Hello all. I am building my first, but definitely not last tube amp. Very little idea what I am doing. A lot of it is still magic to me so I will try not to frustrate eith my ignorance, and research previous questions so I don't duplicate. Looking forward to understanding some of what I am told!

Looking to get some help on a Sony TA-E901 Pre-amp repair! Thanks for this forum.

Ex Australia.
They are 8 ohm. Used in pairs in the 801D4:



I have 4 for sale.

Pictured left- a normal 10" woofer (Peerless)
Right- B&W 801 D4 woofer







I'm not sure how to price these.
I don't really want to sell these- but they are better off as musical instrument in a good home, rather than an enormous paperweight / museum piece at my place.

All stored properly.
Made In England.
Build date 2022.

I will measure the shipping box dimensions and weight and update the post ASAP.

?Offers until they are gone.

Hello! I'm looking for a schematic for the Krell showcase or S-1500 amplifier. Krell service will not sell me one.
I have a non adjustable DC offset caused by the driver board. The driver board has nearly 60 surface mount transistors and diodes on a multi-layer board. Must be some type of servo-control of DC bias. This is most complicated driver board I've seen in my 40 years of repair. Thank you for reading!

Box full of parts, the usual and maybe some not so usual
Transformers, capacitors etc....
Prolly at least 1k$ worth
Hope to give them to someone that is broke and could use the stuff

Hello Audio Enthusiasts! Some of you may know my work on www.audiocircuit.com, where for many years I have been helping to advise Acoustat owners. I was an engineer and manager with Acoustat, starting when the David Hafler Co bought Acoustat out of bankruptcy, right up to the very end of US production under Rockford Corp ownership (sad day that was!). So I thought I'd lend a hand here, too, because I LOVE Acoustats and want to help as many owners as possible to keep their Acoustats running for many years to come. I don't sell parts or do repairs, but my advice is FREE! So let me know how I can help YOU with your ACOUSTAT's! (And this being a DYI crowd, I don't mind discussing modifications to the speakers.)

Andy Szabo

Hello,

The circuit in the diagram works with symmetrical supply. How can I run it with only a 9v battery?

Some time ago I purchased a box of 6P43P pentodes.
At the time there was little data and no plate curves available on these tubes and I was not too sure what use they could be put to.
As they were under a dollar each I figure what the heck.

Running the 6P43P thorough my uTracer3+ with 200V on the screen it provided over 200mA of plate current at -6V on the grid.
That is way ahead of a 6BQ5 in terms of delivering plate current and it seems these could drive lower impedance loads than the suggested 6BQ5 8K PP load.
The plate curves also looked pretty linear with very little kinking at low plate currents.
A data sheet value of 12 watts plate dissipation and 2 watts screen dissipation also looked good.
Va maximum is shown on the data sheet as 300V same as the 6BQ5.

The 6P43P bias point for 35mA plate current at a Vs of 250V is Vg1 of -26 volts.
The 6BQ5 under the same Vs=250V, 35mA plate current requires about Vg1 of -9.5 volts.
The 6P43P gm is stated as 7.5mA/V and the 6BQ5 at 11.3mA/V
So it would seem a 6P43P is going to require 8.7dB more drive voltage and a input stage gain increase over a 6BQ5 design.
To keep the design small and simple I decided to limit the front end to a single stage.
I also wanted to use significant amounts of local feedback to reduce the total global feedback required around the output transformer to improve stability.
That meant I would need a lot of gain in that single gain stage. I figured I would need over 44dB of input gain.

A pentode stage can provide a lot of gain however the output impedance tends to be higher limiting bandwidth.
A triode with this type of u did not seem possible.
Cascode stages can provide a lot of gain. One has to be careful of the output impedance or bandwidth will be limited.
In a Cascode stage total gain is largely a function of S in mA/V of the lower device divided into the top load impedance.

This means S, load impedance, bandwidth and gain can be traded as required.
The higher the tubes S the lower the load impedance can be and so the wider bandwidth for the same gain.
As I wanted a lot of gain and wide bandwidth I looked for the highest S tube I had on hand so the load impedance could be as low as possible.
The 6Z51P pentode operating in triode mode measures a S of 18~23mA/V with Va=85V and Ia=7.15mA.

Two tubes were arranged as a LTP. With a load impedance of about 23K ohms two 6Z51P operating in triode cascode mode yielded a balanced stage gain of 53dB and produced a balanced output of 48.7 RMS, 0.4% THD @1K with no feedback.
The low 23K total impedance provides wide bandwidth.
I used a pair of BJT for the top of the cascode.

This balanced input stage is coupled to a pair of 6P43P in PP using UL feedback for the screens with fixed bias.
The PP load impedance is 5K ohms and the plate supply is 330~342V.
The screens are feed from a regulated 275 volt supply and capacitor coupled to the UL taps on the transformer.
The amount of UL feedback was selected to result in 208V on the screen at the full power at lowest plate voltage point of the output swing to insure adequate plate current was available for full power output.
The bias is fixed and provided from a regulated power supply.

The result was surprisingly good for a pair of under 1 dollar tubes.

THD at 1 watt 1Khz was 0.0119%
THD at 1 watt 20Khz was 0.083%
THD at 1 watt 30hz was 0.0998%

THD at 19 watt 1Khz was 0.09%
THD at 19 watt 20Khz was 1.01%
THD at 19 watt 30hz was 0.599%

After finishing my 4-ways and using them for several months with a 8 channel DAC/DSP based on 4 cheap $2.00 PCM5102A boards, I decided to venture into electronics design for the first time and try to build a decent 8 channel DAC/DSP.

My system is all active, so crossover duty is performed by a Raspberry Pi 5 running CamillaDSP. The key concepts of this new DAC/DSP are:

• Modular design: Each major part has its own PCB. This increases repairability and upgradability, especially important for a first timer.
• The Raspberry Pi must not be on all the time. I've encountered corrupt file systems more than once on power losses, so I decided to add a controller circuit that will turn on/off the pi. I decided to go with an Arduino Nano for this.
• The Raspberry and the MCU circuit will be powered by a 5V 5A SMPS of good quality. A 5A linear PSU would be too expensive and/or complex for this project.
• A linear PSU with active noise cancellation will power the DAC boards, (both digital and analog parts), the galvanic isolator output side and 12V trigger out.
• To avoid noise from the Raspberry into the DAC (through I2S lines), a 6 channel galvanic isolator circuit will be part of the I2S signal path.
• There are 4 DAC boards. Each is basically a set of 8 TDA1387 in parallel (like the ones as used in ProtoDAC) with an active I/V stage using 2 NE5534 and a relay based muting circuit.

Major components of this project:

• A IEC socket with a switch, fuse and a CLC EMI filter
• A meanwell RS-25-5 SMPS (5V 5A)
• A 220VAC -> 12V-0-12VDC toroidal transformer (custom made from a local supplier)
• A Linear PSU with 3 rails (+5/+12/-12), each rail with a de-noizator active noise cancelling circuit, all on a single PCB
• A Raspberry Pi 5 running CamillaDSP and other support softwares
• An Arduino based system control board, on its own PCB
• A Raspberry Pi shield with a galvanic isolator for the I2S signal and a serial connection to the system control board
• Four TDA1387x8 stereo DAC boards, each on their own PCB
• Several minor components, like a two color LED power button, shielded cables, connectors, etc.

I am not aiming for ultra high end. I just want a decent NOS multichannel DAC with DSP capabilities, all in a single box.

In the next posts I'll describe each of the circuits, providing Kicad schematics and pictures of the populated boards. Here are the boards as they came from JLCPCB. Black one is the linear PSU, blue is the control circuit, green the isolator shield and the white ones the 4 DACs. Their build quality is amazing!

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.

Being a pretty much beginner in audio amplifier building scene, here is a simple discrete amplifier I designed in Ltspice. I have not yet built it, but will plan to do so as soon as I have a free weekend (or two). There are most likely many technical inaccuracies concerning this design, so if there is something I should change in the schematics or do differently, I would be glad to hear your suggestions.

The component selection is based on what I have on hand.




The schematics, only one channel shown 🙂







I ran some simulations as well, here is the response curve...







... and the THD data at full power. It gets down to 0.002% and less at smaller output power levels.

System won't let me stay logged in. Help?

Hello everyone.

I would like to create my own stereo system from the WONDOM JAB3+ 2x50 W amplifier board. I have 4 speakers, 2 woofers and 2 twitter (see image), which supposedly support 50 W. These speakers were part of iLoud Micro Monitor.

I'm not sure how 4 speakers are connected to this JAB3 amplifier so that the frequency separation is correct. Could you tell me how to connect the 2 woofers and the 2 twitters to JAB3? Will I have to use a separate circuit to separate the frequencies? Could you give me a diagram with simple instructions?

Regards.

Very cute little DC/DC converter module 🙂
I've bought it from BangGood for about 30 euro, including the shipping to EU: Riden RK6006/BT
This is suitable PSU for it: RD6006 or RD6006W Switching Power Supply 400W 60V

There are good reviews for it on the WEB, but not so much info in this forum.

