So, bad weather here and I went for the very last action, replacing transistors in tone amp section - and run into issues.
1. Replacing D902a,b with BC640 went good, I even believe that sound had improved (basses do not sound "annoying" anymore)
2. Replacing 901a,b and 903a,b with BC639 -> The sound had improved significantly (high tones became really sweet) - but background noise went horrible! I also had some occasional visual "pumping" of bass driver on my loudspeakers.
I put back the originals and all was good again. Now seeking for replacement for 2SC100 (original transistors are marked BC, 4TC, C1000). Any idea? Would 2SA1815 be the right replacement?
1. Replacing D902a,b with BC640 went good, I even believe that sound had improved (basses do not sound "annoying" anymore)
2. Replacing 901a,b and 903a,b with BC639 -> The sound had improved significantly (high tones became really sweet) - but background noise went horrible! I also had some occasional visual "pumping" of bass driver on my loudspeakers.
I put back the originals and all was good again. Now seeking for replacement for 2SC100 (original transistors are marked BC, 4TC, C1000). Any idea? Would 2SA1815 be the right replacement?