Questions on Ampeg Reverberocket R212R Reissue

[Poor Otis]

Found a Ampeg R212R over a year ago,bought it from a estate sale,got it dirt cheep in very good condition..it sounded good for 6-7 months,then started breaking up..I figured it was time to re-tube since I do not know the history of the amp. Upon inspection, theirs 3-Sovtek 12AX7s and 2-Groove Tube 6L6 in it! I was told to never mix the brands of tubes up! Is this a true statement of not? Can I just replace the tubes or do I need a tech to adjust the bias? I have heard alot of different opinions about the type/brand of tubes that will bring the best out of this old Ampeg..but to be honest,I'm pretty confused about the whole thing..so..I need some Help!
Also..how can I get more out of this basic nuts&bolts amp..or can I..?

Thanks for reading..
Respects
Poor Otis

 

[Barnzy]

You can swap out each preamp tube (12AX7 and it's derivatives) as needed, for tone or to replace, one at a time with no issues. Your power tubes need to be changed as a set and replaced with a matched set. Proper biasing should be done at this time to ensure peak performance of your amp. That's general amp owner maintenance. Some people can get pretty tricky and will bias to taste and mis-match tubes for tone, but I would leave that up to those with advanced amp circuit knowledge. There is no reason whatsoever to insist that the preamp tubes and poweramp tubes are of the same brand. You can have an assortment of preamp tubes in the preamp, chosen for tonal reasons, but keep the 6L6's as a matched set.
Barnzy

 

[Poor Otis]

Good Info... Thank You