Retubing a TriAxis a 2:90

Hey y'all...

I'm looking to retube my TriAxis and 2:90, and I was hoping to get a few opinions from people who have done this.

For the 2:90 6L6's -- I think I'm going with the SED Winged C's. They seem to have the most votes from people I've talked to. Also, does anyone know if I need to have a trim pot for it? If not, would one help?

For the TriAxis (and 2:90's) 12AX7's -- I'm a bit lost. Any suggestions? I actually think the stock ones sound decent, but I'm open to ideas.

For the past three years I have been delving deeply in 12AX7 tube substitutions in my Triaxis -> 20/20 rig, and I can probably help you. I have experimented extensively with more than 30 variants (mostly NOS).

First, though, please tell me which modes you gravitate towards, and what you'd like to accomplish (i.e. more/less compressed, articulate, overdriven, bass/mid/treble, dynamic, etc.)? Your budget and patience levels are also important factors, but if you're obsessed like me, you'll probably find a way to navigate those obstacles successively.

Timbre Wolf said:

For the past three years I have been delving deeply in 12AX7 tube substitutions in my Triaxis -> 20/20 rig, and I can probably help you. I have experimented extensively with more than 30 variants (mostly NOS).

First, though, please tell me which modes you gravitate towards, and what you'd like to accomplish (i.e. more/less compressed, articulate, overdriven, bass/mid/treble, dynamic, etc.)? Your budget and patience levels are also important factors, but if you're obsessed like me, you'll probably find a way to navigate those obstacles successively.

Click to expand...

I like a nice balanced tone. I don't want to completely cut my mids (like pure metal players), but I want a good solid amount, with healthy amounts of gain, yet I want it to sound creamy. I suppose I want it to sound like John Petrucci.

I know it won't scream like a 5150, but that's why I'm also buying a 5150. I just want a great sounding, warm and buttery tone that's creamy yet has a tight low-end response, and highs that aren't too bright.

I hope I didn't confuse you there.

Okay now, in my way of thinking, "buttery" and "creamy" is somewhat at odds with a "tight low-end" (this is true when discussing human dietary habits as well). And, though "balanced tone" is a noble pursuit (and I do know what you mean), the philosophy I've evolved is that I'll leave "balanced" to the hi-fi crowd, because as a guitarist, I want character, which by its very nature is at odds with "balanced." What I've found is that the lauded hi-fi "balanced" neutrality (often typified by the Telefunken smooth plate ECC83) leaves me cold. Mini rant over, but at least now you know where I'm coming from.

You didn't say what Triaxis mode(s) you prefer, so I'll try to generalize. The tube that comes immediately to mind when I hear "buttery/creamy/healthy amounts of gain/not too bright" is the RFT ECC83.

The RFT ECC83 has "character" to spare. It is the earliest-breakup 12AX7 variant I know of. It does not clean up well (very compressed), so I'd only recommend it for V1 (lead 1 input, for a looser or impressionistically blurred high gain character) or perhaps V4 (lead 2 gain, for somewhat more focused gain - though attempting to force more articulation/definition opposes the nature of the RFT). If you want to confirm where V1 and V4 are located, there's a diagram in the manual; V1 is closest to the input, and they number sequentially towards the output. Another nice thing about the RFT is that it is still available for relatively cheap (i.e. less than $15 on eBay, if you dare).

If the RFT sounds like it may be too sloppy (and it is, that's why I like it), you may want to consider another "character" - the Mullard long plate/halo getter ECC83. This late '50's Mullard is my personal favorite for the lead 2 gain position (V4), and it is definitely NOT the same as the later-production short plate Mullard ECC83/12AX7 variants (and none of these should be confused with the GT12AX7M). Lows and low-mids are tight and distinct, and the whole sonic spectrum is clear, detailed and available in one dynamic package. Unlike the RFT, this tube will clean up beautifully, but when it is overdriven, it sings smoothly, like no other. If ever a tube was used to express the paradoxical "buttery but tight," it would be this one in V4. The bad news is that it is expensive ($45 used, $100 NOS), but consider that it will last very long when weighing the true value of this gem.

