Would you buy a tube amp if you were unable to use vintage tubes in it ?

I would say there is no substitute for great design. In simple inexpensive amps perhaps the tube can get you somewhere better and more sophisticated. But for carefully designed high end amps, the tubes are chosen for availability and general character and then the rest of the component is designed to achieve a very specific sound. The goal is the specific sound characteristics… and all the components are chosen to achieve it. I am certain this is how companies like VAC, Conrad Johnson, and Audio Resesrch create their components. I have heard an interview here and there that supports this as well as worked with high end audio engineers. So you can change their sound… but typically the sound quality is balanced on a knife edge between a number of characteristics and it’s only likely to be different but unlikely to be more sophisticated. 

I have a tube integrated and an all tube phono stage.  The integrated uses 3 JJ 12au7s in the gain and driver stage and a quad of unidentifiable 6L6GCs in the power output stage. The only identifying features I can see through the vents on the top are the plates and the bases of which there is no silk screening on either. What I can see suggests maybe German made TAD but their catalog example has a red base wherein the amp's are black or a Psvane that has the same plate structure and a black base. A more definitive identification might be possible if I could see the getters. Either way Luxman says nothing about tube life other than that the implementation promotes reliability and long tube life and that Mickying with them in any way voids the tubes 3-year warranty. So, I can only go with that.

My phono stage on the other hand is the manufacturers special addition which incorporates Genelex Gold Lion 12ax7LPS/B759s with Mundorf silver, gold and oil capacitors with Teflon coated, silver plated wire point to point. I don't think it can be tricked out any better than this and you should hear it!

Further I think all the suggestions regarding tube "rolling" is a little insane simply because you can't demo duplicate copies of your equipment side by side to make a definitive judgement and going through all the trouble of re-biasing and warming the amps up to their fullest potential leaves you without any subjective means of judging the sound differences because your brain forgot what it heard the second you stopped listening to the previous set of tubes. What a crock!

  Sorry but I have to call BS that tube rolling doesn’t matter. I have 3 pairs of new production JJ12AU7’s in my never going to use drawer. Within those JJ’s I have the plain and the gold pin. I just spent $3K to have my Rogue M-180’s brought up to new specks and upgraded to “ Dark “ status. I pulled the JJ’s at about 40 hours of burn in as I couldn’t take it any longer. I put in a quad of Seimens Nickle plates. I have a quad of Tekefunken G73-R’s to go in when the project is fully setup. I replaced the 2 new production Tung Sol 5751’s at about 100 hours with NOS Tekefunken 12AX7’s and after a few days traded those for NOS 5751 GE 5 Star as it was too edgy.  FWIW it takes about 1 hour to cool down and start up different signal tubes, and there is no biasing. That being said I was very impressed with the new production Tung Sol’s. I’m loaning them to a friend that I trade tubes with to try in his guitar amps. The one thing the JJ’s are very good for is filling the spot when you ship for repair or to sell the gear. I have a 12 wpc Had Inspire that takes a rectifier tube in addition to input and power tubes and all three positions are self biasing. I have 6 rectifier, 7 input and 6 pair of power tubes ALL NOS. I can tell a difference in all of it. I also have 4-5 pair of new production power tubes and can tell with those too, but only 2 pair are the same value as I can roll from EL34 to KT150. To answer the actual question posed , yes I would still use tube gear. However I’m very concerned about the quality of new production power tubes. On my low power system I’ve been able to avoid room treatments by tube rolling. But with the higher power gear still breaking in and not being properly setup I can already tell I’ll need treatment. One thing I’ve heard but not experienced is “ gear that plays just as well with the new production tubes provided Vs tube rolling. Maybe some of the heavy hitters with manufacturing experience will chime in on that. So todays problem is do I trust buying an octet of new Tung Sol KT-120’s to replace the Psvane KT-88’s that Rogue currently ships with. But I can just spend $1100 with Uncle Chester and rest assured that he has the best on the planet. Or get out my shoe box full of lightly used SED Winged C’s and enjoy sonic bliss. Whoo hoo , Life is Good, Mike B. 

The one thing the JJ’s are very good for is filling the spot when you ship for repair or to sell the gear.   
 

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