High “whistling” noise from my guitar/bass amplifiers in my home recording facility

Ok, re "no whistle with no input" AFAIK all guitar amp input jacks short the input until a plug is inserted. The lack of whistle shorted shows at least the noise is getting in via the input and NOT via power line nor speaker cable.

Now, with a guitar plugged in does turning the VOLUME pot down on the guitar kill the whistle? If so it suggests that the RF is NOT getting in via the cable screen and since "zero VC" is equivalent to shorting the input this suggests less than 100% internal screening in the guitar. The tone pot "shorts" the input same way but only at 3kHz or so and up.

Have you checked that the strings are bonded to jack earth?

On that "Mkll" filter B.D. I am pretty sure the input is also shorted sans plug. Try a lead from tin to amp but with no plug in input. The fact that the filter made little difference tells me that the RF field must be very strong. The filter is in fact just a gash one I had that is fitted to the front end of all S1 amps and, as I said before, I never had a report of RFI trouble with the amps before, in any case, all products have to pass EU EM testing.

Dave.
 
OK...but where/what would causing the EM interference only in your neighborhood...?
Again...what is near/around you?
If it's pure residential for a couple of miles around you...then...what could be causing that?
Where do you live...what's the environment like around you?

The tone controls are just glorified volume knobs for your H/M/B...so yeah, turn them down, and you are simply turning the noise down. It's not really getting filtered out.

Well... yes I live in a residential area and nothing has changed since before when I DIDN'T have that problem - except one fact... last year the Gaz company dug in the whole street to put some new gaz installation stuff. I wonder, couldn't that be a reason?...

Ok, so the Tone Control pot is NOT filtering, just turning the noise down... while in my view wasn't it because it "filtered" its frequency - as it operates on exactly the H/M/B frequency of the sound? (Of course I'm not "literate" in electronics, just a musician's experience and common logic.)
 
Ok, re "no whistle with no input" AFAIK all guitar amp input jacks short the input until a plug is inserted. The lack of whistle shorted shows at least the noise is getting in via the input and NOT via power line nor speaker cable.

Now, with a guitar plugged in does turning the VOLUME pot down on the guitar kill the whistle? If so it suggests that the RF is NOT getting in via the cable screen and since "zero VC" is equivalent to shorting the input this suggests less than 100% internal screening in the guitar. The tone pot "shorts" the input same way but only at 3kHz or so and up.

Have you checked that the strings are bonded to jack earth?

On that "Mkll" filter B.D. I am pretty sure the input is also shorted sans plug. Try a lead from tin to amp but with no plug in input. The fact that the filter made little difference tells me that the RF field must be very strong. The filter is in fact just a gash one I had that is fitted to the front end of all S1 amps and, as I said before, I never had a report of RFI trouble with the amps before, in any case, all products have to pass EU EM testing.

Dave.

Ok Dave, here we go:
I plugged just a naked plug in the amp (no cable attached to it). It "whistles" but in less volume. And as far as I just touch the active pin, even with a screwdriver, the "whistle" gets louder.

The filter DOES stop the "whistle" but ONLY in this case: Filter=>Cable=>Amp. So, a cable alone plugged in the amp "whistles". Adding the filter it stops! But the "whistle" reappears as soon as I add another cable in the filter input (to bring the guitar in), so, Cable=>Filter=>Cable=>Amp or
Guitar=>Cable=>Filter=>Cable=>Amp ! IMV this suggests that the guitar or bass at the first end don't really play a role, it's the cables that are capturing.

The tone pot, "shortening" the input by 3kH, doesn't it exactly kill the "whistle" which is 2.5kH ?

Yes, my strings are perfectly bonded for all my four guitars and a bass.

A reminder, the phenomenon is present with all my four amps (three tubes and one modeling Line6).
 
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I don't know if you have an organization in your country that oversees radio frequency distribution, but in the US there is a group called the Federal Communications Commission. If you do, it might be time give them a call. In the US, they will come out and find the offending source for you. If you have already done so and are still waiting, you may want to try this--find a portable(Battery powered) system that will drive headphones and walk around the area trying to find where the whistling sound is loudest. You would need a system with a high impedance input, such as a wireless guitar system. The receiver would also have to be capable of running on batteries, and be capable of driving headphones (even at a low level). If you had access to a battery powered headphone amp, so much the better. By the sound of it, you would need a short cable plugged into the receiver, to pick up the whistling sound (And not the guitar). I hope you manage to get this sorted out.

