Where is the noise coming from and how to isolate?

calleballe11

Experienced
Hey guys.
I recently bought a Fender hot rod deluxe amp to go with my Ultra for smaller gigs. I love how the axe sounds as an fx-only device.
I have one concern though...

When I turn the volume up on the amp, there's a LOT of noise. But if I plug my guitar straight into the amp it's near silent. What bothers me is that even if I press bypass on the Ultra the noise is the SAME. Of course turning a heavy drive sound on increases it a bit more but thats to be expected. Disconnecting the guitar from the Ultra doesn't make a difference either. I have also tried taping the power plug with electrical tape so the ground is lifted.

I've adressed similar issues before but noone seems to be aware of the Axe's severe powering issues.
Any help would be greatly appreciated!
 
Really need a bit more info to be able to help you out. Ground loops are tuff- and depending how you have the axe mounted, there are a number of variables to troubleshoot.
Is it RF or a ground loop? Cables can introduce allot of noise.

You have already identified the issue is present without a guitar plugged in- isolate the remaining variables between the axefx and amp.
- shorten the cable
- if the axefx is in a rack- buffer the axe from any other metal
- if you are plugged into a power conditioner, perhaps the conditioner need to be grounded

these are just a few ideas to try
really need more info on the setup
 
really need more info on the setup
+1 and if you are trying something start as simple as possible:
- only guitar and amp (we know it works)
- turn on the axe fx, without connecting any audio cable, only the power one
- guitar into axe-fx into amp
- guitar into amp, axe-fx in amp effect loop
- 4CM
and so on...

When you are doing that leave your equipment on the floor, so the connection will be only via the audio and power cables.
 
okay..I've been doing some evil experimenting:

-Axe->FX loop is same as input noise wise.
-Tried plugging guitar into different power sockets and it doesn't make a difference.
-I also tried removing my home made power cord extension for the axe (which has no ground on the plug, like taping it with electrical tape but permanent), and when I did this the noise was a GREAT deal louder, probably twice as loud or more.
-removed rack case, doesnt make a difference
-turning the axe of doesnt help, neither does bypass, its the same as soon as its plugged into the amp
-Shortening the cable does reduce noise!



There's still some noise there but I guess the axe produces a little noise when going into an amp? I don't have a big analog pedalboard to A/B with.
 
To me it really seems you have a ground loop and you have no idea about how to deal with it.

The equipment must be grounded via it's power cord, we're talking about your life man.

You can open a ground loop in many ways without danger. Do a search on the forums, on the wiki and on the Internet you'll find plenty information.
 
What about trying the balanced xlr outs from the Axe to the amp loop using XLR to standard TS jack cabling - this breaks the earth on the loop cables. You would need to make sure the Axe's power cable is earthed though if doing this.

Or use Humbuster cables in the loop?
 
Reduced noise from shortening the cable sounds like RF-

But, I still don't understand your setup. The more info you can give on your exact setup, the easier it is to help figure out whats going on.
 
What about trying the balanced xlr outs from the Axe to the amp loop using XLR to standard TS jack cabling - this breaks the earth on the loop cables. You would need to make sure the Axe's power cable is earthed though if doing this.

Or use Humbuster cables in the loop?

Yeah, this is the next thing I'll try! I've noticed when playing through IEM's the xlr outs can reduce even more noise even if im using my cheater plug, which I am, all the time. None of my other gear requires this :(

Does humbuster cables work for the Ultra though?
 
Reduced noise from shortening the cable sounds like RF-

But, I still don't understand your setup. The more info you can give on your exact setup, the easier it is to help figure out whats going on.

The setup doesnt matter. I get the noise almost all the time. In this example, which is at home, my setup is just: Guitar-->Axe front input-->Axe left TS output-->Fender hot rod input. Tried different amps, tried different effects, tried different venues. Something inside the axe-fx seems eager on picking up ground loops.
 
To me it really seems you have a ground loop and you have no idea about how to deal with it.

The equipment must be grounded via it's power cord, we're talking about your life man.

You can open a ground loop in many ways without danger. Do a search on the forums, on the wiki and on the Internet you'll find plenty information.

Then I have to find other equipment. The noise is overwhelming. I can't find anything doing a search that would help my specific situation. Would love an ebtech HumX but it doesnt come in a EU version.
 
The Ultra can add a lot of volume level, plus it outputs a line level signal, not an instrument level.
Try to set it to unity gain (all shunts, no fx blocks, powramp sim off) to troubleshoot.
 
The Ultra can add a lot of volume level, plus it outputs a line level signal, not an instrument level.
Try to set it to unity gain (all shunts, no fx blocks, powramp sim off) to troubleshoot.
Thanks but the noise is the same even if the whole unit is bypassed and no instrument is plugged in. It does not change if the output1 volume knob is full or at minimum.
 
hey, an alternative to the humX is the Ebtech "hum eliminator", which works in any country. Contact the Ebtech team via email on their website, and they can help you out with understanding the problem. I had a problem and the guy was nice enough to offer advice, and in the end i didn't even need one of thier products.
 
hey, an alternative to the humX is the Ebtech "hum eliminator", which works in any country. Contact the Ebtech team via email on their website, and they can help you out with understanding the problem. I had a problem and the guy was nice enough to offer advice, and in the end i didn't even need one of thier products.
Thanks! Will definitely mail them!
 
When several devices are connected, only one should be grounded.
Make sure the amp's power cord is grounded and the Axe is not, or vice versa.

EDIT: disregard this, see below.
 
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Make sure the amp's power cord is grounded and the Axe is not, or vice versa.
NO!!!
ALWAYS ground equipment via it's power cord.

You can break the loop using an insulation transformer on the signal path.
 
NO!!!
ALWAYS ground equipment via it's power cord.

You can break the loop using an insulation transformer on the signal path.
Yek's right. You want a star ground configuration - only one device is connected to ground, and everything else is grounded through it. It's the multiple ground connections that make the loop - hence the name loop ;-)

I'm fighting my own RF noise issue - isolated to the cable from the G90 to the front input, coming from a switching power supply somewhere in the system. I suspect the Axe, but can't tell (obviously). Since all cool impedance effects are negated by putting the G90 between the guitar and Axe anyway, I may try the rear XLR-> rear XLR trick.
 
Yes, Yek's right from an audio standpoint, but by disconnecting ground from any electrical equipment that has a ground pin on the power plug, you're putting your life on the line. Before ground pins became standard on sound gear, people were getting electrocuted by their equipment. The good news is that the noise won't bother you at all when you're dead.
 
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