Adapters can be used for different mount styles and even sizes. For example a common adapter is to use a 1.4" exit driver on a 2" entrance horn. PRV even make a 1" to 2" adapter. But beyond those obvious mechanical matching issues, will a certain driver work well or poorly with a different horn? And how can we determine that for a good match? How do we know the internal geometry of a particular driver?



Horns come in many shapes, sizes and profiles. We might look at a Smith horn that has no vertical expansion at all, but a wide horizontal expansion, to a Kilpsch horn with a long narrow vertical expansion and somewhat wide horizontal expansion - to a long horn that looks somewhat like a trumpet, to the Yuichi and others with mixed expansion.



I'll cite a recent example. Forum moderator @kevinkr recently went thru a good deal of trouble and expense to learn what driver works best for his new Yuichi horns. The Yuichi is a wide horn, but not very tall. In fact the horn very quickly goes to over 90° flare in the horizontal axis, while remaining with zero expansion along the vertical axis for about half its length. The horn is very much axi-asymetric, as opposed to a round horn where the expansion is axi-semetric. Is the horn a rapid expansion, narrow, or somewhere in between? What driver geometry would work best on this horn?
This is what the Yuichi looks like inside.

I recently was glancing at posts and someone mentioned that they had a ZEON based computer with approx 150gig of memory and it was taking several hours to render projects but this was compared to days with a weaker system. I recently was gifted several servers and about a terabyte of ram. Two of the servers can handle 4 cpus. I believe that I can set up a server with 4dies 24cores 48threads and 512gig of memory. The system is absolutely useless for me but it would be interesting to render some of the projects and see how it performs compared to other's systems.

I believe the the model that was being discussed was a wire frame stress model or some such.

At any rate I am requesting some one to tell me what software is needed and offer a project file to be rendered so that we can see the performance.

Jeremy

Greed is killing me 🙂 I bought a used pair of DX3 with one reportedly distorting. A common thing with Lowther needing alignment methought . Yeah, right ! There is nothing to be done except $$$ replacement and I will have mismatched drivers anyway.

I'm looking for a transformer for a Counterpoint SA-100.

Hey all,

I'm working on a new amp build - sissysit24 😉 Zen recommended a choke. I have a few questions - hoping to sort things out.

I read up on https://www.diyaudio.com/community/threads/how-do-you-calculate-choke-size-in-a-power-supply.159832/ which covers this topic but is closed so started a new one.

Assuming I did the math right on things:

1. I think the amp is 25w, need to verify that
2. I think the current draw, based on the 24v 25w would be approx 1 amp ish. ( per channel )
3. Based on the formula I think I would need a 2H choke
   1. (24 / .01)/1200 == 2
   2. I'm not sure I'm doing this right!

I'm a little unclear / hazy on where the choke would be placed. If I am understanding things correctly the choke has an in / out. I would place this choke between the dc + of the rectifier and the + in of the power supply board. Is that right?

I'm planning to use the W12 from @rhthatcher . In this configuration I would end up needing a total of 4 chokes - 2 rectifiers per channel. I think each rectifier would be passing .5 amp - is that right? ( each channel would draw aprox 1 a, dividing that evenly I think makes sense?)

When I go to look for a choke from Hammond the size / current I came up with above don't make sense to me. I think I'm either off on my calculations or just don't understand things well enough yet! If my understanding above is correct then something like Hammond 193NP would be a sensible choice?

Thoughts? Am I in the right ballpark here or off? If there is a thread / doc that covers this please let me know. I've googled and searched but not exhaustive. Most of what I found related to using chokes in tube amplifiers.

The most recent edition of my book is available on my website, ejjurich.com. I discontinued using Amazon. The old print versions were not of the best quality and were printed before text was checked for grammar. Some of the print book covers may make reference to different editions; they are all basically edition one with some updates. There are resellers selling old print copies of Vacuum Tube Amplifier Basics for ridiculously high prices. The current version of the book is available as a downloadable PDF document/eBook file for $12.00. It is also available as a PDF document/eBook on a CD for $15.00.
Why PDF?
PDF documents are readable on just about any device. Unlike standard eBook reflowable formats, content remains static. For technical documents, maintaining a static layout is best. Also, in the PDF, images are mostly color, including project circuit layouts.
Note: The CD version is only available in the US and Canada. The $15.00 price includes media postage.

I am using diyinhk es9038pro DAC board.

PCM I2S connection taked from datasheet.

Then use DSD signal: sound is mono.

I am trying to find solution to change input signal routing using i2c from amanero.

Maybe someone has experience with programming i2c outputs of amanero and can explain me how to write register values correctly in amanero?

I need the resistor and capacitor values for the output filter.

They burned so bad that the relays are also melted and not working!

-

Looking for Bliesma M74B-6 drivers (pair)

Hi,
Before I reassembled those powered speakers after repairing one of them, I tried some so simple mod
to improve THD of each amp section.

This can be applied to a lot of amps, when they cheap out a bit on capacitors in the power section…

To prove my point, I ‘ll run a similar mod and video on a Rotel 840 BX II, which doesn’t have the capacitors mentioned on
the schematic ! Increasing many times the original capacitance feeding the power section, is needed to obtain a meaningful
THD improvement 😊, here between -8 dB and almost -20dB on the best of the two power sections…

I cheaped out myself putting only 470uF on some of the two channels, depending on which one it was…the better one or the regular one, to give them a name 😉.
I certainly could have pushed somewhat further than the -80 dB THD figure , I obtained overall, but felt that was ok for these amps 😉!


Login to view embedded media

Looking for Purifi PTT10.0X04-NAB-01 or Purifi PTT10.0X04-NAB-02 drivers (pair)

SMAPPP stands for Solhagas's MAgnetic Push Pull Planar.
It'll be a line source 224 cm high; 88 inches for you imperials.
I haven't decided yet if it will be a combined mid and tweeter membrane or seperate membranes.
It will in both cases be one frame with one magnetic structure.

I have a couple of design concerns.

First one is the suspension.
Will it be enough compliance if the membrane is mounted between two 2 millimeter thick nano tape and the distance to the active part of the membrane is 20 millimeters away as depicted below?

Looking for Hypex PS500DIY

Anybody has the original crossover diagram ? Not a DIY/clone version with different woofer , not RS1 and not RS1sc but 1S . Also is Proac version of D2010 with or without ferrofluid ? This was never cleared out with all the cloning mania in the past. I know that the tweeter is not the same becuase I substituted one of the tweeters in Response 2s with standard 2010 and it was different . more efficient and raspy
Years ago I built a clone based on Troels project with optional Hiquphon Owi1 (no ferro) tweeter and original woofer and it sounds like a bucket of rusty nails. Speakers are boxed for several years and it's a waste of a nice tweeter.