Hope you don't mind how long this post is, but if you'll bear with me, I'll tell you one more trick I've discovered: try a Mullard 12AT7WA (M8162/CV4024) in the V2 position. This is the lead 1 gain position, and the main input for lead 2 and clean modes. Beautiful lows and low-mids through open and airy present (but not obtrusive) highs will now bloom in your clean modes, and your lead modes will open up in ways you've never experienced. Gain will drop a little, but you can adjust your presets for that. These babies are the '70's and '80's versions (early '60's versions are more expensive and brighter) that are plentiful and available for $20 or less. A friend of mine had this to say when he tried one of these valves in his Triaxis "I must admit that last night I couldn't stop playing my guitar for hours. I had a smile on my face that refused to go away. Man, what have you done to me?" I'm confident that you'll like it as well.

I only gave you my top recommendations. Let me know if you'd like to hear about the runners-up, or if you want more opinions on the other tube positions (V3 and V5, plus the 2:90 input and PI positions). Remember, that when you make any of these tube changes, you'll have to tweak your settings to taste to bring out the best in your Triaxis. Enjoy!

Timbre Wolf said:

Okay now, in my way of thinking, "buttery" and "creamy" is somewhat at odds with a "tight low-end" (this is true when discussing human dietary habits as well). And, though "balanced tone" is a noble pursuit (and I do know what you mean), the philosophy I've evolved is that I'll leave "balanced" to the hi-fi crowd, because as a guitarist, I want character, which by its very nature is at odds with "balanced." What I've found is that the lauded hi-fi "balanced" neutrality (often typified by the Telefunken smooth plate ECC83) leaves me cold. Mini rant over, but at least now you know where I'm coming from.

You didn't say what Triaxis mode(s) you prefer, so I'll try to generalize. The tube that comes immediately to mind when I hear "buttery/creamy/healthy amounts of gain/not too bright" is the RFT ECC83.

The RFT ECC83 has "character" to spare. It is the earliest-breakup 12AX7 variant I know of. It does not clean up well (very compressed), so I'd only recommend it for V1 (lead 1 input, for a looser or impressionistically blurred high gain character) or perhaps V4 (lead 2 gain, for somewhat more focused gain - though attempting to force more articulation/definition opposes the nature of the RFT). If you want to confirm where V1 and V4 are located, there's a diagram in the manual; V1 is closest to the input, and they number sequentially towards the output. Another nice thing about the RFT is that it is still available for relatively cheap (i.e. less than $15 on eBay, if you dare).

If the RFT sounds like it may be too sloppy (and it is, that's why I like it), you may want to consider another "character" - the Mullard long plate/halo getter ECC83. This late '50's Mullard is my personal favorite for the lead 2 gain position (V4), and it is definitely NOT the same as the later-production short plate Mullard ECC83/12AX7 variants (and none of these should be confused with the GT12AX7M). Lows and low-mids are tight and distinct, and the whole sonic spectrum is clear, detailed and available in one dynamic package. Unlike the RFT, this tube will clean up beautifully, but when it is overdriven, it sings smoothly, like no other. If ever a tube was used to express the paradoxical "buttery but tight," it would be this one in V4. The bad news is that it is expensive ($45 used, $100 NOS), but consider that it will last very long when weighing the true value of this gem.

Hope you don't mind how long this post is, but if you'll bear with me, I'll tell you one more trick I've discovered: try a Mullard 12AT7WA (M8162/CV4024) in the V2 position. This is the lead 1 gain position, and the main input for lead 2 and clean modes. Beautiful lows and low-mids through open and airy present (but not obtrusive) highs will now bloom in your clean modes, and your lead modes will open up in ways you've never experienced. Gain will drop a little, but you can adjust your presets for that. These babies are the '70's and '80's versions (early '60's versions are more expensive and brighter) that are plentiful and available for $20 or less. A friend of mine had this to say when he tried one of these valves in his Triaxis "I must admit that last night I couldn't stop playing my guitar for hours. I had a smile on my face that refused to go away. Man, what have you done to me?" I'm confident that you'll like it as well.

