Mark IV

[Scrapinger]

Well maybe I'm lucky and maybe not...I got the last run of the Mark IV's. I bought mine new last year. The tone is incredible, but I have had a lot of little annoyances a few big problems. It's back at Boogie after I blew 2 power tubes within a week in the class A slots. The first tube was an EL34 which came with the amp. The second was a 6L6 that I pulled from my Mark IIB. There was never an issue with these tubes in the Mark IIB, other than sub-optimal tone. But they blew as soon as I put them in the class A.

Boogie says that the amp checks out fine and they think it was just bad tubes. Both tubes really blew good in a blaze of glory with crackles, pops, hum and glowing orange and white. Has anyone had a similar issue with their Mark IV? What do you think the odds of blowing.

Can anyone think of an issue other than the amp that could cause tubes to blow. Could power spikes? Low voltage? I am at a loss. I've got new tubes to put in there, but I am afraid they will be toast in no time. On the up side, Boogie has put in 4 new 6L6's at no charge.

 

[ryjan]

Boogie says that the amp checks out fine and they think it was just bad tubes.

This is good enough for me. What would be the point in starting yet another meaningless speculation thread.

 

[Restless Rocks]

Things like playing the amp cranked wide open into either a badly mismatched speaker load or into one of those nasty power soak attenuators would over stress any tube (and eventually your output transformer). Also disconnecting your cooling fan while doing any of this would make the situation even worse.