Using Different Power Tube Types Simultaneously (PrimaLuna)


Always needing a quick answer on Sundays when the shops are closed..Murphy’s Law, Lol...

Just wanted to triple-check before I make a severe-consequences-mistake here :  Is it okay to mix one, brand A EL-34 in with three, brand B KT 77s in a PrimaLuna Prologue Classic integrated amp which normally uses a matched quad of power tubes?  I’m pretty sure I’ve been dealing with one, possibly two GL KT 77s that have been intermittently problematic for about 2 weeks but which have now gone bad to the point that re-seating doesn’t help and amp gives the red light consistently.  I don’t have a backup quad of KT 77s and need to trace down the bad tube(s).  I have the original EL 34s that came with the amp and they were working fine when I switched to the KT 77s last Spring.

if this is safe to do, is it also safe to play the amp with this mixture of tube types until I can get a replacement KT 77(s) delivered?

Apologies if this is 1 + 1 = 2 level basics...This is my first tube amp and my best Google search terms are turning up nothing but tons and tons of guitar amp articles that may or may not be applicable to my situation.  Thanks in advance.
lg1

Showing 3 responses by jjss49

I would install the stock quad  and order a new quad and keep the others as back ups


good advice from tuberist
good luck lg1

kt77's very close to el34's in response and need for bias, sonic character just a teeny bit different

would be more of a problem if you tried to mix el34's with say kt88 kt90 etc etc which are much more powerful with very different response
primaluna's materials talk about this - you should read them

you can do it but it is not advised if good sound quality is the objective