Marshall Boogie
New member
- Joined
- May 15, 2020
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I recently had a problem with my Mark v 90 watt. I was mysteriously blowing pre-amp tubes and couldn't figure out why. I started evaluating the way I was using the amplifier for clues as to what could be going wrong. One of the things I had taken to doing was to enter variac mode from normal without putting the amp in standby. Thinking I might just be surging the tubes with this move I suspended it and started only changing power modes in standby and sure enough, no more blown pre-amp tubes.