Do It Yourself

The "super power caps" that Nissan is going to be using in their upcoming hybrid electric diesel cars that they'll be using instead of batteries.

How can I measure if my DAC puts out common mode DC from the balanced outputs?

Basically a two part question. I want to get some isolation feet for some of my gearses and speakerses. The speakers are easy, as I know they are M6. But... 1) How would I go about determining the thread size where I don't currently have a screw? In other words, the component has a threaded insertion point, but I don't know what size it takes. 2) For those components where I want to replace the current feet, what's the proper way to measure the screw so that I arrive at the proper thread size?

I have several OPA627 and OPA637 in 8 pin dip. Some I ordered from digikey, some from ebay that could've been digikey samples and some from ebay that aren't. The problem is I acquired some when there were some fakes going around. I didn't separate one order from another and put them all together. I'm sure some are real and some are fake but is there a definitive way to tell?

As many of you know, I for one have stopped releasing all new designs for a few years now after I got fed up with people building crap and claiming it was somehow connected to Kevin or I. Now this also means I don't release the PCB's for many of the older projects as I want to change something and often... make them smaller. So this hasn't stopped people selling crap with our circuits but at least they don't get any of the updates. Now here is an amp I saw come up for sale in Japan a while ago. The new owner contacted Kevin to try and trouble shoot it but yeah, we don't offer any real help with these things. Something about the PSU did peak my interest so when …

What is the best way to break one? Thanks, Biggie.

Hi folks, my friend bought a power amp from a small manufacturer locally, it's single ended, non-feedback, discrete stuff, two big toroidal trannies inside (450W each), diamond output stage, using 6 pair of 2SC5200/2SA1943, output power is about 100w @ 8ohm, here's the FFT result they send us, gosh, there're lot of distortion between 90 - 900Hz compared with 1k - 20kHz (but, there's still a peak at 2kHz), what reasons do you guys think that may course these distortion? How do we tweak it to make it lower distorted in those area?

I've posted this already on another well-known headphone forum, here however I see DIY is more prominent. I'm thinking about bying an used pair of ESP 950s and seriously modding them. I've considered making a totally DIY ESL headphone, but making the headband and enclosures for them is too much for my limited skills. Kosses though seem to be a fine ESL headphone as they are, and from pictures of their insides on Wikiphonia it seems that there are some mods easily possible. 1) Removing damping and maybe adding 'phase corrector' like on old Fostex T50 - a felt ring which suppresses high frequencies coming from outer parts of their drivers to even out phase and f…

Any you guys know what's in this box? [url=http://www.head-fi.org/forums/6245035-post760.html]Head-Fi: Covering Headphones, Earphones and Portable Audio - View Single Post - REVIEW: Audiotailor

http://nervenet.info/HT_delay/ I bought 2 of these to delay the HV startup of the megatron, I'll let you guys know how they turn out. Seems like a pretty nice drop-in

A friend asked me to come up with a phono stage that is of reasonable quality but not too over the top. Here's my first go. Basically, it is a hybrid cascode gain stage followed by a passive RIAA filter and a cathode follower. The idea is that the single gain stage should not only provide enough gain, but it should be reasonably quiet. The Zout is also governed by the plate resistor which keeps the filter stable even as tubes age. In a sense, it is much like Pete's pentode phono, other than that the cascode should be a bit quieter than a pentode. That's a lot of should's, so it remains to be seen whether it actually works. The only really tricky part I anticipate is se…

Yet another stax project soon. A lot of people are going to want this i think. Birgir knows what it is, and had better not drop any hints hint: diffuse field.

I'm looking to give my headphone cables a more professional look like this http://redsecta.files.wordpress.com/2012/03/650cable.jpg I want to find splitters like this guy used

I decided to recase my original dynahi. I wired the ac inlet, then hooked up the transformer primaries (Avel Lindberg transformer) gray and bown wires went to hot, blue and violet went to neutral. I got correct voltage on the primaries and secondaries when I threw the power switch. I mounted the original psu in the case. This is the board http://gilmore.chem.northwestern.edu/dynahipsbig.bmp I connected one pair of secondary wires to AC1 and the other pair to AC2. The order went 1 to orange, 2 to yellow, 3 to black, 4 to red. I threw the switch and the fuse blew. Now the transformer primaries and secondaries are shorted when checked with a meter out of the cir…

Hopefully I'm at the right place this time. I want to build a kevin gilmore blue hawaii amp. As a starting point I found the original http://headwize.com/?page_id=751 and the more recent http://gilmore.chem.northwestern.edu/BlueHawaii-T2-Servo-v1-2.zip (needs LTSpice). Is there a recent version without servo, with PCB's and all that? CCS is yet partly diskussed, has someone experiance with "mu follower Output" to decouple the complex loads partly from the tubes (see schematic)? What about a PS if no 500V pnp is found? From the PSRR viewpoint I'd start with the concept: "care about higher harmonics, PSRR can start to decrease at a cut-off in the 1 kHz region. And: …

I have two OBH-11SE's. One of them is broken -- it's mono; other than that, it sounds fine. I got it used. I suspect the previous owner was messing with it. There appears to be an additional jumper from Q9 to Q11 (similar to the one from Q5 to Q6) -- could this be the cause? Or is it a red herring, some sort of tuning thing? I don't see a stray dollop of solder anywhere, but I could be blind. Does anyone have any ideas? Does anyone have a schematic of the thing? Tell me what to measure and where, and I will.

