Question about hum

Fixated

Inspired
Hello I have a quick question.

I have a revv g20 amp and for some reason when I plug in my fm9 as a pre pedal, there is a large amount of hum. I tried pressing the ground loop button and it’s still persistent. I should also mention that I’m using a humbuster cable from output 3 to the input of my amp.

I do not have this problem at all on my Mesa boogie Fillmore.

Any suggestions?

Thanks a lot
 
I should also mention that I’m using a humbuster cable from output 3 to the input of my amp.
Is the TRS end of the cable plugged into the FM9? Are both units on the same power circuit?

Is it hum, 60-cycle, that is there whether the guitar volume is off, or is it EMI noise that goes away when you turn down the guitar volume and as you turn in a circle?
 
black trs side is in the fm9 and the blue side is in the amp input.


Noise does not disappear when turning down guitar or turning other way.


I have plugged the guitar amp and fm9 in same power strip (live wire music grand). The hum was bad. I then moved fm9 to a separate strip and the him was still bad.

I just tried putting fm9 directly in the wall socket and the amp in the live wire power strip. The him is much quieter. Why is this?
 
Is the TRS end of the cable plugged into the FM9? Are both units on the same power circuit?

Is it hum, 60-cycle, that is there whether the guitar volume is off, or is it EMI noise that goes away when you turn down the guitar volume and as you turn in a circle?
I can’t type in my message directly to reply. I sent the information above
 
black trs side is in the fm9 and the blue side is in the amp input.


Noise does not disappear when turning down guitar or turning other way.


I have plugged the guitar amp and fm9 in same power strip (live wire music grand). The hum was bad. I then moved fm9 to a separate strip and the him was still bad.

I just tried putting fm9 directly in the wall socket and the amp in the live wire power strip. The him is much quieter. Why is this?

Sounds like a ground loop (notwithstanding that you’re using a humbuster cable). They can be tricky to address, in part because they are often room-dependent and because there is no universal solution.

Consider interrupting the audio ground path between the FM9 and the amp’s input - for example, using a transformer-isolated connection or by physically disconnecting the audio ground on the cable (but always be ready to swap to a normal cable - i.e., because in the absence of an alternate path to ground, the signal will then be noisy because the ground connection is absent!) or by putting the cable through a feed-through box with a switch to lift the audio ground.
 
Sounds like a ground loop (notwithstanding that you’re using a humbuster cable). They can be tricky to address, in part because they are often room-dependent and because there is no universal solution.

Consider interrupting the audio ground path between the FM9 and the amp’s input - for example, using a transformer-isolated connection or by physically disconnecting the audio ground on the cable (but always be ready to swap to a normal cable - i.e., because in the absence of an alternate path to ground, the signal will then be noisy because the ground connection is absent!) or by putting the cable through a feed-through box with a switch to lift the audio ground.
i got a behringer hd400 today in the mail from amazon. the hum is away but now im starting to hear a clicking noise... is there a better box to use for this issue?

i tried both the humbuster and a regular mogami cable

thanks a lot for responding
 
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