Which 12AX7 for my 18 watt plexi build ?

[copperheadroads]

Im getting ready to build my amp & i going to order the tubes
I was thinking Tung Sol or EH for the preamp ...What do you think ?
JJ's for the rest

[Chuck H]

My personal preference for any 18 watt type amp would be a Sovtek 12ax7WA for the first tube and the Sovtek 12ax7LPS after that. JJ's for the EL84"s are a good choice IMHO.
The Sovtek 12ax7WA has a little less gain and top end than many 12ax7 tubes. But does have the advanage of not being overly bright (which can happen in an 18 watt amp) and very low microphonics. I've had a few that seem poorly balanced on the filament and HUM quite a bit. Find out if there is a sound test process involved and pay a little extra if you must for a quiet tube.

[big_teee]

I like Tung-Sol 12AX7 Reissues, they have a tone I like.
Sometimes it's tricky to get one quiet enough for V1.
Not sure what all works best for the 18 Watters, but they sound good in the bigger Plexi's!
T

[imaradiostar]

Slightly off topic but when I had an EL84 plexi I ran a 12au7 in the phase inverter- the EL84's require very little drive so the reduction in gain was helpful. Also 12au7's seem to distort in a pleasing way.

You mileage may vary, of course.

jamie

[jonamojo]

keep an eye on ebay I bought 2 brand new nos Blackburn mullards labeled RCA in rca boxes for $30.00 jan phillips are another good score use the internet to learn how to identify nos brandings. I've tried all the new ones mentioned above, I use a mesa quad preamp and that sucka don't lie. I can pop the trunk off and test tubes in various gain states. What sounds alright clean my be microphonic in a high gain situation. In essence you can purchase nos for about the same as the new russians. Look for GE,Sylvania,RCA thow tele's and bugleboys are going to cost you.

[Rhodesplyr]

My experience has been that the only way to pick the tube you'll like most in your amp is to obtain a selection and experiment. I've had several clients pick the plain-jane current-production Chinese 12AX7 in blind tests. The JJ ECC803S tall-plate is also a good one.

Or, to put it another way, it's hard to predict what's going to create the sound you want and suit your playing style without experimentation. Try having someone run a blind test for you, swapping in different tubes to see which ones you like without telling you which is which.

[km6xz]

Rhodesplyr is right, no spec sheet or recommendation is going to predict how a particular amp's circuit conditions are going to interact with an individual tube. Current and old production tubes vary all over the place between samples of the same production run.
The old NOS were closer originally but you need to factor in aging and they will often drift apart. Modern tubes are built with a lot less QC and precision than when major makers were under a lot of pressure to maintain consistency. Tube production technology was at its peak in the 60s and went down as markets dried up and profits disappeared later on. New companies generally do not have a tradition of precision production or engineering. So, grab any tubes you can find, new, used, NOS, put them in a hat and without looking pull one out and try it without the bias that comes from seeing which is which. Tubes really do not have a sound.
They have a set of parameters that, when operating in a real circuit combine to make a different transfer function than the same tube in a different circuit. Base course-grained performance of a tube, as measured in a static test setup, will be frequency response neutral, and flat far out in the RF region which is why claims of one tube having a brighter, HF boosted sound where another brand has a mid dominance is nonsense. Without reproducing the test environment of the amp, speaker, acoustic space, all circuit parameters, playing style, pickups etc, it is useless internet chatter to recommend a particular brand or model of tube as having a particular characteristic sound.
People who insist on their golden ear recommendations are best ignored because they will only end up costing you a lot of money needlessly. Blind testing various tubes will produce a little perceived difference but only your playing, in your individual amp, in your individual acoustic space will one produce one you like best.
If the amp is a head and is isolated a little from the cab, such as a pad under the amp, a proper 12AX7 should last 15 years or more, a lot more. A combo has shorter tube life due to being in a high vibration environment.
Tube life is also regional. Heater voltage really impacts life so old amps run in modern power grids which tend to be higher mains voltage give shorter tube life. Gain is effected a lot by heater voltage in preamp tubes and power/life expectancy is impacted in power tubes even more. Too low voltage is as hard on power tubes as too high voltage. Measured at the sockets, it should be close to 6.3volts, or 12.6V is heaters are operated in series inside a tube.
In high vibration environments, micro-phonics are the first indicators of preamp tubes being damaged. Some experience, some of the best for low microphonics are the cheapest Chinese tubes. Cost is no indicator of performance in tubes nowadays, cost only indicates marketing efforts. A properly designed preamp section with tube socket isolation of V1, and envelope dampening will greatly increase usable life before microphonics limit a tube's usefulness.
I am mentioning these life expectancy factors because it would be best for you after going through the bother of hand selecting a tube to not have do it again in a year due to preventable risks to the tube.

