Vintage 1950s Gregory Mark I Tube Combo AmpNotes The sound from this is wild. Total beyond distorted noise that sounds kind of like a ring modulator effect. The amp powers on, there's an ever present hum, and the "tone" is ideal for a someone in a noise rock band. I bought this at an auction. It was the same model amp that my old man mentioned was his first ever amp in the late 50s early 60s. Being sold as is A Vintage 1950s Gregory Mark I Tube Combo Amp in Poor condition! At Evolution Music,