I am in need of schematic or any other service info please for ML-3 serial number 0223. It does not have dampening switch and only single fuse. I recall 36000 sprague capacitors. Any help greatly appreciated.

Also can anyone refer any good service Techs in my area?

Tim Naples FL

Im selling mundorf BS series coils.
2 x BS140 4,7mH
2 x BS140 12mH
2 x BS150 5,6mH
Price for all 6 coils 150 euro plus shipping. Psyment by paypal.

I made this amplifier for test my home DIY speakers (two way TL).

D4 on component layout wrong polarity, in post #253 is corect componenet layout.

I bought these amplifiers from an old man at work.
He brought them in because he heard i love tubes and he wanted to be rid of the heavy turds at 80 something years old...
I offered him $500 for these and the preamp which was also a diy effort.

The workmanship was poor and the amps didn't work. The boards were a rats nest and the builder used 5 different types of green wire.
I bought them for half of what I figured the iron was worth because I knew i could do something with them eventually.
(The preamp has SUTs)

I drew out the schematic and it did not make sense and it also didn't work, so I knew I'd need to overhaul the whole thing in order to make something worthwhile.
Luckily the A-340 dynaco is an extremely easy to use transformer. I could copy the dynaco mk2/3 but I already had 2x small tube sockets.
Instead I went full Williamson.
I am in fact William's son...
I put 6cg7 in the front sockets for va/pi
And driver.
I built a fr4 circuit board with a bias/balance adjustment pot.
I rewired everything using cloth wrapped wire to Retma color codes.
Now they both fire up and bias in and it's time to put signal through them and start fine tuning them.

Hello all,

My Roland Space Echo Re-201 has an issue, and i’m struggling to troubleshoot. When I have an input plugged into the J3 instrument jack, when the SW3 switch is set to ‘Echo’, there is no dry/direct sound outputted. Please can someone help trace where this dry signal goes on the schematic? The echo signal is outputted on this setting, but just not the dry sound. I’ve been trying to trace, but i’m finding the schematic confusing. Ive been inputting a 1k square wave and tracing with a scope from the OP 13 board to the OP 14B board, i will attach.

I have changed all the electrolytics and this hasnt fixed the issue. I suppose it must be simething else, transitor etc. sometimes when i put a loud signal through it, then the direct appears, which makes me think transistor?
Any help or advice is appreciated, Thank you,

Hi team,

I have a K502 with a quad of 11BM8 tubes (similar to the thread kcroy created here https://www.diyaudio.com/community/...unsure-what-tubes-to-use.290013/#post-4684440 but the B version of it). Bought from Antique Electronic Supply in 2008

While moving I managed to loose the schematic that was supplied with the kit when I bought it so wondering if somebody has the same kit as myself and has a copy of the schematic to spare.

I have found the schematics of other kits (3 links below) and as I see the differences are minor to negligible but would be great if I could have the original to be able to compare 🙂

• https://diyaudioprojects.com/Gallery/displayimage.php?pid=99
• https://diyaudioprojects.com/Gallery/displayimage.php?pid=123
• https://diyaudioprojects.com/Gallery/displayimage.php?pid=368

The layout is identical, pretty much all caps have identical values, just certain resistors are different I presume for adjust the gain between the different tubes used amongst the different versions (10GV8, 11MS8 and 6005).
Small project behind this amp is:

• Do some major cleanup + new case
• Replace the power transformer since now it's 110V and I want to be able to plug it straight into 220V (dual output 11v ac for filaments + I presume somewhere between 165V and 200V for B+ but need to measure)
• Replace the output transformers
• Introduce a bias circuit on the tubes

Thanks in advance for any help.

Hello,

I started studying electronics a few years ago and have recently started repairing equipment for local musicians. This weekend I built a stereo ribbon microphone to mount on top of a field recorder.

Hi. Lately i’m working on an old synth and just for test purposes i’m trying to replace some old transistors. Ordered them from china (they will be with me here in Greece in a couple of months) but i may have a chance to find equivalents locally too.

-The “very” odd ones are the k81 ones. I assume they are similar to 2sk81.
Can’t find any info regarding their pinout in english.
Are they jfet, n channel fet, mosfet, or what?
Some people say that they are close to the j113, with different pinout. What is their type and what is their pinout? Is j113 a correct equivalent, or is there anything other equally mainstream more suitable? Any idea?

-i also look for 2sc2785 equivalents. Similar sources said that bc546 is a good equivalent, with just different pinout. Is this correct? Anything more suitable, equally easy to find?

- And lastly there is a 2sa1175 (as a muting switch i guess). Same sources suggested bc556. Is it ok? Better equivalent that can be found as easily?

Thanks in advance

Hi all,

Attached is a preliminary schematic of a return-to-zero FIRDAC I intend to build. No idea when I will find time to design a PCB, stuff it and debug it, but I'll get there eventually. It will be a DAC that can only handle raw DSD. If it works well I may or may not decide to also make a PCM version that uses an FPGA board to convert PCM to sigma-delta modulates.

The circuit with the stacked dual transistors on page 2 is (or at least should be) a low-noise bandgap reference. I have the concept from D. F. Hilbiber's article in ISSCC Digest of Technical Papers from 1964, see https://www.diyaudio.com/community/...ith-ic-voltage-regulators.359652/post-7021353 It should have better noise performance than almost all modern bandgap references, because those almost always amplify a V_BE difference by a large factor instead of stacking V_BE differences. Only half the transistors are needed; I can't predict whether the BCM56DS or the NST45011 stacks will work best and they don't have the same footprints, so I want to reserve space for both.

The reason I can't predict whether the BCM56DS or the NST45011 stacks will work best is lack of information about the base resistance of the BCM56DS. It's a matched pair of medium-power transistors, so chances are that the base resistance is low, but I can't be sure of that. The NST45011 is specified to have a 1 dB typical noise figure at a 1 kohm source resistance when biased at 0.1 mA, which implies a base resistance of about 130 ohm, which is not bad but not very good either. (There are matched transistor arrays from THAT and Analog Devices with good and clear noise specifications, but I find those much too expensive.)

The fifth page has a clock doubler and a return-to-zero circuit, among other things. JohnW doesn't like the RTZ circuit I used in 74AHC02 and 74AHC08 DAC with 97 dB(A) dynamic range because he is afraid that the switching of the flip-flop may disturb the gate output signal when the flip-flop isn't slow enough. To avoid that issue, in this circuit, I split the RTZ logic from the actual DAC.

