Do It Yourself

Hi all, As part of my home theater build, have decided to go for 3 way actives for front LCR… so, need to build 9 power amps for fronts and 8 amps for surrounds… to pair up with my Sherbourn PT-7020A pre/pro. I needed something as easy, but more powerful. This is when I and my friend John found the datasheet of TDA7293. This IC can run up to 100V, low distortion, and can easily be paralleled. Having built single chip amp and extensive listening TDA7293 is my favorites for IC power amp applications. I have been looking for a source of PCBs using parallel TDA7293s… there are not many out there that you can buy. We then decided to do our own PCB. Our schematic is almost…

I've got a couple normal bias Staxen I'd like to build an amp for, any ideas for any simple mods to make a normal bias KGST? Edit: apologies if this is a simple mod, I've done searches but what comes up is for going the other direction (normal->pro)

What's the polarity of the Turbulent Labs driver? Is the green dot + or - ?

Yet Another XLR Question... Building my first balanced amp, some connection questions: What do you do with the shield? Reading the RANE app notes seems not appropriate for parts of this, since I am using 4-pin XLR, and the 3-pin standard has pin 1 as ground. I am reworking the previous 4-conductore rewiring my phones right now, and chopped the previously wired 1/4" plug cable part way to wire in a 4-pin female/4-pin male (the male will be the main phone connector into a 4-pin female on the amp), turning this cable portion into an adapter for when I want to use the phones from an SE amp. The main cable terminates at the phones in a 4-pin mini XLR, in which the …

Hi: I am organizing a mini group buy of HGSSHV PCB boards. I intend to move very fast so please read this post carefully if you are interested. I'll be using the kgsshvampv16mini.zip for the amp boards and kgsshvpsminifinalstn9360.zip for the PSU boards. The amp boards are the one-board-per-channel, off-board heatsink version. Both amp and PSU boards have provisions for current production parts. See here for the Gerber files and the KGSSHV thread for more information. I plan to use SeeedStudio to fabricate the PCB boards. The boards will be 2 layer, 1.6mm thickness, 2oz copper, HASL surface finish and standard green color PCB. Each set of the boards includes …

never mind

I'm looking to do a group run of the KGST boards, please followup on this thread if interested. Thanks -

Staxen amps (at least the Mafia versions) use either el34 or 6S4 (with the Megatron including some 12's ...) I sold my tube tester years ago after getting out of SET's and such. What do you all think about testing these tubes? Is there a simple test rig, perhaps even 'in circuit' we can use to test the tubes without having to deal with a full blown tester?

I'd like to call into question some do's and don't I've heard about building Stax amps. I'm an engineer who works on scientific instrumentation and have heard a few things I don't understand based on my experience, so thought it's worth a discussion here. Please correct me if my thoughts on these issues is incorrect, from an engineering perspective. High Voltage resistors are necessary In general HV boutique resistors are really only needed when there’s a large differential voltage. Let's take a high quality but not HV resistor, the KOA Speer which range from 250V-1kV working voltage http://www.koaspeer.com/catimages/Products/MF-MFS-RK/MF-MFS-RK.pdf Take…

I ordered some of those teflon 9 pin sockets off the eBay user many here have used. They look fine but I've not used 9 pin teflon before, at any rate getting a tube in one is extremely difficult. I can remove an individual pin and put it on pretty well, but leveraging all nine into the socket is a nightmare, I can't imagine trying this with a soldered socket. At least when unsoldered the pins have a little play to align themselves. Other experience? Do I actually need to pull all the pins, try to use and pre stretch them before use? Ugh ...

Does anybody have a source? All I see so far is chassis mount.

Crossposted from diyaudio: http://www.onsemi.com/pub/docs/pcn/PD20685.pdf On-semi are discontinuing all of their TO-92 products because of a disagreement with a subcontractor. List includes all the MPSWs.... //UFN

Can anyone recommend a reliable PCB manufacturer in China?

Trying to make some DIY USB cable, but I cannot seem to find USB 2.0 type B male plugs anywhere in USA, only some from China on eBay with long shipping estimates. Found some type A plugs on Amazon. For type B, looking for something like these: http://www.ebay.com/itm/170578212079?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

My original Dynahi built in 2008 is still going strong and sounds just a good as they day I finished it. I replaced the 50K volume pot with a 10K as it should've been years ago. I believe KG said 50 was to high. With the 10K the amp sounds perfect but I think I've lost the use of the full range of the volume control. I only use the first 25% now where I used to use up to 50% or more with the 50K. Do you think it would be ok to switch to a 25K volume pot?

