Time To Replace Tubes?

I was wondering when do you guys decide to change your tubes?Are there any indications to listen for to know that you are at the end of your time with a set of tubes short of them blowing up on you?
I have a Wright 3.5 that has the 2a3,6sn7 and 5y3 rectifier tube in it.I was using a set of NOS Brimar's in the 6sn7 position.Recently i started thinking my mids were not there in my system and thought that my newly acquired modwright Sony 999ES may have been part of the problem.Well on a whim i swapped back in the stock EH6sn7's that came with the amp.I have very low hours on those tubes as i put the Brimars in not long after getting the Wright's.WEll my lordy the soundstage became huge and warm and just awesome just with swapping back in those EH's.
Maybe they just work better synergistically with the Modwright player i don't know.Maybe the Brimars are still fine but sounded lean with this player?
But back to my original thought on this is there something you can audibly listen for when you know your tubes are going?
Now i wonder if replacing the 2a3 or the 5y3 will bring even more sonic gains?It sounds incredibly better now just with that 6sn7 swap.I was looking into new speaker wire and possibly a tube preamp and here all i really needed to get those mid guts were to put back in those EH's.I'm loving that too cause they are a heck of alot cheaper then the NOS route.
What a pleasant surprise!! : )
In your case you don't need anyone to tell you it's time to change those tubes, or that one is better than the other; you figured it out on your own with your own ears. I don't think NOS is always necessarily better than current production. There's plenty of fine late production tubes out there that sound swell...even better than NOS in some cases, as you've found out. That's not to say there may not be an NOS 6sn7 that bests the EH you like...just that the Brimar's you have don't sound as good to you (they may sound good to someone else though...stranger things have happened). The other way to tell if and when tubes need replacing is to have them tested by someone with a tube tester, or buy one yourself and test them. Obvious signs fo failing tubes are noises like pops and clicks and or rushing sounds. Familiarize yourself with typical tube-life you may expect from the various types you use. I did like the late production Sovtek 2a3 tubes in the Wright 3.5's. I think that's the one tube Sovtek actually does a good job with (haven't liked any of their other tubes I've heard). I hear the NOS RCA's do a good job for 2A3's but you will have to pay some large coin for a good pair. Some company is also making some 300B's that run at 2.5 volts to be a drop-in replacement for a 2A3. You should probably check with George if you want to try that. No experience there. I think swapping any of the tubes has the potential to alter the sound. Probably the least potential would be in the 5y3 rectifier, not to say that it wouldn't have any potential. My experience with those amps tell me that the other two tubes have more impact. YMMV as always.


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.

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.
Thanks Marco-
Ya know the Brimars 6sn7's(in the Wright 3.5's) sounded better when using my other players(Quad 99cdp,Jolida 100 level 1 mod,and Music Hall CD25 level 2 mod)but since receiving the Modwright 999ES they sounded to thin for my tastes but maybe they were just ready to be moved out.Whatever the case i am loving life again with the EH 6sn7's again in the Wright's.I run passive using EVS nude attenuators and it was really getting to the point where i was concidering a tube preamp to get the lushness back again.Well it is back and i am really happy with the sound right now.So i guess there is a lesson to be learned here that might help some other people.When you think that you may need an equipment upgrade or cable upgrade just remember to check those tubes first or swap them out.Oh and get the best source you can possibly afford i have learned as well as this Modwright has taken the performance to the next level for me and i will probably be posting my other players for sale down the line when i get around to it.Those players were/are really nice players too but this one just presents things better to my ears but of course it was more then double what i paid for any of the others.Not an add for Modwright just my experience citizens. ; )
I think i remember reading that there are gold EH 6sn7's now but i may be wrong.Does anyone have any knowledge or experience with them and how they sound compared to the standard EH 6sn7's if in fact the golds do exist?
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.
TJ Full Music 2A3's are much nicer than the EHGolds which aren't bad at all.
Thanks folks for your help and information first of all!! : ) VERY HELPFULL and i appreciate it.
Larry510 i am curious as to what speakers you are using?i have very efficient horn speakers(103db) and seem to get enough power with the 2a3 tube and was wondering what sonic changes occurred for the better for you by using that 300B?
I currently am running the stock Sovtek 2a3 which alot of people seem to think is a decent tube and it does sound good in my system.
The Wright amps i am using are self biasing so i don't have to worry about that which has been a nice feature since coming from PP amps that i had to bias which i found myself always being concerned about.So it does sound like a tube tester may be what i need.I am totally ignorant of them and their use so is there any recommendation for an inexpensive one made for knucklehead simplicity?
Larryken have you found the 2a3's you mention including the EHgold 2a3 to sound better then the Sovtek 2a3's?I have heard alot of good things about the Sovtek so haven't bothered swapping and George Wright sends them out stock as he did the EH6sn7.I am back to the EH 6sn7 and loving it so figured he selected those tubes to use for his design.I am sure that finding just the right NOS tubes would be a positive step but the price of the new production tubes makes me not want to go that route if i don't have to and these EH6sn7's are doing it for me right now for sure.I don't think i gave them enough time for them to break in before yanking them.I was just on another thread where some SET owners were talking about them and saying they were comparing them to some NOS mullard and they were shocked at how close they were in sound?So i am not crazy....well maybe ; )
Seeburk - I'm not sure if there's a TubeTesterForDummies, rand most that I know of are quite old. I use a BK707 and, though it does take some getting used to, it can be very versatile. Unfortunately it will not test the larger 2A3 and 300B tubes. On the other hand the price of a good tester spans a large range depending on where you happen to find it. You can find one at a garage sale or auction for $50, or one here on A'gon for $500. Supply and demand. Be aware that some tube testers actually utilize a tube in their circuit. Also it would be good to find one that has been somehow confirmed accurate or recently calibrated/adjusted.

