Hi Bruce, it was a JMP 100 watt bass head that had a small Marshall logo script on the front. Not sure what the valves were but at the time I thought they were EL34's as after a mishap doing a gig on a ferry it had a melt down and vaguely remember EL34 being mentioned. Originally bought when I was mainly playing rhythm guitar as it had better midrange and not as harsh top end. Little did I realise it would be used for Bass a few short years later. Didn't take much to drown out the stage levels as it as so loud and mostly plated it 'just on' at around 1 out of 10. Never went past 2 or 3 as it was deafening and blasted most front of house pa's. You can look it up on http://www.legendarytones.com/Marsha...ppers-guide-1/