November 26, 2021, 02:45:30 PM

Author Topic: Issue with right channel humming  (Read 145 times)

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Offline ncsMD

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Issue with right channel humming
« on: October 29, 2020, 06:31:18 AM »
Hi all,

I recently assembled my 3rd crack, no speedball. I'm having an issue with a faint hum in the right channel. Seems to go away when I turn the volume pot all the way down. I tried tracing the ground path as well as checking for cold solder joints (especially along the right channel) and couldn't seem to come up with anything. All of my resistance and voltage checks listed at the end of the manual came out within range. Let me know what other checks I should do to troubleshoot the issue.

Below is a link to the photos. Thanks all!


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Re: Issue with right channel humming
« Reply #1 on: October 29, 2020, 06:40:51 AM »
In addition to reheating/reflowing all the joints, I'd try taping the braided signal wire closer to the outside edge of the chassis. I might also be inclined to rebraid that wiring a bit tighter.

cheers, Derek

Offline Paul Birkeland

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Re: Issue with right channel humming
« Reply #2 on: October 29, 2020, 06:55:30 AM »
I see a lot of wires just poking through terminals and sticking straight out.  They should be wrapped around and crimped to what they attach to.  For a lower terminal, it's good enough to bend the wire up vertically and to ensure that solder flows between the wire and the body of the terminal strip.

The Alps volume pots are not designed to have wires soldered to the pins on the pot.  There are PC boards available on eBay that you can mount the board to, then you can solder wires to that board without being worried about damaging the pot.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man