EL34 Tube (Ruby BHT)

[jtp337]

One of my 4 power tubes failed, so I need 1 replacement. I don't want to replace the entire set since they're new-ish. Is this a good call?
And where should I buy them from (Canada)?
(I'm assuming when I get it, I can just pop it in without biasing or doing anything really, I'm still new to tube amps)

Edit: I ended up buying a pair on eBay for $40 total.

 

[rcm78]

How old are they? Ruby warranty's their tubes for 6 months.

 

[jtp337]

Maybe 2-3 months, but I don't want to bother them for one tube.

 

[Bloodrock]

Ruby's are crappy Chinese tubes. Do yourself a favor and buy 4 new matched tubes of better quality.