I have a '72 studio lead that I bought new. I think the original speakers were not 50 RMS watts. I blew them out in short order after playing full-out 70's rock. I find that the amp has a very nice sounding distortion when turned up to 10. Remarkable for a solid state amp. I would play next to all kinds of tube amps, and the other guys would say something to the effect of: "Damn, your amp sounds better than mine."
I refurbished this amp recently, and put in two 10" Emminence Rajin' Cajun speakers. Tone heaven, and it feels so cool to play the same amp I was gigging with back when I was 16.
Good tunes,
Ron C.