Squealing problem with M4...Jeff help!

[bstaley]

I am trying to use my Axxes GRX4 to switch between my Triaxis and M4. I have it hooked as follows:

Guitar >> GRX4 Input
GRX4 Loop 2 Send >> M4 Input
M4 Output >> GRX4 Loop 2 Return
GRX4 Loop 3 Send >> Triaxis Input
Triaxis Out >> GRX4 Loop 3 Return
GRX4 Out >> Axe-FX Input (for effects)
>>> power amp, speakers

If I turn on loop 3 to use the Triaxis it sounds fine. If I turn on loop 2 for the M4 it squeals like crazy. Almost like an uncontrollable feedback. Here is what I tried:
-Remove Triaxis and try M4 in loop 3
-Try both front and rear inputs of M4
-Toggling the ground lift on the M4

I'm not sure what the problem could be. The GRX4 is designed to switch between preamps. Any ideas?

 

[3 Mile Stone]

and is it fine without using the Axxess?

 

[bstaley]

and is it fine without using the Axxess?

Correct. I have been using just the M4 but today I decided I want to put my Triaxis back in the rack and use both.

 

[MarcoR]

If I turn on loop 3 to use the Triaxis it sounds fine. If I turn on loop 2 for the M4 it squeals like crazy. Almost like an uncontrollable feedback. Here is what I tried:
-Remove Triaxis and try M4 in loop 3
-Try both front and rear inputs of M4
-Toggling the ground lift on the M4

Sounds like you're not turning off loop 3 when you turn on loop 2.

 

[bstaley]

If I turn on loop 3 to use the Triaxis it sounds fine. If I turn on loop 2 for the M4 it squeals like crazy. Almost like an uncontrollable feedback. Here is what I tried:
-Remove Triaxis and try M4 in loop 3
-Try both front and rear inputs of M4
-Toggling the ground lift on the M4

Sounds like you're not turning off loop 3 when you turn on loop 2.

No, that's not it. And like I mentioned above, I tried running ONLY the M4 in loop 3 just to make sure that wasn't the problem. I definitely did not have more than one loop on at a time.

 

[MarcoR]

No, that's not it. And like I mentioned above, I tried running ONLY the M4 in loop 3 just to make sure that wasn't the problem. I definitely did not have more than one loop on at a time.

I presume you’ve taken the Axe-FX out of the equation?

 

[bstaley]

No, that's not it. And like I mentioned above, I tried running ONLY the M4 in loop 3 just to make sure that wasn't the problem. I definitely did not have more than one loop on at a time.

I presume you’ve taken the Axe-FX out of the equation?

Yep, I just did that after typing my last response. I now have guitar into grx4, into m4, straight into the poweramp. I totally disconnected the triaxis and axe-fx. I only have loop 2 on. It doesn't make any sense.

 

[MarcoR]

That is weird… I guess you’ve tried the other loops with the M4. For shits and giggles, try Guitar--> M4 input --> M4 out --> GRX4 loop return --> GRX4 Out --> poweramp.

 

[Jeff Hilligan]

Any luck with the issue?

 

[bstaley]

Any luck with the issue?

No unfortunately. Is there anything out of the ordinary with the M4 with regards to impedances or signal levels that won't play nice with a switcher? I would assume I'm not the only guy out there using the M4 with a preamp switch.

As a side note...this wouldn't be an issue if we had a Mesa-ish MKIV module from Egnater, but I digress...

 

[Jeff Hilligan]

no...
run just your M4 into power lets take the pre amp out of the equation. Then see whats next..

 

[bstaley]

So I figured it out and got it working. Turns out I had to enable the buffer on the GRX4 and it worked fine. What I don't understand is why the Triaxis worked fine either way but the M4 didn't.

The only thing I am doing out of the ordinary is with the Triaxis I come out of the Effects Send instead of the regular output. Some guys are doing this because it bypasses the opamp that supposedly takes away from the sound quality. Maybe something about the levels/impedances of the Effects Send versus the regular output caused the Triaxis to not squeal.

This is where I wish I had a better understanding of electronics.

 

[3 Mile Stone]

Glad you figured it out, it's always something simple like that. Can't believe I didn't think of it either.