Do It Yourself

I enjoy thinking about different ways to accomplish the often-overlapping electromechanical goals of audio devices. Every few years I get to considering electrostatic headphone connectors, and every time I end up finding the same collection of vintage part numbers, shared experiences, and a few useful drawings that can be put together to probably lead to a functional socket or plug, if you want to make one yourself. I appreciate and have used that information, and now I'd like to consolidate it and create some actual specifications to help anyone trying to make a plug or socket. The most useful thing to start with would be plug specs. Pin diameter, length, pin circl…

The part tested ok and seems to a 15 volt reg mc 7915ctg mc 7815ctg

The part tested ok and seems to a 15 volt reg mc 7915ctg mc 7815ctg Bottom right is where the reg were Below the vishey 4700uf caps

This topic has needed its own thread for quite some time (years), so starting one. I may see if I can get a mode to move some of the posts here (Carbon thread, not sure where else they are littered). 11 hours ago, Pars said: GRHV question: I'm building a pair of the singles intended for 400V output. On the BOM I have, there are 2 680uf caps for each board; 1 is a 550V caP, the other a 450V cap. I presume the 550V would go right after the rectifiers in the schematic, and the 450V on the output. The BOM that was posted by jamesmking uses 4 x 470uf 550V Kemets. Is there much difference between the 680uf and 470uf in terms of sound or anything? BTW,…

kgsshv-carbon with the sic-fets turned into 6ca7 was going to be next year

I am starting this thread for all that are or will be building JoaMat's mini T2 to share information, ideas, thoughts and experiences. The attached schematic is an updated one .The resistors in the BOM are thick film ones and can be replaced with thin film ones for likely better outcome. The power supply requirements for this amp are +400VDC, -460VDC (EL34 output stage), +220VDC (6922/6DJ8 front end), +15VDC, -15VDC (servo, cathode current source) and 6.3V filament supplies for the 6922/6DJ8 and EL34 tubes that can either be AC or DC. I also plan to use the +15VDC for the CPC1117N high tension delay. EDIT (Feb. 2020): updated schematic and BOM (Thanks Joa…

Hello all, I'm working on a little project with my old SRD-6 energizer and a cheapo TA2020 amp. I'm trying to put together a compact transportable setup for my SR-5s. I have done a few modifications to this box already, such as wiring the transformers directly to the speaker taps on the back of the box and directly to the Stax socket on the front, completely bypassing the bias board and the loudspeaker switch. Those mods have done great things in terms of sound quality, but what I'm interested in now is modifying the bias circuit to operate as a self biasing one. As I understand it, Stax accomplishes this by tapping some of the output signal from one of the transformers, …

enough people have been asking for this, we finally decided to do it. It was easy from the current layout. Best to stick with +/-400v power supplies http://gilmore.chem.northwestern.edu/kgst.jpg

This thread is a follow on to the original SRX Revisited thread and the SRX-Plus Group Buy thread. As of 2024, I count at least 12 members with working SRX-Plus Amplifiers: JimL congo5 MLA Sorrodje mwl168 luca jose blueman2 Juggernaut1101 tomislavkufrin simmconn oldie ============================================================= Here is an initial Bill of Materials for the Amp. Please provide input on errors and omissions and I will update. This is my first ever electronics build, so bear with me as I learn the ropes. I am initially building a KGBH psu, so do not have the BOM fo…

finally. higher signal to noise ratio, more than 110db. takes signals up to 20 volts peak to peak unbalanced, 40v peak to peak balanced. no input attenuator that adds noise for those stupidly high voltage dacs. ( requires 30v power supplies) (volume control in the middle) thd about .005% no feedback. work in progress 4 layer board. preamp2025f.PDF

Here are my BOM for a pair of BH. https://www.mouser.tw/ProjectManager/ProjectDetail.aspx?AccessID=b44788bc7f for GRLV and GRHV. copied from Carbon build thread. http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=b6d687c7f7 http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=54687aa8fa Parts I already have or going to buy from local dealer are NOT included like LEDs, insulators, IC sockets. Someone need to check if all resistor value are correct. I hope I could finish it at the end of April

Hi. I want to ask about Raspberry Pi Camera. I am absolute beginner. I want to make a project where Raspberry Pi camera send the image to the Raspberry Pi in greyscale and based on white or black, the stepper motor will rotate forward or backward. I want to ask, is it possible to make this project using Raspberry Pi or do I need to used other microcontroller also?

9 years ago i started tinkering with the idea of a board to upgrade both of my SRD-7 to SRD-7 MkII, and then eventually a lot of stuff in my life went sideways and the project got shelved with a lot of other stuff. It did not work! it kind of worked. I screwed up something in the way the voltage multiplier was hooked up to the extent that there was only 26vac across the zener. I re-drew it yesterday. It's possible that aliexpress 1n4007 diodes were a factor. I'll use uf4007 sourced from mouser for the next revision. I know this shouldn't be hard. I'm kinda dumb for a smart guy. Sometimes i get a brain cramp. At the time, 9 years ago, my only high-bias stats we…

The first completed DIY project in 3 years and in my new workshop lives! It's a battery powered Philips TDA1541A based stereo DAC, About 18 months ago I needed something to kick start me back into DIY after breaking down my old setup and moving to Florida. So I built a 10'x11' room in one of the garage bays and proceeded to slowly unpack. I ran across a few threads about the TDA1541 and became curious. This is what I settled on for the first try. It's on a test board I put together so I could mess with different power supplies and experiment with controlling relays to turn the power on and off. It's sounds surprisingly good! Very easy to listen to…

