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PostPosted: Wed Jun 28, 2017 2:58 pm 
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Bottle Rocket

Joined: Sun Aug 10, 2008 10:21 pm
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Location: Champaign, IL
TL;DR: I moved into a house, and am having major hum/radio interference issues, possibly due to a nearby radio tower. I have been trying to rule out issues with my house’s wiring, but nothing’s worked so far.

Hi everyone! Not sure if this is the correct sub-forum, but I really need some help! Gather ‘round for my sad tone tale...

My fiancé and I just bought our first home, which was built in ’89, where I get to have a whole bedroom as a little dedicated guitar studio! I never thought I’d have any problems with my guitar gear, as I’ve lived in some places with really shoddy wiring and never had to deal with anything besides slight hum issues. After weeks of moving labor, I set up my room and finally got to let loose. You can imagine my sheer disappointment when I flipped on my Mark Five 25 and heard the most horrendous, loud, biting hum I have EVER heard in my 16 years of playing. Hum as loud as the high gain Mark V output. So loud that the simple thought of even plugging in to that depresses me... Not knowing what was going on, I resolved to go into research and problem-solving mode, where I have been for the last month.

The sound is the worst hum/buzz I have heard, with pop radio mixed in. Think when you have your guitar pickups facing computer equipment, but on steroids + Justin Bieber. It fluctuates as I walk around the room, near the walls especially, even if the guitar is sitting on a stand and I am not touching any part of the rig. I also found out there is a large radio tower broadcasting a half mile away.

My setup:
Ibanez S7420QM ->10’ Planet Waves cable -> Mark Five 25 -> Bugera 2x12 Cabinet w/ V30 & CL80

A history of the ideas I’ve tried:
Changing Cables . No change.
Moving Outlets/Room. No change.
Amp at different house. No hum whatsoever.
Changing Guitars. A little better, but still present (maybe poor shielding in my main?)
Tested Outlets w/ Tester. All tested “Wiring correct.”
Had Power Company Out. No problems on their end, they tightened connections.
Inspected panel. Everything looked normal, I tightened all connections.
Searched for Ground Rod. Found where ground wire exits panel through a pipe to the ground.
All breakers off but Room. No change. This excluded anything in the home being a source of EMI.
Amp power into Ground Lift. No change.
Amp power into Hum-X. No change.
Ferrite Cores on Cables. No change. Tried on amp power and instrument cable (at same time)
Isolation Transformer. No change. Huge disappointment there.

I am learning as I go along since this is my first house. From what I can tell it doesn’t appear to be a ground issue, as the ground lift adapter/Hum-X/Iso Transformer did nothing at all. Everything looks legit in the electric panel. My focus has shifted to the radio tower. I realized the sound was worst when facing the window, which is the direction of the tower. The last thing I tried was a layer of aluminum foil as a shield over window, which did nothing.

I’m at my wits end, I’m depressed, and I can’t practice with this noise. I’m regretting buying this house which is otherwise awesome. Does anyone have any ideas?? Thanks for reading.


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PostPosted: Wed Jun 28, 2017 9:49 pm 
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Location: Norfolk, CT
Power conditioners are made for this problem, they have worked for me in an identical situation. I am not familiar with the hum-x or what type your isolation transformer is.

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PostPosted: Wed Jun 28, 2017 10:08 pm 
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Dual Recto

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Light dimmers can be the devil, even in another room that you would not think will affect anything. Been there, done that.

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PostPosted: Wed Jun 28, 2017 11:05 pm 
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Mark IV
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I am guessing this is noticeably worse with a guitar/cable plugged in? The amp has reasonably good shielding and should block a lot of it, with no cables plugged in the input or loop.
Not really familiar with the MV25, but the preamp tubes should have metal shielding cans on them. Most, anyway, modern Mesa's do. Could yours have been removed? But if you are picking it up through the guitar cable, the cans won't help so much.

