The output electrolytics are 3.5mm pitch, 8mm diameter to fit the bulkier polymer type. You could squeeze up to 680uF regular electrolyte caps in there
Hello pcgab,
The group buy did not happen, because the project morphed into an "altoids amp". A very nice project, for sure, just different.
There was an earlier post with smaller boards, one board per channel. You can buy 3 of those boards for $18 and change. That is the exact same package I uploaded and built. The gerbs are known to work.
The second post (the one with two channels on one board) has not been ordered. I made those for X. who asked for one board with 2 channels per board, and that was the layout proposed for a group buy. However, that group buy did not happen as the amp morphed into something else.
You could still buy boards made from my first post with gerber files. I ordered and built those boards, and know they work. They will cost you a shade less than $19, and you'll get 3 boards, 2 for stereo and one for, well, whatever.
If you use gerbs from my second post, the one you shoed interest in, those will cost approx twice as much, probably around $38. I'm guessing at the price because I have not ordered or built that package. In exchange for your $38, you'll get 3 boards, one for stereo, and two more for, well, whatever.
Two of the small boards would fit nicely inside a Hammond extruded enclosure. Use a plug-in-the-wall power supply that outputs 16V A/C, then build a small rectifier/regulator/cap multiplier board for power. Think O2. Not portable but would make a nice, small desktop.
Regardless, there is no group buy, but you could still order boards for yourself from the OSH Park website. There are other PCB vendors, but Ive not used them and do not know if the gerbs would meet their standards.
If you are still interested, send me a PM and I'll make sure you get the right set of gerbers, which have on channel per board, built and tested. There are many gerb viewers out there, GC Prevue being my preference. I'll also walk you through the OSH park ordering process, it's really easy.
The output electrolytics are 3.5mm pitch, 8mm diameter to fit the bulkier polymer type. You could squeeze up to 680uF regular electrolyte caps in there
Strictly FYI, I've used PPS caps in earlier builds, but on the input, and they sounded just fine to me. They are also small, the size of polyester caps. I got the idea from Sjostrom audio. A few years back he hosted a diyaudio headphone amp project based on the TPA6120 (at least I think it was the TPA6120). The input had a 470M pulldown to gnd, a 0.47uF PPS in series, another 470M pulldown to gnd. I think that was followed by an RF filter, but my memory of that is vague. NWAVGuy reviewed his design on his website, probably still there.
I am still open to a GB if enough folks want it - it did not morph into Altoids. They are two very different amps. One is desktop and one is portable and sound signatures are different as well.
As usual, if you want to be part of the GB, just add you name to the list and when we get 5 people we can do it. My offer to run the GB was the standard pricing of $17 for continental US and $23 for elsewhere for 2 boards (2 stereo amps).
Thanks to Mlackey for providing the Gerbers - they will not go to waste!
Cheers,
X
I've had good results with PPS caps, using Kemet SMR for through hole and Panasonic ECPU SMT. I think they're an excellent alternative to PET / PP
Lol, you guys know so much more about electronics than I do. X, I hope that when you've finalized your mint tin amp design, you will create a somewhat idiot-proof BOM so that a schmuck like me will stand a chance to order the right components! At least there aren't too many parts, eh? I'll be in for two boards when the time comes. Very excited about this project. Thanks for the work that you, BDHM, and other contributors are doing here.
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I'm in
I PMed you and I'm in for 2 boards,
Group Buy for 10 JFET head amp:
- Pcgab 2 boards
If there was anyone else who PM'd me, I may have lost your name or forgotten - please just reply to this post with a quote and add your name.
I PMed you and I'm in for 2 boards,
I've drawn up a BOM for all the necessary bits and pieces. I'll publish it as soon as we're 100% sure of everything
If you all think it would be helpful, I'd be happy to post a bit about the mint tin amp on Head-Fi in the next week, to see if I can stir up some additional interest for the group buy. They do have a DIY forum over there as well. Especially since this looks like a comparatively inexpensive, easy-to-solder project, I think people should be quite intrigued. And it seems to me a very innovative circuit...the whole concept is so cool. Class A in a mint tin!
If you're interested in that amp, why don't you just ask for the Gerbers and then order PCB from PCBway yourself, just USD19 for 10 PCBs including shipping (from China) to the US.
Or order from OSH Park, USD13 for 3 PCBs before shipping, it's US based so shipping within US won't be expensive.
With some PCB houses in China, you can print 20 such PCBs for USD7.5 (so 37.5 cents each), before shipping.