How long can I expect tubes to last on a preamp or MW CD player?

Secondly, what would be the signs of tube deterioration?  Without a tube tester, is there any way to tell how much life they have left short of they aren't working anymore?  I have 7 tubes between the TRL DUDE and MW 5400 Signature Truth.  I may have hit that point on at least a couple tubes.  Seems to have dropped a little in SQ.  The 2 SNL7 tubes on the MW are only a couple months old.  The rest have been on 24/7 for at least half of their lifespan, about 4-5 years with NOS tubes in them.  I still have the original tubes with very little use.


the tubes you are referring to is the 6SL7 gain tubes in your dude

try swapping them side to side see if the channel imbalance switches

call or email brent jessee or jim mcshane tell them you need replacement tubes for your dude - they will know what to send you (google search will give you their contacts, they are stalwarts in audio tube supply...)

good luck
I had a volume balance problem, perhaps it is your tubes.

Turned out to be one of my Cayin A88T's 6sl7's (it also has 6sn7's).

had several used GE 6sl7 downstairs, that proved it was just the tube, not the amp or anything else in the chain. 

bought new 6sl7's from Brent Jesse.

Picked a Sylvania model because the chrome tops would look different from the 6sn7's (I had mixed them up once).

Sylvania did not sound as good as the unidentifiable Cayin tubes, or the used pair of GE's.

Brent had me break in the Sylvanias for 60 hours (no signal needed, just leave then on). Still not as good.

I picked alternate GE, I paid postage only, Brent gave me full credit, and, the GE's I ordered and love were half the price.

Just spoke with Brent today about the 6SN7 tubes and 5AR4GZ34 rectifier tubes. He seems to be hot on the RCA 6SN7 GT tubes and the Mullard GZ34 tube. I looked up my records in my emails sent and figured out I bought the DUDE in late 2016-early 2017.   I bought the MW 5400 about the same time. So the tubes were left on probably 160 days 24/7 and shut off when not in use much of the rest of the time. No matter what, Brent figured by the sound of my system and this amount of use that it is time to change the tubes and it should make a very significant difference. I won’t leave them on anymore when not in use like I did before.   I will talk to Andy at Vintage Tubes in Michigan on Thursday about the 5 tubes I will need. Tomorrow I will be able to safely open the DUDE without fear of curling my hair or worse. 

Thank you e & j for your personal experiences on what happens when tubes begin to deteriorate in sound due to age. I’ve been able fortunate to assemble a really good sounding system because of good ears and a fair idea of what real music sounds like in my head. But I still have a long way to go on understanding the technical aspects of the various components.