Jim
 
Sorry, too many threads to go back and reread them all. I don't remember whether you mentioned using a line conditioner or not. If not, buy an APC uninterruptable power supply and plug the amps into the line conditioner side. The non-battery side has very good line conditioning. Or even try it on the battery side and see if the noise goes away with the UPS unplugged from the house. That'll tell you if the sourece is through your power or nearby EMI/RFI.
 
I don't know if you have an organization in your country that oversees radio frequency distribution, but in the US there is a group called the Federal Communications Commission. If you do, it might be time give them a call. In the US, they will come out and find the offending source for you. If you have already done so and are still waiting, you may want to try this--find a portable(Battery powered) system that will drive headphones and walk around the area trying to find where the whistling sound is loudest. You would need a system with a high impedance input, such as a wireless guitar system. The receiver would also have to be capable of running on batteries, and be capable of driving headphones (even at a low level). If you had access to a battery powered headphone amp, so much the better. By the sound of it, you would need a short cable plugged into the receiver, to pick up the whistling sound (And not the guitar). I hope you manage to get this sorted out.

Jim

Yes, that's the case, I called the "Telecommunications Organism" here and am waiting for a tech to come and measure. By the way, what you say is interesting because I did something similar (but much heavier): I took one amp with a cable and a guitar plugged (all put in a small chariot) and with a long power extension from my house I made a tour of +/-20m around. The whistling was present everywhere and especially louder when coming close to the LandlinePhone-TV distribution boxes that we have in front of each house. I may try what you suggest with a wireless guitar system. And I'm hoping that the tech person will come soon and confirm what it is exactly and they will sort it out. A painful awaiting time...
Thanks for your suggestion though.
BD
 
Sorry, too many threads to go back and reread them all. I don't remember whether you mentioned using a line conditioner or not. If not, buy an APC uninterruptable power supply and plug the amps into the line conditioner side. The non-battery side has very good line conditioning. Or even try it on the battery side and see if the noise goes away with the UPS unplugged from the house. That'll tell you if the sourece is through your power or nearby EMI/RFI.

True, too many threads, so I'll put again a recap to all what I did for testing. Your idea is good but I think one of the tests I made is similar and showed that it may not be the power issue.
 
Here a recap of all what is done in the last 4-5 weeks with that problem:

1. Since some time I've got a "whistling" noise when I plug cables with or without guitar (all three of them) in any of my FOUR amps (three tube and one modeling Line6). Frequency of the noise +/-2,5 kH. I've never had that problem before.
2. To exclude the possibility of interference from a unit, from lights LED, or else, I shut down the power in my house (switching off all the breakers in the service panel) leaving only one wall socket, so absolutely everything disconnected - but the "whistling" is still present !
3. I tested by bringing one amp and a guitar to neighbors in the one and the other end of my neighborhood and the noise is present everywhere !
4. One of the neighbors (a just retired electrician) got the power supply in his place through a transformer (as a filter) and a stabiliser - still the noise was present.
5. That neighbor measured the ground and voltage in my house and they're in good limits: 10 Ohm, 238V. (My house is just 15 years old.)
6. I also tested by going to two other friends' places in different areas further away from me and... NO NOISE over there !!
7. I tested with one of those battery powered pocket mini amps like the VOX AC30 that you use with headphones for practice - the "whistling" still present !
8. That all suggests that my problem is NOT related to power lines or to grounding, but to an electro-magnetic emission coming from somewhere.
9. I tried passing through a DI box - the "whistling" still present !
10. I borrowed from a friend a wireless system (transmitter on the guitar and receiver on the amp) - the "whistling" still present !
11. I made an XLR mike cable "one-end-bond-shield", so the shield connected to ground from only the one end, like sort of a "Faraday cage" for the cable - the "whistling" still present !
12. I was advised and assisted to make a filter with inductions and capacitors corresponding to the frequency of the noise (+/-2.5 kH). That filter was made but... gave no solution - the "whistling" noise IS always present !
13. An interesting detail, when having a guitar plugged, if I turn the Tone Control knob lower, the noise goes weaker till disappearing. So the Tone Control works like filtering it. But then my sound goes too dull which is not what I want. And that's not an acceptable situation.
 
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BREAKING NEWS !