Sounds like you may have a case of good old fashioned front-end overload. Too strong of an electromagnetic field, too close. Can get into all kinds of electronics. Any other devices (esp. a radio or stereo) in your home doing this?

As a Ham radio operator, over the years I have often fought interference problems causing issues for neighbors, but that was only with about 100 watts. Commercial radio transmitters often run at tens of thousands of watts.
I will also guess it is an AM radio station tower (esp. since you hear the station and hum)? Those are the worst, but high level of power, that close by may not matter.

Wish I had better news for you.

You may consider having the amp checked out by a tech. It is possible that a failing component could add to the problem, though I won't go into the why's and how's here.
Also some things can be done to the amp that may help a bit, i.e. adding a small choke or ferrite beads to the connection from input jack to first stage(s).
Again, a qualified tech can explore these possibilities. There are also ways to shield your entire music room but none are inexpensive or even practical.

I sincerely wish you luck.

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PostPosted: Thu Jun 29, 2017 9:50 am 
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Bottle Rocket

Joined: Sun Aug 10, 2008 10:21 pm
Posts: 7
Location: Champaign, IL
Markedman wrote:
Power conditioners are made for this problem, they have worked for me in an identical situation. I am not familiar with the hum-x or what type your isolation transformer is.

EBTech Hum-X is a single outlet ground noise filter that seemed to be well regarded for ground loop noise. The isolation transformer I got was a Tripp Lite Hospital Grade unit. I could try a power conditioner, but I'm just worried that it won't help since the other power items in the same vein didn't. :shock:
JOEY B. wrote:
Light dimmers can be the devil, even in another room that you would not think will affect anything. Been there, done that.

I thought that too, but since I shut off all the breakers but the music room, killing power to any dimmers, I hoped that I eliminated that possibility?
Old BF Shred wrote:
I am guessing this is noticeably worse with a guitar/cable plugged in? The amp has reasonably good shielding and should block a lot of it, with no cables plugged in the input or loop.
Not really familiar with the MV25, but the preamp tubes should have metal shielding cans on them. Most, anyway, modern Mesa's do. Could yours have been removed? But if you are picking it up through the guitar cable, the cans won't help so much.

You are correct that it's worse with the cable. Radio is slightly present with no input, some fluctuating hum and radio with a cable plugged in, and then all hell breaks loose with a guitar plugged in. I'm going to work on shielding my guitars electronics with copper tape. All of the metal preamp tube covers are intact, and as part of my troubleshooting, I took out all the tubes and reseated them.
Old BF Shred wrote:
Sounds like you may have a case of good old fashioned front-end overload. Too strong of an electromagnetic field, too close. Can get into all kinds of electronics. Any other devices (esp. a radio or stereo) in your home doing this?

Nothing else has exhibited any symptoms. I don't actually have a radio or a stereo, oddly enough. TVs, Computer Speakers, Bluetooth Speakers have all been fine...
Old BF Shred wrote:
As a Ham radio operator, over the years I have often fought interference problems causing issues for neighbors, but that was only with about 100 watts. Commercial radio transmitters often run at tens of thousands of watts.
I will also guess it is an AM radio station tower (esp. since you hear the station and hum)? Those are the worst, but high level of power, that close by may not matter.

It's actually an FM tower, broadcasting 7 stations. Using some online map tools, it looks like it's actually closer to a 1/4 mile away. One thing that has puzzled me and my friends - why is there so much hum? I can understand one of the stations coming through, and I've seen that before in certain situations. I just never would have expected the interference to come in the form of this bizarre hum!
Old BF Shred wrote:
Wish I had better news for you.

You may consider having the amp checked out by a tech. It is possible that a failing component could add to the problem, though I won't go into the why's and how's here.
Also some things can be done to the amp that may help a bit, i.e. adding a small choke or ferrite beads to the connection from input jack to first stage(s).
Again, a qualified tech can explore these possibilities. There are also ways to shield your entire music room but none are inexpensive or even practical.

I sincerely wish you luck.

Thanks for all your insight into this.


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