It's solid state, I think. Randall calls it a Valve-Dynamic. I've also heard it referred to as "Trans-tube"
Link to better explain Valve-Dynamic
http://www.randallamplifiers.com/abo...lvedynamic.asp
Edit: I'm really not picky about amps. I just want a bigger amp with reverb. If I had my druthers, I'd have a Fender Twin Reverb, but I'm shelling out a grand for one.