03-22-2017, 04:31 AM
The M-12 Mercury is here and out of curiosity used the adaptors to try a pair of 12AX7s in place of the original octal 6SL7s. The sound was what one would expect; slightly more gain; a tad more agressive with more top end; slightly earlier breakup; not quite as warm. No big deal but good to have as an option. The difference is subtle. I like the warmth of the 6SL7s.
The amp has some noise issues and from what I have been able to find on line, the hum is caused by some grounding issuss. The solution coulc be a simple matter of uncoupling the ground by moving a couple of wires. When I get the time in a month or so I'll get it to my tech and give a report after that. In the meantime, here is a link a thread in another forum that addresses the issue, post #21 in particular: http://www.tdpri.com/threads/1960-ampeg-...905/page-2
The amp has some noise issues and from what I have been able to find on line, the hum is caused by some grounding issuss. The solution coulc be a simple matter of uncoupling the ground by moving a couple of wires. When I get the time in a month or so I'll get it to my tech and give a report after that. In the meantime, here is a link a thread in another forum that addresses the issue, post #21 in particular: http://www.tdpri.com/threads/1960-ampeg-...905/page-2