I only gave you my top recommendations. Let me know if you'd like to hear about the runners-up, or if you want more opinions on the other tube positions (V3 and V5, plus the 2:90 input and PI positions). Remember, that when you make any of these tube changes, you'll have to tweak your settings to taste to bring out the best in your Triaxis. Enjoy!

Click to expand...

Wow, I've hit gold! Thanks for all the info!

While I'm digesting it all, let me just clarify a few of my points...

By "balanced" I didn't actually mean balanced inputs/outputs (such as XLR cables), but more along the lines of good 'balance' (mix?) between over- overdriven and a smooth (less distorted) sound. I guess you could say a break-up point not too low, not too high?

My favorite modes are the Lead 2's... particularly the Lead 2 Yellow. It exhibits the the "buttery and creamy" tone I was talking about, at least, in my opinion it does. I honestly wouldn't mind not changing Lead 2 at all, but I can't do much with Lead 1, so I guess we're looking at just changing two tubes?

I probably won't go with the RFT ECC83, because it sounds like the kind of tone I would be getting with the 5150/6505 I am planning to purchase, but the Mullard long plate ECC83 sounds gold. I don't mind the cost too much. But as far as your suggestion of putting the Mullard 12AT7WA in the V2 position, should I do that along with replacing my tubes with the Mullard long plate, or are they mutually exclusive?

Thanks for all the great info!

I guess when I said I knew what you were talking about when you referred to "balanced," I was wrong. I thought you meant having somewhat even response amongst the frequency bands (i.e. not too bright, or too middy, or too bassy/tubby). Just goes to show you that these terms are a source of confusion if not defined. Don't get me started on the term "warm" though! :wink:

So the RFT is not balanced in your terms, but I'd say the Mullard long plate is, as it does clean well, it does soaring gain well, and it transitions smoothly. If you go with the Mullard long plate, you won't be sorry at all - it is worth every penny. I do recommend changing both tubes: Mullard 12AT7WA in V2, and Mullard long plate ECC83 in V4 for lead 2 - the combination is heavenly. When you've installed them and redialed your presets a bit (the 12AT7 will change the gain a bit), make sure you've got an open schedule so you can play 'til your fingers are sore because you won't want to stop (drink some water every now and then, just to stay hydrated).

A tip on purchasing the Mullard long (17mm) plate ECC83: look for the acid-etched codes near the bottom of the tube - they should read "f91" or "f92" on the top line (this is sometimes blurred or missing), and the second line should begin with "B8_" or "B9_" Check out http://www.tube-classics.de/TC/Tubes/Valvo/Phlipscode.htm for an illustration of the Philips manufacturing codes.

Please post back with your results.

Timbre Wolf said:

I guess when I said I knew what you were talking about when you referred to "balanced," I was wrong. I thought you meant having somewhat even response amongst the frequency bands (i.e. not too bright, or too middy, or too bassy/tubby). Just goes to show you that these terms are a source of confusion if not defined. Don't get me started on the term "warm" though! :wink:

So the RFT is not balanced in your terms, but I'd say the Mullard long plate is, as it does clean well, it does soaring gain well, and it transitions smoothly. If you go with the Mullard long plate, you won't be sorry at all - it is worth every penny. I do recommend changing both tubes: Mullard 12AT7WA in V2, and Mullard long plate ECC83 in V4 for lead 2 - the combination is heavenly. When you've installed them and redialed your presets a bit (the 12AT7 will change the gain a bit), make sure you've got an open schedule so you can play 'til your fingers are sore because you won't want to stop (drink some water every now and then, just to stay hydrated).

A tip on purchasing the Mullard long (17mm) plate ECC83: look for the acid-etched codes near the bottom of the tube - they should read "f91" or "f92" on the top line (this is sometimes blurred or missing), and the second line should begin with "B8_" or "B9_" Check out http://www.tube-classics.de/TC/Tubes/Valvo/Phlipscode.htm for an illustration of the Philips manufacturing codes.

Please post back with your results.

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Wow, the Mullard long-plate is hard to find... know of anybody that has any in stock? Preferrably new, er NOS. The 12AT7WA is easy to find, though (www.tubestore.com has 'em).

