Question: When you get this clipping sound, what is the volume level of the empeg itself set to?

If it's well below 0db, you shouldn't get clipping no matter how high your EQ is cranked.

For instance, if your empeg is set to -20 db on the volume scale, and you've boosted an EQ band up to +7, then the net gain on that band is actually at -13 and should still be OK. (In Theory.)

*Chirping* sounds? Digital clipping would tend to sound like a crackle.

I've sometimes heard amplifiers make a chirping sound when they overheat. Wonder if it's the amplifier.