The main difference with the bigger brother RD6006 is the absence of battery charging and the time/date setting.
With my Android 14 phone and their Android App I couldn't connect to it via the BT...

Here I reworked and uploaded a simple Python module for controllling it: RK6006 Python Module
This Python module allows to read and control the following options:
- Switch ON/OFF the output and read the state;
- V&A set and read Voltage and Current;
- Output read Voltage, Current and Power;
- OVP and OCP set and read Voltage and Current;
- Read the output Capacity(in Ah) and Energy(in Wh) from the switching-on of the module;
- Read the Internal and External temperature in Celsius and Fahrenheit;
- Read the Protection Status: Normal, OVP, OCP;
- Read CV/CC output mode: CV, CC;
- Switch ON/OFF the Take Out option and read the state;
- Switch ON/OFF the Boot Power option and read the state;
- Switch ON/OFF the Buzzer and read the state.

There is some kind of slew control and settling times for both rise and fall with different currents is about the same and is 200ms.
There are no overshoots on enable/desable the output, nor on changing the output voltage.
There are some small spikes on the output voltage, when step changing the load.

Hello all I'm wanting to start a new project but need a little help from someone more experienced in reading and creating schematics. This amp The Shell Manhasset or 2020P is one I own but it has some issues and I'd like to recreate a simpler version of it. What I want to do is remove some of the bells and whistles so to speak. If someone could look at the schematic and redraw it with only one input and remove the loudness, low pass filter, and all the selector knobs. As well as the electric eye circuit to make it a basic amp it would be greatly appreciated. I know it's asking a lot but I thought maybe someone would like a challenge. Oh and there is a mistake in the schematics which show 12ax7 12au7 12ax7 as the drivers but they must have made changes at some point because the amp actually has 12ax7 12au7 12au7 tubes in it as well as factory printing on the amp matching that. Not a big deal but thought I'd mention it.

So anyone up for the challenge ?

I was absolutely surprised by how the sound changed for the better. The Fosi Audio ZD3 plays like a top-class DAC.

Hello!
I am building a speaker/sound trailer for my bicycle, to use at events/large rides/etc. And I enjoy EDM and techno and bass and want it to succeed at that.
I asked a question about what to build (with photo and description of build) on reddit (www.reddit.com/r/SoundSystem/comments/1eia1kb/looking_to_upgrade_my_bike_sound_system_with/) and got several recommendations for a tham15. (And similar responses in the 12v sound system Facebook group) Details of my setup in the Reddit thread but I have a 2x300, 1x500w amp with the 500w channel unused


I read a bunch of things (references below) and have the below plan - and am hoping someone will chime in if it's a bad idea!
I'll buy:
1 sheet 3/4 ply:
https://www.homedepot.com/p/SANDEPL...ual-0-709-in-x-48-in-x-96-in-454559/203414066
Standard wood glue
15" driver (see questions)

Then using the the plans below cut everything out with table saw and miter saw (except for the horn baffle), glue together all but the side panel... and then pray.

Question:
1) Does this plan make sense? Would you recommend a different speaker or plan for my setup? My focus is on using my unused 500W channel to have a good sound at 50hz, and then being lightweight, small, and cheap - with about equal importance for those three.
2) I'm debating on what drivers to use. Looking through recommendations on the forums, what is currently available, and is less than $350 I see the below drivers, and would be curious which you would recommend? I know these aren't the features I need to look into - but I'm not sure how to read the other specs well enough to make a determination myself.
Dayton Audio 15LF: $150, 22lb
Eminence Kappalite 3015LF: $289, 10lb
Eminence Kappa Pro-15LF: $209, 25lb
PRV 15SW2000: $189, 30lb
B&C 15NDL88L: $350, 15lb
3) Is the finishing/paint/seal on the outside important to the sound? What do you recommend doing? (I'm looking for fun, not professional, look)
4) would getting a dsp be essential?

Thanks!


References and what I got out of them:
The design and discussion, people have strong opinions on reflectors but as a newb i shouldn't do them:
https://www.diyaudio.com/community/threads/tham15-a-compact-15-tapped-horn.175658/
Wood glue is fine:
https://www.diyaudio.com/community/threads/what-is-the-best-adhesive-glue-for-speaker-boxes.312142/
Ideas for drivers:
https://www.diyaudio.com/community/...or-tham15-x4-from-a-single-20a-outlet.385960/
I probably shouldn't do 1/2in ply but maybe it's ok especially if I do a cubo?
https://www.diyaudio.com/community/threads/tham-15-cutsheet.408349/page-2
Maybe I could do a cubo
https://autoconfig.freespeakerplans.com/plans?view=article&id=44:cubo15
https://forum.speakerplans.com/cubo15-vs-tham15-measured_topic104372.html
https://www.diyaudio.com/community/...uper-scoop-and-folded-horn-subwoofers.231894/
What is a folded horn, tapped horn, scoop (post 12 especially)
Cutsheet:
https://forum.speakerplans.com/uploads/12282/Cutting_Diagram_for_THAM15_MK1.pdf
General discussion of tham15:
https://forum.speakerplans.com/martinson-tham-15_topic53906_page1.html
Reference drawing of tham15:
https://www.martinsson.cc/blog/index.php?entry=entry090721-180410 - the horn mouth baffle is the only one that needs to be cut

KSC2690A-Y NPN active product
KSA1220A-Y PNP END OF LIFE product.

For sale:
KSA1220AYS ONSEMI PNP - 160V -1,2A 175 MHz hFE 160 - 320
TO126 isolated
Packaging: bulk
ORIGINAL PHOTO.
1 set 50 pcs = 40 USD + Shipping cost 7,75 USD ( registered priority , cardboard box + antistatic bag ) .
If you buy 2 sets or more shipping cost is free.

Regards
Robert

Hello guys 😉

This is my current project. Its a MiniDSP style active crossover heavily inspired by Cyperpits Octavia. Its still a work in progress and most of all a experimentation/test bed for me to learn how to design audio electronics.

It's based on a ADAU1466, similar to what is used in the fusion amps. The goal is to have a stereo analog input, SpDif in and out as toslink and RCA, 8 analog outputs and a trigger out to wake up amps as signal is detected.

For now I have only finished my "DSP core board" The DAC's and ADC are just cheap aliexpress modules for now. I almost finished my own DAC and SPDIF-out board based on the PCM5102A's. The ADC board is also conceptually done but still needs a lot of schematic and pcb work. This is what it looks like on the inside.


When I get my own DAC and ADC board the connections to the DSP board will be done via ribbon cables with every second line being GND to ensure good signal integrety.
I designed it this way with seperate PCB's as it allows me to focus on one thing at a time without making it unnecesarily tight and expensive to iterate. I can then try different DAC's or ADC's at a later time without having to pay for a new DSP chip and vice versa. It needs a fairly big box to allow all the connections on the back anyway.. Each pcb is 99x99 mm so they stay in the cheap range at JLCPCB. Its a 4 layer PCB with SIG on top, GND, POWER and SIG/GND on the bottom. Im currently using a Wondom ICP5 to program the DSP instead of the expensive USBi as I had it on hand. However, I hope to be able to make my own USB programmer based on the freeusbi and integrate it on the board eventually. But the software part of that scares me a bit as I have zero idea how it works with windows drivers and whatever..

It all started because I was playing around with a Wondom Jab5. I really loved Sigma Studio but I really did not like the wondom quality. The noise floor was unacceptable and eventually one of the amplifier chips on the board just died.. Having fallen in love with sigma studio I couldn't just go with a minidsp and my fusion amps also do not allow you to use sigma studio even though it is beeing used behind the scenes in both devices. I couldn't find any other product with less questionable quality than the wondom or the likes...
So I got the brilliant idea of making my own xD
As a Mechanical engineer I knew that I was waaay out of my comfort zone. However, thanks to opensource projects such as FreeDSP, analog devices excellent documentation and engineering support, and youtube channels such as Phil's lab it seems it may actually be possible for me to make something that works 😍

The DSP board is working and the overall unit performs surprisingly well. I belive the limiting factors currently is mostly the ADC and to some extend the power delivery for the ADC's which will be much improved in my own design. However, I have some wierd issues that I am currently trying to trouble shoot:

1. When the ICP5 is connected I get a lot of audible noise in the speakers both white noise, a whine and some kind of periodical ticking. It goes away when the programmer is disconnected again. This was also the case when using wondom dsp's with this programmer. Im not sure if it will be different with a USBi or if its something with my design. I was considdering to add some kind of isolation between the ICP5 and my DSP but was afraid to overcomplicate things in the first go.
   Any ideas how to get rid of this? it is a bit annoying when experimenting in sigma studio.
   
   
2. I get a bit of noise and a periodical clicking noise as soon as I connect my AC/DC adapter. Even though my DSP is turned off (I only break the positive line, the negative is connected directly to the DSP board) and no source is connected. This is the adapter i use: Ac-adapter-100-240v-to-12v-3a-dc
   I also tried a 7v mean well one, while it gets significantly better its still there. Not sure if theese adapters are simply not suited for audio, or if my power interface is to simple. with limited knowledge on this matter i pretty much coppied the Octavia power input with some small changes (added a fuse and a diode to the reverse polarity circuit).
   