Some guys insist MUSES 72320 is better than relay-based vol control, but I highly doubt that. Any tried that? (Let's ignore those CS3310 etc which are not so good, we only talk about that 72320)

Background: Just for fun, I'm going to build an energizer using a small Class-D power amplifier and a transformer. The inspiration was that I'm basically junking my recently-purchased and rejected Topping EHA5 and O can use the chassis and connectors. The rest I plan to junk. I bought a high voltage DC-DC converter for the bias voltage and a pair of toroidal transformers meant for a tube amplifier. The transformers are so big I may have to mount them on top of the Topping Chassis! For the amp I'm hoping that the Texas instruments TPA3116d2 Class D chip will do a good job. If I don't like the soun of this chip, I'm only out $10 for a populated board from Amazon!!! OK…

I could not help but notice that the dead tree carcass machinists have a thread on wood machining. But dead trees do not make the best cases for stax amplifiers. So i'm a little surprised that there is no thread dedicated to CNC machining metal. The motivation for this thread was that I turned 50 years old a few weeks ago and for my birthday I decided to buy myself a CNC machine so that I could make my own cases for my stax builds. I decided to buy the foxalien Vasto, https://www.foxalien.com/products/cnc-router-machine-vasto?sca_ref=725103.t6qfXeHAnx based on not much more than I needed to machine 400mm by 400mm and the reviews on youtube are very positive. I'm waiting f…

Now, Kerry is currently about to test the latest revision of the Kevin Gilmore Digital Attenuator, and since a few people have asked for a Group Buy we hereby probe the interest. Kerry is mostly inclined for the 50k version. Please put your request into the referenced Google spreadsheet. The information in the sheet in rgrds to price is from the former group buy and only to give an idea of where we might end with this group buy. As last time we will investigate cost of fully assembled boards as well as bare boards (with stencil) if people wants to DIY. https://docs.google.com/spreadsheets/d/131vk972PEIm-J4r5IbZT7IP7CAqoMfP4j0RfE0J0xeM/edit?usp=sharing Let me kno…

I'm happy to report that the goldenreference low voltage dual power supply works as designed, and tests less than 1 microvolt of noise. Going to have to take it to work and put it in a screen room to really measure the noise. http://gilmore.chem.northwestern.edu/goldenreferencedual.jpg however there is one silkscreen error seen by the extra + near the 47uf cap on the right side. I will update the files shortly. All 4 of the 47uf caps need to have their plus sides pointing to the left. very happy with this

So I'm turning one of my garage bays into a workshop. I'm able to fit 8' x 10' with a 9' 6" ceiling no problem. I need some ideas on counter surfaces and cabinets. I'd need some storage, an area for a desktop and 4-6 amps, 2 dacs, and a preamp. Lastly an area to work on projects. Is there an online layout tool that doesn't have a huge learning curve or anyone on here that can do a layout? I'd gladly throw a few bucks their way for some time.

I met Per Lundahl at Capital Audio Fest last year, and in trying to figure out what I could use I'd have for Lundahl transformers I asked about winding something that can drive e-stats, planars, low impedance, speakers from separate taps. I had also just bought a bunch of 6336B dual triodes, so thought that might work. The transformers came and many months went by but finally rigged something up. Basically right now it's just 6336B with both triodes in parallel, running about 200mA with a B+ of 260V. There's an e-stat output that steps up, and also 50 ohm and 6 ohm outputs. The grid voltage is set by a bunch of 9V in series. The black box in the middle on top o…

After almost ten years of loyal service, my KGST is starting to show signs of malfunction. Since last week I have a loud hum in the left amplifier channel. I replaced the tubes with another pair and readjusted the balance and offset. No hum could be heard and I could enjoy the music undisturbed again. The next day the hum unfortunately returned. Readjust everything and the hum was gone. After switching the amplifier off and on again, the hum returned. I have swapped the filaments, but that didn't solve the problem. I also left the gyro turned off, but that doesn't make any difference either. Hopefully someone has a good tip to try.

so due to a comment i made over there, someone wanted to know if i had the eddie current dht filament schematic. here it is. eddiecurrentfilament.PDF

So I've been looking at a bunch of tube/solid state hybrid dynamic amp schematics, and every one of them is some form of bad, or really bad. (one person/ex company in particular) Low voltage plate, capacitve coupling of a high impedance source into a low impedance, poor balance etc. There had to be a better way. true balanced input. dc coupling. low impedance output. no feedback. proper use of a tube (pure transconducance) etc so I came up with this, work in progress. 4 x 3 inches ubaltobaltubeschem.PDF

I am moving Kerry's mini GRHV\GRLV GB discussion to its dedicated thread here. I also included JoaMat's mini T2 here to see if we have enough interest for a GB. The table will be updated periodically as more people participate. Apologize if I missed someone or something - just let me know so I can correct the data. I put down one set for those that have not decided on the number of sets they want. The plan is to have assembled GRHVxxx boards, rest of boards will be PCB only. See discussions on the PS in this thread. mini T2 build discussion in this thread. Construction notes: R3 and R2 determine the regulated voltage for GRLV. The …