100W Ultimate Fidelity Amplifier

Any idea which transistor this is
 

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I finished my P30ZF yesterday in the late evening. Not heard yet.
Dont know if a delay with relais is necessary, i built it in. The supply i an old one, which was build for an headphone amp in the past. The regulators are adjustet to +-24 Volt. The R-core delivers 2x18 Volt, 1 A.
I first had a little trouble with the BD140 on one channel. After 5 minutes the heatsink became very hot. I tried to find out some mistake, found none. The values are all ok, the transistors are soldered in on their right place. Changed the BD140 and one BC560 on the negative rail...the mistake was remaining.
I soldered a new board and all seems fine , only a little heat now.
 

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Testing....👍
What a very nice preamp. Sound ist very good. The only thing i dont know...what is the pot for ? Apex wrote for THD, but an other member answered there is no effect...
Can i make a measurement to get an effect ? In the moment i have adjusted the pot for 500 ohm each...

Peter
 

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