Thank you very much for your reply, Zen Mod. Please look at my initial measurements sheet, attached to a previous post. On each channel I have a trio of P and a trio of N that have a lower bias. Even though I have now adjusted the bias equally to the two branches of each channel, both reaching the value of 70 mV, those two trios (a P trio and an N trio) always remain at lower values. This phenomenon happens in a similar way to the other channel. I thought it was normal, that it was due to the topology of the amplifier, that's how it was designed. Do you want to tell me that this is abnormal with X250.5? Wow! Please, enlighten me. Thanks a lot.
what I would do, to determine state of matching in your amp ( was it there some replacement adventure in past, or not) :
-exclude 2SA1943 from game, exactly as I wrote in my previous post.
-check/set amp's relative and absolute offset
-set amp Iq gradually, to have it 25C more than ambient, on top of heatsinks
then making new complete table of values across 0R47 source resistors
from that table everything should be crystal clear
putting back big bipolars is trivial, same as re-setting Iq, if needed at all
