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Which preamp tube would you choose?

Which 12ax7?

  • Tung Sol

    Votes: 25 40.3%

  • Mullard

    Votes: 14 22.6%

  • JJ

    Votes: 23 37.1%
  • Total voters
    62
JN8642

JN8642

Aug 19, 2015
449
485
34
#1
Hey there,

I'm re-tubing my Mesa Bass 400 (6550) soon and am sold on Tung Sol for the power section.

Just wondering what you guys think of these that are in the poll and why you'd choose them for the pre-amp section.

Currently, it has the Mesa brand pre-amp tubes which I heard are just re-branded Sovtek's or something and Sovtek power tubes. It was last re-tubed in 2009 by the previous owner and I've it for over a year now and have used it a ton and think it'd about time for some new tube goodness.

Thank in advance!
 
#3
JN8642 said:
Hey there,

I'm re-tubing my Mesa Bass 400 (6550) soon and am sold on Tung Sol for the power section.

Just wondering what you guys think of these that are in the poll and why you'd choose them for the pre-amp section.

Currently, it has the Mesa brand pre-amp tubes which I heard are just re-branded Sovtek's or something and Sovtek power tubes. It was last re-tubed in 2009 by the previous owner and I've it for over a year now and have used it a ton and think it'd about time for some new tube goodness.

Thank in advance!
Click to expand...

I have recently rolled Tung Sol 12AX7, Mullard ECC83, Mullard CV4004, JJ ECC803S, and JJ ECC83S and a few others through several bass amps. The tubes provided similar tonal changes in each amp, but there is no guarantee they will provide the same results in your amp.

My goal is for my amps to be capable of producing clear/tight lows, articulate mids, soft/smooth high mids, and slightly glassy highs with relatively neutral EQ settings. I consistently preferred the Mullard ECC83 in V1 and JJ ECC803S almost everywhere else.

The Mullard ECC83 really emphasizes the lows and mid bass. Notes seem deeper, tighter, and more focused. The upper mids are soft and the highs and lows are extended. Chose this tube if you want relaxed mids, smooth extended highs and strong tight bass and mid bass.

The Mullard CV4004 has a similar upper midrange softening to the ECC83 but less extreme. It does not emphasize or tighten the low end. Choose this tube if you want smooth extended highs and neutral lows and mids.

The Tung Sol 12AX7 has a brightest and hardest upper mid range. I think the bass may be a little stronger than the CV4004 but it lacks the mid bass emphasis and focus of the Mullard ECC83. Chose this tube if you like a lot of clank, fret rattle, or pick sound. Probably closest to Mesa branded Chinese 12AX7s.

All of the preceding tubes are made by New Sensor and have rather low cathode to heater voltage specs. I wouldn't run them in any circuit with elevated cathode voltages. The Mesa Schematic shows 172V on the cathode of V2B so I would use a JJ ECC803S there.

The JJ ECC803S seems pretty neutral to me. If anything it might be a bit lean in the low end. It does have a bit of shimmer but lacks the Tung Sols hardness in the upper mids and extended highs. This is a very tight and articulate sounding tube and it has the highest cathode to heater voltage specs I have found. You could probably load your entire amp with these and it would sound great. Use this tube for a tight muscular sound that is free from extended lows or highs.

JJ ECC83S I haven't bought any of these new, but I have pulled several out of guitar amps because I thought they sounded horrible. The examples I have are consistently low gain, dark, and have a tendency to sound a bit crunchy if used in the wrong place. So far I didn't like them in any of my bass amps. I did find them useful in reducing gain and ice picky highs in a JCM 800 Marshall Super Lead and a vintage Vox AC30 Top Boost.

The tonal characteristics I outlined above will be most apparent in V1. For V1 choose the tube the best meets your tonal goals. Use a JJ ECC803S in V2. Use either a JJ ECC803S or Tung Sol 12AX7 in V3 and V4. I would avoid the JJ ECC83S.

If you want to have a little fun, buy 3 JJ ECC803s, and one each Mullard CV4004, Mullard ECC83, Tung Sol 12 AX7. 1) Put the JJs in V2, V3, V4 and roll the other tubes through V1 and note which tube sounds best. 2) Move a JJ from V4 to V1. Roll the other tubes into V4 and note which tube sounds best. 3) Move the JJ in V3 to V4 and roll the other tubes through V3 and note which tube sounds best. 4) Alternate between final tube selections made in steps 1-3. Choose the best combination.

