The Simul-Satellite has a unique power section. It is basically a Mark III Greenstripe (Class A is wired for Pentode) with the added benefit of a Tweed setting. Not a bad clean poweramp or clean amp in general, don't bother trying to get any gain/saturation from it tho, its pretty flabby. I run a Quad Pre through mine and it sounds fantastic! I swapped the stock 6L6 tubes for KT66's a while back and never looked back. Sounds pretty beefy.