74LV574A's connected as shift registers on the third and fourth pages are the logic circuits used as DACs, they have low-noise reference supplies that are separate from the RTZ logic supply. As they run on a doubled clock and there are zeros inserted between each pair of data bits, simple shift registers work as RTZ FIRDACs. It's like the DSC2 DACs, but with return to zero. It's a balanced four-tap FIRDAC, balanced to keep the load on the reference supply as data-independent as possible. For matching reasons, I've connected the 74LV574A flip-flops in an ABABABAB style, with a second 74LV574A in BABABABA style.

Regards,
Marcel

Edit, 12 May, 1 October, 14, 15, 22 November 2022, 1 and 12 February, 26 May, 16 July, 1, 3, 6 and 8 August, 17 and 18 September, 15, 17 and 22 October 2023, 6, 10, 21, 29...31 March, 1, 8 and 15 April, 2 and 18 May, 28 July, 26 October, 1 and 7 November, 2, 3 and 9 December 2024 and 9, 11, 15 and 16 January 2025:
See posts #20 and #21 for the version (DAC3_5.pdf) I built and did some measurements on (using NE5532's rather than OPA1678's in the filter because the latter were out of stock), see post #1931, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7483396 , for the latest BOM and schematics, and see post #241 https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7175580 and its links for the latest layouts. The latest schematic versions are DAC3_10_holdtimefix.pdf and DAC3filter_6.pdf. Versions 9 and 10 of the DAC layout (with or without hold time fix - the fix only consists of four resistors with updated values) are meant for 0.21 mm PR7628 prepreg, the earlier versions for 0.36 mm. See post #272 https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7182183 for the (old-fashioned) KiCad files.

I corrected the literature reference in this opening post.

Measurements:
The most relevant measurements are in posts #35, #60 (noise floor), #75, #79, #88 and #764 (distortion and noise floor driven from an Amanero), https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7403333 The measurements of post #764 were done by Hans Polak. Some measurements by bohrok2610 on a variant of the DAC can be found in post #955, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7417293 and post #1090, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7419240 , and an overview of measured noise floors in post #1092, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7419247 It seems that the noise floor is quite sensitive to far-off phase noise and spurious tones on the clock. Later measurements by bohrok2610 on his variant with an improved board layout can be found in post #1928 and a few posts below it, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7481890

See also bohrok2610's measurements on low-signal-level distortion and 10 kHz distortion starting at post #2467, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7635702

For comparison, using the same sigma-delta modulator, the DSC 2.5.2 has low-level distortion with a similar looking spectrum, but about 20 dB worse, see https://www.diyaudio.com/community/threads/simple-dsd-modulator-for-dsc2.370177/post-7407497

On the other hand, ska managed to make a DAC with a similar spectrum but about 20 dB lower distortion products, apparently using a very simplistic approach. The sigma-delta modulator design is different, so the difference might be due to the DAC itself or due to a different dithering scheme in the sigma-delta modulator or both. The information about ska's design and layout is sparse, but there is some information spread out over posts #3834, #3837, #3844, #3847, #3850, #3851, #3863, #3865 and #3887. See also ska's thread about the same DAC, but with a better sigma-delta modulator, https://www.diyaudio.com/community/threads/discrete-fpga-dac-project.407618/

The measured noise of the bandgap reference with BCM56DS is smaller than the calculated noise with the NST45011, so the BCM's are the winner. Hence, in version DAC3_9, the NST45011's have been removed.

Hold time fix:
Measurements from Markw4 showed that the delay of U22, U24, U26 and U27 was only 1.7 ns, shorter than the anticipated typical delay and quite close to the 1.5 ns minimum hold time required by the SN74LV574As. Reasons may be the fact that I designed the circuit using TI data but switched to Nexperia for U22...U27 because the TI parts were not available, and that U22...U27 see a smaller capacitive load than the 50 pF used for the datasheet measurements. To fix this, R124, R127, R129 and R131 have been increased from 39 ohm to 270 ohm.

The prototype is fully functional with the original 39 ohm, with 270 ohm and even with 560 ohm. This last value is not recommended because it could lead to set-up time issues, I just tried it as an experiment. The noise floor with 270 ohm resistors is in post #1927, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7481723

Supply currents:
The measured supply currents of the prototype at 27 Mbit/s are in post #88, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-6999623 Add 50 % to have some margin for exemplaric spread.

Supply sequencing:
There are some supply sequencing requirements, fortunately ones that can easily be met. Again see post #88, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-6999623 , for details.

Alternatives to components:
The TQ2-12V relays can be directly replaced by Zettler AZ850-12 relays, which are sold by Conrad (among others).

The latest filter design has NE5532's instead of OPA1678's in the second and third stages of its schematic, because the prototype also used NE5532's. Both should work, as the filter was originally designed for OPA1678's.

The OPA210 and OPA2210 could be replaced with OPA209 and OPA2209, respectively. They are very similar, although some specs of the OPA209 and OPA2209 are slightly worse. If neither OPA2210 nor OPA2209 is available, OPA1602 should also be usable as an alternative.

Header length:
The headers connecting the filter PCB to the main PCB have to be relatively long because of the height of the capacitors used in the reference buffers. I hope the ones suggested in the latest BOM are the right size, I guess they are as I didn't get any complaints.

Skipping the last filter stage if DC offset doesn't matter:
You can skip the last filter stage if some DC offset is acceptable, for example because the offset is blocked somewhere further down the signal chain. On the filter board, you can then skip U₆ and U₁₃ with the surrounding components and connect the outputs of U₅ and U₁₂ straight to the 49.9 ohm resistors. Ray (nautibuoy) made filter boards without the last stage, see posts from #647, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7365893

Output signal level:
A 0 dB DSD sine wave produces a differential output voltage of about 2 V RMS.

.dsf test files:
See post #762, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7403044 , for .dsf files with repetitive silent patterns, these can be useful for measuring just the analogue circuit noise (without the effects of the ultrasonic quantization noise). See post #2610, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7643831 , for a Pascal program that generates a non-repetitive silent DSD512 .dsf file. With small modifications, the Pascal program can also generate a tone.

The program and .dsf file attached to post #2696, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7652259 , are meant for checking to what extent a DAC generates intermodulation products between idle tones around half the sample frequency.