   
   
   
   
3. I am having some wierd EEPROM issues. Most of the time it works as intended but sometimes it just refuses to write the program to the EEPROM. The wierd thing is I do not change any settings related to the EEPROM to stop it working or to get it working again. It seems pretty random. Its not related to on time. Can this be a SPI noise thing? related to the ICP5 (guess not because sigma stuido can talk to the DSP just fine)?. Faulty EEPROM?

Please critizie all you want, I want to learn from this 😀

Yesterday I listened to a Youtube of 2019 BAF where Linear Audio was presenting and Nelson commented that he wanted to redux The Beast and would appreciate lower cost JFETs that did not require lowest noise figure.

Has there been any discussion about possible configurations of The Beast using parts that can be acquired from Digikey or Mouser?

I have been thinking of possible parts to use and running parts through the curve tracer. More parts on order to also run through the curve tracer.

A possible proof of concept would be a 200mA bias version for a headphone amp.

The JFETs will like have to be SOT23 package. I have an initial favorite for both N and P. I will post measurements when I have all the measurements finished.

My thinking is to cascode the JFETs using the hockey pucks from the F4 Beast. This will allow using higher Idss JFETs and operating the JFETs at ~3V Vds and also operating the JFETs un-degenerated. Most of the heat winds up in the pucks.

The voltage rails can be normal First Watt rails if desired.

Just getting started with possibilities.

Anyone here ever use a spare audio amp as a sort of 'bench power supply' for a second amp?

I'm a city dweller and the power line at my place wanders constantly. I would love to have a regulated 120Vac source of power on my bench. I've got a spare Hafler amp sitting around (lol doesn't everybody?) and a couple of filament transformers I can run backwards to step up to 120... hmmmm... I bet it would work...

After more than 25 year of inactivity and building my first speaker more than 50 years ago, I'm planning to try it again and build an open baffle 3-way system... but I can not decide on the coaxial. Would love to use the B&C 12CXN88 but unfortunately it is way over budget. I have an alternative list but can not decide:

B&C 12CLX64: https://www.bcspeakers.com/en/products/coaxial/12/8/12CLX64
Oberton 12CX: https://www.oberton.com/en/products/ferrite-coaxials/348-12cx.html
Lavoce CSF122.50K: https://lavocespeakers.com/single-product/?id=217
Celestion: FTX1225: https://celestion.com/product/ftx1225/
BMS 12C262: https://bmsspeakers.com/index.php-130.html?id=bms_12c262

For bass I will use two SB Bianco 12OB150's (U-frame).
Coaxial will be on pure open baffle, 18 inch wide.
No DSP or anything complicated just passive XO (I have limited knowledge 😉 ).
Input and comments welcome. Thanks.

hello Jean Michel

i think your horns deserve a exclusive thread at this forum , where all related issues can be discussed, questions made and be answered, and contribute to common knowledge about your horns.

maiby someone else wants to start with the first questions.

Angelo

Does any one know what’s the part number for those regulators IC10, IC15 and IC16….amp is an AudioPipe

I have a power amp I ALWAYS run from a Variac as it is designed for 115v and my wall voltage ranges from 120-125v. I have a Kil-a-watt on the Variac so I can ensure I am delivering 115v. I also know, via kil-a-watt, it draws just under 2amps.

The Amp has a 5amp slow blow fuse.
The Variac has a 5amp fast blow fuse.

In the past couple months I have blown a several fuses in the variac. This has never happened before and now it seems to be a chronic issue.
After first fuse replacement the amp ran fine for 10 or more hours.
After the second fuse replacement the amp ran fine for an hour.
I opened up the amp and checked values and voltages - everything seems fine.
Powered it on and it ran for a few hours and blew the fuse again

Tonight I made a Dim Bulb tester using a 300w incandescent bulb.
I powered everything on and the bulb had a slight glow and amp ran fine.
I then put the Kil-a-watt after the bulb and powered everything on; the Kil-a-watt showed under 100 watt. Turn the Variac to max and still only 100 watts.

I'm assuming I should have gone with a larger bulb but also not entirely sure.
My goal was to run it connected to Dim bulb and when the amp acts up I would see a change in the glow and could investigate.

So ultimately, what size build should I run?

Dear Hive mind,
I am restoring/reapiring a Nakamichi BX300 and need help.
The cam controller that sets the transport to allow play is not allowing the deck to enter play mode. It keeps scrollling all the time. I need to know how to "register" the cam in the correct position.

While doing this I have broken a wire (Arghhh!!!) and now can not find where it broke off. It is a white wire from the connector that also services the wires for the cam switches. Can anyone tell me where it goes please?!
Pictures attached, I hope they help.
The cam motor no longer works since the wire broke, but it is not the power wire, I tried that.
Thank you

For sale gold seal triode TO-3 imported power amplifier tube, MJ21194G MJ21193G MJ21193 MJ15024G MJ15025G MJ21195G
have ON and Motorola
old used and new
Please check out the photos below

I bought these new from Bloom Audio and have used them in my Miro DACs. I have abandoned opamps, for now, so someone else should enjoy these.

A pair of Burson V7Vivid (single): $60 plus shipping
A pair of Burson V7Classic (single): $60 plus shipping

PayPal F&F only.

Hello, is there any way to check for transistor wear?

The measurements are fine on measuring instruments, but the oscilloscope with Lissajous figures shows erroneous images.

This amazing little amp has been discussed as part of the DB thread but I think it deserves its own thread given how it has quite different objectives from the Pocket Diamond Buffer (PDB) HPA.

This desktop variant uses TO-126 output BJTs with dedicated heatsinks and does not have the separate MOSFET rail switching needed for the pocket one. The setpoints have been optimized for a moderate 40mA nominal bias current that will let you run in full Class A operation for most headphone uses. It will leave Class A around 250mW into 32 ohms. Of course, you can adjust the emitter resistors to run higher bias currents. I have used it with +/-9v, +/-12v, +/-15v and +/-18v supplies and they all work great. It was designed for 15v rails but I don’t think performance suffers much from using lower voltage. For your particular use case you may want more voltage. High impedance 300ohm cans like more voltage, for example. There is lots of room for input cap rolling and I have used huge 4.7uF 400v MKPs and also smaller 0.47uF film to bypass 10uF Elna Silmic electrolytic caps.

Here’s a photo of a built up amp board in operation:

With larger MKP caps only:


I initially struggled with an oscillation but chased it down to a feedback compensation cap that was too large. That’s all fixed now rock solid. A stability analysis on LtSpice pointed me in the right direction. So the schematic shows a 470pF cap needing to be replaced with 47pF. It’s an easy swap and I’ll do this on the SMT pre populated boards that I will be offering in my shop. I will also have bare PCBs for those wanting to assemble it themselves.

Here is schematic for the overall amp, very simple. Power supply in, audio in, audio out and volume pot with MicroMatch IDC cable to an RK09 pot helper PCB (included).


Here is schematic of the Diamond output stage:


Here is a SMT prepopulated PCB so all you need to do is to install all the through hole parts:

Both sides:

Here is the board assembled with big 4.7uF MKP caps:


Standard BOM calls for ECB pinout TO-126 BJTs (Toshiba TTA004 and TTC004) but if you have some classic Toshiba 2SA1837 and 2SC4795 (BCE pinout) you can mount them in the bottom like I did here - leaves a cleaner look on top giving you lots of access to the parts:


Testing on the bench:

Nice low distortion but second harmonic dominant distortion profile for 1Vrms into 33ohms:

You will find that this headphone amp sounds very natural and clean, but has an incredible power reserve to deliver bass slam while maintaining great control authority of the driver transducer cone. It’s a wonderful headphone amp to listen to for hours. For normal headphone use (under 500mW power) basic AC/DC modules designed for delivering circa 350mA into 15v can be used with a 7812/7913 voltage regulator and it will work fine. You can also make really fancy PSU with linear trafos, cap multipliers, CLC, and low noise LDO’s etc. with a proper PSU capable of 750mA and +/-15v you can drive up to 1.5W into 32 ohms (for those fans of the HiFiMan HE-6).

I’ll be offering the SMT preassembled PCBs for $59. Bare PCBs for $22. Boards are all 1oz copper and ENIG finish.

https://xrkaudio.etsy.com/listing/1659118057

BOM is here. Note that BOM calls for OPA1642 but the pre-populated PCB has NE5532 installed. This was due to availability issues but I can assure you that the NE5532 sounds fantastic and measures well too. If you want to swap it out later, you are welcome to do so.

If you want to boost the output BJT bias current (80mA) for operation to a higher power under Class A, use this 2.2ohm metal thin film emitter resistor (R213/213/312/313):
https://www.mouser.com/ProductDetail/Vishay-Dale/TNPW12062R20DEEA?qs=vHuUswq2%2BswIE18TmZVkaQ==

Note that the heatsinks will get significantly hotter and the PSU also needs to provide more quiescent power.