So for whatever reason a number of different projects are coming together at the same time. This is the latest. http://gilmore.chem.northwestern.edu/kgsshv.jpg Its the high voltage version of the kgss with higher voltage pnp transistors, a cascode current source for the 3rd stage, the lsk389 part (or singles) and much higher voltage output transistors. The result is something that runs on +/-500 volt power supplies, and is as close as i know how to do to the T2. (except fully solid state, and easy to build) The transistors that go on the heatsinks are already insulated, which makes that part easy. Not a lot more money than an exstata, and much better sound. …

so pars posted this. http://www.diyaudio.com/forums/group-buys/315474-pure-tube-es9038pro-9028-9018-akm.html#post5259820 all sorts of wrong. lets start with the fact that current output D/A converters really like driving a zero impedance. 27 ohms is not a zero impedance. So with +/-1.2ma you get +/-32mv and then you use the tube to amplify the crap out of it. Nope, definitely not the way to do this. All sorts of noise etc... a while back there was bakoon and audio-gd pointing fingers at each other as to who designed satri and when. so here is the satri version 4 circuit satriic.PDF and here is how audio-gd turns it into both the I/v converter…

I've been messing around with a Counterpoint preamp I have owned for several years on and off. It's always had a slight amount of hum, not real bad, but it bothered me. Over the years I've managed to make it worse, and then much better, but never quite gone completely. After dealings with a couple of former service techs on diyaudio, I finally decided to try once again to rectify this. I was prodded to look at the PSU, particularly the heater supply (I'd already done some work and parts replacement in the HV section). Looking at the heaters, I had recalled seeing some ripple on them back when I rewired the umbilical (both before and after). About 50mV of r…

Don't be fucking wit sharp toos when you're tired, especially only 10 minutes after the wife says 'should you be doing that when you're so tired' ouch! ` That's gonna leave a mark...

So some parts are rolling in. I'm excited to finally get the solder iron up and running again. I'll jump on the balanced connections in a week or so, but I bought some extra wire and RCA connectors to build a pair of interconnects. I'll be using: DH Labs Pro Studio for the wire. Twisted pair inside with a shield outside (pretty standard) DH Labs RCA-3 connector. Now, the RCA-3 connector is a little different than what I have used in the past. It looks like this: It looks very much like these would be great for a digital cable (and they are 75 ohm as well). For audio, though, I have a twisted pair inside the cable with the shield outside. I'm fairly sure…

Hello All... After realizing I missed out on the latest group buy I thought about having a run of boards made. I believe 3oz copper is recommended for the GRLV and in order to get the boards to an affordable price with that weight it looks like 20+ would do it. While I'm at it, is there any interest in ALPS quad pcbs as well?

Hi new to the forum and I am interested in building a kgsshv or kgsshv carbon. I have done other projects from amb.org built a beta22 / lcdduino / volume control system. I am unaware if there are any guides or published places to get information on where to start these builds / parts lists? I have found the circuit board gerber files and I am guessing I have to send those to get my pcbs manufactured? But I am a bit confused as there are many versions and variations of build files. For example I see Kgsshvcarbon v1-6 and along eith them left / right / servo / ground. Any advice would be appreciated.

Hi all, I've been more and more interested in building my own amp after having built a relatively simple Elekit amp. I've been reading through the KGSSHV and KGSSHV Carbon build threads and I think I've found the google drives for the schematics and various documents, but it's still a bit confusing where to begin, and I'm not entirely sure I should jump right into trying to build a KGSSHV Carbon. I'm also unclear where one sources the PCBs for any of those builds - seems like various members hold extras and there are some floating around on eBay of dubious origin. Anyway, I'm not exactly certain what build would be good to start out with, or what the differences are …

I'm looking for suggestions of interesting DAC designs and/or PCBs/kits. I guess I'm shooting for the higher end of things, and PCM1704-based stuff has gotten my attention. So far I've found the Hagerman Chime and TentLabs kit. Any opinions on these? Anything else I should consider? Also, are there any standalone USB-I2S or analog output stage kits worth looking at? Thanks!