I'm feeling dirty...

Discussion in 'General Discussion' started by WA Paul, May 17, 2021.

  1. WA Paul

    WA Paul All dogs go to heaven

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    Multiple Internal Server Error issues...

    Due to finding out our house has a dirty electricity issue! [​IMG]


    The problem: Getting nasty buzzing sounds through my amp (Kemper and Kemper Cabinet) from the room I've converted to my office. I believe the noise is EMI/EMF from dirty power. I'm using a Furman SS 6B power strip with some minor filtering, PRS / Van Damme instrument and speaker cables. I'm wondering if I need more filtering, like a Satic whole house filter or an upgraded power conditioner/filter.


    Anyone run into this issue? I know it is not a ground loop issue, since touching the strings on the guitar doesn't make the noise go away. Plus the Kemper has ground lifts which had zero impact. The Furman is supposed to mitigate 60 cycle hum as well.


    I do have some challenging issues with the room - the other side on one wall is our refrigerator and the back wall is shared with the garage where the main electric panel, central vacuum and sprinkler control boards are located on the shared wall.


    While my Kemper noise gate will 'solve' this issue, I have to have the gate on max which kills dynamics. I'm trying to solve the problem so I can roll back the gate to a more reasonable level. Only using H9 in the effects loop. All my guitars are humbuckers and all equally pick up this noise (which of course is worse when flipping to coil tap mode). Only when I flip to the piezo does the noise stop, since that isn't a magnetic pickup.
     
  2. WA Paul

    WA Paul All dogs go to heaven

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    Part 2

    I had our electrician install a new clean circuit just for my guitar gear. No improvement!


    Working with the electrician recently, we tested the lights (original halogen to new LEDs) before adding a dimmer and there was no increase in noise from the old halogen lights. We also tested noise level from digital dimmer (the worst!), analog dimmer (current switch) and no dimmer - no dimmer was worse than the analog dimmer, so we put the analog dimmer back in.


    I've recently bought some Green Wave filters to try and their meter. Our whole house averages around 200 mV per outlet, well above the recommend level of 25-50 mV. Adding the filters to my signal chain had zero impact because I never had any ground loops to begin with. My Furman strip is now reading about 68 mV versus 200 mV before adding the Green Wave filters. But zero impact on the noise issue.


    Appreciate any help on this!
     
  3. RickP

    RickP Established 1960, Still Not Dead

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    The power may be fine, but magnetic fields in the room from lights, unshielded electronics or monitor screens, and electric motors can wreak havoc on a clean guitar signal. Normally these type of fields get better or worse as you turn or move through the room. Your pickup and control wiring, and even you cable, can pick it up. I lean towards this because you said it goes silent on the piezo.

    I get some of that in my room, as the house was built in the early 50s and that part added in ‘66. Old wiring, a utility room (freezer, washer, dryer) next door, and a large computer screen all contribute. But out in the center of the room, it’s pretty workable. One “sort of” workable fix (not sure if this is a Kemper thing, but it works for the Axe FX) is to put an EQ with a very narrow width on the offending frequency, in the same manner you notch out feedback. If it turns out to not be in a critical guitar tone range, it isn’t terribly noticeable, but the reduction in the apparent noise is.

    Short of replacing the wiring and treating the whole room in some kind of shielding, you just have to live with a bit of it. Noise suppressor pedals can sometimes help, with less light-switch-like on/off sound than hard gating. Nothing is really perfect, though.
     
  4. LSchefman

    LSchefman Hears Tones

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    Or it could be a signal ground loop regardless of touching the strings. That doesn't always work as a test. Rick's right, it could be EMI/RFI, which of course is not going to be reduced by the power strip. But ground loops can be difficult gremlins to chase down.

    It's a process of elimination chasing down noise - as you can imagine, back in the day when I had five racks of analog gear connected to a 64 inout console, and 500 patch points in a patch bay, noise gremlins cropped up often (in. fact, with just about every new piece of gear I added). Then I'd have to chase it down.

    My studio tech taught me to do what I suggest here:

    The first thing to try is to disconnect everything from the Kemper, including the guitar, plug in some headphones, turn them up slowly, and see if the Kemper's making any noise all on its own. I suspect it won't. If it doesn't make noise on its own, I think the problem is most likely coming from something other than the power lines, because you'd hear that noise through the Kemper.

