OK everybody, time to make my contribution to this thread.
Last Friday, I received the board for the PPA from Tangent, including ALPS pots + TREAD board.
This was actually my first serious DIY electronics build ever, and I succeeded! Thanks to everyone contributing knowledge, instructions etc. etc. Special mention for Tangent's excellent webpage with part selection guide, build instructions etc. etc. Actual build time was around 3 hrs. Was succesful on first power up, thanks to excellent step-by-step build guide.
The amp is running @ 21.5V, using 3xAD8610. Output buffer bias is set to 20mA, but will up that to 30mA tonight just for the fun of it. Will be adding a battery board somewhere this week (16*AAA), running off 24V from wall wart.
Also, I have biased into class A, but I migth have overdone it: from reading this thread, going above 1 V drop across R10 (=1k) really shouldn't be necessary. Thing is: I have trouble hearing any difference; I'll try reducing voltage drop across R10 to close to 0, see if that gives audible change.
Question, though: the max voltage drop across R10G I can create using R9 pot is about 1.8. R10L/R10R max out at only 3.3V. Is this difference in adjustability normal/by design?
Another question: I have added a fixed bass boost, R7=10k, C7=0.1uF (6dB boost). I can not say that I find the functionality of the bass boost very pronounced. I even wonder if it is working at all, considering I have difficulty telling whether it is on our off. Any pointers for obvious places to look?
The build has been very much fun. Somebody I can build a PPA for? :-)
Edited by Koen - 5/17/10 at 10:04am