4CM noise problem

[pmrm87 0]

Hi everyone.

 

I'm using the following setup: Guitar to helix, 4 cable method to Carvin Legacy VL300 amp, amp to Carvin Legacy 412 cab, and xlr outputs to mixer then stereo cabs.

I'm also feeding a stereo loop pedal via sends 3 and 4.

 

So:

Guitar -> Helix guitar in -> Helix Send 1 -> Amp In -> Amp Send -> Helix Return 1 -> Helix Send 2 -> Amp Return (i use the send 2 instead of the 1/4" out because this way the volume is not affected by the helix volume knob).

Also:

Helix Xlr Outs to mixer, and Sends 3 and 4 to Loop Pedal, then mixer.

 

You can see the scheme in the picture

 

Problem is, when i plug the guitar straight to the amp, there's no noise, no hum, everything clear on all chanels. 

When i plug the guitar to helix straight to mixer, with amp simulations, no noise, no hum, everything clear.

When i use the 4CM, lots of noise. 

 

You can hear it in the video. first guitar straight to amp. then plug the guitar to helix guitar in, and the remaining 3 cables. And you'll hear the diference...

 

https://youtu.be/D6eNThp-BkM

 

 

 

Already tried:

-change all the cables, audio and power.

-plug the power to diferente places, then same place.

-change the outs from line to instrument, and vice-versa.

 

Nothing works. Any guesses??

 

 

[Joepeggio 70]

Transformer Isolate one, or both of the loop cables. (not the guitar to Helix and not Helix to Amp input)

 

Edit: Maybe amp input cable may work too. Since its low impedance grounded signal coming from Helix.

[ColonelForbin 311]

Transformer Isolate one, or both of the loop cables. (not the guitar to Helix and not Helix to Amp input)

 

 

 

This is what ya need to do! I use one of these; many options exist:

(I run the two cables from amp fx loop send and return through this box to and from Helix send and returns)

 

https://www.sweetwater.com/store/detail/Hum

[Joepeggio 70]

This is what ya need to do! I use one of these; many options exist:

(I run the two cables from amp fx loop send and return through this box to and from Helix send and returns)

 

https://www.sweetwater.com/store/detail/Hum

Good choice. I haven't used that one yet, but we have a few of these (below) and they work well, though i have to admit, I do not use 4 cable. I like my 8 1/2 minute set up of guitar and vocal. ;)

 

One thing I do like about the one below is its many I/O formats, and it converts between all of them.

 

https://www.sweetwater.com/store/detail/DTI

[pmrm87 0]

Thanks a lot, I'll try this, had no ideia! 

Between those two options, any advice?

[vmoncebaiz 44]

The FX loops can be noisy when placed in front of certain amps (or even amp models).  Try to use the 1/4" output instead of the second set of Send/Returns.  See if the noise level changes at all.  You could also try to use the 1/4" outs into the front of the amp, and put the Helix's send/return in the amps fx loop.