I just got my cleans back!

[phantomlord2oo]

Hey guys. I just got my 12AT7 tube I ordered from Mesa and I put it in the V3 of my Triaxis and I finally got the headroom I've been needing. It's great now! I HIGHLY recommend everyone who owns a Triaxis to do the same thing. It's great and only affects the RHY channels so you can still keep your awsome lead tones!

+Mike+

 

[Timbre Wolf]

Hey guys. I just got my 12AT7 tube I ordered from Mesa and I put it in the V3 of my Triaxis and I finally got the headroom I've been needing. It's great now! I HIGHLY recommend everyone who owns a Triaxis to do the same thing. It's great and only affects the RHY channels so you can still keep your awsome lead tones!

+Mike+

Glad to hear your enthusiasm, Mike. I prefer a 5751 in V3, for this purpose, but a 12AT7 will do it as well. Gotta love your newly-found cleans, now. Did you actually mention to M/B what you wanted the 12AT7 for? I ask, because they do expressly prohibit such changes in their warranty stipulations.

Just a minor correction on your note: the V3 position does indeed affect all modes in the Triaxis, but it doesn't do so adversely (in other words, there is stil plenty of overdrive left for searing/soaring lead settings).

- T

 

[phantomlord2oo]

How different is the 5751 from the 12AT7? Does it give even MORE headroom or sound better or what? I didn't tell M/B what I wanted it for, I just ordered the tube from their web store. Why would they prohibit that kind of a change? It's their tube for cryin' out loud!

I was reading from a website and it says that the V3 doesn't come into play until later in the chain of the preamp. The guy explains it better:
"V3 is the tube placed between the programmable master volume and the Dynamic Voice. As mentioned before, the Triaxis uses a TL072 opamp for the Dynamic Voice and the signal always passes this opamp. Therefor I highly recommend using a lower gain tube with more headroom to prevent overdriving either the tube or the opamp. NOS 12AU7 or 12AT7 tubes would be my choice."
I got that from: http://www.tubefreak.com/triaxis.htm

Also, I was reading more about what he recommends for tubes in the Triaxis and he said that I (we) should use another low gain-ish tube in the V5 position. Here's what he says:
"Because V5 is the fx return buffer and main output tube it's not a bad idea to look for a lower gain tube for this application as well. If you are using fx with high outputs, then the V5 tube can be distorted, using a lower gain tube, such as for V3 will prevent this."

Now all I use in the Triaxis' FX loop is a Rocktron Hush Super C and that's only on when I use my high gain stuff. Would I benefit from doing this change or should I just stick with what I've got?

+Mike+

 

[Timbre Wolf]

I've found that I like the 5751 a bit more than the 12AT7 in V3, basically because of its slightly better dynamic feel. The gain rating (mu) on the 5751 is 70, while the 12AT7 is 60, so they're very close, in those terms. But as you drop gain, you diminish lively responsiveness, so it was a fine line between dropping a little and getting better clarity, and dropping more and losing the dynamic feel. I felt the 5751 gave me the clarity I liked, without losing the dynamics.

I'm well aware of Maarten's (a.k.a. TubeFreak) Triaxis tube essay. It was what originally inspired me to take on the retube task, several years ago. I have a lot of respect and appreciation for Maarten, and have actually sent him some tubes to try out. He does not have a Triaxis, though, so he hasn't tried out his theories on re-tubing it.

I differ from him on V5, because I've tried his suggestion for a low-mu valve there, and it ended up functionally raising the noise floor. So I went in another direction, trying out a 12BZ7 (same mu rating as 12AX7, 100, but twice the transconductance), and functionally dropped the noise floor a couple of dB. I also use the Hush Super C in the effects loop (the only device in there), and have no problems with this. So I'd recommend you stick with a 12AX7 in V5. Doesn't hurt to experiment, though, and I encourage you to do so - try a 12AT7 there, and see how you like it. Maybe if I used the Triaxis' record out, I'd reconsider (well, I do use it, for my tuner, but no problem there).

Oh yeah, regarding the Mesa warranty: I can only guess that they wouldn't want us bonehead guitarists plugging just anything into their preamps, and then whining to them if it causes problems. I think it is just their legal "out" for problems that are obviously user-error. But I've never discussed this with them, yet.

- T