I'm sure as great collectors, we've all owned a few stinkers.
For me, it's my DOD Death Metal. I bought a Zoom Ultrafuzz off ebay, and the guy sent me this pedal along with it for free, as he said "it had a problem with the power supply" and i could have it. Now i suspect he just wanted to get rid of this steaming pile of sh#t.
It has 4 knobs, helpfully labelled "Rip", "Guts", "Pain" and "Scream". These translate to "bass, middle, treble" and "level" respectively. Notice something missing - yup, it has no gain control! The distortion is contasntly on 10 - actually 11, maybe even 20.

Sound-wise, it just sounds like my Boss Metalzone with the gain fixed on 10 - except it's also more solid-state and shrill and harsh - yes really. I can't imagine this pedal being useful for anyone, even death metallers!
Anyway, would like top hear other people's stories. Have a feeling Behringer is going to feature heavily on this thread
