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Old 13th Jan 2022, 7:22 am   #43
Robert Gribnau
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Join Date: May 2017
Location: Konongo, Ghana
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Default Re: Contemplated PCL86 push-pull home brew stereo amplifier

Quote:
Originally Posted by etherman View Post
As for negative feedback, I could not detect any audible effect in the produced audio. Or is it mainly to guarantee stability?
I don't think it's mainly there for stability reasons but I could be out of my depth on this one.

You could temporarily try it out with a lower value for R11, at least to see if the phasing of the feedback is in order. With good phasing you should hear some drop in volume, with wrong phasing the feedback will be positive, which increases the volume and, if the feedback is strong enough, the amplifier starts to oscillate (howling-like sounds).

Just to be sure: Is one tap of the secondary connected to ground (and the other one to R11) like in the schematic? Without the connection to ground, the feedback from the secondary will not work.
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Last edited by Robert Gribnau; 13th Jan 2022 at 7:28 am.
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