Devices addressing line (dirty power) interference.

[Pete McAvity]

Heya, all. I’ve read up on different suggested devices to combat dirty power sources, but most seem to be opaque as to hum vs. noise, single coil reception, neon & fluorescent lights, etc.

I’m looking for suggestions for combating dirty AC specifically. I had a bass gig last weekend w/ an early Ampeg V4 which exhibited a loud hum (despite recent recap job) at my 125 year old house w/ knob & tube wiring, but once at the venue it idled quiet as a mouse. Hum was LOUD and consistent at home when plugged into ohm matched cab with no instrument plugged in, so I’m deducing that I own possessed wiring, my new Wi-Fi router is an invasive species, or something of that ilk.

What conditioners, etc. have youse found to be effective in tamping this down? Every amp (albeit old) I plug in here is noisy, and after having experienced a nice quiet baseline on the few that I’ve done cap jobs on, any and all uninvited ethereal accompaniment is making me see red.

Thanky.

[Fred Treece]

I am not an electrician, but my understanding is that knob and tube electrical systems are ungrounded, which is probably the source of your hum. They also are notorious for underpowering modern appliances and other household electrical hardware. Adding a power conditioner to your humming amplifier amounts to adding another power drain on an already stressed system.

There may be an electrical engineer here on the forum who can address your issue, but you also might be better off consulting a local electrician.

[Jim Kennedy]

Get an outlet tester:

https://www.amazon.com/ground-tester/s?k=ground+tester

It will quickly tell you if you are grounded, or your hot and neutral are switched. In a 125 year old house, grounding is the most likely culprit. Grounding today is much more sophisticated than when it first became the norm. With all the digital and wifi equipment that we all have in our homes, clamping a ground to to cold water pipe doesn't hack it any more.

[Dave Mudgett]

Might want to visit this thread, where a number of people have been discussing issues like this for a few months now - https://bb.steelguitarforum.com/viewtopic.php?t=385869

Always a good idea to check outlets with an outlet tester. But that's just a start to dealing with difficult noise/hum issues. In many houses, especially old ones, this is a VERY THORNY problem. I can attest to this myself, and my house is 'only' 65 years old, and I have upgraded all the wiring down here in my music areas.

[Pete McAvity]

Ack.
That’s right- most of my outlets are not grounded. They have all been rewired recently by an electrician as most were “bootlegged” to make a tester read as grounded.

Thanks all, and Dave thank you for the link.