It's a MRX Phase (Block letters) 90, and was made by MXR nor Dunlop I believe. I bought it used in the early 80s. No sound at all now Chuck. For a few weeks out of the blue it would pop loudly through the cab after being engaged and I would click it back off, just thinking it was something with a cable or power supply. I brought it home to see if it happened there too. Nothing at all now. AC or DC makes no difference. I thought some solders now covered by the e-tape may have been touching the metal box from the foam being shot, but I don't think that's the case now. Possibly something got cooked. I can't complain really it served me well since the very early 80s. We all gotta go at some point!