How often do you re-tube?

[organ]

I just ordered a new set of tubes for my EL34 SE int. and forgot about my EL84SE.

Here's the thing, the EL84 amp must have at least 1000+ hrs on all tubes (6CA4, EF86, EL84) by now. Maybe even 1500 hrs. All the tubes are Electro Harmonix. The amp still sounds dynamic. I don't think the sound quality has decreased at all.

Should I keep using them until a tube failure or buy some fresh ones?

I"m just curious because I've heard of people using amps for years and years without the need to re-tube and the tubes still test strong. And there are also amps that run tubes very hard which result in a shorter lifespan.

I wish I had a tube tester.

I've used a lot of tubes but sold many of them to a friend for his guitar amp, so I've never used a tube to the end of its life.

How do you guys determine when it's time to re-tube?

[VR3]

I waited until they were microphonic

[organ]

How many hours of use do you think your tubes got before going microphonic?

[Lasareath]

The tubes in my Integrated amp are rated for 100,000 hours. I hope it's no where near that yet because I only have one spare set.

[VR3]

All my tubes were NOS -

I left them on everyday, all day... they lasted about 1.5 years, 2 years

[Lasareath]

Mine are rated for 11.41 years if left on 365/24/7

The Integrated Amp is currently 8 years old but it is turned off from time to time.

[organ]

All my tubes were NOS -

I left them on everyday, all day... they lasted about 1.5 years, 2 years

Wow! That's 17520 hrs for two years. Now that's a long life. Thanks.

[organ]

Mine are rated for 11.41 years if left on 365/24/7

The Integrated Amp is currently 8 years old but it is turned off from time to time.

Is that one of those mini tubes that Musical Fidelity uses on their DAC's and buffers?

[george daniel]

Really depends,,if power tubes are properly biased and played daily,,2 years is a reasonable lifespan as a rule of thumb,,however,,I have some old Tesla's(not JJ) that I've owned for 4 years and they still play nicely.A tube tester is a good way to tell.Of course,if you run them on the hot side,they will die quicker.

[Joe08867]

Like George said, properly biased and played daily, 2yrs is a good number for power tubes.

As far as preamp tubes go. I usually swapped them out every 3-4 yrs. But that was after I swapped them to find the right tubes.

[heiney9]

Don't know because I swap small signal tubes constantly. A small signal tube should last atleast 5,000 hours and most OS tubes last 2-4 times as long.

Power tubes, I have a used pair of Winged -C- SED's in a single ended class A amp. Going on abouy 2 years now, but if it gets played more than 3-6 hours a week(on avg) I'd be surprised. Also with the exception of a few pairs of tubes all mine are used. I have a rectifier that was NOS and it's into it's 3rd year of medium duty use.

H9

[cstmar01]

yeah tube life is longer than most think.

My only concern is that the guy I bought my amps from said he had a failure occur about every year. I always have that in the back of my mind when I power them up as well I don't want my amps to die.

I really would like to maybe invest in a tube tester or see how much they run so I can test tubes on a monthly basis.

I do check the bias pretty much every time I power them up to listen to. Haven't had a change in bias yet. Only thing was when my tube made the high pitched ringing sound but that went away and came back again but seemed to do it when the tube wasn't seated well.

I LOVE TUBES.

[heiney9]

What power tubes are you running? If they are current production tubes, then yes, about a year sometimes 2. Power tubes are usually the first to go and they can go often based on the design of the output stage and how hard they are run. Also some tube designations by nature aren't as robust as others. I would just assume power tubes will fail more often than anything else. I have yet to experience that, but I don't run my integrated amps often and the 6V6 based unit is push/pull and very conservatively biased for those tubes. Plus I am using 1950's RCA's which are the creme de la creme of 6V6 tubes and they last forever because they are very rugged.

H9

[cstmar01]

Brock, the tubes I'm running right now are Svetlana 6550C's which the person I got the amp from purchased new from Upscale audio. The other set he sent me was also purchased new from them. He didn't know how many hours he had put on them. Both are the same thing. They might be the wing C not sure, can't remember at this point as I'm at work. I would have to check the box when I get home.

I wanted to try something else when I get a chance such as the Electro-Harmonix 6550EH's or possibly some Tung-Sol 6550. I can also take KT88's in the amp so not sure if I wanted to go that route instead.

[heiney9]

Try them all if you can, although my personal experience with EH, is they aren't worth the expense because they are average. If you really want to go up a notch the Gold Lion KT88 reissue would probably sound great. But be prepared to spend some $$$

New Sensor has been making a reissue KT88

http://www.ebay.com/itm/NEW-Matched-...item48450d3a72

New Sensor also makes the EH's and current Svetlana's. Winged C's are currently being produced by SED. Unless your Svetlana's are much older they probably aren't Winged C's but New Sensors version of the 6550.

New Sensor also manufacturers current reissues of Tung Sol.

H9

NOS 6550's are extremely pricey

[cnh]

Looks like some good info above. Thanks.

Sal, I don't think anyone leaves a tube amp on 24/7; isn't that potentially dangerous if you're not about?

cnh

[cstmar01]

Thanks for the info Brock. Blah not enough time and too many choices....

Is that supplier a good one? do you use them and if so had you had any issues?

[heiney9]

Here's the story on Svetlana if you haven't read it before.

http://www.stereophile.com/news/022304svetlana/

I have not used that seller, it's just one of the first ones I brought up, but 13K+ feedback is a lot of sales..........looks legit.

H9

[organ]

Thanks for your input, guys. I think I will keep using the amp until I see a tube give up. I can't believe all the tubes have so many hours and still doing great. That's including the power tube as well (EL84).

One thing that I really like about new production tubes is the quality. I have never had a tube by New Sensor or SED fail on me. I've been using tubes for about 10 years and have gone through a lot, and the New Sensor and SED stuff always work great. I still need to give more Chinese tubes a try. I'm currently using Chinese 300B's in my cd player and they sound pretty good. As for JJ, the only ones I'm brave enough to use are their signal tubes.

[organ]

Ha ha. Funny how I started this thread, and last night one of the EL84 output started making this very faint scratching sound.
So it's not bad at all. I got about 1500 hours on current production output tubes.