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OK to replace one power tube for amp?

I have Joule Stargate Monos that use the Russian 6C33C-B power tube, two per amp. One of them isn't holding bias very well... wandering a bit. Can I just replace the one tube? Each power tube is individually biased in this amp and I've heard that matching pairs with 6C33s is just not something that happens so it would seem ok to buy 1 but I didn't know if having tubes of different ages was bad.
dhcod
swampwalker's avatar
swampwalker
5,138 posts
 
Should not be a problem since they are individually biased. One question; when you say bias wanders a bit, how much are we talking about?
david12
1,454 posts
 
I have changed one 6C33C on my Ayon Spark, no problem. That is again, as Swampwalker says, because I can bias the tubes myself, not true with fixed bias of course
brf
1,715 posts
 
Short answer, no problem. If the tubes are getting close to their life expectancy, then you may consider changing out both tubes for improved sound performance.
mechans
3,048 posts
 
You can do it but sound wise one will be very much burned in and starting to die while the other has a brand new sound signature. You can do, it but I would replace both.
dhcod OP
710 posts
 
Thanks for the responses.

It's wandering 10-15% every day.
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