What's better, short or long plate 12ax7's

twinfallsbass · #1 07-11-2010, 04:03 PM

In the mood to experiment with preamp tubes. Can someone give us the skinny on the tonal differences of short and long plate 12ax7's?

bongomania · #2 07-11-2010, 04:17 PM

Some of the differences are imaginary.
Some of the differences are so subtle that only "golden ears" can hear them.
Some of the differences are perfectly real, but impossible to put into words.
Some of the differences are real on an individual basis, i.e. there is a measurable difference but one batch or one individual tube or one brand etc. may differ from others with the same plate length.

twinfallsbass · #3 07-11-2010, 04:27 PM

Thanks for the reply bongomania. Why did the manufactures make the two different styles then?

derridiandrift · #4 07-11-2010, 06:12 PM

I asked this question of my tech the last time I bought some tubes. He told me that the long plate 12AX7s are intended to produce more distortion/less headroom. I probably don't have that completely correct, but the gist is that they are supposed to break up earlier.

johnk_10 · #5 07-11-2010, 07:13 PM

Quote:

Originally Posted by derridiandrift

I asked this question of my tech the last time I bought some tubes. He told me that the long plate 12AX7s are intended to produce more distortion/less headroom. I probably don't have that completely correct, but the gist is that they are supposed to break up earlier.

wow. i've never heard that about long verses short plates. and i haven't found that long plate tubes distort more than short plates do. i've found that long plates can sometimes be more microphonic, but it isn't always the case. i think that most audiofiles prefer the sound of a long plate since they seem to offer a larger soundstage and wider frequency response with more dynamics (less compressed), but again, it depends more on the individual tube and isn't limited exclusively to whether it has a long plate (17mm) or a short one (14-15mm).

just my opinion...........

Rick Auricchio · #6 07-11-2010, 07:31 PM

To add to Bongomania's list:

Some of the differences are subtle; you'll only hear a difference in a solo environment, but never on a gig.

johnk_10 · #7 07-11-2010, 07:35 PM

IME, the differences that you hear depends ALOT on its associated circuit design. in an old fender or even my '07 SVT VR i can hear the difference between various brands & types easily, but in my Eden WT550-B or Genz Benz GBE600 the difference is neglible or none at all.

agedhorse · #8 07-11-2010, 07:46 PM

It depends very much on the impedances of the circuits they are used in, the plate voltages, the load currents and how much gain the circuit uses. The difference may be noticeable but may not be as well.

There is not fast and accurate answer.

Bongolation · #9 07-11-2010, 07:52 PM

The main difference is that typical longplates go microphonic faster and are more fragile. Someone here is BOUND to say it's not so, but blow him off, he doesn't know what he's talking about.

Go shortplate on music gear unless it's stationary and vibrationally isolated. This is a service issue, screw tone. It's not that big a deal for bass. Go for minimum noise floor and maximum ruggedness. "All else is commentary..."

twinfallsbass · #10 07-11-2010, 08:52 PM

So I actually did a test on my new Shuttle 9.0. I had a Telefunken 12ax7 that is a smooth/long plate and a JJ ECC83 that's a short plate. What I found was that the JJ pushed the preamp into distortion ( LED would come on ) sooner than the Telefunken. With the gain set at 3:00, the Telefunken would make the LED faintly blink, while the JJ was coming full on. I will also add the Telefunken sounded way better than the JJ.

Jim C · #11 07-11-2010, 09:29 PM

Is it fair to compare long vs. short plate when they are not the same brand?

John K - I to have had some amps that were sensitive to preamp tubes and some that were not; while I haven't done enough testing between short and long to devlop a strong opinion, I have found that Mullard and Telefunken have always sounded the best for both MI and stereo use to me; have not found as much love with NOS RCA or Sylvania as an all around winner; thoughts / opinions?

twinfallsbass · #12 07-11-2010, 09:45 PM

Quote:

Originally Posted by Jim C

Is it fair to compare long vs. short plate when they are not the same brand?

