Guitar amp buzz even with balanced power supply. Help!

[[email protected]]

About 2 weeks ago I noticed a new guitar amplifier buzz in my studio. I have since tried multiple amp & guitar combinations and they all have this nasty buzz. We have dirty power in my area so I've been using a Furman P2400 AR & IT for balanced power or a Tripplite isolation transformer. This setup has been working great for the last 4 years, then 2 weeks ago this buzz started. Occasionally an amp will pick up a very faint radio signal too.

From what I understand, I shouldn't be getting any sort of power line interference with balanced power so I'm not sure what to look for next. Any ideas what could be causing a buzz when I'm using balanced power?

The buzz seems to be roughly around 1khz. It does go away when I turn down the guitar. I have moved the guitar all around the room and the buzz does not change like regular guitar buzz.
There are no power lines or anything obvious that could be causing enough EMF/RFI that would cause this buzz. I have disconnected everything one the circuit other than the guitar amp and the buzz is still there.

 

[JohnRoberts]

did anything else change 2 weeks ago...?

What is picking up the buzz..? 1kHz is pretty HF for buzz...

Does it go away if you disconnect the guitar, short the guitar amp input...

Where is it getting into your gear?

JR

 

[[email protected]]

It seems like the guitar is picking up the buzz. if I turn the guitar volume down the buzz stops. The question is where could the buzz be coming from if I'm using balanced power. That rules out mains ground loops & dirty power, the usual culprits.

The buzz is probably lower than 1kh. It seems higher than normal 60 cycle though. I stuck a frequency analyzer in front of the amp & the dominant frequency bounced around 1khz.

I've attached a recording of it.

Nothing changed in the house 2 weeks ago.

 

[scott2000]

Have you ruled out the Furman or whatever?

 

[CJ]

what is balanced power mean?

try a Les Paul and see if it still does it.

 

[radardoug]

Whats the guitar? Does it have humbucking pickups? Your balanced power will be doing very little.

 

[abbey road d enfer]

Check Earth/safety ground continuity.

 

[JohnRoberts]

Lead guitar pickups are high impedance so sensitive to electrical noise in the area.

If you walk around the room with the guitar buzzing can you use the noise to identify where it gets louder?

JR

 

[DKatz]

That's 60Hz harmonics. From something like fluorescent or LED lights, or SMPS. Might not be on the same circuit. Furman specs indicate good RF filtering but not in this frequency range. Some isolation transformers isolate ground which is not what you need.

 

[[email protected]]

Thanks for the replies.

Have you ruled out the Furman or whatever?

I have ruled out the Furman by using a Tripplite isolation transformer.

what is balanced power mean?

try a Les Paul and see if it still does it.

Lead guitar pickups are high impedance so sensitive to electrical noise in the area.

If you walk around the room with the guitar buzzing can you use the noise to identify where it gets louder?

JR

I've tied 5 different guitars (all humbuckers) & 4 different amps and the buzz is the same with all. The buzz DOES NOT get louder or quieter as I move around the room or move the guitar around like normal guitar buzz. It stays the same volume & tone throughout the room (25' x 12').
Balanced power means the power is isolated & balanced from mains & ground interference. Google balanced power supply.

Check Earth/safety ground continuity.

Earth ground continuity is irrelevant when using an isolated balanced power supply. That's the point of a isolated balanced power supply.

That's 60Hz harmonics. From something like fluorescent or LED lights, or SMPS. Might not be on the same circuit. Furman specs indicate good RF filtering but not in this frequency range. Some isolation transformers isolate ground which is not what you need.

There are no florescent lights or SMPS in the house. The only thing on this circuit is amplifiers. I do have the same problem if I plug the amp in in my control room which is also on an isolated balanced power supply. The Furman I'm talking about is not the usual power conditioner - it's an isolation transformer with balanced power. This removed ANY interference that could come from ground loops or mains supply. It seems the buzz must be from something environmental like RFI but I don't know what it could be from or how to track it down - or get rid of it.

 

[DKatz]

Balanced power is not optimum for noise rejection in many guitar amps.
Earth ground continuity is absolutely relevant! Whoever told you otherwise doesn't know what they're talking about.
No SMPS in the house, wow. No computer, phone charger, modern TV...

