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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

Showing 3 responses by mechans

mechans
3,048 posts
 
Philips made Mullard not the other way around. 12 years on an output tube is incredible never mind EL 84s. Time for a new set.
mechans
3,048 posts
 

I still think it prudent to get some new output tubes.  That family of tubes run hard, and even with limited use, it's time. 

he tap test, no matter how widely used , even by some dealers, isn't a good test. Even the gentle focused tap test isn't what I would use.  A microphinic tube with make bad sounds, when moved and more importantly,  when played- they produce  a feedback sound and ring and they also transmit any physical perturbation. 

As for figuring out which of multiple potential tubes go I would be inclined to remove the suspect and roll in another tube.  That does require a set of "good" back up tubes.

  I was going to say remove and replace but I didn't want to get political.

mechans
3,048 posts
 
You really should get those Mullards or whatever Philips brand you have hidden in your basement.  The Mullards are really good sounding if you like a warmish signature.   In addition  true NOS command serious money these days.
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