Hey guys, I am working on recapping/refreshing an AU-20000... I have been inside of a AU20K once before, several years ago for a basic recap. This time around I want to be a little more thorough.
I am not well versed at selecting proper transistor replacements, especially smaller ones. I have a few resources bookmarked for finding transistor subs but I know its not cut and dry and can depend on the circut/application. Im hoping using this thread for a QnA can at least be a good resource for future restorations on this amp.
This unit was properly working before I started so I wouldn't say there were any immediate problem areas, so I more looking to replace any 'known issue' transistors or ones that would improve long-term stability or sound quality.
I am also aware of the many other one-off issues to look for and address in this specific amp, those are well documented elsewhere. Want to focus on transistors here (and while there are a lot of threads regarding this amp, not so many with detailed transistor subs).
Here are the boards, and transistors. Any input would be greatly appreciated and sure others will find this valuable in the future (hopefully)
Edit: Adding bold text to any considered problematic or noisy
F-2511 Protection board
2SC1364 > KSC945C
F-2501 EQ Board F-2505 Flat Amp Board
2SC1313 > KSC1845
2SA726 > KSA992F
2SA917 > 2N5400
F-2505 Flat Amp Board
2SC1313 > KSC1845
2SA726 > KSA992F
2SC1951 > ZTX694B
F-2495 Tone Amp Board
2SC1708 > KSC1845
2SA726 > KSA992F
F-2496 Meter Board
2SC1313 > 2SC2240 or KSC1845 or BC337
2SC945 > KSC2383 or KSC945
F-2498 Filter Amp Board
2SA726 > KSA992F or KSA992E or BC327
2SC1708 > KSC1845
F-2507 Driver Board (listing transistors from the different versions)
2SC1400 > KSC1845
2SA847 > KSA992
2SC945 > KSC945 or KSC2383
2SA733 > KSA992
F-2508 Regulator Board
2SC1313 > KSC1845
2SA726 > KSA992
2SA847 --- KSA992
2SC1708 > KSC1845
F-2497 Emitter Resistor Board (aka Pass through board)
2SC1364 > 2SC1815 or KSC945C or KSC2383
Output Transistors (Sankens)
2SA909 > MJ21193G
2SC1586 > MJ21194G
For now, I am not including the Driver Boards and the Regulator board. Will circle back to those once I get these harder to access boards covered first.
And please I am not expecting someone to spend a lot of time and research on finding replacements, just hoping the collective can throw out a few here and there and I will update the OP with recommendations.
I am not well versed at selecting proper transistor replacements, especially smaller ones. I have a few resources bookmarked for finding transistor subs but I know its not cut and dry and can depend on the circut/application. Im hoping using this thread for a QnA can at least be a good resource for future restorations on this amp.
This unit was properly working before I started so I wouldn't say there were any immediate problem areas, so I more looking to replace any 'known issue' transistors or ones that would improve long-term stability or sound quality.
I am also aware of the many other one-off issues to look for and address in this specific amp, those are well documented elsewhere. Want to focus on transistors here (and while there are a lot of threads regarding this amp, not so many with detailed transistor subs).
Here are the boards, and transistors. Any input would be greatly appreciated and sure others will find this valuable in the future (hopefully)
Edit: Adding bold text to any considered problematic or noisy
F-2511 Protection board
2SC1364 > KSC945C
F-2501 EQ Board F-2505 Flat Amp Board
2SC1313 > KSC1845
2SA726 > KSA992F
2SA917 > 2N5400
F-2505 Flat Amp Board
2SC1313 > KSC1845
2SA726 > KSA992F
2SC1951 > ZTX694B
F-2495 Tone Amp Board
2SC1708 > KSC1845
2SA726 > KSA992F
F-2496 Meter Board
2SC1313 > 2SC2240 or KSC1845 or BC337
2SC945 > KSC2383 or KSC945
F-2498 Filter Amp Board
2SA726 > KSA992F or KSA992E or BC327
2SC1708 > KSC1845
F-2507 Driver Board (listing transistors from the different versions)
2SC1400 > KSC1845
2SA847 > KSA992
2SC945 > KSC945 or KSC2383
2SA733 > KSA992
F-2508 Regulator Board
2SC1313 > KSC1845
2SA726 > KSA992
2SA847 --- KSA992
2SC1708 > KSC1845
F-2497 Emitter Resistor Board (aka Pass through board)
2SC1364 > 2SC1815 or KSC945C or KSC2383
Output Transistors (Sankens)
2SA909 > MJ21193G
2SC1586 > MJ21194G
For now, I am not including the Driver Boards and the Regulator board. Will circle back to those once I get these harder to access boards covered first.
And please I am not expecting someone to spend a lot of time and research on finding replacements, just hoping the collective can throw out a few here and there and I will update the OP with recommendations.
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