Variants:
Besides Ray and his simplified filter board layout, there are three others who designed variants:

post #429, PCM variant for Raspberry Pi by Thorp, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7272503

posts #955, #1923 and #1928, single-board version by bohrok2610, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7417293
https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7481890

post #1847, latest version of Markw4's mix and match between my DAC and stuff from Andrea Mori and others, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7455840 See also his summary post #1880, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7457164

bohrok2610 did some experiments with the filter to reduce the harmonic distortion at 10 kHz from about 0.003 % to even less, see post #2238, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7620060 for an overview, and see post #2380 https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7625079 for information that is more recent than the overview, and that seems to refute my hypothesis in post #2238, although a later measurement seems to confirm it.

The schematics of the filters he tried are here: https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7635719 and here (well, a description actually): https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7680453

He also did many most interesting experiments related to distortion at low signal levels as well as 10 kHz distortion. There is a whole series of posts related to this, starting with post #2467, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7635702 An attempt at explaining the results can be found in my post #2485, and an extended and updated version in the pdf file attached to post #3265, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7686002

Markw4 made a DAC board layout with some extra test points, see post #2620, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7645321

Hans Polak suggested making the FIRDAC longer by cascading the two SN74LV574A's. A longer FIRDAC is less sensitive to the phase noise floor (not to be confused with close-in phase noise), but doing it according to Hans's proposal has the disadvantage that the suppression of data-dependent reference current gets worse. A calculation shows that the suppression around odd multiples of half the sample rate (where you need the suppression most because of idle tones) theoretically remains intact, see post #3428,
https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7729904 All in all, I cannot predict whether Hans's version would be an improvement or a degradation.

If you are good at lifting SMD IC pins, it can be made on the original PCB, as Hans pointed out in post #3433, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7730150 He explained in more detail how to lift pins in post #4038, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7887181

2A3SET tried Hans's suggestion and subjectively likes the result, see post #4047, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7896594 More information about 2A3SET's set-up, including a fully passive reconstruction filter, can be found in posts #4052 ... #4060.

Calculations:
The way the original filter was designed is documented in sections 1 ... 5 of the attachment of post #3028,
https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7672339 Section 6 contains calculations on how to combine a passive LC filter with an MFB stage.

The attachment of post #2269, https://www.diyaudio.com/community/attachments/jitterfirdac_en-pdf.1282828/ , might be useful for people who want to design longer FIRDACs.

Quasi-multibit digital sigma-delta modulator:
The low-level distortion products bohrok2610 found do not occur when the digital input signal comes from a properly dithered quasi-multibit modulator. See post #4043, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7895559 for the latest version of an implementation on a cheap FPGA.

Suggestions for further improvements:
Even though the DAC works quite well, there are suggestions for further improvements all over the place in this thread, too many to link to in this opening post. I've commented on some of them in post #3526, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7747974

As mentioned, another potential improvement would be to make the FIRDAC longer to make it less sensitive to the phase noise floor (not to be confused with close-in phase noise). When this is done by using longer shift registers while keeping all measures to cancel out data-dependent reference current in place, it should reduce the audio noise floor you get with an imperfect clock.

Hello from an audiophile DIYers team who also happen to be metallurgists and have put a lot of energy and resources to produce the purest possible silver conductors for audio. We do not want to breach any forum rules, we just hope to inform the members (and we have some members here in our team) of our presence and answer any questions they may have.

Are you old enough to remember LEAP 4? only the best loudspeaker design program ever written IMHO.

If so and you want to bring back the good old days of DOS, you can now run it on your window machine, cracked and ready to go. Please see my post in the general loudspeaker forum for details and BTW, someone just posted a LEAP 5 crack .... Good times and thank you Chris Strham, you were brilliant and I cherish our many conversations.

Hi everyone,

If you recall, I'm a big fan of XSim, but I'm embarking on converting a 2-way (AMT tweeter + 6.5" mid-woofer, ported) to a 3 way with the addition of a bass cabinet and 3-way plate amplifier. I took my original FRD measurements for the tweeter and mid, and have spliced in the Dayton reference data for the woofer. None of the levels or delays are probably accurate, they are just here to see how far I can get in this design while I consider whether or not to proceed.

Based on my good luck with LR4 in my center channel I'm trying to use that slope again here. Ignore the phase plots, this is VirtuixCAD under Wine/Linux so the graphics are not 100%.

Thoughts?

Hello everyone,

As mentioned in an old thread from years ago, running this program on newer Windows versions is nearly impossible. Additionally, the original installation files are no longer available on the official website and you can no longer purchase it.

After searching through my dad´s old computers, I found .iso files of the program and was able to make it work NO USB KEY needed. This has been tested and confirmed to work on:

• Windows 11 (64-bit)
• Windows 10 (64-bit)
• Windows 7 (32-bit & 64-bit)
• Windows XP

For proof, I recorded a short video demonstrating all three programs running on Windows 10 (64-bit) -> Video link

Installation Steps​

1. Download the "LinearX Leap5 + FilterShop.rar" uploaded to Google Drive. It contains two folders: "LEAP" and "FilterShop".
2. Extract the .rar file and move both folders to C:/Program Files/.

• Inside the "LEAP" folder:
  • LEAP_XVR.exe → Crossover Shop 5.1.0.334
  • LEAP_ENC.exe → Enclosure Shop 5.2.0.350
• Inside the "FilterShop" folder:
  • Fshop.exe → Filter Shop 3.4.0.808

You can create a shortcut for each executable by right-clicking the file and selecting "Create shortcut" to place it on the desktop.

Important: Fixing the "System Error: Number Decimal Symbol is Not a Decimal Point"​

Before opening the programs, it is necessary to change the decimal symbol in Windows from a comma (",") to a dot ("."), as the software requires this setting to function correctly.

Steps to change the decimal symbol:​

1. Open Control Panel.
2. Navigate to Clock and Region → Change date, time, or number formats.
3. Click Additional Settings.
4. Find the "Decimal symbol" field and change it from , (comma) to . (dot).

These steps apply to Windows 10, but the process is similar on other versions.

To simplify the process for everyone, I decided to upload only the necessary files—this way, installation is as easy as copying and pasting folders.

Greetings from Argentina!

Over the last week or so I have been working on my 1995 Wadia 16 CD player that stopped working back in 2007 and has been languishing up in my attic for more than 7 years. It worked fine for 12 years then suddenly crapped out. I opened it up back then and poked around, but without the prospect for obtaining any kind of dealer or factory support (Wadia was in and out of being a viable company for years), I quickly abandoned my effort. I remember being really pi$$ed off that a $7000 CD player was essentially junk because some tweaky high end "company" knew how to design, but wasn't so interested in the business aspects of running a company; a hobby run amok. If it hadn't weighed 45 lbs. and was in outwardly mint condition, I might have thrown it out in the trash along with a case of Budweiser to ease the pain of the garbageman.

