No sound from both channels

mrpink · 1169

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Offline mrpink

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on: February 20, 2018, 04:19:52 PM
Just finished my crack and I'm not getting any sound from either channel. Just a low volume crackling that gets louder when i turn the volume up. Voltage readings are good. T3 and T20 resistance readings are inconsistent...it's highly dependent on where I place the probes. I've re-flowed a lot of the joints, both LEDs are lit, tubes glow, transformer passed inspection during the build. I'd love some help debugging this. Thanks in advance.

EDIT: uhhhhh well, after checking solder joints a second time, and giving it a good long stare, i tried to plug it in one last time. It works perfectly. I have no idea what was wrong but I'm super happy. I'd still like to hear what might've been the issue since I couldn't find any posts about BOTH channels not working.
« Last Edit: February 20, 2018, 08:18:01 PM by mrpink »



Offline SpoookyAction

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Reply #1 on: December 20, 2019, 02:13:13 PM
I am having the same issue, I finished my build and everything is lit up and measures perfectly but no sound at all. No hiss, buzz, or hum.



Deke609

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Reply #2 on: December 20, 2019, 03:25:08 PM
My guess would be a bad signal ground connection. I'd check the black wiring from the headphone jack to (a) the pot (including the joint where two black wires connect to the lug with the 10W 3K resistors), and (b) the lug of the first 220uF cap close to the transformer.

I'd look for two things: (1) loose (or missing) connection; and/or (2) a wire with the black insulation (wire coating or "dialectric") inserted into the solder lug hole -- the latter may seem secure, but the insulation will electrically isolate the wire from the lug.

If that's not it, PB will get you sorted out.

cheers, Derek



Offline Paul Birkeland

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Reply #3 on: December 21, 2019, 06:00:14 AM
T3 and T20 resistance readings are inconsistent...it's highly dependent on where I place the probes.

EDIT: uhhhhh well, after checking solder joints a second time, and giving it a good long stare, i tried to plug it in one last time. It works perfectly. I have no idea what was wrong but I'm super happy. I'd still like to hear what might've been the issue since I couldn't find any posts about BOTH channels not working.
I wouldn't run the amp with inconsistent resistance readings.

The common issue that I see that causes something like this is a bad solder joint on the headphone jack where the black wires meet.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man