I just realized this covers only V2 & V4... what do you recommend for V1, V3, and V5? Can I go with 12AT7WA for the rest, or do you recommend others? Heck, while we're at it, what do you recommend for the 2:90?

I just have time to address your question about finding the Mullard long plate 12AX7 and the CV4024 today. I’ll try to get to other valve recommendations soon, but it takes me a while to write up, and I’m somewhat long-winded (can you tell?).

Hey, can some of you other Triaxis mad scientists chime in here - what tubes have you all found to be successful?

David Foster often sells Mullard CV4024/12AT7 for less than the TubeStore (much better deal if you buy 5 – check out the WeberVST buy n’ sell board, 6/13/05, for details: http://www.webervst.com/vstbbs/bbs.html ). David’s site is http://members.dslextreme.com/users/davidfoster/. I have done business with, and can highly recommend Doug Preston at http://www.dougstubes.com/, where he sells the Mullard CV4024/12AT7.

I agree that the older long plate Mullard ECC83/12AX7 is difficult to find, especially for a reasonable price. I have taken my chances, successfully on eBay, but you have to trust the seller to accurately present test data, and trust your ability to correctly identify the tube (that’s where knowing the type/manufacturer/date codes I mentioned above becomes essential). I bought a couple of these used from Michael Marx at SND Tubes (http://www.vacuumtubes.com/12ax7.html). SND is the best “sure” deal I know of (if you don’t want to risk eBay), because Michael tests them, and even the used Mullards are reported to last a very, very long time – I’ve never had one fail. Another avenue I’d highly recommend is to ask Jim McShane (http://pages.prodigy.net/jimmcshane/) if he has any available. Jim is a very respectable dealer. You may also ask Doug Preston about the longplate Mullard, as he’s a worthy character in my book.

Hey man, I dig your "long-winded" replies. Details are good.

Take your time, I know you're a busy man, but I'd love to hear all your knowledge about the TriAxis+2:90 and associated tubes. This forum doesn't get much action, but your knowledge has already infinitely raised the value of this board.

BTW, some guy on petrucciforums.com retubed with JJ's, and I've got to admit, they actually sound quite nice. Granted, guitar & pickups make all the difference, but I was quite impressed:

http://home.comcast.net/~leadfootrider/fusion_2.mp3

What do you think?

Long-winded it is, then!

I had checked out that clip from Leadfootrider (it was posted in this forum too). It is difficult to really assess a particular tube’s performance without feeling its pulse under my own fingers, but that clip with the JJ ECC803s sounded great for the style. No offense intended, however, fusion doesn’t float my boat.

This reminds me to state my style(s) of favor. Actually, there are too many to generalize about, which is why I gravitated toward the chameleonic Triaxis in the first place. Here are my guitarists of influence: David Gilmour, Justin Adams, The Verve’s Nick McCabe, Big Jack Johnson, The Innocence Mission’s Don Peris, Syd Barrett, Jimi Hendrix, Freddie King, Robyn Hitchcock, Aerosmith’s Brad Whitford, Southern Culture on the Skids’ Rick Miller, Hank Marvin, Johnny A, Dandy Warhol’s Peter Holmstrom, Link Wray, George Harrison, Stevie Ray Vaughan, Ted Barnes of Beth Orton’s band, Ry Cooder, Johnny Meeks of Gene Vincent’s Blue Caps, B.B. King, The Cramps’ Poison Ivy, The Misunderstood’s Glenn Campbell, and Reverend Horton Heat’s Jim Heath. Probably more I’m overlooking now (apologies).

I guess I tend towards the cleaner side of the gain spectrum. And to this end, I originally found the Triaxis to be too gainy, shrill, and compressed for my taste (this, from someone who’s used it for over 12 years – hah!). After lots of experimentation and tweaking, I feel I’ve reached my goals by retubing.

You’ve got my V2 and V4 revelations. Now for the others:

V1 only is used when in Lead 1 modes, and is the main input for those modes (with V2, in my case the Mullard CV4024) serving as the next gain stage. I’ve already mentioned to you my fondness for the RFT ECC83 in this position. The RFT has an appealing musical looseness, with somewhat rolled off highs (kind of mushy lows, though), and an early breakup that only suits higher gain sounds.

