tubes for mark IV

[carloc80]

is it safe to run the Mark IV with 2 Mesa tubes in the outer sockets and 2 JJ in the inner sockets? A tech today has told me that it's not safe and the 4 tubes must be all the same...
thanks

 

[#2121313]

The rules to follow are:

Sockets are: A B B A

So the 2 outer sockets (A) should be a matched set and the two inner (B) should be matched. Now, if your amp is Simul Class, which are Mark IV is, then you can run either 6L6's OR EL34's in the outer (A) sockets, BUT the inner (B) must ALWAYS be 6L6's.

Technically (as per Mesa's warranty) you should only use Mesa tubes, in fact they say your warranty is void otherwise.

But I don't know anyone who only uses Mesa tubes, but to answer your question YES you can mix brands, just keep the pairs matched as mentioned above.