[big_teee]

Unless you own a Amp Shop like a lot of you do, You have to just try a few different tubes a long.
If you have a amp shop near by, you might be able to try several of the 12AX7s they have handy!
Tube swapping gets expensive if your buying your own.
I'm sure that is why Copper was asking, trying to make an educated guess.
Some of you got it, most didn't!
T

[km6xz]

That was the whole point, there is no "educated guess" possible since nothing is known about personal preferences, the circuit conditions, playing style, strings, acoustic space or any thing else that makes more of a difference to perceived sound character than tubes do.

Besides, if the OP did not have anything to compare with, i.e., not having a shop or tubes to switch, how would he determine if he needed to change tubes? The subtle differences only become apparent when compared directly to another tube when all other factors remain exactly the same. Sound character and all our senses are differential meaning they register only as a difference between two states. Sense of touch is for change of touch, not touch. Same with sound character. If there are no tubes to change to between character will not register as related to tubes. If he does not have differences to compare, he is lucky because he does not need to get caught up in the crazy tube claims and counter claims, his amp is what it is and he should just enjoy playing it until a tube fails. Tube sounds are of interest only to hobbyists who isolate the one factor in their imagination but no listener could care less. A song is a good song and performance if it is enjoyable to the listener or somehow connects with them and that has nothing to do with differences between tubes that can only be heard when directly compared in very short intervals between samples. The only time a listener might notice is when they know the song as done originally and they are comparing the cover version. The original is the standard because it had nothing else to be compared with so sounds right by definition. A cover band tries to make their sound similar because it will be compared to the reference. If that same band with their existing gear came out with the song first, whatever it sounded like would have been the definition.
Maybe focusing on original content and songs that connect can cure the fetish of tweaking components in amps for minute changes because when a song connects with an audience the tone becomes a problem only for those trying to copy it.
In production of original songs for major albums in the studio, you might be amazed how little care is devoted to tweaking tubes and such since at that level players know the tone characteristics fought over by hobbyists on forums does not mean squat. In fact, a tone that is not great is often sought to give an edge to a particular song. Getting that tone reproduced later is the problem for the cover bands to follow or even touring the band has to do later. The recording and a concert are entirely different sonic experiences however and not that much effort is put into reproducing the tone of the original by the band which did it.
Player technique is a lot more important than amp characteristics. Take most major records and note how the guitar player sounds like himself on every cut but also notice how the equipment list on the credits shows 8 different amps were used. Some session players do not carry any amps to gigs, they know they can get what the producer had in mind with any competent amp that happens to be at the studio. It is the amateurs and hobbyists who focus on little nuances that are dwarfed in significance by bigger issues like song quality, playing etc.
We would stress over mic placement or vocal arrangements(things that really matter), but not guitar amp details.
So, the OP is actually lucky if he has no access to a pile of tubes to switch, so he can just focus on songs that connect with an audience.

[big_teee]

Just some ball park suggestions would be nice.
I like X or Y better than Z, in situation A,B or C!
Most of us are not starting recording studios.
Just trying to make the clone sound a little better.
Peace, & Tone

[JoeM]

...
Player technique is a lot more important than amp characteristics...

That pretty much sums it up.

[big_teee]

So you professionals are telling everyone to not worry about what your gear sounds like?
Just Learn how to play guitar?
You do the same with your own Gear?
I don't believe that for a minute!
I bet everyone of you have your own equipment fine tuned and sounding its optimum.
I want my amp to sound good, regardless who is playing on it!
Anyway enough of this!
Later,
T

[JoeM]

So you professionals are telling everyone to not worry about what your gear sounds like?
Just Learn how to play guitar?
You do the same with your own Gear?
I don't believe that for a minute!
I bet everyone of you have your own equipment fine tuned and sounding its optimum.
I want my amp to sound good, regardless who is playing on it!
Anyway enough of this!
Later,
T

Of course not. But there's just too little QC in new production to just simply recommend any one type over another, and even so at band levels the differences are immaterial. Everybody simply recommends their favorites anyway, even if there's no sonic benefit one way or another.

[big_teee]

Of course not. But there's just too little QC in new production to just simply recommend any one type over another, and even so at band levels the differences are immaterial. Everybody simply recommends their favorites anyway, even if there's no sonic benefit one way or another.

I agree!
What I was disagreeing with were a couple of statements.
That if someone gets on here and asks what tube of a type you like?
Or if you have experience with a certain amp what works well in that amp for you?
But, to say on every tube question, just to learn how to play guitar?
Then we don't need this tube category!
Those answers, seem to be real prevalent these days!
Later,
T

[km6xz]

The whole point was suggesting a tube, any tube is not going to be any closer then he is now. No one on the forum except the OP knows what sounds good in his mix of variables. Pick one out of a hat. If the tube is functioning, the amp will sound fine.

Besides, if the amp sounds bad now, there is a technical reason and that needs to be repaired before dealing with the very subtle differences that working, non-defective tubes make. If he had a basket full of tubes he might find something that appeals to him more than others but the chances of it being one that another person 1000 miles away likes in his own amplifier and with his own playing are long odds.
If there is a problem, fix it. If a tube is bad, replace it, and play. If it sounds good or bad to the audience, the tube will not be the reason. Good and bad are not sound characteristics that are tied closely to a tube difference.