True, true. But the Telefunken did sound way better, and to me, that's what really matters.

johnk_10 · #13 07-11-2010, 09:51 PM

Telefunken smooth long plates are my favorite. and Amperex bugle boys probably my second fav. IMO, NOS RCA's are the bees knees in old fender amps and i think actually sound good in everything. same with original tung-sols, original mullards & brimars. after that philips/sylvania's are good, with GE's being my least favorite. IMO, most GE's don't sound as good as alot of the reissues, unless it's a specific type, like a triple mica 5814A(12AU7 substitue) or 5751.

of course, this is only my opinion and YMMV.

Craig_S · #14 07-11-2010, 10:18 PM

I'm not a tube guy, really. I haven't played through an all tube amp since I was in my teens. I have used a few hybrids along the way. Of the tubes I've used in preamps, the long plates always sounded better to me. They seem to give a life to the sound that short plate tubes don't.

Seans · #15 07-12-2010, 03:52 AM

The JJ is nowhere near in the same league as the Tele's or Mullard etc.

But as said before, individuals of the same brand vary and listening is the only way to find your best, I have listened to and graded all my old valves and found that my Burman is the perfect amp for grading, it really puts out all the signal you put in (not everyone's cup of tea), but ideal for exposing low grade components, put a chinese or similar new valve in there and it really sounds terrible.

Looking at my valves there is only one long plate Mullard in my top 10 @ number 3.

Bassflute · #16 07-13-2010, 09:30 AM

Quote:

Originally Posted by twinfallsbass

In the mood to experiment with preamp tubes. Can someone give us the skinny on the tonal differences of short and long plate 12ax7's?

The long plate Sovtek was intended to be a replica of the venerable Telefunken 12AX7, which has achieved legendary status in the audio world. They were renowned for clean, warm, rich sound with huge dynamic range. I had one in my old Trace, where tube swapping was delightfully responsive.

Quote:

Originally Posted by bongomania

Some of the differences are imaginary.
Some of the differences are so subtle that only "golden ears" can hear them.
Some of the differences are perfectly real, but impossible to put into words.
Some of the differences are real on an individual basis, i.e. there is a measurable difference but one batch or one individual tube or one brand etc. may differ from others with the same plate length.

Some of the differences are blatantly obvious if you have an amp that is responsive to preamp tubes, like my old Trace was, or a LOT of guitar amps are...these can make a huge difference. Then there's the Eden WT800 BS preamp tube, which does absolutely nothing but glow and generate heat - I think you could connect those tube sockets with

A) wires, or
B) aluminum foil

and those amps would sound exactly the same. The tube does absolutely nothing there.

Cheers,
Cameron

stflbn · #17 07-13-2010, 09:39 AM

Quote:

Originally Posted by Bongolation

The main difference is that typical longplates go microphonic faster and are more fragile.

This was my general understanding.

aborgman · #18 07-13-2010, 09:41 AM

Quote:

Originally Posted by johnk_10

IME, the differences that you hear depends ALOT on its associated circuit design. in an old fender or even my '07 SVT VR i can hear the difference between various brands & types easily, but in my Eden WT550-B or Genz Benz GBE600 the difference is neglible or none at all.

Bingo.

...and as an engineer, I'd make the argument that the less effected by tube replacement (or any component) a circuit is, the better the design is.

Seans · #19 07-13-2010, 11:19 AM

Quote:

Originally Posted by aborgman

Bingo.

...and as an engineer, I'd make the argument that the less effected by tube replacement (or any component) a circuit is, the better the design is.

I disagree, there is a clear difference between a china 12ax7 and a Mullard, but if your amp produces the same sound then I would say its down to low grade components or just a bad and restricted electronic path, and for sure you are not getting everything out that you put in.

Like I said before the Burman was made with the best components available and Greg was certainly in the top 10 Amp designers, the differences with any component added and blind tested through the Burman be it Valves or leads or Basses are astounding.

aborgman · #20 07-13-2010, 11:31 AM

Quote:

Originally Posted by Seans

I disagree, there is a clear difference between a china 12ax7 and a Mullard, but if your amp produces the same sound then I would say its down to low grade components or just a bad and restricted electronic path, and for sure you are not getting everything out that you put in.

No, I'd say it's down to a good circuit.

Circuits that are tolerant of component variance are better than those that do not.