Hello All: I've recently purchased an Ampeg SCR-DI pedal for quiet practice at home. (Ampeg: Pedals - SCR-DI) In short, I've run into an issue when practicing with headphones that after a minute or two of clean sound (and with the fuzz off), it starts with this terrible signal degradation that turns into a sort of growl, then scream in the headphones. Initially, I thought this was my instrument cable creating the issue. But this morning, using a completely different cable (and not having anything plugged into the aux jack) it happened again. The same thing has happened on two different basses (a Kala U-Bass and a Fender Jazz). It could be the headphones - that's the one thing I've not eliminated yet - but has anyone else run into this? Any tips for troubleshooting? Is this a bum unit? (I hope not.) Let me know what you think.