Other tubes I’ve appreciated in V1 include:
Tungsram ECC83 – clean, tight, late breakup; sort of the anti-RFT. Tungsrams are the most balanced (in my parlance, meaning all frequency ranges evenly represented) 12AX7 I have tried. While they are lower gain, like the Telefunken smooth plate ECC83, they are still dynamically responsive (unlike my experience with Telefunkens, which, by the way, also lack strong bass/low-mid representation that I favor). I passed on these articulate and percussive tubes in this position because they kind of buck the nature of the Lead 1 modes.

RCA 12AX7A – these are the later-production short, gray plate tubes that are so inexpensive it is ridiculous! And they’re fantastic tubes. They have a great solid bass foundation, with somewhat scooped mids (compared to the long plate Mullard ECC83), and piquant highs (sometimes harsh) that are slightly less distinct than those of the Tungsram. I have not tried older, long plate RCAs (gray and black plate), but if this somewhat shunned later-production version is any indication, they should be stellar.

JAN-Philips ECG 12AX7WA – while these were my least favored in V1, they are interesting nonetheless. They have bold lows, with markedly blurry low-mids (impressionistic = early breakup in these frequencies), and quite zingy high frequencies (which may mellow over a 100 hour break-in time). These are good if you like crunchy power chords.

And now, my favorite for V1… Raytheon long black plate, halo-getter12AX7 – Made in USA in the early ‘60’s, these beauties are kind of obscure. They’re often found, used, in old Baldwin organs (with “Baldwin” markings painted on them). Like the RFT, these break up early. Unlike the RFT, they don’t lose articulation because of this early breakup quality, and they are very uncompressed/responsive. They can be clean as a whistle, then come alive with an effervescent bloom of upper harmonics when you hit the strings hard. They’re not as strong in the low frequencies as the Mullard long plate ECC83, but if you try them, you probably won’t mind when they reveal their lively character to you.

‘Nuff for today. I’ve got to go play my guitar. :twisted:

V2 revisited
This position is for the clean modes, the main input for Lead 2, and the gain tube for Lead 1, so it is undoubtedly the most influential tube in the Triaxis. You know that my favorite is the Mullard 12AT7/CV4024, but here are my observations on a couple of others I tried here:

“Philips” E180CC/7062 – these are medium-mu valves (about 47, compared to 12AT7’s 60, or 5751’s 70). They are also nearly 1/2” taller than your standard 12AX7, but this is just fine in the Triaxis. I say “Philips” because I have examples branded as Mullard, Valvo, and Amperex (all Philips conglomerate brands), but they all were made in Heerlen Holland (they have the delta-shaped manufacturer mark), and they all perform about the same (except the older, Bugle-Boy “pinched-waist” that the hi-fi crowd esteems). Anyway, these have superb clarity and openness. They have reduced lows compared to the CV4024, so I don’t prefer them when I’m playing with my Strat (as I most commonly do). But if I were to record with P-90s or humbuckers, I’d sub the E180CC in V2 for improved cleans, and to avoid potentially bloated lows.

GE 6201/12AT7 5-star, 3-mica – these are slightly crunchier and drier sounding than the CV4024. They’re very responsive, with a frisky top end, but they lack the clear and powerful lows I love in the CV4024.

JJ ECC81 – while they tend to emphasize the lower frequencies, they are not as open, airy, or musically dynamic as the CV4024.

Mullard M8162/12AT7 older-production – to avoid confusion, these are not the later-production CV4024 I generally am referring to here: they are ‘60’s versions of the same thing, with the old Mullard “shield” logo. They are much brighter than the later-production 12AT7 (which I’ll refer to as “CV4024”, though, technically, that’s not a valid distinction), lacking the juicy low frequencies, and with high frequencies that are much more assertive than the more passively “open” younger brother CV4024. Kind of like a cross between the GE6201 and the E180CC. I really liked these in V4 to lower the Lead 2 gain a bit.

RCA black plate/3-mica 5751 – more on these as I discuss V3 tubes.

