Roland Cube 60 pings at low volume

[RolandRD]

I have 2 Roland cube 60's that have the same issue, but at diff volume levels. I can not turn up the volume past 9 oclock on either unit. If I go past that, the amp will make a pinging sound (like a ships radar) if I touch the strings in any way shape or form. Guitar is at least 10-13 feet from speaker and I can not get any louder than bedroom level on one and loud stereo jam on the other. No way in the world could I jam in a session with a live band with these things. And no, its not feedback, per say, that comes in diff, though, if I let it ping long enough, it will start to squeal. Not a reg feedback squeal, but, it will ping and carry on to a steady squeel. There is not raising or lowering the squeal like regular feedback. If I can remember my youtube log in, I will record it.

Till then, any ideas?