| Author | Message | ||
     Gio |
Hi everybody, I bought on ebay a MMan HD-130 head (early model), and I use it with a Marshall 2x12 150 watt cab. The EL-34 are 4 Svetlana. I play very rarely with my band, more or less 3/4 hours a month. One month ago the amp stopped playing, and the amp tech who repaired it said it was a question of overheating, but he was unable to determine the cause of it. Usually a play the amp at the hi-vol setting, turn the volume at 3 and the master at 5. The tech said also that the amp sports about 100 watts, is it normal? Would it better to change the Svets to JJ E34L, which are supposed to carry better the high voltages of MMan amps? thanks a lot in advance (ps: there is no impedence mismatch between the cab and the head) | ||
| Terry |
You may need to set the Bias...If you have 12AX7 try a new one. Svetlana are just fine. | ||
| Gio |
thanks terry, setting the Bias would make the tubes run less hot? I have the 12AX7, maybe I'll try a new one. | ||
| Michael Kaus |
The bias on MM with the 12ax7 should be set NO HIGHER than 14-15mA idle current. 12-13 would be better if you are having meltdown trouble. Most people don't take into account the high(700+) volts on the plate when figuring their idle draw. Mike. |