V357 Trimmer

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Murdock

Well-known member
Joined
Jan 28, 2015
Messages
858
Location
Germany
I have an active DI here from TAB Telefunken. It’s called V357.
It had a broken input IC TAA320 and a broken BC107C transistor. I also replaced the old elkos.
Now I would like to match the two outputs.
My understanding of transistors is almost non existent...
can someone please tell me what the two trimmers R32 (100k) and R34 (10k) do?
I gather one is for symmetrical clipping?
What should I look/aim for?
I played around a little with my signal generator and oscilloscope.
I set both resistors so I have the same level and also the same „breakup“ point at which distortion kicks in.
But I noticed that at one channel the -1dB point is at 56KHz while on the other it‘s „only“ 50KHz. I know I can’t hear either of them but I would like to know why the trimmers also have an effect on the frequency response? Because before trimming the „50KHz“ channel only went to 45KHz.
 

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  • TAB V357 Schaltplan.pdf
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