Do new power tubes have a burn/break in period?

FuelGTRX

FuelGTRX

New member
I just put a new quad of JJ KT-77's in my Quickrod and I'm wondering, do new power tubes have a burn/break in period?
 
I think other then the warm up period which is like 5 minutes, nope. They sound best when absolutely freshy.
 
No, most tubes are burned in during testing when they are manufactured.
Did you bias the amp?
Steve
 
Steve, yeah, I biased the amp up. Man, the QR runs some high plate voltage, mine was running at about 505. I averaged the tubes to around 30 mA per tube.

So far, I'm liking the KT-77's. They really tamed down the aggressive mids that the QR has. Really made the amp sound more balanced. I'm going to leave them in there for while to see how I feel later on.
 
I really think they have a break in period. It totally depends on how long they were burned in during matching. Even if they were burned in for 24 hours, they will probably still drift a bit. That is why I say check the bias again after 25 or so hours of playing time. You may or may not need to touch-up the bias at that point.
 
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