Haha, yes it's fixed, and I gigged with it yesterday for the first time as a guitar amp for my church's 4th of July event. I pulled 2 of the 6550s so I could crank it louder through my Kustom 4X12.
I've used it for bass a couple times and it works well for that too. It's basically a Marshall JCM800 2203 based amp. Just a few component differences in the preamp.
Basses: Warmoth 5 string Jazz, El Nino(J/MM "Geddy), Michael Kelly ST4 acoustic bass, SX Jazz fretless