Do It Yourself

This is a very niche topic so if you are not planning to buy or write programs for the Keithley 2015 or 2016 thd or p multi-meters then this post will probably not be interesting to you - especially given their skyrocketing prices on ebay and their age. If you are planning to buy one because it has audio analysis built in then there are a number of limitations and issues you should be aware of before deciding to buy. Some of these limitations effect the accuracy and validity of its calculations and are not documented in the manual, some of the limitations effect usability and some effect it programmatically if you access it through gpib or rs232. If you look on the i…

Oh effing snap. The LCDuino-1 I/O processor - Head-Fi: Covering Headphones, Earphones and Portable Audio

I'm trying to make a Super Symmetry Dynahi (not dynalo) the best possible way. (without getting in the ridiculous). Anyone could direct me to the up to date gerber files, a BOM, any other resources are also appreciated. Also if any of you previous builders have recommendation on best practices and what to avoid while making the susy please share ! Thanks

I'm going to create a thread for this amp since it is my intention at the end of the build to publish the schematic and any relevant details so that anyone who's crazy enough can build this amp. So for now this (and the amp) are a work in progress and just somewhere where I can share pictures. Actual information will come later. Night #0 of PS chassis fabrication: I did a preliminary layout of all of the parts on a large 17" x 14" x 4" Hammond Steel chassis that I happened to have laying around. It seemed big enough so I took rough measurements of where everything was located so that I could tweak them later for better alignment and symmetry. I'm not all that concerne…

This one has been brewing for a while now but since I wanted to build a nice balanced amp it moved up in line. Basic setup is the same as the old Dynalo but now with Super Symmetry input, higher rail voltages and naturally a bit more power. Input stage changed to THAT340 which is a quad bipolar transistor array with matched NPN and PNP pairs. It is cheap and easy to source so no jfet drama. The other transistors are new as well and the pinout is different to reflect that. Here is a look at the new PCB design which is pretty much ready: It is 138*86mm. Another thing from the same vein is a fully discrete unbalanced to balanced circuit that we have …

Finally found a way to get cheap output transformers for my amp after reading this page. All resistors are 1/2W unless otherwise noted, coupling caps should be 250V or better. The power supply capacitors are all 240VAC motor run caps from Aerovox which I scrounged for $5 a pop from the surplus store, and the chokes are also cheap surplus store goodies. You don't have to go nuts on the PSU like I did, I just felt like building an amp with no electrolytic capacitors anywhere in it. The output transformer is actually a 50W toroidal power transformer from Amveco (~$20 each from Digikey). If you have high impedance 'phones or simply listen loud then connect the seco…

So this started a few weeks ago when someone found a picture of my 100 watt night light. Its an 833A tube. (new picture below) And he wanted a megatron made from 8 of these. (10 vac at 10 amps each tube) so 800 watts filament power just for the output tubes. By the time you make the +/- 1kv power supplies running at 40ma, and the power for the 300b driver tubes etc, way past the limit for usa 120v 20 amp service which is 1850 watts. And with the top of the tube at silly and dangerous high voltage... bad idea. So i started looking for slightly less silly alternatives. I think the 211 tube fits the bill. running with +/-750v power supplies at 35ma. So a megatron with…

I've been lending a hand with board layouts for a few projects, notably for a build of Kevin Gilmore's DynaFET design, and doing so made me realize two things: (a) there aren't any DIY projects for amps with a truly high-end feature set, and ( I want one, but I can't really afford it. The DIY crowd has some amazing analog designers and has produced some really astounding designs, but the supporting and surrounding circuitry often isn't much more than a pot and maybe a selector switch, and sometimes a power LED or relay control circuit. There's so much more that could be done to make amps more convenient, self-monitoring, and just plain nifty. So I decided that this was an…

So after a successful T2 project, it is time to tackle something i've been playing with on and off for quite some time. The KGITSOJC The Kevin Gilmore in the style of John Curl preamp. Now if you want to read over 700 pages of babble and bullshit, you can go over to diyaudio and read the two threads. But suffice it to say that the Blowtorch circuit sounds very good, but JC is of the opinion that only 2 people in the world are capable of building and getting the thing to run. I kind of disagree with that because i have one exact copy of the blowtorch amplifier running right next to my version. He has some reason to say this, parts matching is ultra critical,…

I bet everybody knew this was coming but we've been moving fast and the board is taking shape. If it's not clear from the photo then this is a massive slab, 16" x 12", so quite a bit bigger then the production version. It will be built like the BHSE with the board mounted to the top of the chassis, with the tubes sticking out of the top and the components on the bottom. Massive heatsinks are needed to keep this beast cool and a single angle bracket is used on each side of the board to connect all the parts together and make assembly just a bit easier. To honor the Stax legacy the following will be printed on the board: "With the utmost respect and admirati…

A mate at Auriculares posted the link to this article which may be of interest for you DIYers. Not being a DIYer myself I found it interesting nonetheless.

I'm thinking of having some of the golden reference, dynalo, and alps quad pot boards made. The place I was thinking of using was seeedstudio.com Is there a better place for small runs? Their least expensive option is 1mm thickness, 1oz copper in green. Are those specs good enough?