For the 8pin Wurth IDC cable with matching connector for the potentiometer, get this cable (or its equivalent).

The ZEN Amplifier concept is simple. But it works great.
Here is such an amplifier but with less current and uses IRF610 as MOSFET.
It makes a simple and sweet headphone amp.

Building shouldn't be difficult.
The heatsinking it takes is not so much.
There is some THD, but it is mainly 2nd harmonic.
So, it would be good listening.

The amp is designed for 32 Ohms headphones.
For other impedances it may need tweaking to make it alright.

EVENT OPAL setting bias

Hi everyone, I thought that I'd share this situation and ask for some assistance as I "fine tune/optimize" the amps.

While my Event Opal monitors sound okay, I decided to take some measurements.

I'm the second owner and given that one heat sink operated noticeably warmer then the other, even at idle, I wanted to ensure bias is set correctly/ optimally.
And, I have some reason to believe that the first owner had been messing around inside...

There is no trim pot for offset, only for bias (white vr bias, the black vr is for output level to balance freq response)

The monitors have been discontinued for a few years.

The manufacturer set bias according to crossover distortion ( AP analyzer).
I only have access to an oscilloscope.

* The values across the 0.05 ohm resistors on the left side are suspect.

Are the other values "normal" or indicative of something not quite right?

What is the best/ optimum way to set bias for these amps?

See attached measurements, photos, schematics,etc...

Cheers

SW 🙂

Some turntables come with a way to adjust the speed, some with a way to see the speed, but most do not have either. This project is for the person who wants an inexpensive but accurate way to see the speed of their platter on a digital readout. The display is five seven segment LED displays, two whole numbers and three decimal places. The Tachometer cost under $50 USD to build and is quick and easy to build. It is on 2 ¾” square PCB so will fit in most any table internally with a window to see the display and the trigger LED.

The project uses an Arduino Nano to perform the timing counts, calculations and run the display. The Arduino Nano’s clock crystal is neither stable enough nor accurate enough to use for the clock, fortunately the Nano can be configured to accept an external clock as the timing base. I used a 10-Megahertz oscillator that is good for +/- 2.5 PPM (Parts per Million), so within 9,999,975 to 10,000,025 Hertz. That’s a 0.00025% error rate, accurate enough for even the most stable tables. The 10-Megahertz clock output is run through a divider chip with does two divide by 10’s, so the clock is 100 kilohertz to the timer counter.

The Arduino has three timers built in but to make the timing accurate you must shut off the other two timers, timer 0 and 2, so there is no processing overhead to mess up the timing. Timers 0 and 2 are 8-bit timers, too small for counting the 100 kilohertz clock, produces too many overflow interrupts. Timer 1 is a 16-bit timer which is adequate to the task. As you can see from the source code the setup() procedure’s first five lines manipulates the processors registers to set the timers up. The processor uses two interrupt service routines for timing, one internal to count the number of times the counter over flows and the clock pulses, and one external interrupt connected to a Hall Effect sensor which is placed under the rim of the turntable platter and a small button magnet is glued to the underside of the rim of the platter. The magnet is small enough and light enough not to affect the platter balance.

The PCB has a 5-volt regulator on it so you can feed the board 7.5 to 12 volts DC. The optimal voltage in is 9 volts DC. While the regulator can handle higher input voltages the heat dissipation may be too much, 12 volts is pushing the thermal limit of the PCB heat sinking capability.

Note: the cost of the tach is using Blue LED displays, we build one with Red LED displays, a lot cheaper, and it still looks good. The hall effect sensor is around $10 but I designed a small ½” square board with a $0.60 hall effect sensor on it so cut the cost to about $1. So, an overall savings of $15 with Red LEDs and the home-made sensor. I will post the gerbers and part number for the Hall Effect sensor in another post.

This post has the PCB gerbers, the schematic, the BOM, a couple pics, and the code.

Operations: when the tach is powered on it runs through the setup of the Arduino and, before it exits, turns on all the LED segments for 5 seconds, this is a test to show you if you have any issues with your soldering. Then the main code runs, loop(), which looks at the number of overflows of the counter, which being 16 bits can only hold 65535 clock cycles before it trips the overflow flag and resets. If the platter isn’t turning the overflow count will keep going up, but once the number of overflows is over five, long enough to see the platter isn’t turning, it shut off the display. As soon as the platter starts turning the overflow number is reset by the triggering of the hall effect sensor and the display comes on. Whatever speed the turntable is spinning the speed will be displayed whether it is 33 1/3, 45, or 78 rpms. My table is a Denon DP80 built into a heavy plinth and typically displays 33.332 to 33.334 which is extremely stable and what Denon was known for. A friend is working with some Pioneer high end tables with a custom platter and heavy plinth and is seeing similar numbers, once the tables warm up. For grins I stuck a magnet to the side of an old, cheap Girard table and it was varying a lot more than I would like to see in an audiophile table.

Hello all. I am a longtime member and viewer of the DIY Audio Forum but have not posted yet. I find the forum to be essential and have completed a few projects now utilizing the expertise from the members here. I have attended a few Burning Amp festivals and encountered some of you there. The web store has also been one of my my main sources of goodies. I find myself in need of assistance now so hoping to jump in on the Iron Pre thread with some questions. I am not an engineer! Projects built to date:

ACA - kit
Starving Student - kit
EAR 834P phono preamp - from PCB w/ homebuilt chassis. The inspiration for this came from Lenco forum and Skunkie on YouTube
Aleph J power amplifier - Ali Express chassis w/ mods by me
Iron Pre SE preamplifier - homebuilt chassis - in progress

My system, which I love, is a mix of yard sale and and DIY - Aleph J amp, Starving Student as a preamp (placeholder for a few years now, time to go!), EAR 834P phono stage, Tascam CD200 to Schiit Modius DAC, Technics SL1700 dd turntable (underrated table!). Nagaoka cartridge, and Altec Bolero 890C speakers.

I look forward to participating. Thank you!!

Hello

I have the pass 5 Turbo v2 and a problem. After I had the amplifier with an input signal and without a speaker at the output in operation, the right channel failed and outputs only a weak signal. The heatsinks on the right side also got cold. At the output I then measured an offset of more than 1 volt.

What can be the cause of the failure and which components can be damaged or what to do?

Thank you

Torsten

Hi all,

I'm experimenting with methods of de-coupling the woofer in part of a 2-way monitor speaker. Woofer driver being used is the Satori MW16. I've thought of some different methods from research and came up with the following conclusions:

-Mounting the drive unit on rubber well nuts (isolation grommets) similar to the TAD high end speakers (attached below) works well for isolating the baskets and lowering unpredictable magnet movement down to the upper bass frequencies (~200-300hz, depends on specific driver). This is good for a midrange speaker that will be crossed over around that point, however at frequencies below that, when used as a woofer, the magnet exhibits greater movement than if it was rigidly mounted to the enclosure, diminishing the transient response of bass frequencies as this is a loss of energy.

-Rigidly couple the magnet of the speaker to the inner brace of the enclosure and isolate the driver basket from the front baffle. This, in theory, should mean that no part of the resonant basket is touching the enclosure, yet the driver remains steady as its coupled by the magnet directly to the enclosure. There can then be a ring of rubber, foam, etc gasket to ensure air tightness.

-Combine both of these solutions. By combining both solutions, the speaker can still be "bolted" to the baffle using well nuts, so that it is stable, then further mounted directly using the method above.

One small issue arises in my speaker, is that the front baffle is angled back at 7 degrees for time alignment, and the magnet shape and design of the satori speakers are less then ideal for this type of mounting, therefor asking if anyone has some ideas to throw around on possible solutions or experimentation of their own.

Kaden

Hello everyone,

I been lurking around diyAudio fairly often in the last few months.

I started my career as an electronics technician back in the early 90's. Went to school, got certified and went out into the world. This was around the same time that PC's starting showing up at home and in the workplace. I quickly found that PC's were the "wave of the future" and my skills were (kinda) transferrable.

Long story short, I made the jump, and went into computer field. However, I never lost my interest in electronics; especially audio. Now that my computer career is winding down (retirement), and the kids are gone, its time to pick it up again.

I still remember some stuff, but I am looking forward to re-learning all the stuff I forgot!

Hello,
I am working on repairing a JL HD750/1 that had 2 of the 4 output MOSFET shorted (ordered 4 FDP2552 replacements yesterday). When I removed the heat sink clamp from the output MOSFETS there is a secondary PCB that is perpendicular to the main PCB. That daughter PCB (labeled thermistor board) connects to R554 terminals of the main PCB, and surrounds two of the output MOSFETS and has a few SMD components on it. One of the components near the MOSFET drain flanges has some thermal gap pad covering it, but two of the components (labeled capacitors) did not have any pad covering them.
It looks like the terminals of the capacitors were free to short out to the drain flange of the MOSFET. I can see where the ends of the components left marks on the flange in the attached image.

