Sorry for keeping you waiting. Whenever I think that I have got a speck of time, brand new problems jump up and materialize themselves left and right. I actually got the amp done last week in about two short evenings, but I initially had the plan to only post when I had the schematic ready. I haven't completed it yet, but it's pretty far along. I will finish it one of these days, I hope.
1) The FETs are indeed cascoded with V1, they are the first thing the input signal goes through. Sadly, as you can probably make out from the photos, there is no information whatsoever on them.
2) The Power Transformer does have some numbers on it, but it's jibberish. Judging by the size, it should be 50VA.
3) The many little resistors are in series and together form the load resistor of V2. It seems to be about 110k short of the 330k given in the original schematic. What a really ridiculous move to alter the board for a few cents saved...
4) I am an idiot starting work without proper desoldering equipment. Had I spend a few bucks more, I would have been finished in half the time.
5) I changed a few cathode resistors to Amtrans and the RIAA to Shinkoh, the cathode resistor of V2 to an Elna Silmic II (ended up not bypassing that with 1uF...), all the Caps of the B+ PSU to Panasonic 100uF 400V bypassed with Panasonic 1 uF film caps, the diodes of the B+ supply to Vishay Ultra Fast Recovery Soft Switching and the coupling caps between V1 and 2 as well as V3 and output against Mundorf Zn. The RIAA caps were substituted with Charcroft Silver Mica of the same values. I removed the resistors and caps between V2 and 3 and the one from there to ground and substituted a 100R Allen & Bradley Carbon Comp. I found so many people who did this mod and nobody wrote about any problems with it.
The amp sounds noticeably different, I would say. Where it was good before albeit maybe lacking emotions a bit, it is now sparkly and alive.
I still think, this little amp is one of the best deals in hifi at the moment. A few little tweaks might make it something really sweet and worth having.
