Why do loadboxes sometimes squeal and oscillate at loud volumes?

[santiall]

Here's an interesting thing.

guitar->amp->Suhr (no feed to the RME) == no oscillation
guitar->amp->Ultra-G (with EXTERNAL phantom power) ->Suhr (no feed to the RME) == == no oscillation

As soon as I connect either of those to the RME, that's when I get the oscillation.


I take my Orchid 1:1 isolator, and put that between the Suhr output and the RME... the oscillation disappears. So I guess I was putting the 1:1 isolator in the wrong part of the chain all along!

there you go! at the end it was a grounding issue, and as per above, not surprising with all that going on.
Are you using an XLR between the Suhr and the RME input?, that may also solve the problem. It is more out of my curiosity as you will be perfectly OK with the isolator.

 

[Orvillain]

there you go! at the end it was a grounding issue, and as per above, not surprising with all that going on.
Are you using an XLR between the Suhr and the RME input?, that may also solve the problem. It is more out of my curiosity as you will be perfectly OK with the isolator.

So all in all, I was being a dummy and trying to break the loop at the wrong point. lol.

No XLR from the Suhr, unbalanced jack only.

I've got two options now though.

1 - Suhr only. Take the amp output straight to the Suhr. Take the unfiltered output from the Suhr and go into my 1:1 isolator box, and then into the RME.
2 - Complex mess of hate. Take the amp output straight to the Ultra-G. Use the THRU jack to the Suhr. Take the DI XLR output of the Ultra-G to a PS400 portable phantom power supply. Lift the ground on the Ultra-G. Take the output of the PS400 to the RME.

In either situation, I'm now able to run my guitar or my reamp box into the front of the amp, and get a full amp-only signal at the computer, without oscillation and without a ton of extra noise going on.

I don't like the sound of the Suhr with the DI level too high. I'm just going to have to try and keep it low.

 

[santiall]

So all in all, I was being a dummy and trying to break the loop at the wrong point. lol.

No XLR from the Suhr, unbalanced jack only.

I've got two options now though.

1 - Suhr only. Take the amp output straight to the Suhr. Take the unfiltered output from the Suhr and go into my 1:1 isolator box, and then into the RME.
2 - Complex mess of hate. Take the amp output straight to the Ultra-G. Use the THRU jack to the Suhr. Take the DI XLR output of the Ultra-G to a PS400 portable phantom power supply. Lift the ground on the Ultra-G. Take the output of the PS400 to the RME.

In either situation, I'm now able to run my guitar or my reamp box into the front of the amp, and get a full amp-only signal at the computer, without oscillation and without a ton of extra noise going on.

I don't like the sound of the Suhr with the DI level too high. I'm just going to have to try and keep it low.

indeed complex mess of hate... I guess that already answers if you want that setup.

how about amp->suhr->Ultra-G XLR out->XLR RME input +phantom (I assume that the RME will provide phantom?). It's just to simplify the external phantom PSU, otherwise use it

 

[Orvillain]

indeed complex mess of hate... I guess that already answers if you want that setup.

how about amp->suhr->Ultra-G XLR out->XLR RME input +phantom (I assume that the RME will provide phantom?). It's just to simplify the external phantom PSU, otherwise use it

Yeah I'll try it!

Thank you btw!