Effects loop squeeling

[Beavis]

Ok i Have a Laney GH100L and Tc electronics M300 effects. When i run the M300 throught the effects loop i get a squeeling noise when the amp is run at high gain sounds, clean its fine, is this a tube going or somthing else, I can set the input level on the M300 and adjust the effects level, but when i get a point when it doesn't make a noise it has sucked most of the tone.

Any Idea's please help

Beavis

[Gresh]

Are you sure it is the loop and not the unit?

Take the TC out of the loop and check for the squeel again....then use a quarter inch cable connected to the send and return so you are sending the amps own preamp signal through the loop circuitry and see of it squeels.

Those two checks will tell you what portion of the chain is causing the squeel...how to fix from there, I have no idea?

[Beavis]

It only squeels if the unit is attached

any idea's

the unit is brand new

Beavis

[mike777]

I have three things I could think of:

Is there a switch that allows you to select a loop level on either unit? It is usually labeled a -10/+4 switch. This is may be the issue, Usually, you would select +4 when using rack equipment but really it boils down to which works best with your rig. Some units may only run a +4dB signal level though the XLR ports and -10dB through the 1/4" jacks. If they both have selectable line levels than make sure both are matched and start wit -10dB.

It may also be as simple as an input and/or output level adjustment on the processor. Start low in your adjustments and tweak them until the levels are about the same as when the processor isn't in the loop or switched on.

One more thing that I can think of: Does this processor have distortion in it? I'm not familiar with this unit. If it does, distortions often don't provide desired results when used in an FX loop. I'd edit out the distortion in the patches that have it activated and use the distortion in the amp or through a separate box plugged between the guitar and the amp's input. If you'd rather leave the distortion on in the loop-try lowering the distortion signal level and amount (again, that's if this applies). Hope some of this helps.

Mike 777 Haug