To make a long story short, the 16 is back up and running perfectly. There were a couple of minor issues including a dirty laser, but nothing that was a show stopper. Troubleshooting analog is one thing, but with the advent of microprocessors and FPGA's, modern electronic equipment is becoming more and more non-user serviceable. Thankfully all of this was in good shape, along with the transport, even after 7 years of zero to 100+ degrees F and wide humidity swings.

I think a lot can be said of Wadia's attention to detail when compares the Teac VRDS servo PCB to the Wadia PCB. The Teac isn't even close.

In the end, the last thing that needed to be done was re-solder the servo board digital output shielded cable that runs to the Wadia digital IO board. I broke it loose at the servo board end when I unwisely attemped to remove the bottom chassis plate which has the servo board mounted to it. You get to the servo board from the top. Since I had no idea where it was soldered to I figured I'd email Wadia last Friday and ask them if they had schematics and assembly drawings for the 16. Based on what I've read here in the DYI forums and elsewhere, I wasn't expecting even a reply from them, but it took little effort to at least try.

Wouldn't you know it, they not only replied, but sent me PDF's of all the schematics and drawings they had on the 16! Now that's customer service!

A while ago, I got similar results from Krell, so I also have complete schematics on the KRC preamp and the MDA 500 amps if anyone needs them.

Regards,
Doug

For sale 4 pairs tube adapters.Like new used verry short time and verry good quality.Buyed by Banzai music Germany and Tube Town Germany.
Price for all 8 is 120 euro or best offer plus 7,90 euro tracekd shipping inside EU!The last pair adapters are for 6sn7 to 6f8g!More info on contact.

Verry good tube amp transformer for sale.Zransformer with copper shild and specifications that you can see on picture.Price 100 euro including shipping to EU with tracking and insurance.Payment by Paypal.More info or offers on contact.

One pair, like new, only few weeks old. Price 50 euro plus shipping.

Hello. I'm a new member here, longtime lurker.
Audio science, snake oil, subjective, objective - it is all of interest to me.
Mostly interested in learning about tube circuits and modifications to said circuits to substitute one tube for another. Too much to learn, not enough time. Thanks

Greetings to all and thank you for giving me access and any guidance you can provide

I didn't find a lot of information out there on this topic. How can I switch out a 30uH inductor for a ferrite bead? I did a little searching and it looks like the low pass capacitor going to ground becomes quite a lot smaller (instead of around 1uF after an inductor, with the ferrite bead that value becomes 0.001uF). But is that all? Are there any other considerations (for it to function)? I did see in the datasheet that layout runs must be compact to the chip. I also saw that it must be able to carry enough current and must go to around 120 ohms at 100MHz.

Welcome to SylphAudio thread!

Our New Product Release Roadmap for 2024



****

SE800 PFFB High Power Class-D Amplifier
Supply Voltage: dual ± 25V min, ± 85V DC max
Unclipped Power (<1% THD+N, ± 85V): 350W-8Ω, 700W-4Ω
Input configuration: Single Ended
Output configuration: Single Ended
Input sensitivity (PFFB): 2.6V RMS
Voltage gain (PFFB): ~25dB
PCB area: 140mm x 70mm
Overvoltage Protect: ±88V to ±91V DC
Undervoltage Protect: none, UVLO @ ±12V DC
Speaker Protect: none, requires external SP

Can be used with a 2Ω load if powered with a lower power supply voltage around ± 60V DC, can reach 800W output (< 10s burst signal).
Designed with PFFB to reduce load dependency and improve noise and distortion. 5W at 4Ω THD+N is around -82dB, with THD at -94dB.
Rugged and super-stable PFFB design based on TI, implementation by SylphAudio.

ETA: Jan 2024

Sample pictures



FB100 and FB360
We've applied the largest feedback factor possible without reducing the output power capability. Which results to exceptional performance.

FBUltra
Under development, composite OPA1612 and LM3886 design.

Sdudio monitor speakers. Simply the best.

Originating from a user of the German HiFi-Forum. Very solid database imo. Includes HiFi and PA. You can also submit your own entries.

https://diyspeakerdb.com/

1pc 2SK180 NOS TOKIN V-FET(SIT) Original, Made in Japan, similar 2SK77 | eBay

watanabetomoaki | eBay

Find this 2SK180 Tokin sit's seller in Japan.

Shipping cost are not high. Any Diyer know & try his batch of hockey puck's ?

EDITORS NOTE: This is the single depletion mode Mosfet amp that Nelson Pass demonstrated at Burning Amp this year. END

Nelson Pass said:

I just opened an unexpected arrival from Jon this morning....

Click to expand...

After seeing this, who can resist?

(Tea-bag, thanks for the photo)

Nelson Pass said:

It's worth noting that I am considering some other tweaks
on this as well.😎

Click to expand...

J-fet CCS? 😎🙂

Uk, need Mylar 4/6/12 um: where to buy ... ??? thank you for any help.

I have some spare parts if someone has a whammy board and they need a good deal on some parts to get them going. This has MOST of what you need to get the power supply completed.

What is included:
- brand new Talema 18VACx2 25VA transformer

- all the heat sinks (low profile)

- 6 Panasonic 3300uf 35V caps

- 4 IN4004 diodes

- 4 5.1 ohm resistors (for the CRC psu)

- red LEDs

- 2 pairs of different 220uf caps

- a pair of Nichicon UEH bipolar 22uf caps

- opa2134 opamp

- a pair of 1uf poly caps

- assortment of Vishay/Dale RN55 1/8th watt resistors.

I am asking $60 shipped and will throw in some Mogami wire.

Unfortunate work circumstances force me to sell of some DIY parts. I am selling the whole setup below for $325 shipped Conus. I did a rough estimate and sourcing these parts brand new would put you around $450. Keep in mind I only have the 3 pairs of daughter boards.

Here is everything you get. Keep in mind some parts have been used, some brand new, and the m2x boards untested.