Before you start rolling tubes, set your graphic off and adjust your tone controls as close to flat as you can. When rolling tubes, leave the tone controls alone so you get a clear idea of each tubes tonal characteristics. Adjust gain as needed to keep a consistent volume, but note adjustments so you have an idea of each tubes gain characteristics.

Report you findings in this thread.
 
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#4
Wasnex said:
The Tung Sol 12AX7 has a brightest and hardest upper mid range. I think the bass may be a little stronger than the CV4004 but it lacks the mid bass emphasis and focus of the Mullard ECC83. Chose this tube if you like a lot of clank, fret rattle, or pick sound. Probably closest to Mesa branded Chinese 12AX7s.

All of the preceding tubes are made by New Sensor and have rather low cathode to heater voltage specs. I wouldn't run them in any circuit with elevated cathode voltages.
Click to expand...

I had the opposite impression from the tung sol and mullard RI tubes I've tried - the mullards seem a bit brighter and the tung sols more well rounded in the low mids, but I also only tried them in the first position in a few amps. I would take either over JJ any day of the week just because of the issues I've had with JJ branded tubes over the years (many early failures and poor stability), but also agree with the assessment that standard JJ 12AX7/ECC83 tubes tend to sound a bit muted in the highs/darker compared to most new sensor/Chinese production.

I've not had any issues with new sensor tubes in regards to the cathode voltage. I know new sensor tends to just reproduce the old data sheets online, but if we believe them as their specs the datasheet does show 180V for the Link Removed, same as the standard JJ 12AX7. The 803S that you recommended actually lists 100V heater to cathode as a limiting value.
 
#5
Well, you know what they say about everyone having opinions. Here's mine.

None of the currently produced tubes sound great to me. Some sound better than others and both the JJ and Ruby fall in the better sounding category.

I use older USA or European tubes in my bass preamps. I have used tubes by G.E., RCA, Sylvania, Mullard and Telefunken. They each have a sonic flavor to them so one that I love may not be your cup of tea. Also, just to muddy the waters, Tube manufacturers used to buy tubes from each other and put their own label on them so the label does not always tell the whole story. I will still give you my take on some of the more common types that are still available. I bought most of my supply off Ebay, by the way.

Telefunken ECC83(European designation for 12AX7) A fantastic sounding tube with low noise. Very transparent with sweet sounding highs that are never harsh like some of the current tubes. This is a really great tube for folks that dig a very clean tone. Available in the more coveted Smooth Plate design or Ribbed Plate. Both versions sound lovely to me.

English made Mullard ECC83. A fine sounding tube with a buttery warmth to the lows. Clean highs.

RCA 7025 (low noise 12AX7) Sounds similar to the Mullard. A little more hi fi to my ears. Not a lot of coloration.

G.E. short plate 12AX7A Another great sounding tube. A little brighter sounding than the RCA.

Sylvania 12AX7A/7025 Lots of tube warmth in this design. One of my favorite tubes in SWR preamps.

Of course, YMMV. My hearing is damaged so I am working with a handicap. I will say, however, that I frequently get compliments on my tone so I must be doing something right.

One other thought....many of the older tubes have pins that can get corroded and most of them are. I clean them with one of the rectangular erasers or very fine sandpaper or steel wool. Cleaning can save some problems.
 
#6
Chuck M said:
Telefunken ECC83(European designation for 12AX7) A fantastic sounding tube with low noise. Very transparent with sweet sounding highs that are never harsh like some of the current tubes. This is a really great tube for folks that dig a very clean tone. Available in the more coveted Smooth Plate design or Ribbed Plate. Both versions sound lovely to me.
Click to expand...

Hard to go wrong with a vintage Telefunken. They can cost a bit (tctubes.com vintage vacuum tubes).

There is a reissue Telefunken available. They don't specify if it is based on any of the originals.

