Have I killed my MKIII?????

[welshboogie]

Right Guys,

Following on from my previous post about a thin and weedy distortion tone by using a Strat, I powered up the Boog tonight to run some ideas using a boost pedal etc etc.

The amp powered up fine in Standby, all tubes etc glowing as normal.

When I came off standby, it gave a deep POP and then starting humming bad. I glanced around the back to see one of the EL34s (its a Simul Class) burning bright bright Orange and almost smoking!!!

Turned it off, unplugged the 34s and ran it for a short while in Simul Class with just 2 6L6's and it was fine, almost better tone-wise than ever before!! - I think my bad tone was down to a problem!!!

Now, I ran this amp at about 7 for a 3 hour gig on Saturday in Class A, is it possible that I have damaged the output stage?? - the tubes are all very recent (a few months)

Please Please Help!!!!!!!!!!!!! :!: :!: :!: :!:

 

[newtomesa]

Shouldn't you pull the 6l6's to run in simul-class (inner tubes)?

I don't have a simulclass, but I believe they all run the outer tubes in the half-power/class A mode.

But i guess you got sound out of the amp that way, im confused now!

 

[welshboogie]

Shouldn't you pull the 6l6's to run in simul-class (inner tubes)?

I don't have a simulclass, but I believe they all run the outer tubes in the half-power/class A mode.

But i guess you got sound out of the amp that way, im confused now!

It was my understanding that Simul-Class runs the 6L6's and the EL34's and Class A was just EL34's

I forgot to mention that I tried swapping the EL34s around to see if it was a bad tube but the burning valve remained on the "inner" EL34 (closest to speaker)

 

[newtomesa]

Right from the mesa operation manual,
"The inner tubes must be 6L6's while the outer tubes must be EL-34's".

The amp doesn't intelligently run EL-34's, they must be in the correct sockets, the outer. If you unplugged the EL-34's from the outer sockets and ran in class A, you should not get any output at all.

Do you have the 6L6's in the outer sockets, and the EL-34's in between them?

 

[welshboogie]

Sorry, perhaps I didn't explain well enough - I ran the amp in Simul Class with only the 2 inner 6L6s.

Can we get back to the main question please!!! :roll:

 

[newtomesa]

Just trying to help find the solution, if you had the tubes installed in the wrong locations you may have just damaged the tubes.
I wasn't trying to imply that you were stupid or anything! Thanks for the vote of confidence.

 

[welshboogie]

Sorry, didn't mean to offend, I'm just in a corner at the mo' because I have a very busy month ahead with the band - 6 gigs a week!!!.

I revalved the Boog earlier in the year in preparation - give it time to burn in etc etc and now it drops it pants and shakes its *** at me - just to let me know who's the Boss!!!!!

It runs fine with the 2 6L6s and the manual says its OK to as well, so its a toss up between using a tranny Fender Deluxe or running the Boog -2 tubes!!!

 

[Boogiebabies]

The outer sokets are Class A. You have to have tubes in them or your OT may fry as they are not shrted to ground like the 6L6's when you switch from simul-class to class A. I would try new EL-34's or 6L6's in the outer sockets and see if it works in Class A. The pop may be a filter cap, tube or your output transformer. The only question is if it was a bad tube, why did it not blow the fues. I would check your fuse and rating as well.