George certainly knows his tubes. You should see his NOS stockpile. I don't think that means that he necessarily provides the very best tube for the purpose with his amps, nor does any manufacturer that I know of. That would be a very expensive proposition in most cases, although it would seem to make sense given it would make their product sound better. I think to stay $ competitive, no one does it. Probably the Sovtek and EH that he does provide are damn good bang for the buck. I think the Sovtek 2A3 is one of the few tubes that company does very well. I think I settled on some JAN 6SN7's in mine, but I don't recall what else I rolled with them.

I recently acquired the Wright Mono 10 amps, and I've tried three sets of tubes so far: Sovtek 2A3, EH 2A3 Gold, and now the Sophia 300B 2.5v Princess. Personally, I like the EH tubes a lot more than the Sovteks. I find the EH tubes more detailed and a deeper soundstage than the Sovteks. I'm not all that crazy yet about the Sophia's, but I've only run them a few hours so far. I've been told that these tubes take quite a while to break in.
Hey Stew - How do you like the Mono 10's you got? Are they working out for you in your system?


I own a Wright WLA12A preamp, which also uses 6SN7s. When my stock EHs got noisy, I wrote George for recommendations and got this response:

Dear Dave,

NOS are almost always a better choice for 6SN7's but the availability is getting harder to find these at a good price. My favorites are the mid 50's to late 60's production angled plate 6SN7GTA or GTB, RCA are also nice, the best are American made Raytheon, Westinghouse or Tungsol,good luck. The EH's are robust and fairly reliable as well, but a bit forward.



Taking his advice, I found some reasonably priced Sylvanias from the 60s, and they've been a major improvement, much smoother highs than the EHs. I tried some Sovteks and they were pretty bad in my amp, although many mfrs seem to use them as their OEM tube. I also tried some NOS GEs from the 70s that I got for free, and while they were slightly better than the EHs sonically, 2 out of the 4 were noisy. I haven't had the inclination to try any of the $100/pair 6SN7s, as I don't think my pretty basic preamp and system warrants them.

All in all, I'd rate the EHs pretty high considering their price and availability. You can improve on their sound with older tubes, but unless you're lucky enough to get them cheaply like I did, you'd probably have to spend a lot of money for the improvement.
Thanks once again for the replies folks!!
Yeah i think i will have to rely on my own ears jax2 rather then to buy a $500 tube tester that i really don't know anything about.That money can buy alot of affordable tubes.
Smeyers, thanks for your input on those 2a3's.I think i will have to check out those EH2a3 gold's myself now after reading your results.I also would be interested to see how you find the Sophias after they break in so keep us posted if you would.
Armstrod, thanks for your reply as well about those tubes.I will keep my eyes open for some of those tubes but right now, like you said, the EH is a good bang for the buck tube.It did actually make things a bit more forward and i think that was a welcome thing for me in my system.It filled out the mids nicely.One thing i have noticed since i put that tube in however is a slight ringing in my ears after a long listening session.I don't know if that is from that tube or from wanting to play my stereo louder now.I never play that loud but i am noticing a slight din in my ears at night in bed the last few days.Weird and i want to monitor that for sure.Wonder if that tube could be imparting any artifacts that could be causing that?I don't know but it is a phenomenon i don't want to have keep repeating.Strange though too as like i said i like the sound of this tube.Well at least i like how everything has gelled lateley which i think we all know is such a welcomed moment to savor in space and time! ; )

See my posting in this thread:


I strongly recommend dampers on at least your 6SN7s, if not all your tubes. They make a world of difference on my preamp, including getting rid of the ringing you're hearing.
A couple of things:

I'd agree that the EH tubes are more forward sounding. I actually like this, since it makes certain instruments (vocals in particular) feel as though they are practically in your lap! Some people prefer a more laid back presentation though.

The Sophias are starting to get better. The bit of fuzziness and lack of soundstage depth is dissapating. I doubt however even after fully broken in that they will be as forward as the EH tubes. David at Sophia mentioned that the 'Princess' tubes do take a long time to break in.

You may want to invest $50 in a Sound Level Meter. This is an easy way to determine how 'loud' your music is playing to see if loudness might be causing the ringing in your ears. Radio Shack sells both digital and analog versions.

- Stew
Well i am a musician and have been playing in rock bands standing next to cymbals and going to concerts for more then 20 years.I am familiar with louder tones and this ringing almost seemed like it was coming from some strange artifact and i am guessing it was presented in that tube.I do believe my system to be VERY revealing as i can audibly hear every little change i do to anything it seems.I think that Armstrod may have hit the nail on the head there with suggesting some tube dampening.That seems to make alot of sense to me and i will certainly give that a try.
Thanks for that update on that Sophia Tube Stew as well.I don't really think this thing with my ears is a sound pressure issue unless i am just getting older(and i am ; \)
and my ears are sliding down into the aural abyss......nooooooooooo.
I don't think that is the case though as this phenomenon was in direct proportion to putting back in that EH6sn7.The strange things is that i like the tube and am not really noticing the pain while listening.Go figure.
Thanks for all your help everyone in this thread!!
You guys da best : )

>>Hey Stew - How do you like the Mono 10's you got? Are they working out for you in your system?<<

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