Do I need new tubes?
Until recently, when I turned on my rig it immediately sounded full bodied and rich. In the last few weeks I’ve noticed it doesn’t reach this state immediately, but rather until at least after an hour. From then on it’s fine.
Is this a sign my preamp tubes are aging? My amp is solid state and always on.
FWIW, I am running Mullard reissues in my McIntosh C220 for over 10 years with no issues. I run it about 20 hours a week, so that's about 10,000 hours so far. Tubes tested strong a few years back when the preamp was sent to Audio Classics for a repair. However, this is a hybrid design, so maybe it’s easier on the tubes.
FWIW, when I asked a Mac rep how to tell when I need to replace the tubes, he said "your preamp will sound broken", whatever that means. |
I have the same tubes in my preamp as well and they should last a minimum of 5000 hours. Depending on how they are configured, maybe as much as 10,000 hours. Oh and I have used the RCA Cleartops @dogearedaudio mentioned and they are great and not that expensive. Bought a matched pair from Brent Jesse for I believe $100. All the best. |
My own experience with the tubes in my preamp has been that when I had tubes that were getting tired or sick, things sounded more fatiguing and generally worse the longer they played. However, my own personal experience has been that when I have been running with tubes that are all in good shape, the longer it played the better everything sounds. |
That helps, but also raises the question, did you buy NOS or "used test strong" Tele’s? They may not be as strong as they could be. And honestly, the Telefunken 12AU7 is not one of their best efforts, IMO. The 7316 is by far the best 12AU7, but they are quite expensive now. The RCA clear-tops are highly regarded and are not much more expensive than new-manufacture varieties. I happen think the Genelex Gold Lion small signal tubes are pretty nice, so that might be a way to perk up your CJ. |
See if you can find a good audio shop close by with sophisticated tube tester, e.g., AVO or TV-7 and have them tested. Or swap all out from back ups, if you have them. Last resort, find a decent tube tester on ebay. I bought a B&K 606 for about $150. Basic good/bad on a scale, shorts and gas emission. I own five tube amps and have over 250 vacuum tubes in collection so it was worth buying. 🤪 Just another expensive hobby. |
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Hoping to piggyback on this discussion, maybe change the header to "DID I need new tubes?" Recently had my RM-9 Music Reference amp repaired, rather extensively, at George Meyer Audio in L.A. after losing the left channel. I'd been running 4 KT-120's, for several years. I was told to replace the tubes, because they "had no gain." I had swapped the tubes, and all other inputs, extensively trying to identify the possible cause of the left channel outage, and each tube glowed, produced output, and responded to volume control on the right channel. Further, I was told not to use those 120's or I'd be bringing the amp back for repair again. He was not very instructive when I tried to ask him about all this. So, did I need new tubes? Which I've ordered by the way. Appreciate any input and feedback. thanks. Jeff
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Do you see any different in glow of your tubes ??? Its funny being 73 yr old and all the years tubes were in TV's growing up and always a place to take your tubes for testing..Remember few drug stores having tube testers..I would look for a place that does guitars and amps and see about getting tubes tested.. I always buy tubes ahead for backup and to exchange to see if new tubes help with issues you are having... good Luck |
