Best New Production 12AX7 Tube, Blind Tests

[mascis]

Here’s a comparison I’ve just done of various new production 12AX7 valves in a Fender Twin. I thought I’d share my results incase anyone else was interested.

The amp is a Twin Reverb Reissue with Celestion G12-65 creamback speakers and has all the stock Sovtek valves. I was plugging into the Vibrato channel (flat EQ) and swapping out the valve for the 1st gain stage of that channel. The guitar I used is a vintage Fender ’75 Deluxe Telecaster with the original wide range humbuckers. I generally play rock, blues, funk, indie and jazz.

I’d read up a fair bit on each valve so to prevent my preconceptions getting the better of me I did it as a blind test by taping some paper around each valve, mixed them up and then numbered them. I kept the playing as consistent as possible, playing some set chord and lead parts as well as some general blues improvisation. I always played the same chord for testing the initial breakup volume for each valve. These are the notes I made for each valve.

Electro Harmonix 12AX7
Initial break up volume: around 3, 3 1/2
Nice warm balanced sound. The overdrive can sound a little gritty though, a bit fizzy as notes decay.

JJ ECC83S
Initial break up volume: around 2 1/2, 3
Seems a bit brighter than previous valve but still quite nice. Still a little gritty on chords when it’s overdriven though.

Tung Sol 12AX7
Initial break up volume: around 3, 3 1/2
Softer top end than previous valve, nice fat compression when overdriven, overdriven lead sound is nice. Well balanced.

Sovtek 12AX7WC
Initial break up volume: around 3 1/2, 4
Lower overall volume, less bottom end, nice top. Seems a bit shrill on break up.

Groove Tubes 12AX7-M (Mullard copy)
Initial break up volume: around 3
Very crunchy, plenty of top and low end. Break up is bright and crunchy on chords. Quite ‘attacking’, nice aggressive sound but tiny bit harsh sometimes.

JJ 5751 gold pin
Initial break up volume: around 3, 3 1/2
Nice sound, soft and even low end, clear bell like top, nice balance. With volume at 5 it has a nice responsive sound but still basically clean sounding. Nice with volume at 7, clean and clear but crunchy with chords.

I decided my favourites were the Tung-Sol and JJ5751, I’m going to try a few gigs with them both and see if I prefer the slightly cleaner sound of the 5751 or not. There were some real surprises to me when I revealed the valves though. I’d only just bought the Groove Tubes Mullard copy and had it in my head that I’d like that because I’d read it would sound smooth and creamy, but I thought it was a little on the harsh side. When I was testing, the one that I thought was the 5751 turned out to be the sovtek WC, because of the later break up. I think it’s a bit odd that the 5751 pretty much starts to break up at about the same level as the higher output valves (to my ear), but the break up is much more gradual and more subtle, it would seem. Maybe the Sovtek was taking a while to break up because it was one of the valves that came with the amp, so it’s been used a fair bit, it may be getting tired, which might also explain its lack of low end.

Anyway, I’m sure some people who are familiar with these valves will disagree with my descriptions of the sound. It was purely to test what I personally preferred the sound of, I just thought I’d share incase anyone else was curious. I must say the differences were very subtle, and it’s hard to make comparisons when it takes a good 1min or so to swap the valves, which is all it takes for your ear to start to lose it’s reference. So I may get slightly different results if I did it again, I noticed my descriptions started to get a little better after I’d tested the first few valves because I felt I had more of a reference to the overall sound.

Anyway I hope this is of interest to someone

[Stevem]

Hear at work I just tested 6 new EH 12at7 and all of them but for two where near as bad as the two I need to replace, these where all of Chinese manufacture!

[matt h]

(deleted)

[Reeltarded]

EH12ax7s sound like notebook paper being ripped across space/time.

[mascis]

Haha! If only I'd been that poetic in my descriptions!

Matt - Ah, I didn't know that about the lower Ra of the 5751, I generally always thought it was just lower gain. Funny how preconceptions play with your head, I was all prepared to not like the 5751 I think because I'd read somewhere on a forum that someone thought they sounded cold and sterile, yet I really liked it in the tests.

I've decided I'm going to use the Tung-Sol's as the general 12AX7 in my Fenders and possibly use the 5751 in position one.

I've read somewhere that the Tung-Sol 12AX7 is based on early American valve designs, is t a sort of copy of the General Electric 12AX7WA by any chance? Does anyone know?

[matt h]

(deleted)

[jjman]

From what I've seen and measured I don't think such an amp overdrives that tube, in either its 1st or second half. Of course the sonic results are probably valid but it's likely the result of how each variant differs in its clean output tone to the 3rd stage, then PI, then the clipping outputs.

[matt h]

(deleted)

[gui_tarzan]

I noticed you didn't try a Shuguang? I bought a bunch of them and so far they seem to be pretty good.

[matt h]

(deleted)

[cbass]

I think the mullard 12ax7 reissue is Russian the el34s is Chinese could be wring though I don't actually own either one.

[M Fowler]

If I try anything but JJ's my ears gringe

[Leo_Gnardo]

GuiTarzan-- reading between lines (and perhaps my own faulty memory) I think the "Mullard" copies were the Shuguangs? or a variant of them.

Currently marked "Mullard" are brought to us from Russia, with love (for your cash) by New Sensor. IOW, another Sovtek variation. Been going on about 10 years now. Same with TungSol. GEC too, for slightly less time. They even have GEC Gold Lion 12AX7/ECC83 and EL84, which AFAIK were not made by the original GEC. I don't call any of them 'reissue' since in most cases the only attempt at recreating the original tube is to paint the logo on the glass.

I've never seen a shuggie marked as Mullard. But - anything's possible in this wacky world of vacuum tubes. All it takes is . . . paint.

[ToneMerc]

GuiTarzan-- reading between lines (and perhaps my own faulty memory) I think the "Mullard" copies were the Shuguangs? or a variant of them.

Currently marked "Mullard" are brought to us from Russia, with love (for your cash) by New Sensor. IOW, another Sovtek variation. Been going on about 10 years now. Same with TungSol. GEC too, for slightly less time. They even have GEC Gold Lion 12AX7/ECC83 and EL84, which AFAIK were not made by the original GEC.

I've never seen a shuggie marked as Mullard. But - anything's possible in this wacky world of vacuum tubes. All it takes is . . . paint.

Yep Mullard AX7 RI is nothing more than a Sovtek LPS, but some folks feel better because it says Mullard on the glass and carton.

TM

[Blackburn]

Yep Mullard AX7 RI is nothing more than a Sovtek LPS, but some folks feel better because it says Mullard on the glass and carton.

TM

I'm pretty sure that adds to the tone.