    If there's no noise with just the Kemper on listening with the cans, see if it's anything besides the guitar connected to the Kemper, by connecting one piece of gear at a time, one pedal at a time (if you're using pedals, power amp, powered monitors, etc).

    Again, don't turn the speakers or amp on to begin with, keep checking by slowly turning up the headphones. Plug one piece of external gear in at a time. Often a ground loop will happen just by plugging external, gear that's connected with an audio cable, into an AC outlet, and not even turning it on. There's your 'Eureka' moment.

    But sometimes you need to turn it on. Be sure you plug in each new piece with the headphones turned down, for ear safety.

    Finally, if the noise only happens when the guitar's plugged in, my guess would be EMI/RFI (electromagnetic or radio frequency interference) from stuff in your house.

    I solved the grounding issues in my studio - which was new construction at the time, by the way - by running a star ground, a large block attached by a heavy wire to a metal stake in the earth, in turn connected to the chassis of offending pieces of gear. You can run a star ground by connecting the grounding block to a cold water pipe, but I don't think you'll need to star ground guitar gear. I think there's a simple solution that you'll find if you approach it methodically.
     
    #4 LSchefman, May 18, 2021
    Last edited: May 18, 2021
  5. WA Paul

    WA Paul All dogs go to heaven

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    Thank you Rick and Les!

    It’s definitely EMI/RFI as it only occurs when the guitar is plugged in, coming in through the magnetic pickups. The gear is quiet without the guitar plugged in and as I move toward different parts of the room it gets worse. By the amp it’s more quiet. Using headphones there is just as much noise. No difference in noise with the H9 in the circuit or out of it. The Kemper has several ground lifts which also had zero impact.

    I do have a computer and TV in the room, but they are off when this noise occurs. I guess I need magnetic shielding to knock it down. Hmm, does a tinfoil hat help? :D

    Any experience with power conditioners or filters?
     
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  6. RickP

    RickP Established 1960, Still Not Dead

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    Total guess here, but I suspect the noise isn’t coming through the power as you’d be hearing that self-noise even with nothing plugged in (albeit somewhat quieter), so I’m not sure how much the EMI/RFI would be affected by a power conditioner. That said, all of my gear runs through older Furman power regulators which, unlike power strip/conditioners, can also correct over and under voltage within it’s range. It’s a good practice, and certainly wouldn’t hurt!

    Your computer gear is likely shielded as far as it can be if it’s not old. But you can’t really shield the screen side effectively, so you’ll get some increased buzz as you get closer. Just sit back a little or turn to one side to minimize it.

    As crazy as it sounds, you might try those little 3 prong to 2 prong ground lifts on each item to see if it helps. It’s a last resort, but I keep a handful of them in my gig box... been a miracle cure in many venues!
     
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  7. dmatthews

    dmatthews Dave's not here...

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    Hmmm...
    Oops... I mean that's interesting.:p
    Curious what the electrician had to say about the issue.
     
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  8. WA Paul

    WA Paul All dogs go to heaven

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    I haven’t tried a power regulator yet.

    My Kemper has ground lifts (which is supposed to be the same as going from 3 prong plug to 2 prong plug based on what I’ve read), no impact. The Green Wave filters lower the ‘dirty’ electricity but the impact on the noise is slight.
     
  9. WA Paul

    WA Paul All dogs go to heaven

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    My electrician is stumped. But I’m the first guitar noise maker (can’t say player!) he’s worked with. In theory the dedicated circuit and amp/breaker should have worked.
     
  10. John F

    John F New Member

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    220V devices like electric dryers, hot water heaters, electric heat and stoves can have filaments that short to ground, causing the neutral to elevate above or below ground. Open their breakers or unplug and see if the symptoms change. Poor grounding and too much load on the same 110v hot side can also swing the neutral above ground. Breakers in your panel alternate legs from top to bottom, possible it is not balanced loading. One leg of 220 into the house from the pole could have weak connection also. Check both legs have same voltage.

    An electric dryer only shuts off one leg of the 220. I’ve seen a broken heater element short to the chassis and produce heat with the dryer off because it had 110v to neutral.
     
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  11. WA Paul

    WA Paul All dogs go to heaven

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    Thank you, John! I will be looking into this with my electrician during our next appointment in a couple of weeks. I can try playing with the breakers on/off before then.
     
  12. Boogie

    Boogie Zombie Two, DFZ

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    Having spent several years designing EMI/RFI solutions, just know that even the most adept EEs have to experiment to eliminate a pesky, unwanted frequency. You can work the math, but ultimately it’s a crap shoot. You can get a variety of ferrites and chokes to put at the service and/or device level, but it’s easier to find and stop the source. Dimmers can be a real problem.
     