So birgir asked for this one, but truth be told, i have been working on it for quite a while, and i have a working prototype. Specs: DC to 200khz +0, -.2 db Slew Rate >350 volts per microsecond Thd < .01% Voltage Peak to Peak, Stator to Stator 2950 http://gilmore.chem....n.edu/togte.pdf This is not for the faint of heart. The amp actually can go higher in voltage by a bit, but anything over +/-750 for the power supply gets to be Very difficult to regulate well. The +/-250 is actually resistor dividers off the +/-750 Its the only push pull fully dc coupled electrostatic amp that i know of Since this schematic i have replaced the 2s3840 with…

I saw this in a post somewhere and assumed it was a typo, but it is in fact real. Here's a linky to the page: http://focus.ti.com/docs/prod/folders/print/opa827.html. Aparently an upgrade to the 627. I'm a big fan of the 627 (I know, it's just an opamp, discrete rules, yadda yadda), so I'm quite anxious to hear what this new flagship is all about.

The end of a headphone plug broke off in one of my headphone amps that has a locking Neutrik 1/4" headphone jack. I tried the straw trick, and even the screw trick (gently), all to no avail. Considering the glue/heat trick. Am I fucked (and not in a good way), or is there another technique I should consider trying to get the piece out? Any inputs are appreciated. TIA.

Hi All: I inquired TKD Japan directly about their 4-gang volume pot 4CP-601 and they referred me to their US distributor. Long story short, looks like I can get the 10K pot for $65 a piece plus shipping. The cost may be slightly lower if total quantity is high. I am still working out some detail information. Any interest?

I was hunting around in the garage last night and came across an old t-amp I put together many moons ago and it has a TKD pot attached, I bought it quite a while ago and don't recall where from. Are these any good? It's 50k so I figured it'd probably be ok for either the SS I'm about to start or maybe even the Dyna. I can't find too much info on it and nobody mentions them. looks the same as this which is listed as a Ko-on. Anyone familiar with these?

I think that I'd like to get some flux to make things like tinning wires (in a solder pot) and soldering to connectors, etc. more easy. So could you please answer the following questions: 1. Do you use flux? 2. If so, in what form factor? Paste? Pen? Other? Thanks for putting up with my total DIY ignorance and for helping me out.

So, I have some nice shiny TO-3 transistors. I'd like to make a PCB with these as output devices and some sort of way to transfer heat via flange that I can mount to a heat sink. I have to admit I've never used this package, so I'm curious.... assuming I cannot mount the can on the fin side of the heat sink (which would require way to much milling and effort), what sort of ways are there to deal with this? Second question, and not at all related to the above... any recommendations for a relatively low voltage CCS? Let's say 60V and 3A or so as extreme parameters. Thanks!

Tonight, I'll be making some new ear pads for my new vintage electrets. The electret arrived with ruined pleather pads. No pleather left, only uncomfortable fabric. As a downside, the fabric ruins all the deep bass. My first attempt to restore the pads wasn't a success. They ended up a bit too small for the baffle. I'll be making them (or try to make them) with a bit bigger diameter, to reach further out on the baffle. They are to fit onto here: And the old pads measure like this:

I'm looking for some new hex keys/allen wrenches. I have the typical cheap set and assorted ones that came with furniture, but those suck because they tend to corrode or get stripped by tight screws. I need a set that is well-made and has more torque than the typical L-shaped keys. I know Klein makes sets, but they can get pricey. Any recommendations?

Ever made something real quick, going against your feeling that it might be a bad idea? Here is one I did today. It isn't as bad as it could be - it was plugged into a fused variac - but still...

so tyll has been going crazy over the bakoon for planars. well there are a lot of things i don't like about that amp, especially the battery power and distortion. so here is something much better, tested last night at .06%thd, no feedback, output impedance 100k which is solely due to the servo... http://gilmore.chem.northwestern.edu/currentsourceamp2.pdf http://gilmore.chem.northwestern.edu/currentsourceamp2.zip also testing curved traces

This concept has interested me for a while now given just how simple the amp could be made. Just two tubes per channel and then a phase splitting output transformer makes for a stark contrast to something like the T2. Now whether this simplicity is better or worse isn't the issue for me, I just want something different. I figured it was time to get the concept of these amps outside of the random thread on HF and PM's. I've been talking to Frank Cooter about this and given how happy he is with his D3a/KT88 amp I'm going to try something similar. I'm always a fan of using what I have (hence my Exstata is a bit different from all the others) so soemthing like the …

well the stax mafia has been fairly busy the last few days. So a person over there was asking about a specific amplifier that they thought was WAY overpriced, and significantly under performing. Helped out by the fact that a certain moderator over there was shilling the hell out of it and doing his typical hatchet job on various posts etc. Well that's enough to get us involved. Combined with a picture of high enough resolution posted on the 6 moons website. Guys, seriously talk about giving away the farm. Well... http://gilmore.chem.northwestern.edu/alostudio6.pdf What a massive piece of crap this is. If you really want to build one, its trivially e…