If you have Carver repair questions, or can help other users with repairs, this is the place for it
M1.5t has 250v rated output transistors with 125v top rail. M1.5t is much underated amp. M1.5t can really take some beating. I think m500 uses 150v output transistors at 74v rail. If every things are equal, I prefer M1.5t for power and headroom.