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PT-25 audio distortion
#20

+1
The volume control is listed @ 500,000 ohms alias 500K or .5Meg. More than likely it has an audio taper. This means the w/ the control turned up half way from the low side to the wiper should read about 50K, and from the wiper to the high side 450K. See pic below.
Linear taper w/the control 1/2 up would be 250K. What that does it put most of the audio gain at the first 1/4" of rotation. Audio taper makes the audio level spread out over most of the controls rotation.
Bad or wrong value pot can mess with the avc circuit causing distortion.
GL


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When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry


Messages In This Thread
PT-25 audio distortion - by WyTex - 12-19-2017, 12:45 PM
RE: PT-25 audio distortion - by morzh - 12-19-2017, 02:29 PM
RE: PT-25 audio distortion - by David - 12-19-2017, 04:08 PM
RE: PT-25 audio distortion - by WyTex - 12-19-2017, 04:09 PM
RE: PT-25 audio distortion - by Phlogiston - 12-19-2017, 04:37 PM
RE: PT-25 audio distortion - by morzh - 12-19-2017, 11:02 PM
RE: PT-25 audio distortion - by WyTex - 12-20-2017, 10:06 AM
RE: PT-25 audio distortion - by Steve Davis - 12-20-2017, 11:34 AM
RE: PT-25 audio distortion - by Phlogiston - 12-20-2017, 11:52 AM
RE: PT-25 audio distortion - by klondike98 - 12-20-2017, 12:01 PM
RE: PT-25 audio distortion - by Phlogiston - 12-20-2017, 03:28 PM
RE: PT-25 audio distortion - by klondike98 - 12-20-2017, 05:45 PM
RE: PT-25 audio distortion - by WyTex - 12-20-2017, 06:16 PM
RE: PT-25 audio distortion - by morzh - 12-20-2017, 06:46 PM
RE: PT-25 audio distortion - by klondike98 - 12-20-2017, 06:48 PM
RE: PT-25 audio distortion - by Arran - 12-21-2017, 01:52 AM
RE: PT-25 audio distortion - by morzh - 12-21-2017, 10:32 AM
RE: PT-25 audio distortion - by WyTex - 12-21-2017, 10:58 AM
RE: PT-25 audio distortion - by Phlogiston - 12-21-2017, 12:05 PM
RE: PT-25 audio distortion - by Radioroslyn - 12-21-2017, 12:33 PM
RE: PT-25 audio distortion - by morzh - 12-21-2017, 01:14 PM
RE: PT-25 audio distortion - by WyTex - 01-05-2018, 02:26 PM
RE: PT-25 audio distortion - by morzh - 01-05-2018, 06:09 PM



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