Tube Life Artifacts


I've been using the same tubes for almost 12 years. They are RCA EL84s (6bq5) in 1959 Leak TL12 plus monoblocks. Recently, I have noticed that one channel seems to be "deeper" in soundstage, almost like there was more reverb on that channel. It's a mild difference, more noticeable on some recordings than others. This difference is consistent with both vinyl and CD, and switched sides when I switched the speaker connections.

Is this evidence of tube deterioration? I have a set of unused Philips tubes somewhere in the basement (made by Mullard, I believe) and I'm about to switch them. If I can find them...
dragunski
I would suggest going to Andy Bouwman at Vintage Tube Services for your RCAs and for his recommendations as well.  Buying tubes on the internet can be a crapshoot; Andy has the real deal, and his advice is priceless as well.
Thanks for the advice. I'll check it out. 

I've been looking at these, including Telefunkens at $190 per pair. Seems a bit high, no?

http://www.audiotubes.com/6bq5.htm

I have no relationship with this seller, and this link is not an endorsement. I posted it for information purposes only. (not sure what the rules are here). 
I haven't used Tele's so won't comment specically on them. I will state that I have been a  repeat customer of Brent Jesse (audiotubes) and have found him to be both a reputable seller and knowledgable. Just my 2 cents


For real Telefunkens, that's not a high price.  Part of what you pay for with reputable dealers like Andy and Brent is their testing and knowledge (there are fake tubes out there).  The premium is, in my view, worth it.
After a week of solid state,  I'm ready to switch back to tubes. Yes, I had a lot more clean power, but it was dry, bland, lifeless, uninvolving.

The RCAs are going back in. Maybe I can get another 12 years out of them.