• Two Triad VPT36-4440 (2x18VAC 160VA) Transformers (USED)
• Four diode bridges using MBR20200CT (USED)
• Two Power supply boards with 60,000uf per rail and CL-60 installed for GLB (USED)
• Two M2x boards with 6l6's DC offset modifications (NOT TESTED)
  • Edcors installed with Copper Strips
• Three Daughterboards - Norwood, Ishikawa, and Cedarburg (BLANK)
• Set of Gold Plated Binding Posts (NEVER USED)
• Unmatched set of IRFP240/IRFP9240 Mosfets (NEVER USED)
• Pair of Gold Plated RCAS (NEVER USED)
• XRK's Daughterboard testing PCB (NEVER USED)
• Mu Metal to cover the Edcor Transformers (to shield the Edcors)
• Spade connectors for the M2x boards and the diode bridges

Some of these parts will show wear from storage or use, but I can guarantee the diodes and PSU's work perfectly. I replaced all of these parts with SLB boards which is why I no longer need them.

Every year I use dumpster parts to make a garden system for the summer. I live in a block of 5 apartment with a communal garden & a bunch of neighbours who love to barbecue! The system only has to last the summer. I don't care if it gets broken & abused.
The first 2 years I made 2.1 systems using D3116D2 chip amps using a laptop PSU - they worked well.
Last year I went in a different direction . . .
DVD / Blueray Receivers have one moving part that is guaranteed to fail. When that part fails they are worthless. You can pick them for $5 - $20.
What remains is a remote control USB player (possibly with Bluetooth) & 5 or 6 amplifiers and an active crossover in a single box,
I picked up an LG HT902PB - 1000 watts (yeah, right). The garden sounded great: a 10" sub & four bookshelf speakers.

In helping my small business friends out, I have installed faulty DVD receivers in two local restaurants & two hairdressers.
These units have untold hidden benefits, not least the ability to control the volume and delay of individual speakers is something you are unlikely to get on even high-end commercial systems.

The tolerance is also impressive. The subwoofer channel claims to deliver 255 watts into 3 ohms, so I guess there'd be few problems running two subs off the one channel.

After modding a Marantz CD63 and a CD67OSE I decided to make a list of all the various mod's I found here and elsewhere on the internet.
I'd like to donate my files to this forum, for all to enjoy! 😀

Of course I do not pretend this list to be complete.
This is all I've done to the players so far and more good tips are welcome!

Greetings,

Ray.

Very small PCB based on Yorkville Amps.

Where to buy transformer laminations, magnet wire and bobbins, preferably in Europe?
And . . . whatever happened to delatsch.com ?
Delatsch sells transformer winding spreadsheets and used to sell all the materials needed, like laminations, magnet wire etc.
but now materials are removed from the web shop.
Little use then by buying the spreadsheets if the needed materials are not available for sale.

Attached is a scan of the NAD 3150 Circuit Diagram, which is of good quality.

I have 4 NHT1259 drivers for sale. I purchased these from Madisound back over 25 years ago, for an isobarik subwoofer project. They were (and still are) highly regarded drivers. They have about 100 hours of use, as they have been in storage for the past 20 years. I no longer have the space to store them.

They weigh over 4 Kg each, so shipping costs will be significant, so a local pickup (south-west France) would be ideal.

I will consider any reasonable offer.

note: photos only show 2, however the other two are in identical condition.

Hello,

New to this forum!
I’ve been trying to fix my Poly 61- the transfomer gets hot when switched on (i heard a bang near the power supply side one time when i was fitting a Midi kit) i have descovered this only happens when under load when other boards are connected, and the bridge rectifier gets very hot, so i’m convinced its this that is at fault. After connecting another board to the supply and taking chips off to lower the current load, the transformer cools and the bridge rectifier still gets very hot. I could’nt find any shorts on the other boards.
In the schematic, you can see this part is connected on the secondry side, and is labelled D3. I will attach.

Please can someone advise me which replacement bridge rectifier part to get? I’m unsure what the numbers mean, and the schematic power supply page is unreadable, it just states the part as 4B4B41?
I’m not sure how to test these components also, and if it is at fault, then it might be tricky to buy another seen as this one is at fault? Will a generic bridge rect diode part work as a replacement? I’m cautious of buying another part and using as it could cause more faults (and obviously dangerous), i’ve spent so much time trying to get to the bottom of this and I can see light (maybe) any help here to advise would be appreciated, thank you


Kind regards
Connor

SOLD -thanks for looking

For those interested, here's an opportunity to save a lot of money. I'd like to get rid of some capacitors that I have left over from various projects.

Mundorf MLytic 10.000 uF / 35V 2 pcs.
Mundorf MLytic 15.000 uF / 50V 1 pc.
Nichicon Gold Tune 10.000 uF / 50V 5 pcs.
Nichcon Gold Tune 4.700 uF / 50V 2 pcs.
Panasonic EEUFS1C512L 5.600 uF / 16V 20 pcs.
Panasonic TSHA 4.700 uF / 35V 2 pcs.
Panasonic EEUFR1H221B 220 uF / 50V 20 pcs.
Kemet LH 4.700 uF / 63V 3 pcs.
Panasonic TSHA 5.600 uF / 50V 4 pcs.
Panasonic EEUFR1V222L 2.200 uF / 35 V 6 pcs.
Panasonic EEUFM1V182 1.800 uF /35 V 6 pcs.
Yageo A750KK477M1AAAE016 470 uF / 10V 6 pcs.
Panasonic 16SEPG270W 270 uF / 16V 6 pcs.
Panasonic 16SEPF150M+TSS 150 uF / 16V 6 pcs.
Panasonic PLG0G182MDO1 1.800 uF / 4V 20 pcs.

New completely 254,9 Euro -so now I ask for the half: 125 Euros plus shipping.

The expected shipping costs can be viewed here (select parcel up to 2 kg including tracking): dhl.de

Due to the current customs chaos, I would only sell them outside of Europe subject to checking the effort involved.

The capacitors are new, guaranteed to be genuine, not from Ali or eBay (or similar). They are stored under good conditions, in a well-tempered, smoke- and pet-free environment.

The buyer receives some additional capacitors for free.

I recently bought a Pioneer PL-5. I got it hooked up and found that it didn't play speeds properly. I found a couple YouTube videos that addressed this problem. I took the turntable apart. Cleaned it, oiled the motor bearing, cleaned all the switches and pots with contact cleaner so and so forth.

I put everything back together and tried it out. I was able to adjust the 33rpm with the adjustment pot, but I couldn't get the 45prm to adjust at all and runs too slow. The speeds will would skip fast for a second and the back to normal and there is an audible noise as well when it happens.

I have a feeling that I will need to recap the circuit board, But I wanted to see if anyone else had any other ideas before I start doing that. Is it even worth the trouble recapping it? This isn't my only turntable and fortunately I didn't pay much for it.

