Hum in speakers, and suggestions for stopping it
Hi, everyone.
Any success stories in scenarios similar to mine, described below? Grounding boxes? Outlet upgrades? Gadgets like the Morely Hum Exterminator (née Ebtech Hum X)? I’m looking for a non-invasive solution (e.g., not getting a dedicated line into the room).
The situation: I had each of my PS Audio M700 amplifiers plugged in to a Stellar PowerPlant 3. The system sounded great, but I knew I'd likely get better sound with the M700s in the wall outlet. I made the switch and there was a huge improvement -- so I want to keep this configuration.
However, there's now a hum in the speakers. Given that there was no hum with the M700s in the PowerPlant 3, I think it's safe to assume the problem is the wall outlet. I can't hear the hum 99.5 percent of the time when music's playing, but ... well, you know.
"My" electrician came out yesterday and said doing a dedicated line to the outlet would entail demolition and/or other options that aren't feasible right now.
Thanks much!
Have you tried unplugging everything in the shared circuit to see if there is a specific culprit? Put a meter mic on the speaker and walk around unplugging stuff with a stopwatch. If the hum exists in the wall but not through the power plant, my would be there is noise on the neutral or ground and it’s finding the biggest transformer tap in the whole house circuit to land on. The benefit of a dedicated circuit - since all circuit neutrals come together in the panel anyway, is really the ground between the panel neutral/ground and earth / waterline. You need to get that noise to have a preference to go elsewhere. Cheater plugs - and I believe hum eliminators - are basically lifting the ground. If you can find the problem, you could put a cheater plug there and not at your amp. To me, a cheater plug is a simple test. I’ve been lucky in my house that I haven’t had this issue - but I have chased it through hospital construction sites before. I actually had a project where we solved the problem by installing a large, dummy load transformer in an IT closet. The noise on the line preferred that load to the IT switches. If you have a spare amp lying around that has a larger transformer than your amps - try plugging that into the same circuit. |
Start unplugging components and plug back in one at a time. Coax for cable, hdmi cables, and Ethernet and like mentioned power cords next to speaker cables all can send signal to a power amp to amplify it. It can be irritating until you can identify the source. “
SOMETIMES it’s this easy. But definitely start there. Ground loops are common. Sometimes it’s a grounding issue with the house breaker panel. We lost the connection to ours a couple decades ago (in 1972 they used a braided steel connection between ground/neutral on the breaker panel and a copper water pipe) which of course, due to electrolytic corrosion failed and I just last month watched our electrician at our new house in TN connect a braided wire to a copper-plated steel rod with a CLAMP. A STEEL clamp. Iron rust doesn’t conduct electricity - although copper oxides DO. When I put in my ham radio tower I used thermite gadgets (Erico Cadweld GT1161V One Shot Ceramic disposable body https://a.co/d/jceML9A ) to weld the solid copper wire to the grounding rods and will do this with our new house in Tennessee shortly - right after final inspection - the steel clamps are industry standard (CODE) and are crap (can I say this here?). Something like THIS is a good investment for starters to make sure your wiring’s right (like HOT black wire to little prong): Klein Tools RT210 Outlet Tester, Receptacle Tester for GFCI / Standard North American AC Electrical Outlets, Detects Common Wiring Problems https://a.co/d/3NI34IS
Good luck, keep us posted.
BTW, anyone looking for the Cadweld gadgets, they’re available elsewhere much cheaper. When I bought ‘em they were about ten bucks (yeah, in THIS century, about 12 years ago).
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