Electromagnetic noise/ interference

SteveW

SteveW

Experienced
It's not my FXIII... But rather something in the room. It's driving me crazy, and I've had it on all of my AXE FX units in this particular room.

It's a very loud hum coming from any guitar, single / double coil, humbucker or not. It changes with positioning in the room, but never goes away and at best is annoyingly loud. Happens on high gain amps more than anything, but as soon as I unplug the guitar (from the guitar end), everything goes away. I know it's something in the room that's causing the problem and I've unplugged everything that's plugged into any of the outlets, and yet nothing changes.

If I move the AXE FX to another room, the problem goes away. Aside from shutting down all the breakers in that room, which I have not yet done, wondering what else? Is there any kind of a setting on the noise gate that I can use to get rid of that particular hum? Can the noise gate be dialed into one specific frequency or frequency range?

I've gone as far as checking all the plugs for polarity, and nothing out of the ordinary appears. Grounds are all correct, neutrals are all correct and hots are all correct. I'm at a loss and really want to get this resolved so I can go back to enjoying my playing. It is that loud that it literally becomes unplayable.
 
Well, I guess I'm going to start by shutting off breakers one by one and then plugging the amp into a different outlet in another room while leaving it in the same place until I find the offending switch/outlet/transformer.

Thank you for your instant reply and guidance!
 
You can try turning off the noise gate and moving around the room with a single coil guitar. See where the noise gets the loudest.

LED bulbs, WiFi routers, Computer Monitors, TV's, and poorly shielded PC's (with big glass windows in them) are also common culprits.
 
In addition to already mentioned culprits, I got this once from a "wall wart" power supply.

For whatever reason, I had moved it to the courtesy power outlet on the front of my rack.

Anytime the guitar was in proximity it created really bad noise. I moved it inside the back of the rack and the problem went away.
 
Robot lawn mowers would be a tough one; I'm on the 8th floor on the water. Any lawn mower around here would just sink... Lol

So here's what I did:
I'm in a two bedroom two bathroom condo, and the problem occurs in my bedroom, no matter which outlet I'm plugged into. It's not an outlet problem.

I shut down every single breaker in the house except one in the living room, where my other AXE FX is plugged in... And I ran an extension cord from the one in my bedroom to that same plug. So everything in the condo was off with the exception of that one plug.

The problem persisted. My bet, is that if I had a 50 ft cable from my guitar and I'd walked into that room, the noise would diminish. I am guessing that it's something outside of my condo, perhaps above, below or beside me. But for sure, it's nothing to do with my condo.

I fucked around with the noise gate and turned it way up and then I set the noise gate itself to a different value, I think around 230k... Which seemed fairly optimal. It's solves the problem in such that when there's nothing going on on my guitar, it's silent. Obviously when I play that hum is still there, bad enough to actually change the tonal qualities, but I think this is as good as it's going to get. Unless I'm prepared to put tin foil on all my walls, I think I'm going to have to live with this.

The downside with the noise gate being tuned so aggressively, is that I really don't have much play on the volume knob before it starts to interfere with the signal. If only there was a way that noise gates could be set up to eliminate narrow frequency bands only, it would probably resolve the issue.
 
SteveW said:
I fucked around with the noise gate and turned it way up and then I set the noise gate itself to a different value, I think around 230k...
Click to expand...
Assuming you're talking about the Input block gate, that 230k is the Input Impedance and unrelated to the gate.

Setting it lower tends to attenuate the high frequencies, so it might seem to help...
 
Yes the input block gate... And I'm guessing that by changing the impedance I was able to cut out a bit more of that hum.
But there's definitely a difference going from one to the other, I scrolled through all the different input impedance options, and this one seemed to have some better impact on my issue, for whatever reason.
It's never going to get better than this, lol...

It's only gotten worse over the past few years, and it's circumstances beyond my control so if this is as good as it gets, I have to live with it.

I even went as far as plugging in a UPS and unplugging the UPS from the wall. There was no change, so I know it's not coming on the 120 volt side.
 
SteveW said:
Robot lawn mowers would be a tough one; I'm on the 8th floor on the water. Any lawn mower around here would just sink... Lol

So here's what I did:
I'm in a two bedroom two bathroom condo, and the problem occurs in my bedroom, no matter which outlet I'm plugged into. It's not an outlet problem.

I shut down every single breaker in the house except one in the living room, where my other AXE FX is plugged in... And I ran an extension cord from the one in my bedroom to that same plug. So everything in the condo was off with the exception of that one plug.

The problem persisted. My bet, is that if I had a 50 ft cable from my guitar and I'd walked into that room, the noise would diminish. I am guessing that it's something outside of my condo, perhaps above, below or beside me. But for sure, it's nothing to do with my condo.

I fucked around with the noise gate and turned it way up and then I set the noise gate itself to a different value, I think around 230k... Which seemed fairly optimal. It's solves the problem in such that when there's nothing going on on my guitar, it's silent. Obviously when I play that hum is still there, bad enough to actually change the tonal qualities, but I think this is as good as it's going to get. Unless I'm prepared to put tin foil on all my walls, I think I'm going to have to live with this.

The downside with the noise gate being tuned so aggressively, is that I really don't have much play on the volume knob before it starts to interfere with the signal. If only there was a way that noise gates could be set up to eliminate narrow frequency bands only, it would probably resolve the issue.
Click to expand...

Man, that sucks. Are you close to the roof of the building by chance?
 
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I'm on the 8th and the roof is the 11th, so I am approximately 30 ft from the rooftop... What are you thinking?
 
Sometimes massive compressors like those used in rooftop A/C units can be problematic.
Was just wondering if one was directly above you.

Maybe a neighbor is running a huge server farm in their Condo. 🤣

Anywho, that's such a bummer you have to deal with that.
 
Yep, there are over 300 compressors up there, to be clear... Lol

I'm going to go with the server farm thing next door....🤣🤣🤣🤣
 
Well, I would almost go for that theory, except that it works perfectly two rooms over. I suppose it's possible though...
 
I just reread your posts and think I am following you now. Even when you run
an extension cord and plug into the outlet in the living room and then use the
Axe in your bedroom you get that noise. But when you are plugged into the
living room Axe you get no noise.

Must be some kind of EMI/RFI coming into that bedroom.

Did you try swapping Axes.... and switching their places?
 
I get really bad noise from the down lights in my room. If you can move the guitar around and it changes, that says to me it’s not the power but EMI in the room.

I switched rooms to the next one over, same lights, no problem 🤷‍♂️
 
la szum said:
I just reread your posts and think I am following you now. Even when you run
an extension cord and plug into the outlet in the living room and then use the
Axe in your bedroom you get that noise. But when you are plugged into the
living room Axe you get no noise.

Must be some kind of EMI/RFI coming into that bedroom.

Did you try swapping Axes.... and switching their places?
Click to expand...
I just received an FM9 tonight... And it exhibits the exact same issue. If I move to the other room with the guitar, no noise; if I stick it in the same place as the AXE FXIII in the bedroom, I have noise.
 
tysonlt said:
I get really bad noise from the down lights in my room. If you can move the guitar around and it changes, that says to me it’s not the power but EMI in the room.

I switched rooms to the next one over, same lights, no problem 🤷‍♂️
Click to expand...
Exactly, it's the EMI in the room that's causing the problem. Only there's nothing actually in the room that would cause it so, it's got to be coming from just below, just above or beside me, any one of three units. I've been chasing this for years but it's gotten much much worse in the past couple of months.
 
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