jazzcrisis said:Does anyone know what the trimmer labelled Fact. Adjust is actually doing? I can't find mention of it in the service manual. Seems like it would affect the gain?
ruffrecords said:Yes, it does trim the gain. Its range is from about 15dB to about 25dB.
Cheers
Ian
PRR said:> need to be matched for symmetrical clipping?
No.
Clipping will never be symmetrical. The Q7 stage won't slam both sides the same.
I think you are investing too much magic into the output stage topology (P-P)... Solid state devices will saturate fairly consistently without matching and that saturation will be dominated by the drive circuitry and/or other external factors (like DC operating point for a single supply amp). If that drive is not symmetrical or identical for pull-up and pull-down, it should not be expected to clip symmetrically, and from observation that amp's drive circuits are not symmetrical.tommypiper said:Can you explain why there won't be symmetrical clipping? Are you referring to the diode or a general principal which effects P-P output pairs? Or something else...?
Not for this design... and not for solid state in general***... In fact I would not expect P type and N type devices to ever be very well matched. The only kind of matching (perhaps) would be for devices configured in parallel to increase output current, but even they generally use emitter degeneration resistors to force sharing making matching unnecessary.In general, do P-P output pairs benefit from matching?
thanks.
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