Any input would be great!

Thanks

Hello All, I recently was gifted AR 8B bookshelf speakers. Of course the foam surrounds are dry rotted and I have the kit to refoam the woofers.
While I am doing that I got inspired to tweak the crossover thinking that i can improve the sound over the original. The woofer is running free-range with no LP filter. The tweeter uses a 5.0 uF capacitor only. Per what I posted below, it sounds like this was done as a cost-cutting effort and not necessarily to deliver the best sound. I'm thinking a 12 db per octave LP crossover at 2000 Hz is a good idea to prevent distortion. According to AR, the tweeter has an "effective" rolloff of 18 db at 2000 Hz using the single 5.0 uF cap. Should a more sophisticated HP filter be used incorporating an induction coil and a cap, and should the HP filter use a 12 db/octave slope as the tweeter was designed to have a natural rolloff giving an effective 18 db/octave slope? Or should the HP filter use a 3rd order filter? Please advise, the more I look into this the more I am getting confused! Thanks!

"The two-way AR8B is the smallest and least expensive speaker system in the current Acoustic Research line. Like all AR speakers, it is an acoustic-suspension model, and it has a newly designed 6-inch woofer that crosses over at 2,000 Hz to a 1-1/4-inch “liquid cooled” cone tweeter. (The tweeter presumably uses ferrofluid or a similar material to damp and cool its voice coil.) The crossover network has been simplified and its cost reduced by designing each driver to have a natural rolloff outside its operating frequency range. As a result, only a capacitor is needed to protect the tweeter against damage from powerful low-frequency signals. The effective crossover slopes are 12 dB per octave for the woofer and 18 dB per octave for the tweeter."

Click to expand...

I thought that I should share my recent amplifier build:





Single-ended 6S41S cathode follower amplifiers that deliver 7 W each. Here is the schematic:



Running the output tube as cathode follower gives a very low output impedance for a single-ended amplifier. These amplifiers can drive difficult loads, but the concept has its cons. The output tubes need over 500 V peak to peak to deliver full output. The driver tube 6E5P-I is a small power tube with high amplification when connected in triode mode. It has a gain around 50 and can deliver quite a bit of current. By using an interstage transformer, I can get the required voltage swing without a very high supply voltage. Also, I step up the signal 1:2 with the interstage transformer and I also step up the signal with 1:2 with the input transformer.

The sound quality is great. It is most certainly the best-sounding amplifier that I have tried with my current speakers.

A couple of years back I scored a decent pair of the old RadioShack Optimus 8B speakers for $50- with some other stuff tossed in for free
Somebody over at AudioKarma was desperate for a set of the mid range and tweeters so I took them out and flipped them [ at a reasonable profit] and the boxes with that great woofer have been sitting in the shed for a long time and I have no idea what to do with them now.
The boxes are in excellent condition although missing the original grill, which I suppose is why they were only $50-
I'm at a loss as to how to proceed so I'd appreciate some thoughts and inspiration from the collective minds of the forum members. I haven't actually finished anything since I made that huge 18" part sub and I am feeling frustrated
Edit
Nova 8B

TI high power amp chip from tpa3251 family

They are in a plastic tube and have been since I bought them about 10 years ago from Digikey. Shipping would be from Germany.

I would like 100 euro for the lot with shipping on top.

I will post photos later.

Thanks

I'm into Audio of all sorts, and have to do most of the repairs myself as it's almost impossible to get any repairs done specially to vintage stuff. This site has valuable information.. Thank you

I'm wondering if there is someone out there that has a working amp circuit board for a realistic sta 2700.

I'm looking to build an Aleph Mini, currently trying to gather parts to order, for now I have found:

https://www.ebay.co.uk/itm/266392011176?mkevt=1&mkcid=1&mkrid=710-53481-19255-0 - the pcb
https://www.ebay.com/itm/156560013829 - mosfets
alternatively, but I'm not sure if it'd be quite right - https://www.ebay.com/itm/115126018088?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=wGG0QMocRHa

https://a.aliexpress.com/_EIU0SPC - enclosure

I'm just not quite sure about the PSU, what board / transformer should I use, and how to wire the potentiometer, switch.

In my search for a monster open baffle woofer I stumbled the W21 21" open baffle woofer. It looks interesting but the more I research Lii Audio the more something seems off. I cannot find much objective information on them. Most of the people talking about them seem to have conflicts of interest. Then I found there are more than one version of this driver....some may even be copies or made by another company?

The driver on Alliexpress looks very different from the one for sale on lii-audio.com website.

The first one seems to have a single voice coil, the latter double. The first one has a lowish QTS of 0.39 and MMS 201g while the other one sports QTS 0.82 and MMS 644g.

Normally I would assume the Alliexpress is fake but then I read this by caisson rj:

I am happy to see some people talking about Lii Audio Xizi founded in 2006 and Lii Song founded in 2016 which is a copy of the original Lii Audio. I visited both headquarter in Hangzhou and it was clear to know which one fake it. If you hold both speakers in hands it's is really obvious. The short story is that Xizi Lii Audio hired one guy to expand the business outside china and that guys screwed him and founded Lii Song and took the foreign market. There is currently quite a lot of new drivers made by Lii Audio that are coaxial drivers that are simply harder to copy for Lii Song so in the future you will see more and more drivers that Lii Audio will only sell. I am talking 21 inches coaxial stuff, premium range etc.

CAN SOMEONE SET THE RECORD STREIGHT? SHOULD I BOTHER WITH ANY OF THESE DRIVERS?

ALSO...IS A 21" DRIVER WITH A 201g MMS even realistic?

https://www.aliexpress.com/i/1005003529835421.html

https://www.lii-audio.com/product/w21/

Does anyone have experience with any of the Lii audio/Lii Song 15/18/21" woofers?

Some sound clips of this speaker recorded with my phone and powered by my SuSyLu 100w Class A amp:

Test of SuSyLu 100W Class A Amp - YouTube

Example of speaker in dark “espresso brown” stain and satin lacquer with Duratex coated baffle.


Example of beautiful build by as8912:


Another Example of a floor standing FAST TL by Plott:

This is a great shot of the internals as provided by Plott:


Example of a floor standing TL version of this speaker by Moutik:


Example of a smaller sealed version with PS95-8 full range drivers by Jimk04, here.