I spent the better part of last weekend researching amps for a new pair of headphones. Reading other people's reviews and seeing their pics is fun, but figuring out whether the amp outputs enough power or if the damping factor is >= 8, well that's tedious. So what started as a few formulas on paper eventually (over the span of a week) turned into a website that calculates all this for you. It's a tool I built for myself, but I hope you'll find it useful too: www.audiobot9000.com

I've got the permission from Dr Gilmore for a second run of boards, so let's do it again. Linky to the spreadsheet: https://docs.google.com/spreadsheet/ccc?key=0AoNVeoQi85GgdFVrMmtReVpWNVBsQUo2Sl9iSkItM2c#gid=0 Please take a look at the notes before putting your needed quantity. If you want something extra (like a single PSU or amp), just put a note under Extra Requirement column. The Megatron is not fully-tested so if you really want to try it, do it at your own risk. Silkscreens for the boards: + Megatron: http://farm6.staticflickr.com/5489/9229564952_a344b73826_b.jpg + KGSSHV onboard: http://farm6.staticflickr.com/5340/9224679066_7e0d75ce72_b.jp…

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?

I can't seem to find it as google returns no results from possible matches from this site, but I do remember somebody (think Kevin himself) discussing and posting a schematic of an updated mod to the SRM-323S to increase the output power to 450v, would be great if somebody or Kevin himself chimed in with the pdf and what needs to be removed and added in place in the 323S for MOAR powah. I've got a spare 323S lying around so want to give it a go. cheers

I want to tackle and finally finish this PINT amp I recently acquired. It's old school and I scored the board for next to nothing, so what the heck. I know the project ended up ceasing because of the crankiness of the 8397. There’s got to be a way to tame this thing. At this point, I’m not sure if I’ve fried the opamps, but I can say that the 8397 gets very very hot. I’m using the LM6172 as my GND channel opamp and this is getting quite warm as well. This is when I power the amp with at least 18v or 24v. I'm getting an unusual amount of DC Offset -- basically the rail supply for each reading that I've done. At first the amp seemed to work but music sounded hollow and not …

I'm building a Xono clone. I need to match 2SK170 JFETs and BC550 BJTs. I'm new to transistor matching - Google has left me a bit confused with the amount of "suggestions". Any clues as to the best / most convenient method, hopefully with a link to a tutorial?

So i just build a crack /w speedball and it all went well and it is sounding great. Except that the stock pot is pretty shit and i wouldn't mind a remote control. After some searching i came across this one: http://www.tentlabs.com/Components/page31/page31.html Some specs: Input impedance: > 40 k-ohm (actual value depends on volume setting) Output impedance: < 8 k-ohm (actual value depends on volume setting) Power: AC or DC, 6 to 10V max, current max 150mA DC, 225mA AC (power connector supplied with module) Volume setting: 64 steps of 1.0 dB Channel imbalance: < 0.15 dB Inputs: 4 Input / Output connectors: Cinch / RCA (can be supplied without conne…

I wanted to re-terminate an HD650 cable to 4pin XLR. What is the best way to strip off the black sleeve without cutting one of the tiny wires? I was trying to carefully clip it with small wire cutters but I keep snipping one of the little wires. I also tried a wire stripper and that was worse. Will it make much difference if one of the wires is not connected (as long as the majority are)? Also, I see that the HD650 cable doesn't have shielding so I assume one doesn't anything to the 5th metal connector.

I'm thinking about using the 4 gang ALPS pot for my dynahi. I want to mount it on a pcb but I don't see any available so I thought if I took two epsilon 27 boards I could make one. The first board would fit the front, the second board looks like it would need the front trimmed off to fit the back section. The grounds are tied together on those boards so I'm not sure how that comes into play since I've never wired a pot for balanced audio before. How do you wire a volume pot for balanced audio and do you think this would work?

Dunno if anyone here might want to say something in this thread: http://www.head-fi.org/t/707823/intellectual-property-giveaway-on-the-discovery-of-terminal-illness#post_10316570 But I will certainly miss him.