Link Removed
 
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#7
There was a Telefunken copy made on the original machines. I think it was in the 1990's and made somewhere is eastern Europe. I have some of those tubes and they sound quite good but not quite as good as the German Telefunkens. Differences in materials may account for the difference. IIRC I have one or more of those marked "Groove Tubes 12AX7A".

As I understand it, there is heavy metal pollution when vacuum tubes are produced and that is why they are no longer (to my knowledge) made in countries that have laws controlling pollution.
 
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#8
Are you thinking new production, NOS, or used vintage?

NOS and used vintage can be an expensive time consuming journey. The better tube merchants offer refunds, so demand that.

As far as new production goes, many of the better brands are owned by New Sensor Corp and are made in Russia, supposedly using plans/formulaes from the original designs. Just like the originals? Nope. Nothing is.

Some amp designs respond little to tube rolling, IE one 12AX7 is as good as another (so long as they are properly functioning tubes). Maybe Andy from Mesa can chime in here.
 
#9
beans-on-toast said:
Hard to go wrong with a vintage Telefunken. They can cost a bit (tctubes.com vintage vacuum tubes).

There is a reissue Telefunken available. They don't specify if it is based on any of the originals.

Link Removed
Click to expand...

JJ makes those reissues, as far as I'm aware. Not sure of the tooling and materials as far as Chuck's comment, I was under the impression that it was more a New Sensor type deal where they bought the rights to the name and that's it. They're also marketing 6L6GC and KT88 which were not made by the original telefunken factory.
 
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#11
"Some amp designs respond little to tube rolling, IE one 12AX7 is as good as another (so long as they are properly functioning tubes). Maybe Andy from Mesa can chime in here."

So true. The Eden amps that used a preamp tube were not much affected by the tube. SWR, Alembic, Demeter and Genz Benz Shuttle are designs that benefit from a good sounding tube.
 
#12
Did all three recently in my SWR 220, the Tung-Sol won by a mile. I like a clear sound.

If I were going for "vintage" tone I'd probably do the JJ.

Some amps it really doesn't matter, as the preamp tube is a formality and not getting hit with enough voltage to matter. You mention a tube power section so that's not a concern.

ETA: reread your post, OP. Not my taste in amps but that Bass 400 is one hell of an amp. You won't be short on power, lol. I'd be very curious to hear that head with a full complement of Tung-Sol tubes, they did wonders cleaning up my Hot Rod Deluxe, I might have to reevaluate my opinion.
 
#13
Yes, the Telefunken's are made by JJ in a good factory, but to Telefunken's specs. They don't say what that means. That could mean that it's a new design but based on the originals, it could be a tweaked JJ design, or it could simply mean that it is production JJ tube with a higher level of burn in and tight quality control specs to ensure consistency and long life. The NOS telefunkens had revisions, they came in smooth plate, ribbed plate, both short and long plate. So there are variations. By all reports, the reissue Telefunken is a good sounding tube.

They may have bought the name but there is a Telefunken company based in the US. They do R&D and offer a line of mics, some such as the U47 and U48 are based on the originals. So in that respect the company is more than about buying the name and branding it on tubes.

The NOS telefunkens that I have sound good in any amp that I've tried them in. I especially like how they perform in studio preamps, to my ears they sound harmonically richer.
 
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#16
Oh, I thought we are talking about new tubes.
IMO/IME the original Telefunken or Amperex tubes sound wonderful in most audio applications.
The old Mullards are very good too.
I don't think any of the new tubes can compare with the above.

Old advertising slogan: Don't be a dullard; use a Mullard.
 
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#17
After rolling through JJs, Sovtek LPS, Groove tubes and Ruby's in my SVP-PRO and SVP-CL. When I purchased a second SVP-PRO it came loaded with Philips JANs in all positions including the 12au7. Those are so far the best sounding tubes I've heard it that specific preamp.
Disclamer... I don't know much about tubes. Just that I prefer the sound I'm hearing now.
 
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#19
I always heard how awesome JJ's were. So I got some for my Electric. Never again. I still have them in there now but when they need to be replaced, I'm going Sovtek all the way. Or Gold Lions. The first time I replaced my power tube set (with the JJ's in there now), 1 of them went bad on my 2 days after. It was such a hassle. Then I learned that a lot of people have been having issues with JJ's for a while now.
 

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