I got busy with amps over xmas and managed to do an AU-999, and a pair of HF-V60 & PR330. Well, I also managed to do an AU-111. I haven't officially signed off on it as I'm now trying to put together some kind of cover (mine didn't come with sides, or a cover) as well as fix up some blemishes on the front panel edging (the front panel and knows are in nice conditions, and the amp has no rust. The bias setup was 2-pot, but I changed it to 4-pot. Interestingly, where there are other differences between 2-pot and 4-pot schematic my amp usually follows the 4-pot version so I guess it was built right in between the 2 and 4 pot versions. I will have to add this one to the serial number database.... I found at least 2 schematic errors. I'm not talking about small value changes or the like... have a look the phono section (btw, a very early demonstration of 'hybrid' semiconductor/tube, no?) Notice that B5 is positive supply (B6 is just a connection to share positive supply to the other channel of the phono section). Then notice that the first transistor is drawn as an PNP which should have higher voltage at the emitter than collector. In fact the 2SC-402 is an NPN, and my unit has Hitachi 2SC650 installed (also NPN). So yes, the diagram should have been an NPN, not PNP. I also confirmed that the supply to the collector is indeed positive (why? read on). How could this have happened? I have an wild suggestion. Someone started on the AU-111 schematic by a 'copy & paste' from the AU-70 which came just before the AU-111 and also used a similar hybrid phono section. However, the AU-70 does use Germanium PNP transistors used and the collector has negative supply; this negative supply comes from the power supply section feeding the negative output tube grids (the AU-111 also uses negative output tube grid supply). However, for the AU-111, the time was right to move from Ge to Si and an NPN was used (I don't think there were many PNP Si transistors at the beginning... correct me if I'm wrong, but I believe that is why the AU-777 and similar amps were all NPN rather than complementary). The other error which actually clouded some trouble shooting I had to do in the project, is related to a tone frequency adjustment and feedback loop on a later preamp stage. I will get to that later. This thread may move slowly... but it will happen. And then there will be a real sansui amp shoot-out! The amp is basically done, getting burned in with new output tubes but I will wait until I have finished the cosmetic side before putting it into full service. This will give a chance to observe it on the bench for extended periods and make sure all is well (as usual, things look good, but I always manage to find something fiddly to fix... and it's quite interesting and probably a problem on most AU-111 so I will share details as it can lead to significant channel imbalance if unattended).