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  13. aphantomvaper

    aphantomvaper New Member

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    Wow, I'm interested. Is it only one guitar or many that induce the noise? Have you tried a gauss meter to check the magnetic fields in the room? It sounds like a switching power supply.

    Is your guitar room near any outside electric lines/transformer? This may not even be from in the house.

    My favorite...can you play your guitar and harmonize with the noise? If you can find the corresponding note the relative frequency of the noise can be discovered. Then you will know if its house current or something else.
     
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  14. bodia

    bodia Authorities said.....best leave it.....unsolved

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    MA Pete had a similar problem in his guitar room, in the basement. His office, and also a room where he played guitar did not have this problem. Those rooms are separated by about 15 feet. Office, dead quite. Guitar room, lots of hum. Much more noticeable on single coil guitars. He had an electrician out and they spent the day chasing their tails to no avail. There's a panel (dry wall pop out) on one side of his guitar room. They finally figured out that the noise is worse the closer they got to the panel. Turns out his problem was due to the little device the water department put on his meter so they could do wireless water meter reads.
     
  15. WA Paul

    WA Paul All dogs go to heaven

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    Boogie - I’m considering trying the ferrites and chokes. I’ve spent quite a bit of time with the electrician trying to identify the issue. LED lights and dimmer do add to the dirty electricity, but the noise content was lowest with the analog dimmer (Lurton Diva) than with the regular wall on/off switch. Weird! Noise / interference was an issue before installing the LED lights (all in one cans).

    Aphantomvaper - all of my guitars make the noise, being picked up by the magnetic pickups. Line runs from the house to the meter on the street and it is near that room so could be an issue. I don’t have a gauss meter. For kicks I tried a free phone ap and it said <1 micron teslas. Which means something to someone I guess? I also tried a frequency measurement app and according to the waveform it’s most pronounced between 600Hz and 3400KHz, prime lower to upper mids! On the Kemper I added a Studio EQ block and set -12db (most cut allowed) on frequencies between those ranges and there was only a slight improvement in noise level. Guitar had a woman tone after those cuts as well on the bridge pickup. :)

    Bodia - yep, smart meters issue all kinds of bad EMF radiation. Our water and electric meters are at the street (cul de sac) about 50’ from the room. You really don’t want them on your house without some kind of screen.
     
  16. Maxime Bousquet

    Maxime Bousquet perfect reality sounds

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    Hi! if i had this problem i would proceed like this ..
    first i would start from zero .. guitar + amps and add one thing at a time, suppose everything was done and you still have noise on your line let's go to another level, locate the circuit (s) in your panel main power supply that are used for your music room, recreated the noise problem and closed every circuit other than your music room! until your interference is gone.
    this will allow you to pinpoint which circuit is causing the problem and also find which device is plugged into it! you will have more chance to find it like this! electrician experience !!:D;)
     
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  17. LSchefman

    LSchefman Hears Tones

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    If it's EMI/RFI, the only 100% solution is a Faraday shield, which is an incredibly cumbersome PITA.

    It's possible that a ground loop can be exaggerated by EMI/RFI, as they tend to pick that up and dirty the signal, but if it's quiet at the Kemper and the speaker, about the only thing you can do that's practical is put shielding in the guitar's control cavity, and even that doesn't always work against the strongest EMI/RFI.

    I sometimes have this problem in my studio with guitars, depending on pickup configuration. I simply wind up turning my body and guitar until the noise is reduced as far as it can be, and leave it at that.

    iZotope Neutron 3 has a guitar de-noiser plugin that's sometimes necessary post-recording, and a lot or the noise issue depends on the time of day for some reason. I always get a spike at around 4 PM, YMMV.

    Noise gremlins are very sly little beings. ;)

    On the other hand, a tin foil hat is a lot of fun to make, and I wear one just because. :p
     
  18. Alnus Rubra

    Alnus Rubra Loving nature’s wonders

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    As I read the beginning of your post, I went visual! I saw you in a full size “Faraday Cage”!
     
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  19. RickP

    RickP Established 1960, Still Not Dead

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    Solved...

    [​IMG]
     
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  20. Alnus Rubra

    Alnus Rubra Loving nature’s wonders

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    “What you growin’ in there Willis?!”
     
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