M80 started squealing when facing new amp

[918AxMan Junior Member Find all posts View Profile Close 918AxMan]

Hey guys,

For my main axe, I play a Martin OCM 16e-Maple with a M80 and an LB6 dual source pickup config, running passive through through a Pendulum SPS-1 and then to stage amp, before hitting the board via a REDDI. Until recently, I played through either a Trace Eliot TA-100 Concert or a Fishman Performer. However, due to road use/wear, I've retired the Trace and the have temporarily mothballed the Performer and began using a single AER MM200 as my stage amp. As soon as started playing through the AER, I have been experiencing a high pitched squeal when ever I face or partially face the amp. The squeal is definitely being generated by the M80, as I can turn the signal completely down on the LB6 and I still get the amp squeal when facing, and in some case halfway facing, the new AER amp. Nothing has changed on my pre-amp setting and the gain level on the amp has been backed off quite a bit from where I had it set on my previous amp, so I'm a bit muddled. Obvious answer, always keep my back to my amp. Well, that is easier said than done. Any suggestions? Thanks.

[Caleb_Elling Administrator Find all posts View Profile Close Caleb_Elling]

Hey 918AxMan,
If you get that noise to occur, does pressing down on the guitar with your hand make the noise diminish or stop? I'm wondering if the noise is coming from the guitar top, the pickup, or the amp.

[918AxMan Junior Member Find all posts View Profile Close 918AxMan]

Hey 918AxMan,
If you get that noise to occur, does pressing down on the guitar with your hand make the noise diminish or stop? I'm wondering if the noise is coming from the guitar top, the pickup, or the amp.

Caleb, Thanks for the reply!

Pressing down, muting, or dampening the strings in any way does nothing to eliminate the sound. Its a very high pitched, squeal, that changes frequency, as I change the orientation of my guitar in relation to the front of the amp. I've recreated the squeal, without the strings on the guitar, and while dampening the top of the guitar. It sounds very close to the high pitch feedback you'd get by holding a mic in front of floor wedge. I never had problems with this until I switched to the AER MM200 amp that I'm playing through now, so maybe there is some weird interaction between the AER and the M80.

[Caleb_Elling Administrator Find all posts View Profile Close Caleb_Elling]

If you're not getting that response from any other amp or PA, then it could be some odd incompatibility between the pickup and the amp. This whole situation still seems off to me though.

If you have the M80 in Passive mode, then the M80's preamp/circuitry is already out of the equation, as is the battery.

Is that amp particularly treble-heavy or bright?