New noise/buzz

alex1fly

Inspired
So I've started running the FM3 as an FX only unit in front of my guitar amp. Clean channel on the amp is fine, but when I hit the high gain channel there's a ton of low pitched buzz. The buzz is not there when I run the guitar straight into the amp. Just thinking through what I can try to get rid of the buzz. I've tried unplugging everything from the FM3 except the essentials (power, guitar in, headphone out), swapping instrument cables for TRS cables and vice versa, turning off all the blocks (the buzz is there even with the IN and OUT blocks off), turning down the input levels, running a noise gate. The buzz is even there when the FM3 is powered off but the amp is on. Seems like I'm missing something basic.... Any thoughts?
 
I have a Mogami Platinum cable, I use it all the time to guitar, then used a regular cable recently and there was a ton of buzz using the regular cable. (in every pedalboard not just Fractal). SO a cable may make a difference.
 
plugged into different outlets?....if so run them into same strip or if you're using a power conditioner...i had a similiar thing and it was one was not properly ground outlet
 
They're both running into the same circuit - either on the same power strip or different ones, I've tried both. There's no noticeable noise when the FM3 goes into headphones or into studio monitors - only in to the guitar amp. The guitar straight into the amp (or into the pedalboard and then into the amp) will buzz a little, but the FM3 into the amp just buzzes like mad whether its from the headphone out, Output 1, or the Output 2 jacks. Buzz is there whether I use Fractal's humbuster cables or several of my cables (TRS and instrument both... really trying everything I can think of here). Doesn't matter either if the guitar is plugged into the FM3. And there's no noise when the amp is on the high gain channel or when I run my pedalboard before it. The buzz even happens when the FM3 is off and the amp is on - the signal passes through the FM3 from the guitar to the amp, I can't hear the guitar but the buzz is there.

I guess I could go buy a ground lift plug or a Y cable to run it in the insert of the amp and see if either of those makes a difference. Just weird to me that amp by itself has no buzz, FM3 by itself has no buzz, but the two together has buzz to the point of not being useable and I've tried 5 different cables to connect the FM3 and amp together.
 
Ground problem it sounds like. Use a ground lift and see if it goes away:
https://www.homedepot.com/p/GE-Polarized-Grounding-Adapter-2-Pack-14404/203684998
Do NOT do that.

https://forum.fractalaudio.com/threads/axe-fx-iii-is-making-my-other-stuff-buzz.154711/post-2183409:
I have some outlets in the house that are only 2 prong. Those little 3 to 2 adapters aren't safe? Why do they sell them? I ask because I don't know.
They are safe when used properly. If your 2 prong outlets have metal boxes and conduit and the conduit is earthed then you remove the screw from the wall plate, plug the adapter in and replace the screw. Ground is provided via the screw.

They're unsafe when people use them to lift the ground. The chassis of the connected device is then not earthed. If a fault occurs whereby the line voltage is shunted to the chassis the chassis is then live which presents a shock hazard.
See Ground lift in the Wiki for many more notes about it.
 
no computers or any other electronics close to the fm3?
There are - pedals, looper, computer, monitors, etc. I unplugged everything except the FM3 and amp and the buzz is still there. The buzz is even there when the FM3 is off. So it seems like it's either cables, something with the power, or something with the FM3.
 
Any other ideas? Ground lift switch does not take the buzz away. I'm really at a loss - been playing with guitar/bass/synth/recording gear for 20-some years and have never been stumped like this.
 
I wonder what your output level is set to in the Setup Menu>I/O. If it is +4db and you
are running into the front of an Amp that could do it.
 
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That buzz is probably interference coming in through your pickups. When you switch your amp from clean to high gain, you're adding a ton of amplification to the signal that your FM3 is putting out. A tiny amount of interference, that you wouldn't notice on the clean channel, gets amplified by a whole bunch.

Try moving your guitar around the room and holding it at different angles. Does the buzz change?
 
I wonder what your output level is set to in the Setup Menu>I/O. If it is +4db and you
are running into the front of an Amp that could do it.
Thanks - +4 and -10 both have the buzz, and the buzz volume doesn't change when I switch between the two.
That buzz is probably interference coming in through your pickups. When you switch your amp from clean to high gain, you're adding a ton of amplification to the signal that your FM3 is putting out. A tiny amount of interference, that you wouldn't notice on the clean channel, gets amplified by a whole bunch.