I discovered a unexpected way to get around the "whistling" noise problem - temporary solution but still a solution !
Someone asked me if by chance I tested with one of those single stomp boxes of the close past. Well, I've got two of them forgotten in a drawer since long time, a Boss Chorus and a Guyatone Phaser. I tested and the Phaser stops the "whistle" even in bypass! (Not the Chorus though). So that means that there IS a way to filter the godforbidden thing. For the moment I still wait for the tech person from the Telecommunication company comes to detect the source and to see how it will be sorted out. After testing with a battery powered amp and still having the noise it's now sure that it is an EM interference from some source. But at least I can continue my work till then. Huffffff..........

Thank you guys all for your valuable feedback.

BD
 
Bad Disciple said:
ecc83 said:
Let me have the Marshall model number and schematic if you have it and a description of the problem. I communicate with a top bloke in Scotland who knows all there is about guitar amp servicing.

Hi Dave, I've sent you a notification about my Marshall crackling problem. Here I just add an audio file with the crackling recorded (as I can't upload it in the notification).
 

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  • Marshall head Crackling +Ending.mp3
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Hello everyone, some last news about that "whistling" EMI noise in my neighborhood (and getting it in all my amps).

Finally, I'm sad to discover that it was a misinterpretation I made with that "solution" which I thought it came using a stomp phaser box! Now that I made a bunch of meticulous tests, I found that it only slightly diminishes the "whistle", if at all... I wonder how could I have that impression the first time! I presume I may have forgotten some tone control lowered (that obviously filters it). So I'm sorry for misleading you all by saying it, but it was what I blindly thought. So no, the stomp boxes don't cancel that EMI "whistling" noise.

But I finally have a last discovery. One of my guitars has two humbuckers and they can also be combined together as two single coils from each (I presume in inversion). And it's ONLY in that case that the "whistle" is DEFINITELY cancelled ! By the way, on my two Strats (an old one and a N3 noiseless PUs) in the positions "two single coils together" the "whistle" gets considerably diminished. So the solution might have to do with the PUs combined by two and inverted I presume.

On the other hand, I'm awaiting until the Telecom company solves the problem as their tech man promised when he came to measure everything. I'll keep you updated.
 
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That cancellation effect tells me that the signal is actually electrical radiation of the AUDIO not RF being demodulated. This would explain why the Series one with THREE RF filters in the input circuit, two external in the tin and one internal, do not stop it, it is not 'RF'! It also explains the tone control's action in reducing it. Do you know anyone with a hearing aid? If so and they switch it to 'loop' function I bet you a pint they will hear the whistle (they would not detect RFI)

BTW BD, belay the part in my PM about having a switch? Don't have anything like that.

Dave.
 
That cancellation effect tells me that the signal is actually electrical radiation of the AUDIO not RF being demodulated. This would explain why the Series one with THREE RF filters in the input circuit, two external in the tin and one internal, do not stop it, it is not 'RF'! It also explains the tone control's action in reducing it. Do you know anyone with a hearing aid? If so and they switch it to 'loop' function I bet you a pint they will hear the whistle (they would not detect RFI)

BTW BD, belay the part in my PM about having a switch? Don't have anything like that.
Dave.

Hi Dave, this seems to me again a precious deduction and my common logic sense agrees with it even if I have no specific tech knowledge. So I'm awaiting the promised solution from the Telecom company while being "educated" in what-it-is-about.

(Ok, I understand about the SB switch and I short answered your PM.)
 
Ok guys, you are fantastic with wanting to help me! Here a wav file. Pls, let me recapitulate. The "whistling" is present EVERYWHERE in my house, even in the mansarde under the roof. There is no other noise like hum or so, just "whistling". The "whistle" is present with humbuckers too and with both my three tube amps. The most shocking: it appears even just with the cable plugged, without any guitar!
So in the wave file I recorded my Strat with (supposed to be) Noiseless N3 PUs and I change the 5 position switch from Bridge to Neck. The Bridge PU seems to have less "whistling". It also has a "push-push" switch putting the PUs in a serial connection where the "whistling" is louder. Strangely, when I play few chords, the "whistle" between them is lower and not recorded, but I heard it when playing.
Another info, I asked my left neighbor (who are a retired couple so no much high-tech) to unplug his wireless home phone, but the "whistling" is still there. So not that.
And no, it doesn't "whistle" from the amp itself, only after plugging the cable and the rest described.
That's all about the mess. That stops me from work and it drives me mad as you can imagine. Any suggestion would be highly useful before I call an electrician.
Thanks a lot!
I have the exact same issue...
Did you manage to fix it ?
 
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