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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
jjss49's avatar
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jjss49
6,612 posts
 
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
tablejockey
3,871 posts
 
I have a PL DLHP

You could mix and match power tubes,but you're not going to hear optimum performance of any particular model. 

One of those you can...buy why? The PL units do not require matched power tubes.
lg1 OP
199 posts
 
“...One of those you can...buy(t?) why?......”

Thanks, tablejockey.......I think I’ve verified that the #3 (going left to right from the front of the amp) KT 77 was the culprit and I’ve replaced it with a stock, PL EL 34.  Are you saying I might get a better temporary balance with the two middle power tube positions running the EL 34s and the ‘77s’ on each end?
tuberist
951 posts
 
I would install the stock quad  and order a new quad and keep the others as back ups
tablejockey
3,871 posts
 
  "Are you saying I might get a better temporary balance with the two middle power tube positions running the EL 34s and the ‘77s’ on each end?"

lg1-
I am referring to the front row small preamp tubes. The PL website mentions the 2 innermost are the gain tubes, which have the most impact, if you want to tinker with SQ. It's not night/day difference, but another way to custom tune to your liking.

The mixed power tube thing seems like a temporary way to hear your setup until you get proper replacements. 
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