Am I missing some isolation pad on these two components, or is this normal? If it is normal, what is the function/goal of these two capacitors against the drain flange?



Daughter PCB, thermal gap pad in the middle covers one SMD component. The two outer SMD capacitors are not covered, and press against the the drain flange of the MOSFET, effectively shorting the terminals of the capacitor together.



Opposite side of the daughter PCB.


Marks on the removed MOSFETS.

I have an HD750/1 that had been going into protect mode for low impedance. After going over the mainboard, I found an issue with the C2 surface mount capacitor. The amp seems to be running fine after removing this cap, but I would still like to replace it before reinstalling the amp. I was hoping I might get lucky and maybe find someone working on this model amp that could help me with the specs for this capacitor. Its C2 near the bottom-middle of the attached picture.

New DAC chip

http://blog.stereophile.com/ces2008/011008ess/
134 dB SNR and -118 dB THD are impressive, but I find some other things in the white paper more interesting, such as the discussion of dynamic element state space modulation by transients:
http://www.esstech.com/techsupp/sabrewp.pdf
The time domain interpolation for SRC is reminiscent of what Anagram does in their DSP-based solution.
Too bad no mention at all of how they achieve their supposed 100% jitter rejection.
Looks like it should be easy to DIY with because it takes S/PDIF input and doesn't need that much around it on the digital side, and can be used as either voltage or current output due to the medium output impedance.

Greetings from Sweden! I'm happy to be here! I am an audio enthusiast working on learning how to fix active speakers.
My current equipment includes:
a pair of HEDD 07 monitors,
a pair of HEDD 05 monitors,
and a pair of Event Opal monitors.

Gentlemen,

for reasons of historical interest and sake of completeness
let me offer some Audire schematic diagrams here.

The company owner Julius Siksnius died some time ago and
can no longer be asked. I did repairs for the local distributor
and we received the schematics by letter or Fax - but the scan
quality is not too bad thanks to my lawyer (you know what a
lawyer is good for). These are the "official" factory diagrams,
in pen and ruler style as usual at the time. Hand written
remarks "in English" are from Julius himself.

I am sorry I do not have any preamp schematics except for
model Legato.

The power amps are pretty similar and use the same driver
structure for each model. The only difference apart from supply
voltage and hence power output is the number of output devices
and some adapted parts values.

He did not include schematics of the power amp supplies, these
are simple and do not need any clarification.

Except for standard current limit and supply fuses the power amps
have no protection circuits and speaker relays.

Everybody is invited to share their Audire circuits here, thanks !

Hello, I am looking for MOSFETS-FQA40N25 & FQA36P15. Matched sets are better, primarily need FQ36P15 as 40N25 is available with few online vendors, Quad or multiples.
Thanks.

SV-128BII 15/15W or 24/24W Power AMP from Sunvalley Japan

SV-128BII 15/15W or 24/24W Power AMP from Sunvalley Japan

We are now doing the heat test from Sunvalley. Once it passes the heat test and received approval
by Mr. Ohashi and his technical team, we will start the production process. (
Only assembled 120V is available ( made and assembled by Sunvalley Japan)

KT150


KT170


KT170

Standard tube set (the best version):
"Tung-Sol KT170* 1 pair", "Mullard CV358 / CV5080 / EF37A (NOS) * 4",
"GOLD LION GZ34 / 5AR4 * 1" "VCAP ODAM 1uf * 2 + Audio Note coper 0.047 X 2"

KT150 is so popular now that it can be said to represent current vacuum tubes.
The rating surpasses KT88 in all, and the magnificent plate loss = 70W attractively exists with unparalleled potential.

Historically, the vacuum tube amplifier circuit has advanced, but it cannot be said that the KT150 potential be maximized
with the conventional circuit. A new concept for circuit design is needed to break the established concept of pentode tube = 8W in SET AMP Design.
As a result of careful design and careful sound determination, the SV-128B II has succeeded in drawing out about three times the output of
conventional Single Ended Pentode tube amplifiers.

As for the output section, this unit can select the plate voltage from normal / high. The KT88, 6550 has an output of 15W or more
in the normal mode, while the KT90, KT120, and KT150 has an output of 20W or more in the high regulation mode. This is the output next to the 845
in the transformer drive circuit in the historical SET amplifier of our product. With a B+ voltage of 500V, this performance is almost unparalleled
in the world. Of course, the operation of the output tube is performed within the rating, and the life and sound quality are not sacrificed at all because of the output.

Hashimoto Electric’s custom-made transformers support the powerful output of the SV-128B II. The rectifier tube is the 5AR4, which boasts high efficiency and robustness,
and the front-stage tube is the famous Mullard, which has the nickname of the European version 310A. The CV358 / CV5080 / EF37A (red color) is placed
in the voltage amplification and cathode follower drive, and the output tube is in full swing.

Type: Pentode Tube -SET power amplifier (KT88, 6550, KT90, KT120, KT150 compatible)

• Fixed bias (adjustment required when replacing vacuum tube)
• Input: 1 system No volume
• Wiring specifications: Manual wiring (only heater power supply uses board)
• SP impedance : 4 / 8Ω (16Ω can be selected by changing the wiring)
• Vacuum tube used: CV358 / CV5080 / EF37A x 4, KT150, etc. x 2, 5AR4 x 1
• Output: 20W + 20W or more (when using KT90, KT120, KT150), 15W + 15W or more (when using KT88, 6550)
• Frequency characteristics: 15Hz to 45kHz (1W 8Ω -3dB)
• Gain: 27dB (8Ω)
• Size mm (including protrusions): W400 x D300 x H220
• Weight: 24kg

This is the permanent solution to get rid of the cell phone interefence of the the driver tubes (EF37A).
This noise shielding is effectively reduce the interference.





Attach files

Ok guys i am in complete loosing my mind here.
I have 2 identical toroidal transformers of my tube pre for b+. They output 230 v ac 120 mA exactly the same for both measured. 4 diodes in4007 in both transformers and now begins the craziness. On the diode's outputs One outputs 315v dc and the other 215v dc. i have change 65467765433567787654478 diodes no luck always the same scenario as above.

I forgot to tell you that the transformer that outputs 315v dc the diodes are normally on the psu circuit and the other transformer that outputs 215 is alone in the air with the diodes only.

I mesure for both transformers only the diodes output.

Hello everyone! I´m from Brazil. I have some technical background in electronics and computer engineering. I don't work with it currently, but this is my hobby at home. I recently fixed a JBL ES250P active subwoofer that I would like to post here, because I used a Chinese amplifier and there was a forum here on diyAudio about this amplifier that I used and it helped me a lot. I would like to share now the experiences I had and the changes I made both to the Chinese power amplifier and also to the original JBL audio and protection circuits to make this JBL subwoofer work again.

Hi all,
absolute beginner's question for a potential first tube project:

Would the design of a push pull EL34 stereo amp with the following characteristics be worthwile ?

-line input into one half of ECC83 as first stage
-then one half of ECC82 as phase splitter
-then EL34 push pull output tubes
-highest quality non-ultralinear output transformers
-negative feedback from transformer secondary to first stage cathode
-? potentiometer adjustable: AC balance, DC balance, bias/bias balance, NFB (adjustables R/C)
-simple design/short pathways, oriented towards Braun CV11or CSV13 EL84 push pull amp (however with ECC82 and EL34)

Any opinions or recommendations ?

thank you so much,

FrankieS

My name is Geoff and I have been interested in music and hifi for more than four decades.
Recently, I refurbished one of my bucket-list speakers, the Gale GS401A, with the help of Dave Smith, from VintageGale, and it gave me an introduction into the hobby of redeveloping and restoring audio equipment. Subsequently, I recapped my Yamaha NS1000, rotated the woofers, and replaced the binding posts, and the improvement was absolutely palpable. As a result, I did the same for my friend and his pair of NS1000M.

I have no technical knowledge, just time, patience, a willingness to learn, and some enthusiasm.

I have now picked up a set of Sony SS-5050 Carbocon and will, no doubt, be seeking some advice.

Hi Errbody!
Back after high-school I use to take just handfuls of adderall, and taught myself to solder and read schematics,
Now years and years later I am reentering the hobby.

Working on putting together a Class A Single Ended Guitar amp from Dave Hunter's book w/o a kit.

Hi guys, I designed an SE amplifier with 6S4S galvanically coupled with a special tube having the high amplification factor and slope in addition to the resistor in the cathode of 6S4S that ensures its negativity I replaced it with a constant current generator with the 6P3S tube set to provide the current of 60mA through the final tube. The results of the measurements after finding the optimal OT impedance are encouraging, very stable operation and at a mono listening the sound is above expectations

Sell my loved maya 200 plus one new module. I don't use it since i bought my bricasti M25. Insted of taking dust i prefer i give enjoyment to another one.

It made me sold my ex yamaha m5000 and viva audio solista...

Can send in europe. shiping and paypal fees for buyer.

Price 1700 Euros.

