SOAR
Duo
I'm glad I stumbled across this thread, due to there being so many similarities between the three ccts here.
There seems to be one area that you have not addressed in your design, and that's SOAR of the output transistors. I decided to use 3 pairs of o/p transistors to minimise distortion (as per D. Self) and, as a secondary goal, try to get as much output power from the amp. I can tell you that with 60V rails, it has incredible dynamic range. It's very clean-sounding.
But I also think that it is important to protect he output transistors against short-circuiting (especially for us DIY's). The articles in last year's Electronics World mag addresses issues of maximising a transistor's useable output. At the rail voltages you quote, I think that there should be more care given to the capabilities of the o/p trannies. I'm starting to think of class G now.....
Anyway, also be careful of the fake Toshiba 2SC3281/2SA1302's doing the rounds. They have been reported on elsewhere on this forum. Take it from me - I'm a victim!
I think the safest is to buy the ON Semi (Motorola) equivalents directly form ON (Min Order Qty is 25) MJL3281A/MJL1302A.
Good luck
Now to get back to that SOAR calculations....
Duo
I'm glad I stumbled across this thread, due to there being so many similarities between the three ccts here.
There seems to be one area that you have not addressed in your design, and that's SOAR of the output transistors. I decided to use 3 pairs of o/p transistors to minimise distortion (as per D. Self) and, as a secondary goal, try to get as much output power from the amp. I can tell you that with 60V rails, it has incredible dynamic range. It's very clean-sounding.
But I also think that it is important to protect he output transistors against short-circuiting (especially for us DIY's). The articles in last year's Electronics World mag addresses issues of maximising a transistor's useable output. At the rail voltages you quote, I think that there should be more care given to the capabilities of the o/p trannies. I'm starting to think of class G now.....
Anyway, also be careful of the fake Toshiba 2SC3281/2SA1302's doing the rounds. They have been reported on elsewhere on this forum. Take it from me - I'm a victim!
I think the safest is to buy the ON Semi (Motorola) equivalents directly form ON (Min Order Qty is 25) MJL3281A/MJL1302A.
Good luck
Now to get back to that SOAR calculations....
I will probably end up putting in transistors of higher voltage and current ratings than those listed. Probably some big motorola TO3 suckers to juice the design up a bit...
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