Try moving your guitar around the room and holding it at different angles. Does the buzz change?
It happens with all my guitars at all angles, but only when the FM3 is in front of the amp. I can even turn the input and output off on the FM3 and the extra noise is still there.

I ordered a humbuster cable. That's kind of the last attempt at fixing this, I think. It works great into an interface/headphones/FRFR setups, I was just jazzed to try it out as a preamp type pedalboard.
 
It happens with all my guitars at all angles, but only when the FM3 is in front of the amp. I can even turn the input and output off on the FM3 and the extra noise is still there.
Sounds like a serious lack of ground or ground loop issue. You say all your guitars. What pups are in “all your guitars”? Mainly asking are they single coils or humbuckers. Are you plugging into the same mains with all the different setups? Do you have any HI Z transformer isolated A/B or amp switching box to experiment with? If you haven’t made or used a “Humbuster” cable yet, then definitely try that before anything else.


Speaking of 1:1 isolation transformers, I just became aware that Lehle sells their transformers through retailers. When I was making more gadgets myself I would have liked to have these. They’re not cheap, but making a one off I suppose would be economical.
https://www.tubesandmore.com/products/transformers_chokes?filters=2341a3027
 
Do NOT do that.
You mean don't do the thing that I've used for decades to remove hum and buzz???
Have you ever owned a rack full of gear? lol
Every sound company I ever used always had a dozen or so of them in the road case.
Some venues just don't have proper grounding. And the fastest, easiest, and cheapest way to determine a ground issue on gear that doesn't have a ground lift built in (which by the way, does the exact same thing as the exterior ground lift I linked to)...is to use a ground lift plug.
The FM3 DOES have a ground lift...but only for the XLR outputs in case the polarity is reversed back at the outlet of a mixer board in a venue.
Again...quickest way to troubleshoot a ground problem is with a ground lift. The FM3 doesn't have one built in for this particular problem. I don't know if the guitar amp he is using has a built-in ground lift either. So the best way is the way I spoke of.
#experience
 
There are - pedals, looper, computer, monitors, etc. I unplugged everything except the FM3 and amp and the buzz is still there. The buzz is even there when the FM3 is off. So it seems like it's either cables, something with the power, or something with the FM3.
The ground lift switch on the FM3 is only for the XLR outputs.
It's DEFINITELY a ground problem if it's still making the same sound with the FM3 turned off (as you stated), but goes away if you unplug the cable.
 
And the fastest, easiest, and cheapest way to determine a ground issue on gear that doesn't have a ground lift built in (which by the way, does the exact same thing as the exterior ground lift I linked to)...is to use a ground lift plug.
The ground lift on modern equipment affects signal only. It doesn't touch the power ground.

Some older guitar amps have ground lifts on the power switch, but the manufacture of those was banned decades ago in most countries, because people were dying.
 
You mean don't do the thing that I've used for decades to remove hum and buzz???
Have you ever owned a rack full of gear? lol
Every sound company I ever used always had a dozen or so of them in the road case.
Some venues just don't have proper grounding. And the fastest, easiest, and cheapest way to determine a ground issue on gear that doesn't have a ground lift built in (which by the way, does the exact same thing as the exterior ground lift I linked to)...is to use a ground lift plug.
The FM3 DOES have a ground lift...but only for the XLR outputs in case the polarity is reversed back at the outlet of a mixer board in a venue.
Again...quickest way to troubleshoot a ground problem is with a ground lift. The FM3 doesn't have one built in for this particular problem. I don't know if the guitar amp he is using has a built-in ground lift either. So the best way is the way I spoke of.
#experience
Do what you have always done. Hopefully you won’t find out how it isn’t the right way to deal with it. I was lucky when it happened to me.
 
Let’s just distinguish between lifting the signal ground vs removing the mains ground. The latter can kill you the former is safe and can be helpful. A real ground loop in the mains (high voltage) can always be properly rectified by a knowledgeable electrician. No mains ground should be walked away from and the venue torn down because it’s either so old or unmaintained that other dangerous issues are probably present. What’s more important…shitty pay and free beer or your life?
 
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