Cheers,

So my neighbors have asked me to assist with a new cartridge for their Technics SL-D202 TT. The arm seems quite nice with tight gimbals and an S shape. I think this would hold a fairly serious cartridge and do it justice. Must be moving magnet.

I'm prejudiced toward Ortofons (I own one) and my vote here goes to the 2M Blue at $200 and the stretch buy is the 2M Black LVB250 at $1000. I don't know the Audio-Technicas at all and would love some input there - especially the more esoteric shapes (Micro-Line and such). Please share your opinion, and thank you in advance.

I'm attempting repair of a Sony Walkman WM-2 that has been in a drawer for many years. I've replaced the drive belt, freed the seized pinch roller and cleaned the capstan and pinch roller. Everything works but the tape wow is unacceptable.
I don't know what performance was possible originally but I'm sure this audible degree of wow would not have been OK.
Any ideas on what I can look at to fix the issue?
Many thanks

Ian

Hello there,
So, trying to further develop my Mickey Mouse amp.

Next step would be this, putting a CCS load on the output tubes.

Topology is very simple, 2 amplification stages through a 6sn7 (china amp) and a cathode biased 300b (450V, 70V at cathode, 220uf and 1k at the cathode).

Looked the whole internet for a schematic, went through Bartoli and other websites (he uses curators mainly for driver stage) but couldn't find anything ready?

Would someone be so kind?

Ps. The schematic is the plain vanilla one, many things have been changed/optimized, but the output stage.

First of all I have to mention that this thread started following Mark’s idea found in this thread https://www.diyaudio.com/community/...apacitors-smd-assembly-max-3a-max-48v.405099/
I needed clean power for a vfet follower amplifier that was getting its juice from a 90w laptop brick followed by a sk80h buck boost converter. Because there was also low frequency noise beside the high frequency one I decided to add the cap multiplier inspired too by an earlier design from same Mark.
So practically the only thing I did was to play around a bit in my pcb design software to put together the pcbs.
It all started here https://www.diyaudio.com/community/...d-assembly-max-3a-max-48v.405099/post-7505998

And then after that this part followed..

A few users asked by private messaging about the single rail pcb but also about a dual rail or bipolar pcb. At the time I had only the single rail pcb so I drew the bipolar version. I call it bipolar because how it`s designed but it can be use as a dual too.

For the bipolar version I created 2 pcbs. One that has a single ground plane for both rails and another that has the two ground planes separated. Initially I done the single ground pcb and then asking Mark for a suggestion I got the dual ground pcb.
On the dual gnd pcb you have the possibility to connect the gnds at the input or at the output of the filter.
For each pcb I will attach the schematic, bom, a few photos of how it looks and the gerbers.

I was planning to release these gerbers in a week or two after testing my single rail unit(I don`t intend to build and test the dual/bipolar pcbs) but then realized that it will be a bit late for those who want to have something to solder in the holidays period.

The dual pcb can be used as both positive, positive and negative or both negative filters.
The lower half of the pcb is designed for a negative filter but if you reverse the electrolytic caps and instead of the pnp bjts you place the npn ones as on the positive rail you can make the bottom part a positive filter so you will have 2 positive filters on same pcb.
If you need two negative filters on same pcb you will need to reverse all electrolytic caps on the upper half and instead of the npn bjts place pnp ones. Simple as that.

Edit1: all the boms miss the heatsink that is needed on the bd139/bd140 devices. After I build the single version I will edit all the boms with the needed part.
Edit2: after testing the single rail pcb I found that there is no need for a heatsink for the bd139/140 devices so nothing to add to the boms. Same thing is valid for the bipolar version too.

I bought a Marantz CD-63 for £35 earlier this week on eBay (well, £45 with shipping). It had one or two things wrong with it to get it for that price, like the drawer mechanism not working (though I can hear the motor going) but my question is regarding the sound and what usually goes wrong (or wears out) on these players. Don't get me wrong, this a cracking player already and I'm rather shocked by quite how good it is - I think it potentially beats most of the Naim CD players I've heard, having more get up and go and just as much resolution (or more ?) - but it seems a bit recessed in the midband (vocals) and seems to be a little less than steady. Also the top end is somewhere near the maximum I'd like, meaning it can go over the top on fierce-ish recordings like Breakfast in America (which I don't think does cymbals very well at all). I'm suspecting a power supply problem - probably reservoir caps getting old. The whole of the music seems to have an envelope around it with all of it moving in level, a bit like someone playing with levels or setting on the amp. I'm not playing it through my normal amplifier as I haven't yet built (or finished designing) its pre-amp so I needed something with a volume control and it's going through a Yamaha AV amp (which can perform surprisingly well). Even through this amp it's obvious that the CD-63 deserves better and, though it is set to NORMAL, I am wondering if some of the DSP trickery might be at least partially responsible for the phaseyness/recess in the mid and the effect of it sounding as though the whole of the music is being processed. In every other respect, though, I'm completely blown away by how good it is and how it rocks along. I don't want to modify it, though I did read @ThorstenL's lengthy piece on TNT yesterday (I actually would have paid a bit more attention to it had I known it was him writing it but I didn't find out until the end). I was kinda expecting to see a TDA1541 inside it but there doesn't appear to be one from the schematics I've had a glance at. With or without, it's still stunningly good and very obviously doesn't have OPA2604s (the world's most boring op amp) weighing it down. Any guidance on what to look for will be most gratefully received.

Does anyone have any idea what this 'trim' is called and where I could find something to replace it?
It was damaged beforehand, and even more so now I have removed all the drivers.

This project is a Group Buy. The public group here must agree - in this thread - on what parts will be sold, by whom, and where. Members must abide by those agreements. Any regular sales of the Group Buy PCB, kits or other specific related items outside of diyAudio or this thread will result in the removal of that person from diyAudio.com This is completely at the discretion of the Moderation Team.

No one shall send unsolicited or blind sales PMs to anyone else on the forum. This has long been against the rules and will also result in the immediate banning of any person who does so.
Keep this Group Buy clean and noncommercial or risk immediate removal from diyAudio.com.

---

---

Hi Guy's

Please Register your details for the Wolverine 4th group buy - Pre Order









Each order will contain:

1. The PCB’s that you ordered.
2. An A3 copy of the schematic. Both 57V and 64V rail voltage versions have been created. (Dropbox Link)
3. The Build Guide, which is a 32 page illustrated A4 color document. (Dropbox Link)
4. BOM in excel, listing all the components and mouser part numbers required to build the Wolverine. (Dropbox Link)
5. Hole Pattern DXF file and 1:1 PDF file of the Hole locations for Heatsink drilling. (Dropbox Link)
6. How to wire a Audio Amplifier. PDF document by Bonsai showing Audio Amplifier wiring best practices. (Dropbox Link)
7. Any future updates to the Build Guide, BOM or Schematic will be updated in Dropbox Link for you to download. So please include the e-mail address you would like to use for this purpose.

To Register your details

1. The total number and type of each EF3-3 & EF3-4 boards you would like.
2. Your full name, full postal address including country and post code,
3. Please include your Phone number for tracking updates once your boards are shipped.
4. Your PayPal e-mail address
5. Your personal e-mail address for the Dropbox documentation link to be e-mail to you.

Once a reasonable number of boards have been pre-ordered we will order them from our P.C.B. supplier.
We will keep all forum members up to date on the progress of the group buy.

Once we receive the boards we will pack them up, calculate shipping and then send out the payment request to each forum member.
Then once payment has been made you will receive a tracking number so you can track your orders arrival.

Please don't use my e-mail address for any other purpose as I don't have time to respond.
Please post any questions regarding the build of the Wolverine to the main Wolverine Build thread on the forum.
Please post any questions related to ordering through to me using the DiyAudio PM system.

You personal information will not be used for any other purpose and won't be passed onto anyone else.

Kind Regards
Stuart & the Wolverine project team.

Wolverine development Thread

Wolverine Build Thread

Youtube build series


We're are also excited to share some great news, which we hope will enhance your amplifier building experience.
The Wolverine team is thrilled to announce that anodized heat sinks are now available for our project.

These heat sinks are specifically designed to fit perfectly with our current boards. Here's what we've got:

• Heat sinks suitable for the IPS Boards V4.9.
• Pre-driver heat sinks designed for V4.2 of the EF3-3 & EF3-4 Output Stage Boards (OPS Boards).
• Driver heat sinks for V4.2 of the EF3-3 Output Stage Boards.

We are offering full sets of these heat sinks, which include installed Mill-Max pins:

• EF3-3 IPS, Pre-Driver & Driver: $27.5 USD (6 Heatsinks Total)
• EF3-4 IPS & Pre-Driver: $22.5 USD (4 Heatsinks Total)

Thank you for your continued support of the Wolverine projects. If you have any questions or would like to place an order, feel free to reach out via PM.

@jjs is in the USA, and I am in Australia, so please PM whoever is closer to you, and we'll arrange some for you.

Happy building!

Best regards,
Stuart & the Wolverine Team

Long time lurker. I recently signed up after years of browsing here.. Just looking to fuel my DIY addictions.

