Time To Replace Tubes?

TJ Full Music 2A3's are much nicer than the EHGolds which aren't bad at all.

There are a few amps that are manufactured with a digital clock built in so you can keep track of "on time" and have some approximate idea of when the tubes might need attention (some ARC amps for one). It is also interesting just to have some idea of the amount of time you spend listening.

You can add such a timer in several ways, the simplest of which is to plug one into a switched outlet on the preamp (if you have one). More challenging is to design a timer interface that runs off the 12v trigger. Or you can just start and stop a timer manually (of course it is easy to forget).

My timer shows about 10 hours per week on the average right now. At that rate a set of 6550 amp output tubes should last at least 2 years. However, it all depends on the amp, the tubes, the amount of use, the level of play and some luck etc.

since tube amps are symmetrical, whenever there's something going on soundwise which is tube-related, you can do things like swap out tubes like you did or, if the funny business is in one channel, switch the left and right channel tubes one by one to isolate the problem. this is especially true for input tubes like your 6sn7s or preamp tubes. bad tubes often make nasty sounds when you tap on them. I don't think it's a good idea to get into the mind-set of 'there's something wrong with my tubes that I can't actually hear'.
assuming you're biasing your tubes, that will tell you how your power tubes are doing: if they're having trouble holding a bias, you may have a bad one. and eventually they just fail, often in very unsubtle ways with loud noises.

hi,

I'm using the Sophia Electric 2.5 volt 300b's in my Wright Mono 3.5s and they are great, they have displaced my nos RCA dual plates.

I'm using a Rayethon VT231 as a 6sn7 and can highly recommend it also.

Larry

Yes, there are gold EH6sn7s. I have one. I bought 4 EH6sn7s at CES. They didn't have enough of the regular ones, so I bought one gold one. The gold referes to the pins being gold plated. The EH rep assured me that there were no internal differneces betwen the gold and regular 6SN7s, just the presence of gold plating on the pins. I don't know if the gold makes any differnece in sound. I think the only reason for the gold is for corrosion prevention, as the tin plating (I'm guessing that's the standard finish on non-gold pins) may oxidize over time, and reduce contact conductivity. Gold, on the other hand, doesn't corrode, as evidenced by gold items that are recovered from ancient shipwrecks that are just as shiny as the day they wer made, and the ability to find golod nuggets in nature, whereas other metals must be refined from ore.

In any event, I'm not convinced gold is the way to go, unless you also have gold plated tube sockets (Do these exist? I don't know). The reason being that when dissimialr metals are placed in close contact to each other, the one less prone to corrosion will cause the other metal to corrode faster than it would on its own. Since gold is the least likely of al lmetals to corrode, it can cause other metals to corrode more rapidly. This effect is much more important when the metals are in contact with water, but it can't help. I think I'm better off using tin pins in tin sockets. Where the pins aer actually in the closest contact will probably not corrode, since there is no air for oxygen to get in. Everywhere else on the pin will oxidize a bit, but these araeas are not conducting anyway. When you remove and reinstall the tube (for whatever reason), the scraping of the pin in socket should clean the oxide layer off.
I'm using these tubes in a pair of Atma-Sphere MA1s. They replace the stock Chinese tubes. Although I don't have enough tubes to retube both amps, comparing one amp w/all Chinese tubes to one w/ 4 EH tubes, the EH one sounds a bit more resolving of detail, and has tighter bass. The difference was not huge, but noticeable.
I guess your original question is still unanswered - does the EH sound better than the NOS because the NOS is worn out or because a good EH sounds better (in this situation) than the perfectly good NOS. Good question. Sounds like you need a tube tester.