[SOLVED] Strange Axe-Fx III underlying hum from day 1

Tommy Tempest

Power User
I'm not sure if what I found is standard on all the AXE FX III units sold, but I always had this underlying hum that never went away, no matter if a cable was plugged in or not. I could never find where it was coming from.
I just installed the latest firmware 1.09 beta and was checking out the new features and came across the AC line frequency under global settings. It was defaulted to 50hz. Since my U.S. standard frequency is 60hz, I immediately switched it to 60hz. Boom, the infamous underlying hum was gone. To test I put it back to 50hz and it was back.
So if you are in the U.S., and you find your AC line frequency default is set to 50hz, switch it to 60hz.
 
The AC Line Freq parameter works in conjunction with the EMI filtering in the improved Input gate.
By itself adjusting the AC Line Freq parameter would not make the hum disappear.
To test this, disable the input gate by adjusting its Threshold parameter.
 
The AC Line Freq parameter works in conjunction with the EMI filtering in the improved Input gate.
By itself adjusting the AC Line Freq parameter would no make the hum disappear.
To test this, disable the input gate by adjusting its Threshold parameter.
Well it did disappear as soon as I changed the frequency to 60hz. I did, however, forget to mention that I use a gate setting on all my presets.
 
The EMI filtering is a brand new feature in the noise gate/input block, and yes, it does default to 50 Hz instead of 60 Hz, BUT, that shouldn't make a difference in the previous underlying noise issues you report. Glad to hear this does work for you as a solution with the new firmware, though, I think its important to clear up that it wasn't the AC line freq parameter that previously was causing the issue. In other words, if someone is still on FW 1.08, and they change the line freq its not going to make a difference. Its only in conjunction with the new FW and feature set that this parameter may make a difference.

Essentially its working better to help cover up the noise, but its doing nothing to address the causes of environmental noise which are the root of the issue. I would suggest still doing things like moving the III away from the computer, away from dimmers, from CFL's, shield your guitar cavity etc, so you can operate the unit in the best possible conditions, and then let the gate help solve the issues of anything else that still shows up, as its pretty impossible to totally get rid of any EMI or RF in the typical home/studio environment.
 
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The EMI filtering is a brand new feature in the noise gate/input block, and yes, it does default to 50 Hz instead of 60 Hz, BUT, that shouldn't make a difference in the previous underlying noise issues you report. Glad to hear this does work for you as a solution with the new firmware, though, I think its important to clear up that it wasn't the AC line freq parameter that previously was causing the issue. In other words, if someone is still on FW 1.08, and they change the line freq its not going to make a difference. Its only in conjunction with the new FW and feature set that this parameter may make a difference.

Essentially its working better to help cover up the noise, but its doing nothing to address the causes of environmental noise which are the root of the issue. I would suggest still doing things like moving the III away from the computer, away from dimmers, from CFL's, shield your guitar cavity etc, so you can operate the unit in the best possible conditions, and then let the gate help solve the issues of anything else that still shows up, as its pretty impossible to totally get rid of any EMI or RF in the typical home/studio environment.
My hum had nothing to do with what was plugged in to the AXE or where it was located. I tried numerous tests to get rid of the hum with no luck. Even the noise gate did not solve this particular hum. Even though it was so slight, it was there and could be a little annoying at high volume levels. And like I said, I had a gate setting, in the input block, on all my presets from the very first day I started to set up the AXE III. My experience of changing the AC line frequency setting from 50hz to 60hz and eliminating the hum, may have been due primarily to the fact that I had gate settings, in the input block, and this new feature improved EMI filtering for the gate. At any rate I thought it was worth mentioning, because whether it's primary intention had nothing to do with what I was experiencing, it solved my issue. Now my III is as quiet as my II was.
 
I guess the best way to answer the question would be to roll back to firmware 1.08, and see if your still get the hum, regardless of if you changed the line freq from 50 to 60 Hz. On the other hand, I guess as long as its gone is all the matters in the end....

My guess is its still the new noise gate settings in FW 1.09, not the line freq parameter alone, but perhaps someone who hasn't updated yet can give it a try for us, as I too have already updated.
 
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