Hey guys I have an older Sony STR DH100 2 channel receiver which uses a DSP chip that's capable of 5.1 or 7.1 surround. Sony designed the PCB to use for several models as theres many places where componants can go that are missing on mine. Ive looked at the datasheet for the DSP chip (BD3474KS2) and there is multiple different outputs including 2 for a subwoofer. One looks to be a mono sub out and the other is a stereo left/right output. Do you think its as easy as tapping off the traces from those pins and Ill have a subwoofer out?

Datasheet for BD3474KS2 look at pages 4&5

Link is to alldatasheet.com website

This thread is to discuss ideas for a budget Classic 3-way speaker. (Sometimes referred to un-eloquently as a Monkey Coffin)

Driver choices, technical performance requirements, whether it is okay to finish it in anything other than Walnut veneer, etc. are fair game.

In fact, there are no limits to the topic - which means it is impossible to go off-topic.

Maybe we can surpass the 14K posts that have yet to resolve the question "Is it possible to cover the whole spectrum, high SPL, low distortion with a 2-way?" 😉

I am refurbishing a pair of Sony SS-5050 Carbocon loudspeakers.
I wish to clean the midrange and tweeter potentiometers and I am waiting with my tin of Servisol to give them a squirt, but I cannot see how to get into them.

Advice gratefully received.

Design comparison between two speakers: ADS L880 and ADS L990.

They are both three-way type. The L880 was launched before the L990 (1983 vs. 1986).

L880
Woofer: 10” cone dia., 2” voice coil, paper cone
Midrange: 2” dome dia., air cooling, woven soft dome
Tweeter: 0.75” dome dia., ferrofluid cooling, woven soft dome
Crossover points: 550 and 5kHz, 12dB/octave all

L990
Woofer: 10” cone dia., 1.5” voice coil, paper cone
Midrange: 1.5” dome dia., ferrofluid cooling, woven soft dome
Tweeter: 0.75” dome dia., ferrofluid cooling, woven soft dome
Crossover points: 700 and 3kHz, 12 pdB/octave all

I own both of them. I can say their sound is completely different. And I used to have a short talk with a retired engineer of ADS. He told me that these speakers received designs in different eras in which ADS transited computer aided system; HP vs. IBM for L880 and L990, respectively.

Anyway, I’d like to ask everyone’s opinions, except sound preferences, which design do you prefer and why?

At Burning Amp this year, I brought with me a Zen variant I christened the "Half-Nelson", as the skeleton started out as an early member of the Zen series, with some bows and ribbons added.

The schematic is shown below. The LM317 is configured as a current source to bias both the input P-channel follower and the output P-channel FET. The current source is shunted by an RC network to provide opposite drive on the P-channel output to increase the possible outpout current. Bias was set at about 1A, and the pot is used to adjust the output centering. The amp was auditioned at Burning Amp, and did ok with a pair of Metronome speakers using an 8" hemp driver.

I've recently spun a second board with some improvements. Hopefully Ill have a chance to populate it over the holidays and bring it up, but I thought it would be good tio present the original concept. Pictures of the amp will follow.

Anyone using the MAX34446ETL+CDJ PMIC? Interested in your experiences with this Power Supply Controller. Specifically looking at integration challenges and performance in voltage/current monitoring and control in multi-cell Li-ion setups. Any insights on its accuracy and efficiency?

Hi guys

I have another question

In the preamplifier.

i have a cathode JANTZEN AUDIO STANDARD Z-CAP capacitor 22mf 400v with a resistor 680 ohm in parallel that goes from cathode to ground.

Also i have a b+ film capacitor JANTZEN AUDIO STANDARD Z-CAP 400V 47μF which is after a 5w resistor then goes to plate. I think this is the decoupling cap if i am not mistaken.

I have a couple or more JANTZEN AUDIO SUPERIOR Z-CAP Capacitor 1200V 0.22µF film caps

Which cap is more important to bypass with the 0.22mf the cathode cap or the b+ cap?

Also the coupling output film caps are JANTZEN AUDIO SILVER Z-CAP 2.2mf 1200v each channel. I have the same brand model 2 caps 0.1mf. is it good to bypass the 2.2mf too?

A lot of questions i know but you guys here are truly genius in the tube electronics than i am.

Thanks in advance guys.

Hi all,

I was wondering if there is an old thread to point me to about how to customise the Onken / Fonken / etc. cabinets for different drivers, or if not, if somebody familiar with these can run me through the tuning process in general terms to make sure I'm not missing any considerations. I've read through and searched within a few Onken-related threads but not found anything comprehensive, but that doesn't mean it isn't out there. I've also definitely seen a few threads asking for advice about specific drivers lead to comments about appropriate box sizing but suggest that tuning will need to be done for them but can't find anywhere saying what this would entail.

Additionally, I've seen other threads saying that some designs for these behave like traditional ported enclosures and others function like aperiodic ones, and I'm not sure which the spreadsheet is for (presumably not aperiodic) nor if the design considerations are different for the other type.

I've been looking at the 2011 thread by Togril on creating an Onken for the Tang Band W5-1611SA, who seemed pretty happy with how their build went. I have the SAF model of the same driver sitting unused at the moment, so I thought I'd see if I came to the same sort of parameters before I start building anything (and I've got some fairly hard space constraints where I'll be putting these speakers that would mean that if I can find a way to design it to be marginally shallower that would help too).

I'm aware that there is a spreadsheet by one of the gurus of these speakers out there - the one by Cyr-Marc Debien from 2000 - and have been playing around with it. As far as I can see, the goal is to figure out an enclosure of about the right volume that is a sensible shape (with the usual considerations around ratios of length/width/height as for any other box) for the driver parameters whilst keeping enough box depth to allow for the required vent length that the calculator spits out. Some drivers will basically be unsuitable, and others can easily be fit into these constraints.

Where I'm getting confused is around decisions to do with vent dimensions - obviously making these wider or longer or changing the total number of them will dramatically change the required vent length, but I'm assuming they also impact sound in other ways so have no idea what I should be picking here as a starting point or what changes are generally likely to be 'safe' vs causing other issues.

Assuming this spreadsheet is a good way for me to design a box, I was also hoping to clarify some parameters / outputs in the spreadsheet itself that have me confused:

Firstly, why there are separate fields for "effective vent length" and "corrected effective vent length" and what is being corrected for? I'm assuming the corrected one is what I should be aiming to use in the final design, but wanted to make sure I'm using the right one, as in the tests I've done it is usually 10-20% different to the 'effective' one.

Secondly, what is the impact of changes to the "n=" / "Onken alignment" parameter on the final result? I'm assuming the 6.34 was what the original bass cabinets 60+ years ago (presumably designed by trial and error) ended up having once more modern simulation/calculation methods were applied to the old designs, and the 5.7 is a better compromise that has since been identified mathematically, but I'm not sure what it is compromising on or what changes up or down from this 'ideal' value are likely to do.

Finally, what influences the tuning frequency for the box/vents that this spits out, aside from driver parameters? Fb is one of the calculated values and can't be set by the user. With other vented enclosure calculators (or at least subwoofer ones) this is something that I believe the designer usually decides on along with box size, target Q etc, and these then are used along with the (fixed) driver parameters to determine the vent parameters, both area and length. Here it seems we are coming at this from the other side - based on a given vent area and driver parameters, a fixed 'optimal' volume, Fb, and Q are set, and the required vent length to achieve this is output. Is this understanding correct?

Hopefully someone can set me straight or otherwise point me towards resources that will help me figure this out on my own!

I have a Sony BHF-1600a 12v capstan motor from a 1" tape player. It spins sooo nice and smooth when I turn it manually.

I would lile to get it spinning, and play around at determing if it is suitable for a turntable motor.

Anyone know the 8-pin pinout labels on the original control board? Or could point me where to find it? I assume either one or two pairs of +12V / 0V pins, and some other speed control pins, but not sure where to find out.

I plan to play around with an Arduino to control it once I know the inputs.

If not, I drop the control boards and tackle running it off the bare magnets with that Arduino + a motor control board like I do with my BLDC motors.

Thanks.

Stereophile
Gramophone Dreams #54: DS Audio DS003 optical cartridge & EMIA, Lundahl, Koetsu, Sculpture A step-up transformers Page 2 | Stereophile.com
Amorphous Core (Lundahl)
K&K Audio's $1500 Premium Silver MC Step-Up (footnote 3) uses Lundahl's LL1931 Ag transformers, which are made with Lundahl's "finest amorphous cobalt uncut strip core" and wound with pure silver wire. According to K&K Audio's Kevin Carter, "The LL1931 provides a very open and detailed picture of the 'space' that was recorded, providing a level of detail recovery that I had never previously experienced with LPs."

