I wonder how many tubes get thrown out because they test weak on a tube tester, when they could perform perfectly fine in a cathode follower circuit.
Replace tubes yearly?
I just watched a Paul McGowan video (PS Audio) about the wisdom of leaving your gear powered on all the time. I get that. He also said that vacuum tube gear is the exception and not to leave it on all the time. I get that too.
But he also mentioned that it didn’t make a huge difference since you probably should replace your tubes every year.
Is that true? I have an Audio Research LS-16 tube preamp from the late 90s or early 2000s. I don’t think the tubes have ever been changed. I’m not really a ’tube’ guy but this unit was given to me 6 or 8 years ago. As far as I know these tubes are original.
At one point I got curious about the different sound quality potential of different tubes and another Audiogon member lent me a set of tubes to try out. I could definitely tell a difference but did not think the new ones sounded better than the original ones. I mention this because at that time the original tubes were quite old and still sounded quite good. And still do.
So, bottom line is, is there any real need to replace tubes on a schedule of some sort. Maybe its different if it is an amp versus a pre-amp?
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Which tester to buy and how to interpret the results is a very complicated subject unless you are just looking for rough results, like avoiding shorted tubes or dead tubes. I had tubes that tested very weak on an Amplitrex (modern, industry standard tester) but still sounding good. I contacted the amp manufacturer who said that in this particular application weak tubes would work fine and I should use the tubes until they sounded bad or died. |
@invalid good point that not all tubes need be top performers. It all depends on the specific design of each amp. I had a ARC sp16 tube preamp that used 6 12ax7 tubes. Only one or two required very high performance tubes. When I bought tubes from ARC, 1 tube always cost more and was designated for use in a specific slot. The others cost less. If I heard noise I would swap out the bad tube but keep it as a spare in that it could be perfectly fine next time. I labeled my used tubes in a hierarchy so I would know which ones sounded best still when removed and would always try that one first. My stash of spares that were removed prior kept me going nicely for many years. That one slot that required the top notch quality tube was replaced just once with a replacement purchased just for that from ARC. Just an example. I’m sure every tube amp is different. There may be cases that require all tubes be replaced once a year. Some amps are harder on tubes than others. It all depends. Tubes can be quite cumbersome and expensive to maintain, especially if there are lots of them, which is something I have always tried to avoid, but of course different strokes…. |
Great thread with a lot of good information. In the past, I have a Conrad Johnson PV8 which I think I ran in my system for well over 10 years and really never gave a thought about the tubes. At some point, I called CJ and asked for a set of replacement tubes. I got them and replaced them in the preamp and Holy Moly, the difference in SQ was absolutely astounding immediately! The preamp sounded fine before, but far more revealing with new tubes. You don't know what you are missing sometimes. Yearly replacement of tubes in general is unwarranted in my opinion, certainly not with input tubes as several above posters have noted. |
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