Triaxis V3
According to the Triaxis manual, valve #3 is the “lead and rhythm mixer” position. The signal comes from V2 (cleans), V1-V2 (Lead 1), or V2-V4 (Lead 2) to V3, then out to the dynamic voice circuit. But just after V3 and before the dynamic voice circuit, there is an opamp that can sound very buzzy and harsh if it is hit with too hot of a signal. This is why Mesa warns us in the manual not to set the master volume above 6.0, or it will result in what they euphemistically call “unwanted clipping.” One other way to limit the signal, then, is to use a lower gain tube, such as the 5751 (70%) or 12AT7 (60%) for V3.

I have enjoyed the Mullard CV4024 in this position, but it is not my favorite valve here. I think this is because having two of these lovelies in the pathway skews the character too much toward the lower frequencies. That would be kind of like dining at a fine restaurant and eating two portions of the same filet mignon (or whatever tofu analog you like) instead of complimenting one portion with a delectable salad. Anywho (burp!), on to my next experiment…

JAN GE 5751 gray plate – clear and clean, but with an unpleasant stiff feel that made me wonder if my pick was somehow covered in an invisible layer of bubble gum (similar to my observations on the JAN GE 12AX7WA; hmmm!?) So on to the next option…

Sovtek 5751 – Okay, it was cheap. But what was I thinking? I’m trying not to dwell on the negative too much here, but this was definitely the wrong direction, and hopefully others can learn from my mistakes. From my notes: “unmusically brash/brittle: the only way to get a good sound from this tube is to listen closely to the pop it makes as one crushes it under foot.”

RCA 5751 black plate, 3-mica – At last, my favorite for V3! The tone is somewhat neutral, with equal availability of all frequency ranges, so it lets the V1, V2 and V4 tube characters through faithfully. Unlike the JAN GE gray plate 5751, this RCA is lively and rich (strips that gum right off the pick and lets you glide).

GE JG 5751 black plate, 3-mica – Has the wonderful dynamic liveliness of the RCA, and comes in as a close second choice for me. But the low-mid frequencies are softer and less articulate than the RCA, which is my clear preference.

Triaxis V4 revisited
Okay, Mullard long plate/halo getter ECC83 (f91 or f92 code) is my favorite all ‘round for this Lead 2 gain position. There is another Mullard valve I’ve quite enjoyed for this position, and I’m not talking about the short plate, later-production Mullard 12AX7 (I63 production code, which can sing well when driven, but has high frequencies that verge on harsh, and lacks the lower-frequency definition I enjoy in the f9 long plates). It is the ‘60’s (older-production) “shield logo” Mullard M8162/12AT7. True, this tube doesn’t allow as much soulful drive as the f9 long plates, but for crunchy clean to mild gain, it really shines with an appealing chime.

Philips Miniwatt ECC83 (I65 production code) would be my second choice 12AX7 type for V4. At low drive settings, it has a the low-mids I demand, but they are not quite as clear and distinct as the Mullard f9 long plate. When driven hard, it sings with a nice upper-mid fizz, but I preferred it at lower drive settings.

“Philips” E180CC/7062 (IV2 and IV3 production codes, labeled Mullard, Valvo, or Amperex) – I’ve mentioned these as a fine alternative for V2, but they are also nice if you want to keep the Lead 2 in the much lower drive zone. Chords ring out with piano-like clarity and note separation, while being lightly crunchy. These are a little less bright than the old “shield logo” Mullard M8162/12AT7, and there will be slightly less gain.

Sorry, I've been crazy-busy with work. Wow, you've been quite busy with posting, hehe! I appreciate all the info! (still slowly digesting it all...)

About playing styles... aaaahhh..... slight problem, I tend to be on the heavier side of the spectrum. Where you think the TriAxis has too much gain for your taste, I think quite the opposite (that would explain my love of the Peavey 5150).

I've decided to go ahead and get a full set of JJ's, because I don't think I'll be unhappy with them, but I'm going to consider the Mullard 12AT7WA's as well. And swap them around as I see fit.

