Electrolytic bypass caps

[valvetones]

Hello,
Does anyone know what a bad electrolytic bypass capacitor sounds like?

When I turn my reverb up, I get some increase in noise.

Also ive got some snap crackle pop going on.

Both noises are distinctly separate from each other, so I think I’ve got two issues.

Anyone ever heard what a bad bypass cap sounds like?

[tubeswell]

You didn’t say what type of amp and you didn’t provide a schematic, so we haven’t got much to go on.

If it’s tube reverb, then tube swap first. (reverb recovery stage)


Then, look for bad connections, including: bad reverb pan cables, loose tube socket pin clamp connections or bad/cold solder joints in the reverb recovery stage (or if it’s a PCB based amp, cracked traces or muffed up trace pads, cooked looking diodes, resistors or silicooties etc)


‘Snap crackle pop’ could also be bad plate resistor or failing output tubes.

[valvetones]

It’s the 63 vibroverb with an EF86 in the front end of the normal channel.
That channel is fine.
The reverb channel increases in hum as I turn the reverb up. It’s not unplayable, but noticeable, and my other vibroverb doesn’t do that.
I replaced every bypass cap on the board, and it execute less intermittent snap and crackle, much less actually, but still an occasional few.
It’s the hum in the reverb control that I’m after now. I both caps that feed that 100k pot were leaking very slight amounts of DC. 5 Millivolts on one and 26mV on the other. Replaced them both, and there’s an improvement but still pretty good hum as the dial is turned up.
Maybe lead dress.

Anyone ever heard what a bad bypass cap sounds like?

[valvetones]

Tapping the volume control knob gets red of the snap crackle pop.
Interesting.
I may have changed out all my electrolytics due to a bad pot.
Pretty GD sleezy.

I’d still like to know what a bad bypass cap sounds like.
Anyone ever heard one?

[dude]

I’d still like to know what a bad bypass cap sounds like.
Anyone ever heard one?

Google it

[shooter]

guessing you're talking about at the cathode?
if it's shorted the cathode is at ground, tube conducts til it melts
if it's open, well just lift a leg n test for yourself