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I've searched this forum for an answer, but couldn't find one. Here's the deal:
When I turn the reverb up, I get 120 Hz (first harmonic of 60 Hz) hum. It is independent of the main volume, ie it always stays at the same level.
The reverb otherwise sounds great. I've checked that both RCA cables are fine, with a multimeter. When I physically remove the tank but keep it connected, I can get the hum to change and get slightly better depending on the orientation of the tank. This leads me to believe that it's acting as an antenna. Are there any options for better shielding of the tank? (also I noticed that only the output jack's ground connects to the actual tank chassis).
To complicate (or maybe clarify
) things, I'm pretty sure the grounding in my appartment is bad to non-existant. My roommate has a power-bar with a ground tester, and it does not light up when plugged into my outlet. Also when I used this very same amp at a friend's place, there was no hum in the reverb. This could be due to the fact that it's a less electrically noisy environment, or due to the fact that the chassis is actually grounded.
So in summary, do I have any options here? can I manually ground the chassis by running a wire to a water pipe? Should it still be hum-free even without grounding? I've never used an old amp without the ground on the plug, but did/do they hum all the time?
could it be a filter cap or other component not doing its job? basically I'm looking for some approaches to take to try and reduce the problem. Thanks!
When I turn the reverb up, I get 120 Hz (first harmonic of 60 Hz) hum. It is independent of the main volume, ie it always stays at the same level.
The reverb otherwise sounds great. I've checked that both RCA cables are fine, with a multimeter. When I physically remove the tank but keep it connected, I can get the hum to change and get slightly better depending on the orientation of the tank. This leads me to believe that it's acting as an antenna. Are there any options for better shielding of the tank? (also I noticed that only the output jack's ground connects to the actual tank chassis).
To complicate (or maybe clarify
) things, I'm pretty sure the grounding in my appartment is bad to non-existant. My roommate has a power-bar with a ground tester, and it does not light up when plugged into my outlet. Also when I used this very same amp at a friend's place, there was no hum in the reverb. This could be due to the fact that it's a less electrically noisy environment, or due to the fact that the chassis is actually grounded. So in summary, do I have any options here? can I manually ground the chassis by running a wire to a water pipe? Should it still be hum-free even without grounding? I've never used an old amp without the ground on the plug, but did/do they hum all the time?
could it be a filter cap or other component not doing its job? basically I'm looking for some approaches to take to try and reduce the problem. Thanks!
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