As far as power tubes are concerned, I _do_ like clean sounding tubes that give a nice round sound. Do you have any recommendations for the 2:90? I've heard great things about the SED Winged "C" 's (by clean-channel players!!). Any opinions on them?

mcmanus said:

About playing styles... aaaahhh..... slight problem, I tend to be on the heavier side of the spectrum. Where you think the TriAxis has too much gain for your taste, I think quite the opposite (that would explain my love of the Peavey 5150).

Click to expand...

Yeah, we have different styles and needs, but I hope you find this information useful anyway. I know I’m a bit of an anomaly amongst Triaxis players, but I’m really enthused by my discoveries. Actually, I don’t want to forget to thank you for bringing up this tube question. I’ve put a lot of time experimenting with this tube obsession, and I am glad to share my results and opinions with you and others. I also hope other tube tweakers pitch in and share their lore (HINT!). Please post your impressions after you re-tube.

Meanwhile, to wrap up the Triaxis:

Triaxis V5 (and beyond)
The V5 position governs the master output (and effects return level and recording output level, if you’re using either). I don’t record direct from the recording outputs, but if you do, be careful not to overload the opamp that’s in the rec.-out circuit (results in buzzy harsh distortion) by running the volume too high. Generally, for this position, I’d recommend a tube that neutrally represents all frequency ranges faithfully:

RCA 5751 black plate/3-mica – (described above) would be my lower-gain recommendation if you’re using a very hot effects unit in the loop.

Tungsram ECC83 - (described above) would be my second choice V5 valve, because it is so true to what is sent its way. It is also a little lower-gain than most 12AX7s, but it is higher gain than a 5751.

RCA 12AX7A – (also described above) would be my third choice V5 valve. It is rougher sounding, and slightly higher gain than the Tungsram, and quite a bit less “balanced” (my use of the term) tonally, being a bit more “scooped” in the mids.

RCA 12BZ7 black plate – Yes, I did type that correctly! This has been my last great revelation. The 12BZ7 is a longer-bottle tube (nearly 1/2” taller, like the E180CC), but it fits fine in the Triaxis. And, although it has the same amplification factor as a 12AX7 (mu = 100), my rig sounds about 2dB louder with this tube. It reminds me of Nigel Tufnel, in Spinal Tap, pointing out that his Marshall volume goes to 11 (“One louder”). This is the “11” tube. This means that you can turn your amp “master” volume down to achieve the same volume, thus effectively dropping the noise floor about 2dB (take note, for when you’re recording), or keep the power amp volume the same, thus hitting the power tubes a little harder. It draws twice the current of the 12AX7, but, again, it works great with the Triaxis. I have tried a number of versions of the 12BZ7 (GE, CBS/Hytron, Sylvania, Philco), and they all have the tonal balance I like for this position. I prefer 12BZ7s with black plates for their proven dynamically-sensitive liveliness and articulate snappiness.

Hey, did you know that you’ll void your warranty with Mesa/Boogie if you use any other tubes than their officially-sanctioned and labeled tubes? I’m here to encourage you to go ahead and void it – act up! They build fine products that rarely need servicing, and these tubes will not harm your precious preamp. (I still recommend you stop running with scissors, and GET THAT THING OUT OF YOUR MOUTH RIGHT NOW!) Ahem!

Okay, you’ve been asking about the 2:90 tubes, and I’ve been putting off addressing that question because I don’t have as much to contribute there. It has been several years since I sold mine, and purchased the 20/20 instead. I remember when I changed out the Boogie tubes for a quad of GE 7581A (a 6L6GC type with great cleans, and nice low frequencies) and a quad of short bottle Sylvania 6L6GC (less bass and treble extension than the GE, but nice mid punch), and I was verrrry impressed at the improvement. I did have the amp modded to be able to adjust the bias, before I installed them. I have not had the pleasure of trying the black plate RCA 6L6GC, but I hear that’s worthwhile, if money’s no object. I also have no experience with the winged-C 6L6GC, but I have seen many agreeable nods in their direction by those that have.

Sometime, I’ll have to go into my notes on EL84/6BQ5 tubes that I’ve taste-tested, but that will be another post, another day.