I wanted a speaker design worthy of the exceptionally high performing ScanSpeak 10F/8424 Discovery 3.5in full range driver. I decided that a short sealed Dagger TL coupled with a sealed bass unit would give me the best overall transient response and clarity. I decided to mate the 10F/8424 with the superb Dayton RS225-8 aluminum cone woofer for bass duties. The design ended up as a 24 liter volume for the woofer and a 1.1 liter 3-sided pyramid Dagger for the 10F/8424. The important external dimensions are: 10.0in wide baffle, 7.5in CTC distance from woofer to fullrange, and 24 liter internal volume (sealed). You can make the height and depth to suit your individual case, but it will need to be deep enough to house the Dagger. The internal dimensions I settled on were 8in wide x 12in deep x 16in tall.

However, if you make it out of 18mm plywood like the ones I had my cabinet maker build - make the box using these dimensions.

Dimensions of sealed box version: most important is to make the width 10.0in (external) and CTC spacing between drivers 7.5in and adjust the depth and height so that you have about 24 liters volume. If you make it out of 18mm plywood it ends up about 18in H x 13.5in D. The 10F is located 4.5in top to center. You will need a rear chamber for tweeter (fullrange) so use a sports cone or wooded “Dagger” tall 4 to 5 sided pyramid. Stuff Dagger and main box with polyfill or fiberglass to taste.

New SketchUp Plans by @jrKC for sealed version here.



The short sealed TL is made of three 6in wide x 12.5in long triangles. Construction will use 1in thick pink XPS foam and regular foam core for the short TL. The front baffle will also use a thin sub-floor plywood in order to provide adequate support for the heavy 8in driver. The design will have the option of a bass reflex vent that can be sealed for use with a Linkwitz transform, or opened up for some additional bass when group delay is not an issue. The system will use miniDSP for XO and EQ duties and bi-amped. Here are predicted results in 4pi space with baffle step and diffraction effects accounted for. XO will be at 500Hz with 4th order LR. The RS225-8 is an exceptionally flat response driver and choosing a slightly higher XO frequency will keep the distortion on the 10F very low while giving more weight to the mid bass as it comes from an 8in woofer. Calculations show that with Linkwitz transform, bass extension should be about 42Hz (f3) with max SPL around 101dB.

SPL vs freq for sealed case at 24v (no Linkwitz transform) - the hump at 2.5kHz is the baffle diffraction:



Impulse response for sealed case:



Group delay for sealed case is 2.5ms at 100Hz and 5ms at 50Hz:



For bass reflex option, here is SPL vs freq at 24v:



Here is group delay for bass reflex (2.5in dia x 11in long vent - rear firing) case, not too bad actually (about 10ms at 50Hz)



Here is the Sureply thin baffle with driver holes and drivers to show basic look:



Here is construction on XPS enclosure beginning:



Here is the enclosure with Dagger TL internally mounted and bracing, wiring, and terminal cups installed:



Currently waiting for liquid nails glue to dry...

Edit April 27, 2015: New LR2 XO @350Hz and new sound clips of many different genres. Have a listen, this speaker sounds fantastic!

10F/8424 & RS225-8 FAST Ref Monitor - Page 2 - diyAudio

Here is the new LR2 XO @350Hz:


Update April 30, 2015: New Butterworth 1st order linear phase XO (BW1 XO):


Phase for BW1 XO:


Step Response for BW1 XO:


200Hz Square Wave with BW1 XO:



1.6kHz Square Wave with BW1 XO:



New sound clip with 1st order BW1 XO: http://www.diyaudio.com/forums/atta...or-10f-8424-rs225-8-fast-bw1-350hz-clip-b.asc

Edit May 14, 2015: Stereo Pair completed!



Edit Dec 16, 2015: forgot to post final lock-down configuration with Harsch XO:


IR:


Step response:

More info on final setup here: 10F/8424 & RS225-8 FAST Ref Monitor

Distortion:


Group delay about 5ms at 50Hz:


Edit Jan 5, 2018: using passive 1st order transient perfect XO for past 2 years.


Recent implementation with film caps and air core:


frequency response and phase using passive XO:


Impulse and step response:


Latest tweaks to the passive 1st order XO with simulation files:
10F/8424 & RS225-8 FAST Ref Monitor - Page 95 - diyAudio





Edit Dec 3, 2018: BOM for XO is here.

Edit: Dec 27, 2018 - Wxn just built a pair using SB23NRXS45-8 and TG9FD-4 with DSP from a DCX2496 here. The results look great and he did a great job on the cabinet:


Nice waterfall:


Edit: Dec. 27, 2018 - I should have mentioned that Aatto built a nice set using the SB23NRXS45-8 with 10F/8424 as well but using a bass reflex box and miniDSP and also with passive XO, but can't remember what he is currently using here:


Also, forgot to mention the nice set with RS225/10F that I built in espresso brown stain - these are working out real well as the WAF is excellent as evidenced by the fact that they are upstairs next to the TV 🙂 :


And of course, here is my current setup. These have been my main speakers for over 2 years now and, I keep coming back them because they sound so nice and balanced. The sharp percussion and wonderful stereo imaging also bring me back. Here they are in my speakerlab, now re-done post basement flooding (back in July 2018) with a new engineered wood flooring, so the echos are a mess and sound treatment is definitely needed now that carpet is missing. Looks nice and clean though - the clutter is building up again (mostly foam core speakers in storage around the corners).


Edit Dec 16, 2019: Thanks to JPS64 for making a super layout for the XO PCB. This will make building this speaker that much simpler.


Edit Dec 21, 2019: new TL floor stander for RS225:
10F/8424 & RS225-8 FAST / WAW Ref Monitor

Measurements of TL here.



Edit Dec 22, 2019: Just wanted to remind folks that there was a design made for this speaker XO with an RS100-8 and RS225-4 here:
10F/8424 & RS225-8 FAST / WAW Ref Monitor



Edit Mar. 20, 2020: Revised plans for the TL in all 3/4in BB plywood.


Photo of the TLs in action next to the sealed version:


Edit March 30, 2020: Vistaton B80 Variant with modified XO



Edit May 19, 2020: this is the XO for the 4ohm RS225-4. You can use your favorite 8ohm 3.5in full range on top. Just make sure it’s 8ohms and adjust R1 to taste.



Edit July 24, 2023: Keantoken developed a crossover specific to the TC9FD-8 to be used in this speaker with the RS225-8. The response looks very smooth and has a wonderful step response. More info here:

https://www.diyaudio.com/community/threads/10f-8424-rs225-8-fast-waw-ref-monitor.273524/page-196

Schematic:


Measured frequency response appears to have 1st order XO near 1500Hz.



Nice stuffing/padding plan collected by GUJoe: