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Old 28th Nov 2022, 2:41 pm   #2
orbanp1
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Join Date: Nov 2009
Location: London, Ontario, Canada
Posts: 672
Default Re: Sony-STR3800L. Output transistors.

Hi SJM,

Chances are the TIP transistors would be OK.
Doing a quick simulation the phase margin with the TIP transistors would be about 30 degrees.
(I tried to use transistors with similar parameters in the other positions.)
30 degrees phase margin is still stable, but it would not hurt to have a higher margin.
Adding a 10pF high frequency compensating capacitor parallel with the R708 47k feedback resistor the phase margin is increased to about 70 degrees.
I would try the TIP transistors with the added compensating cap.

Regards, Peter
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