I will add this about the three 12AX7 tube positions in the 2:90 – they can also be subbed to improve your satisfaction. The 20/20 has similar architecture to the 2:90, with three 12AX7s that do the same functions. There is a main input valve, which is nearest the 1/4” guitar “in” jack. I’d recommend a black plate 12BZ7 here, for the same reasons described above.

The other two positions are phase-inverters for the two stereo-channel quads of power tubes. I recommend balanced-triode tubes here (ask your tube dealer). Since I love the Mullard CV4024 so much, I use them for these two positions.

TTFN (ta-ta for now)

Timbre Wolf said:

Triaxis V4 revisited
Okay, Mullard long plate/halo getter ECC83 (f91 or f92 code) is my favorite all ‘round for this Lead 2 gain position. There is another Mullard valve I’ve quite enjoyed for this position, and I’m not talking about the short plate, later-production Mullard 12AX7 (I63 production code, which can sing well when driven, but has high frequencies that verge on harsh, and lacks the lower-frequency definition I enjoy in the f9 long plates). It is the ‘60’s (older-production) “shield logo” Mullard M8162/12AT7. True, this tube doesn’t allow as much soulful drive as the f9 long plates, but for crunchy clean to mild gain, it really shines with an appealing chime.

Philips Miniwatt ECC83 (I65 production code) would be my second choice 12AX7 type for V4. At low drive settings, it has a the low-mids I demand, but they are not quite as clear and distinct as the Mullard f9 long plate. When driven hard, it sings with a nice upper-mid fizz, but I preferred it at lower drive settings.

“Philips” E180CC/7062 (IV2 and IV3 production codes, labeled Mullard, Valvo, or Amperex) – I’ve mentioned these as a fine alternative for V2, but they are also nice if you want to keep the Lead 2 in the much lower drive zone. Chords ring out with piano-like clarity and note separation, while being lightly crunchy. These are a little less bright than the old “shield logo” Mullard M8162/12AT7, and there will be slightly less gain.

Click to expand...

Oops! I forgot one of my favorites (I have many):

Sylvania JHS long black plate, square-getter – These were made in 1950, and are the oldest 12AX7 types I own. Magnificent clarity and responsiveness, good frequency balance, with strong lows, clear but mellow highs, and somewhat scooped mids compared to Mullard long plate. Rich, beautiful, generally less expensive than the Mullard or the Miniwatt, and definitely worth seeking.

Timbre Wolf you are a legend.
I see you are still busy "evangelising".
I'm still smiling over the Mullard 12AT7 in pos 1 in my Triaxis.

Can't thank you enough.
Rob

OOPS
That should have read Mullard 12at7 in position 2.
Doh!

frednerk_30 said:

OOPS
That should have read Mullard 12at7 in position 2.
Doh!

Click to expand...

Heya frednerk_30... got any sound clips?

G'day mcmanus
Ok you got me I'm an Australian.

Sorry, no sound clips at the moment.
My Triaxis needs servicing - noisy resister or somesuch...
Sound clips are definitely on my list of things to do.

I note that you have a taste for GAIN.
I also note that you mentioned getting a full set of JJ tubes.

I have been using a full set of JJ tubes in my triaxis for the last
6 months, and I consider them to be quite a reasonable tube.
Certainly much better than the Sovtech (not sure which model)
tubes I had in the triaxis previously. I also enjoy high gain.

In terms of sound, I would say the Mullard 12AT7WA (M8162/CV4024)
(as mentioned by Timbre Wolf) has a lot of midrange authority, compresses very nicely, treble is most certainly available.

If you try the tube you might initially find it a little dark and midrange heavy. No it doesn't sound "boxy" but has midrange in "spades". However, tweak the tone controls and see if you don't get a grin that you can't get rid of. Seriously!

The feel of the tube under the fingers is very,very good.

Note: don't forget that (in Lead 11 on triaxis) the gain tube (V2) acts more like a control to adjust the attack envelope (plus gain). Whereas V4 is more of a traditional gain (drive) control. So you will still have lots of gain available. When I first tried the tube a was concerned it wouldn't have enough gain. WRONG.

Anyway, for $US20 I would definitely recommend you "taste" this tube.