Hoffman Amplifiers Tube Amplifier Forum
Other Stuff => Other Topics => Topic started by: davidb on January 24, 2026, 09:25:24 am
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I just moved into a new house and am suddenly encountering a lot of noise in my guitar rig. I've switched guitars, cables, amps, outlets, and no dice. This is with the guitar plugged directly in, no pedals. The noise drops significantly when I touch the metal hardware on my guitars, and I'm not so sure it is a guitar grounding specific issue since it is across my whole stash. Also many of my outlets do not have a proper ground and have a GFCI.
Any ideas on how to fix this? I'm not sure where to go next. Thank you in advance!
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First thing I would do is check your outlets with an outlet tester. They are not expensive.
It's very common to see mis-wired outlets.
One thing to bear in mind is that outlet testers can not test GFCI without a ground -- but a GFCI device can work without a ground since it is comparing current though line and neutral.
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I’m already pretty sure that there isn’t a proper ground in some of the outlets according to the home inspection by the electrician. But it is worth a second check. I think it would be pretty expensive to get a proper ground installed. Would power conditioners or isolators work? That would be a lot cheaper than the electrical work, and it’s already safe to use thanks to the GFCIs
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Do you know how old the house wiring is? Is the wiring two conductor cable - or does the cable have a bare ground wire?
I agree with acheld that all the outlets should be tested for polarity. I would also call the electrician that did the inspection and ask for more details.
GFCIs do not guarantee safety if there are wiring errors.
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Oh yes, if you did have an electrician do an inspection, get the details, have him rank the findings from high to low priority.
An outlet tester will help you know that your line and neutral is wired correctly (at any one outlet). That would be a simple fix for you. And that can cause hum in some situations.
If you're wondering, GFCIs do not cause hum in my experience.
Whether an isolation device or a power conditioner would help you depends on the power/outlets you have and the specific device. I do have buddies who gig with power conditioners due to similar conditions in the dives they play in. I don't know if it would help you.
Don't assume that because a GFCI is present that everything is "safe." Really, the electricians need to weigh in on that.
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I should clarify - we had a professional electrician inspect the house and install GFCIs. The reason we didn't get proper grounds installed everywhere was the expense. The house was built in the 50s.
So I think my options are to try a power conditioner, or get all outlets checked and see if there are any outlets with a proper ground with a meter. I've heard some people say to attach a ground to the water pipes, but I am not about to do any electrical work to the house myself.
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but I am not about to do any electrical work to the house myself
I completely agree that you should not. Even if it is legal in your state, it takes a significant amount of studying to do so safely. The discussion here reveals a certain amount of misunderstanding regarding "ground" and "neutral." If you like and trust the electrician you hire, I would give them a call and describe your situation. There is more at stake than amp hum.
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:icon_biggrin:
n I'll make the counter-point argument;
IF.... you're a 1st-time young home-owner
it is in your best interest to understand and be able to do the basics, electrical, plumbing, carpentry, etal....
each "trade basics" can be learned in 6mths to a year, bonus, most can be co-processed (Learnt together) in that same timeframe. knowledge is power, if you opt for easy way out n just pay for ease n convenience, you have no power n your "home" is nothing more than a managed asset
When I decided to "build new" attached to the old, the Mrs ask, "Have you ever built a home?" "Nope, but I can read a book....." It took a year get the basic architecture, draft the "blueprints", materials list, understand basic guvmint "codes" 5yrs later the Mrs had a "rock-star retreat"
The inspectors all asked the same question;
"Who did your electrical, who did.........." I'd give 'em my classic cheezey smile n say I did.
a good place to start, volunteer as "labor" on a habitat for humanity house build, volunteer "labor" with your "trades" buddy
ask the Amish if you could "lend a hand"
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but I am not about to do any electrical work to the house myself
I completely agree that you should not. Even if it is legal in your state, it takes a significant amount of studying to do so safely. The discussion here reveals a certain amount of misunderstanding regarding "ground" and "neutral." If you like and trust the electrician you hire, I would give them a call and describe your situation. There is more at stake than amp hum.
I am confused, let me try and explain my current understanding and see if you agree. The basement (where I intend to play guitar) has had GFCIs installed to monitor current swings between hot and neutral in the outlets for safety. There is no ground installed there to my knowledge. It seems to me that since there is no ground it is causing noise since there is isolation between ground and neutral in a proper amp. Is that the right direction?
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In the long run, I agree with Shooter. It is what I have done, and is how I learned wiring, plumbing, carpentry. But, the first thing you need is a keen interest in learning those things. Many of us geezers grew up in a time, when many homeowners learned the basics of the trades. Not so much any more. YouTube is making it easier and codes are making it harder.
But I assume you want to cure the hum/buzz now. You are right that in a three-wire 120v circuit there are separate grounds and neutrals. But amps built in the 50s, 60s all had two wire cords. Most had polarity switches, some just suggested that you flip the plug to see which way is quieter.
In your shoes, the first thing I would want to know is if the polarity of the outlets is correct throughout the house.
And if you are confused - I am confused as to why you do not want to ask your electrician about the issue - seems like a logical step to me.
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the first thing I would want to know
........
how much noise a GFI system "injects" onto the AC
how are most professional recording booths wired
what does the Audiophile use for system power
you'll have a better understanding of "What you need" for your application