NOS Tubes make a Huge difference

Just out of curiousity, how long had the tubes you took out been in service?

Dennis, I'd be interested to read your thoughts on the difference you hear with your new amp, once you get it and have had some time to compare. I think the VTL is quite a good sounding amp, but I've never heard the VAC. (Agree about the superiority of the Svetlana EL-34's).

I don't know about 'bass-heavy', but wearing-out tubes will tend to roll off both the bass and the highs to some extent, while also letting go of the bass tautness and transient incisiveness - the whole presentation will become softer and slower. I have had the experience of getting too much bass balance with a particular amplifier (a SS Classe) in a small apartment, and preferring instead to use an amp that gave less bass (a tubed C-J) for its better in-room balance (it was also just plain better period). I take it from your comments that the VAC sounds better up top than the VTL. Congrats on your upgrade. BTW, once you get the new tubes, you may want to try running the VAC full-range, and repositioning the speakers to even-out the bass balance. If that works, then drop the VTL back in on the bottom and see if you still think of it as an improvement or not. (But have you checked to see if these amps yield the same gain?)