I have a Luxman hybrid (D-105u) Cd player and was wondering about tube life in these units. How does one tell when the tubes need replacing in these units? And how long would the tubes last in these players? My player seems to have weak bass and I was wondering if its the tubes causing that. I had another of these units before and never noticed it in that one. The previous unit had newer tubes.

If you still have the "newer" unit, mark the tubes and swap the "new" set with the original ones from the bass shy unit and see if that fixes the problem, also try the tubes from the problem unit in the new one too. (no damage is done as the tubes work, they just may have changed their sound).

The tubes should last a long time (barring any defective ones) as they don't have to do any "heavy lifting" driving speakers.

Other problems like microphonics may arise but that comes under the "defective" category not end of life issues.

Not having any experience with tube CD players, I can't say for sure, but a change of sound would put them as the first item to check on.

Mark T.:music:

I have a Luxman hybrid (D-105u) Cd player and was wondering about tube life in these units. How does one tell when the tubes need replacing in these units? And how long would the tubes last in these players? My player seems to have weak bass and I was wondering if its the tubes causing that. I had another of these units before and never noticed it in that one. The previous unit had newer tubes.
You can rule out the tubes one of two ways:
1) Find a tube tester, pull out the tubes, and test them. or
2) Buy a set of new replacement tubes, replace the existing tubes, and listen. If your problem goes away, then it was your tubes!

The tubes lifespan despends upon how the circuit was designed. Ultra conservatively desinged circuits can have tubes lasting for 20 years, or more (look at some old McIntosh units to see this demonstrated). More typical circuits will allow a tube to run for about 5 to 10 years before replacement becomes necessary. Circuits that are hard on tubes may eat them in a year or less.

My guess is that your circuit proabaly falls into the more typical camp, and that after between 5 and 10 years of operation, your tubes may have fallen far enough out of tollerance that the circuit is no longer performing well any longer.

I recently had a set of tubes in my preamp go out of tollerance, and the bass had become noticably weaker than it used to be. When I pulled them to test them, they all tested somewhat weak. These tubes had been run continuously by me for almost 10 years, but they finally just could not do the job any longer. That is an unusually long lifespan for a set of tubes in my experience. By contrast my power-amp will eat tubes every two to three year, or so; but it stresses the tubes a bit. This does not just include output tubes, drivers also get eaten fairly regularly.