VAC Signature MK2a pre "phono tube questions"

Wrm57

I'll probably start the rolling process by leaving the Chinese tubes there and placing my fav 1964 USA Amperex 7308 into the back

Unless you have specific confirmation from Kevin or Brent, I'd think twice before putting an NOS 6DJ8/6922/7308 into a slot designated for a 12AX7. They are both 9 pin miniature dual triodes but unless the circuits are specifically designed for it, they are not direct substitutes by any means. I realize that Randy White and Dan Wright and some others have circuits into which they can be subbed, but I do not remember reading anything that indicates that that is the case w the Ren pre-amps (great unit, BTW.)

D'oh! I meant medical grade Amperex 12AX7. I mentally misfired because I had VAC install a 6922 switch for the 8416 tubes (at their recommendation) in the linestage and was thinking the tubes I'll use to roll that position. No, I'd never put a 7308 into the 12AX7 socket. :) Thanks for catching it.

My point was missed entirely. People new to tubed gear ask such questions. Those with much experience, especially those with a stash of coveted tubes from yesteryear know that the only way to determine if the tubes they have will work .... is to try those tubes themselves.

As for questions concerning why tube manufacturers don't load up their gear with the best tubes is simple.....there is no best tube. And a manufacturer must be able to provide a suitable stock for production and customer support. There's just not enough of any NOS or UOS tube type for a manufacturer to rely on. So their only choice is to install the crappy Sovtek and EH tubes throughout. For those of us who know the benefits of getting these replaced by other tubes, we are on our own. And often we hear the performance of products that far exceeds what the manufacturer ever experienced.

We all try various tubes in our DACs, phono stages, line stages and amps, and with a lot of effort and a little bit of luck, we find a set with a result that can truly be so impressive. A Tele 12ax7 may sound good at one place but very disappointing at another. And the same for an Amperex 6922 or a Mullard EL34.

As many proponents of SS gear would claim, we tube fans are just chasing one set of colorations with another. That's ignorance. No device is perfect. I have no tolerance for tonal coherency problems, but there is always a tradeoff with noise level, resolution, dynamic contrasts, portrayal of space, etc. The key is to experiment enough and deal with as few tradeoffs as possible to achieve the overall system magic. When a tube is discovered in a link that before was our reference at that link, opportunity arises elsewhere. It's simply not possible to do this with SS.

No manufacturer of a tube product will ever be able to provide a tube or tube set to you that will come close to the set that you ultimately discover that you like for yourself.

Yes, they might. When I am ready to order my LAMMs I will get in touch with Vladimir and discuss with him exactly that along with some other things. Or even if I get a used one. I may still have to try couple of sets but not dozens of them. And I would have no intention to roll tubes back and forth depending on particular recording though it might actually make sense. Unless perhaps if I decide to make compilations using something like Studer 810 deck. Now that would really be audiophile fun.

Sorry Inna, but not a chance. No manufacturer listens to my system in my listening room. Tube selection is not about one component but rather for the entire system. What Vladimir might be able to suggest to "optimize" your LAMM product n the test bench guarantees not at all that this is the ideal r preferred by you in your system.

Rolling tubes for a given music type or even a specific recording would be to much for me as well. I guess this is why many people have multiple phono cartridges with multiple arms or replaceable armwands.