My auditions confirmed Kevin's observation, but my experience with this transformer is limited, because I auditioned it with only one cartridge: the high-impedance (40 ohm) Zu Audio Zu/DL-103 Mk.II moving coil. (Lundahl's website specifically recommends the LL1931 Ag's step-up ratio for use with 40 ohm cartridges. )

I listened to the K&K + Zu-Denon (with a variety of RIAA stages) over many months. Every record testified to the mesmerizing effects of the LL1931's clarity and the goose-bumpiness of its transient bite. Bass reproduction could be thrilling, just-right tight with genuine power. The LL1931's best, most obvious trait was how specifically it rendered recorded information. Its worst trait was that, compared to Auditorium 23's mu-metal SUT (which was designed by Keith Aschenbrenner for use with the DL-103), it made the spaces between details feel empty, causing reverb tails and vibrating cathedral air to go missing or attenuated. The Lundahl transformers (footnote 4) showcased tight bass, intense detail, and a somewhat blunt clarity. The A23 showcased tone-truthfulness, rhythmic bounce, and a more refined presentation of ambience.

According to Per Lundahl, writing by email, "Choice of core material is a question of taste. Our top-of-the-line MC transformers are available with either our uncut amorphous strip core (like the LL1931) or with a conventional mu-metal lamination core (like the LL1933). As it has turned out, the amorphous-core transformer is most popular, but the mu-metal lamination transformer is still preferred by some audiophiles. In THD ... and linearity measurements, the mu-metal lamination version outperforms the amorphous core version, but in listening tests, the amorphous core usually wins."

I asked Per to explain the metallurgical differences between mu-metal, amorphous cobalt, and nanocrystalline transformer cores.

"In true amorphous material, there should not be any crystal structure. Atoms are randomly oriented, and there is no repeated structure such as you find in most solid metals. To achieve this, the melted metal is cooled so rapidly that atoms get stuck in their random positions. ... This very rapid cooling requirement is the reason why amorphous metal is only available as thin film, about 1 mil (0.025 mm) thick.

"To achieve nanocrystalline material, special amorphous iron is carefully heat treated at very controlled temperatures. In this process, very small [nano]crystals are formed."


I have 4 vesions
LL1931Ag Assembled version from Lundahl or Kit format
LL1931Cu Assembled Version from Lundahl or Kit format

I saw the Coachella performances from two days ago on social media, and Lady Gaga’s stage performance was so attractive to me.

Hello there,
I'm really glad to be here.
I've owned my equipment since the early '90s and I'm still very happy with it.
I’ll probably upgrade within the next couple of years.
In the meantime, I’m just keeping it running.

Roksan Xerxes turntable
Oppo BD95 CD player (a newer addition)
AVI S2000MP pre-amplifier
AVI S2000MM monoblock power amps
A pair of RUARK Equinox

I have a DAC, pre-amp, and headphone/pre-amp which use an Arduino, specifically the LCDuino, to control them. The power/config switch is a capacitive touch style with configurable RGB LEDs. I wanted to build a board to make hooking this up easier, then had the idea to modify the LCDuino firmware to use an extra pin to indicate when mute is enabled. Between the SSR trigger pin and this extra mute pin I can use that to turn the switch's LED on when the device is powered on, and change it's color when mute is enabled.

What I've come up with is a dip switch to configure the colors, and a couple logic gates to determine which transistor/dip switch combo should be active. On my breadboard this is working fine but now I want to turn it into a board I can plug in to the LCDuino. I've built a bunch of things over the years, but never designed anything, so before I go buying parts or having PCBs made I was hoping to get some feedback on what I have so far.

I think the circuit itself is ok, but maybe there's a way to simplify it a bit that I'm overlooking? When the device is powered off the SSR trigger goes low, but the mute pin stays high, so in this scenario I need to make sure the mute indicator also goes off. I can certainly work around that in code which would remove the need for the logic gates, but there's very little memory left and I don't want to add more code than I need to. This is especially true in the event of a firmware update where I could lose some of the currently available free space.

I went SMT because of space constraints on the board and in my pre-amp where there's very little extra space to add this in. I've worked with components of these sizes so soldering them won't be an issue. I also added some jumpers so I don't need to populate all of the components depending on how this is used. If I know what colors I want I don't need a dip switch, and if I don't want the mute function I can use JP1 and skip populating most of the circuit. Not all of the headers will be used either, so some of them will be left off depending on where it's used.

The ICs are the same series used in the DAC this will be going in so I don't see why there'd be any issues with those. The resistors and capacitors all seem like ok versions of the through hole parts I've been using. The diodes I picked are what I'm really not sure about. With my breadboard version I'm using 1N4148 because that's what I had extra of but I'm not sure if I picked a good alternative for the PCB version.

The switch is a Schurter 3-101-412 and each LED control line draws 0.05mA when shorted to ground to turn on it's corresponding LED. These are the parts I've picked out so far:

• SN74LVC1G08DBVR
• SN74LVC1G86DBVR
• MMBT3904LT3G
• SD103ATW-7-F
• C0603C104J5RACTU
• RC0603FR-1310KL

I've gone through more PCB iterations than I can count. The current version should have the pin headers in all the right locations which is what dictated the rest of the layout. I also need to be mindful of components on the board this is plugging into which is why there's nothing on the back aside from the headers. It's a 4 layer board with the back side facing the LCDuino when plugged into it. It's setup as as follows:

Front: LED control circuit
Inner 1: power
Inner 2: ground
Back: connector passthrough

Here's a quick demo of the breadboard version in action.

Login to view embedded media

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.

When I decided last year to explore some Stax electrostatic headphones, I discovered that even their older-model headphone amps are jaw-droppingly expensive. So I got an SRD-7 Adaptor and converted it to power high- and normal-bias Stax 'phones. Unfortunately, the sound quality left much to be desired.

The good news is, it's most glaring problems are fairly easily addressed. I just completed these detailed mods for the SRD-7 adaptor:

Transforming the Stax SRD-7

Comments/questions welcome. (This is my first crack at creating web content of this ilk outside of a forum, so be gentle... 🙂 )

"Tweeterectomy", InDIYana 2025 dates are set, and website is updated.
The theme/challenge portion surrounds the DIY build of a 1.5way, something not as commonly seen, called Tweeterectomy.

Dates are May 9/10, 2025 a Friday/Saturday set as usual. Details are at the event website on the front page under the drop down menu at the top here:
https://sites.google.com/site/indiyanaevent/

There has been a lot of discussion about the details for the theme already here:
https://diy.midwestaudio.club/discu...erectomy-but-build-look-alikes-if-you-want/p1

April was just too congested this year with everything else.
If you plan to attend, and are not listed on the attendees list, please PM me at the event website email addy listed on the front page.
If I have included you and you do not plan to attend, please also let me know of this change.

Hope to see you!
Wolf

A few months ago, I inquired about a capacitor/inductor filter I wasnt familiar with, on a post about Dynaudio speakers.

I now understand that this is an All Pass filter used for a time delay/ phase alignment of the tweeter.

On my current build, the tweeter is about 75deg phase shifted from the woofers between 1k-3k Hz. Moving the tweeter back 1cm solves this.
So does one of these All Pass filters with 1uF caps and 0.2mH inductors. It perfectly lines up the phase, and results in a deep null when the tweeter phase is flipped.

Any reason these filters are not more widely used on DIY builds here?

Who's ordered @Gabster 2000 's TD1 board? I ordered two so I'm curious who else is building this one?

https://gabster.ca/Gabster-TD1/

Hello !

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

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

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

The general principle I'm using is this:


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

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


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

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

Experimenting recommended ! 🙂


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

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

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


- Elias

Hi there,
I own a NAD216 amp, it's been playing in my stereo system for almost 13 years now.
about 5 years ago it start making some problems - taking it for service resulted in two things:
1. amp was fixed
2. service guy removed several components / changed several components - making the amp sound way better than stock

three months ago the amp went off again, this time it was due to electrical problem from the AC network.

took it again to service -
this time the service guy (a different one) used the amp original electrical schemes and just went over them and made sure all working properly.

now the situation is simple - i had an improved amp (i do not know exactly by what measuers), i sent it to service and now i got a stock amp again.

i need assistance in reviewing the amp electrical schemes and noting there what places can be "Improved" by manners of:
1. remove / bypass redundant / unnecessary protections
2. remove / bypass circuits that are in no use (bridge channels part / soft clipping)
3. remove filters applied in the amp which are not necessary

i found the schematics of the amp here:
Index of /~jga/nad216thx

link is taken from a thread located here:
http://www.diyaudio.com/forums/solid-state/148986-help-noisy-nad-216-a.html

i could not locate and electrical schemes for any Silverline amps from NAD for comparison, so if any1 has some assistance about that as well, this may also help


would appreciate any kind of help

BR


Ron.

Hi Everyone,

I'm in the process of knocking out holes in a chassis for some small Chinese analog panel meters.
Unfortunately every drawing online seems to be conflicting. I must be getting old but these drawings
make zero sense to me. Does anyone have a physical meter they wouldn't mind measuring for me?
Just need the usual...

• Hole Size needed to slide the thing in from the front. I won't be rear mounting with the face protruding through the front panel
• Physical edge to edge dimensions
• Mounting hole to mounting hole dimension

Thanks so much!

Ron