New Crack, buzz / humming sound on right channel

Roadsign1993 · 1161

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Offline Roadsign1993

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on: August 05, 2020, 04:52:55 PM
i just finished the crack a few days ago, test all passed, today i finally tested it, buzz / humm sound on right channel, if someone can help me, or may know what i did wrong, did reheat/solder already and added a little more solder (no change, still buzz / humm sound). pictures are attached



Offline Paul Birkeland

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Reply #1 on: August 06, 2020, 05:50:38 AM
I would start by trimming those long leads that are poking out of your terminal strips, as those can cause some serious problems if they are left in place. 

Is the hum and buzz there with the volume pot turned down all the way? 

Can you post your voltages for terminals 1-10?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Roadsign1993

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Reply #2 on: August 06, 2020, 07:56:41 AM
its always there, even with no source conntected, and it doesnt matter if the knob is max or min, humm is always there only on the right side (will test voltages once i have  time and update)



Offline Paul Birkeland

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Reply #3 on: August 06, 2020, 07:59:22 AM
Another strategy is to plug a really inexpensive pair of headphones into the Crack, then poke around the circuit while it's running with a wooden chopstick to see if you can find a place that eliminates or changes the noise, then you can focus resoldering efforts there.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline mecha

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Reply #4 on: August 10, 2020, 10:34:25 AM
I have had a similar issue on my Crack. For me, it's the left channel, and it's an audible hum that occurs most of the time. It is not dependent on the volume; it is present at any level at the same volume. The way I am able to try to resolve it was to manually tilt the 6080 tube. At certain positions, the hum disappears and at others it is amplified. I suspect a bad tube, which is unfortunate, but I've also tried the chopstick method, using dead RCA plugs, and trimming/reflowing a good chunk of my circuit. I also had passed all resistance tests. I received and built my Crack mid-June, just in case that tells anything about the source of the tubes.



Offline Paul Birkeland

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Reply #5 on: August 10, 2020, 10:46:53 AM
If tilting the tube remedies the issue, I would be looking at connections around the octal socket.  You can always lightly clean the pins as well, as oxidation can occasionally cause problems.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man