 

[Ike Zimbel]

Where are you located? If you are in the US or Canada, you could be picking up RF from newly deployed 600 MHz range cellular services. I have dealt with several studios that have had issues with this getting into condenser microphones and it wouldn't surprise me to see it getting into guitars. Are you in an urban area? If so have a look at nearby rooftops and see if they have new looking cell towers on them. The fact that the level stays the same when you move around the room does speak to something with broader coverage.

 

[[email protected]]

Balanced power is not optimum for noise rejection in many guitar amps.
Earth ground continuity is absolutely relevant! Whoever told you otherwise doesn't know what they're talking about.
No SMPS in the house, wow. No computer, phone charger, modern TV...

The balanced power has been working fine for guitar amps for 4 years. This problem just started.
According to what I've read on the balanced power supply, it corrects any interference due to ground reference. I could have misunderstood it though. In any case the house ground was checked by an electrician not long ago.
I meant no SMPS in the room or on this circuit. The nearest one is 25+ feet away.

 

[[email protected]]

Where are you located? If you are in the US or Canada, you could be picking up RF from newly deployed 600 MHz range cellular services. I have dealt with several studios that have had issues with this getting into condenser microphones and it wouldn't surprise me to see it getting into guitars. Are you in an urban area? If so have a look at nearby rooftops and see if they have new looking cell towers on them. The fact that the level stays the same when you move around the room does speak to something with broader coverage.

I'm located in more of a suburban area. I haven't noticed any new cell towers or anything in the area. However, assuming something like that is the case, what's the solution? I'm already using an isolation transformer/balanced power supply.

 

[JohnRoberts]

I still have questions. I believe you wrote that if you turn down the guitar volume the buzz goes down.... is that the guitar volume pot on the guitar itself, or inside the guitar amp?

Since you decline to say where you are located, do you have 50Hz or 60Hz mains?

Balanced power (many here know exactly what it is, or supposed to be), it is of little value to reduce guitar buzz, and of limited utility with properly designed gear/systems.

JR

 

[[email protected]]

I still have questions. I believe you wrote that if you turn down the guitar volume the buzz goes down.... is that the guitar volume pot on the guitar itself, or inside the guitar amp?

Since you decline to say where you are located, do you have 50Hz or 60Hz mains?

Balanced power (many here know exactly what it is, or supposed to be), it is of little value to reduce guitar buzz, and of limited utility with properly designed gear/systems.

JR

When I turn the guitar volume down the buzz quiets down but doesn't go away entirely.It's definitely entering through the guitar but it doesn't act like regular guitar buzz in that it doesn't get louder or quieter when you move around.

I'm located in Portland, Oregon so 60Hz mains.

The "balance" part of the balanced power supply isn't really any special help with buzz for guitar but the isolation part is. The isolation transformer guarantees no ground loops and noise from dirty mains power (or it's supposed to anyway). That's the reason I started using the isolation transformer or balanced power/isolation supply in the first place. The electricity from the utility in our area is very dirty. Without the isolation any amp, even our P.A., sounds harsh & distorted. The isolation/balanced power solved that. It reduced buzz & hum in all my amps.

Everything worked fine with this setup for 4 years, then this buzz developed about 2 weeks ago. No changes to the electrical in the house or any new appliances, etc. It just seems unlikely to me that the buzz is coming from the mains supply as it's isolated.

 

[Ike Zimbel]

I'm located in more of a suburban area. I haven't noticed any new cell towers or anything in the area. However, assuming something like that is the case, what's the solution? I'm already using an isolation transformer/balanced power supply.

The new cellular services are being deployed everywhere, so there may be a new tower in your neighbourhood.

 

[JohnRoberts]

Something appears to have changed from your discussion. Some times things break, and sometime new sources of interference pop up... 5G anybody?

Apparently 5G interferes with aircraft avionics so they are still trying to sort that out.

JR

 

[abbey road d enfer]

Earth ground continuity is irrelevant when using an isolated balanced power supply. That's the point of a isolated balanced power supply.

Ridiculous claim.

 

[so]

I hope your "irrelevant" earth ground is at least connected to earth ground, or whatever your Code is. If I were playing a guitar and it hummed strangely, I'd fear being part of an undetected fault; you are assuming the pickup is the only possible source of guitar noise. A human is a fairly large capacitor plate to everything nearby. If your balanced power is floating you may not have touched the wrong thing yet. If you've already answered this question please pardon me.