Hi MeJames.
I know you told me that the infini caps are very worthwhile for either a 450 or 750. Wondering if you have done the super balanced input upgrade or now of anyone who has.
I have the opportunity to buy a new/demo rew 750 which is curent except for the super balanced input.
VTL said the following
The Super Balanced Input further improves the common mode noise rejection of the amplifier, removes any ground loop hum and improves its sonic characteristic by opening up the top end and making the sound much more effortless and dynamic. Yes the sonic change makes the amp sound closer to the S-400 whereas the older version of the balanced input stage gives the amp a more classic tube sound. I would say a little rounder, darker velvety sound.
Based on this I may like the older balanced version.
cheers Shane