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a lot of bad reviews on them due to microphonics or total failure. But some of these were from a couple years ago. have they improved and whats the chance of getting a bad on now compared to then, or HAS it changed?

I have bought about a dozen of these over the last year, and have had nearly half of them go bad in one way or another. Perhaps the newer ones are better...

When they work, they sound great. As great as any new production 12AX7 I've heard.

The next best thing, to my ears, is the JJ ECC803, the long plate tube they have. It's less prone to failure and sounds about as good as the TS.

I bought five TS 12AX7 (1 or 2 years back).
these works well (all of them)....
Maybe i was lucky

I guess I was lucky too. They have been very reliable for me. I use Tung Sols or JJECC83s depending on the amp and both seem to hold up fine.

I've read several places that the new tung-sols are very sensitive to cathode to heater voltages, kind of like the sovtek 12AX7LPS. They work great most of the time, but if they're used as a cathode follower, the triode can fail if the heater isn't elevated.

I've used a dozen or so and I haven't had any failures. I also have elevated heaters on everything that uses them. I don't know if that means anything, but they work great for me. They sound really good to, just a bit more gain than the JJ ECC83S and a little better overdriven tone. I just sold a 'wreck xpress style amp that used 3 of them and it sounded really good.

Matt

My Tung's hold up very well so far no failure.
They are from Tubestore, I don't know if they check their preamp tubes...

Do you guys find that if in V1... they lack a bit of bite.... they are a bit tame for my liking anyways.... I keep it in the PI position to smooth out the Plexi 50... but really feel it lacks attack on V1.... almost acts the same as a ECC81....

I noticed that they get (at least in the V1 spot) a bit hotter to the touch than the JJ 803S, and my NOS RFTs and Teslas..

Maybe this has something to do with it? Not that I've had a problem with them yet though.


//edit: just did a few temp readings with each tube fitted in V1 and a 10 mins warmup period
Tung-Sol RI 12AX7 : 58°C (136.4°F)
JJ 803S : 52°C (125.6°F)
NOS Tesla E83CC : 48°C (118.4°F)
NOS RFT ECC83 : 46°C (114.8°F)

Put me in the lucky category. No problems with mine. Love the warm, swampy tones I can get. The JJ's were to brittle sounding to my liking.

My favourite preamp tube at the moment, I haven't tried NOS stuff though... about 6 tubes in various amps and tube based pedals, zero failures.

pylet2000 wrote:I have bought about a dozen of these over the last year, and have had nearly half of them go bad in one way or another. Perhaps the newer ones are better...

When they work, they sound great. As great as any new production 12AX7 I've heard.

The next best thing, to my ears, is the JJ ECC803, the long plate tube they have. It's less prone to failure and sounds about as good as the TS.

I've always felt that the long plates in pre's make it a major candidate for microphonics. I always go for tubes with stubby plates. I don't know anything about the current 12AX7 TungSol but I have some 6V6 TungSols. If the build quality of these is anything to go by* I'd feel good about the 12AX7's.

*The question is: "Is it?"

-Paul

I've gone through more than 50 TS 12AX7's on repairs, new builds, upgrades and have had a total of 3 failures...all of these resulted from use as a cathode follower without elevelated heaters as Morcey2 mentions.

In my own amps I have had TungSols running without issue for couple of years now and they still sound great...

Clubsman - I find that they have plenty of bite in V1 and I haven't seen any other current production pre-amp tubes (JJ, Sovtek, EH, Svetlana)that balance the 3-dimensional qualities with a full tonal range - some of the Chinese tubes give a good bite but loose the 3-dim aspect. Now NOS -thats completely different story...

Randy

I don't know enough about "cathode followers," etc. to know, but should the tung-sol 12AX7s work fine as drop-in replacements for an 18watt build?

I read good things about them and I wanted to try them on the next build...

As long as you are not building a TMB, you should be able to use them in all positions. If you build a TMB, then you'll need to use a JJ or Chinese tube in V2.

I have generally had good luck with Tung Sols, with only one bad tube so far out of a few dozen. I also use JJ ECC83s. I like to combine different brands of tubes on some amps, because the blend gets the best tone. fortunately there's no rules.

rjgtr wrote:I like to combine different brands of tubes on some amps, because the blend gets the best tone. fortunately there's no rules.

+1

In my 1974X I have a Tung-Sol 12AX7 in V1, a 12AX7EH in V2(PI), and an EI 12AX7 (I got a good one ) in V3.

Happy New Year

drake

I've been using the 12ax7EH for years and love em..To me a complexity in sound others don't have. Having said that--I havn't tryed much thats come out in the last 3 years. Havn't tryed the GT12ax7s or the JJs......I've been so happy with the EHs and they last! I would love to do a side by side on the JJs/GTs/EHs though-....I really doubt I'd change anything.
I have done side by sides on the EHs and Sovteks and preffered the EHs.....Though I just found out they're made in the same factory......Are they the same tube? Could I have compared a tired Sovtek?

rjgtr wrote:As long as you are not building a TMB, you should be able to use them in all positions. If you build a TMB, then you'll need to use a JJ or Chinese tube in V2.

Err. I'm building dockery's tmb. Which tube socket is V2? And can tung-sols be used on the other sockets?

Speak of the devil, I bought 2 of the culprits and one went out after 10 hours use. It was used as a cathode follower. I read somewhere that this is a problem, evidently they are not a good current source but an excellent voltage pre-amp.

The problem is cuased by the fact that the cathode of a CF is typically sitting at a couple of hundred volts or so above ground, while the heater supply is grounded. The 200V+ differential between heater and cathode is too much for some tubes, and the cathode's internal insulation breaks down. The trick to get around this problem is to connect the heater ground connection to +ve voltage reference, of say +70V DC, in what is refered to as "heater elevation". This reduces the voltage differential below the 150V max that many 12AX7s are rated at.