I just had a friend do a few upgrades to my VTL ST 85 tube amp.
The sound of the amp always pleased me, great tone, dynamic with tons of bass.
Unfortunately everytime I borrowed a solid state amp I was impressed with how quiet and detailed it was, so the search went on to improve the VTL.
First I replaced the signal caps with Multicaps RTX and Cardas caps. This took a long time for the caps to settle in. Did it help? Well for me the beginning was tough but they ironed themselves out and started to sound very nice, but the noise floor was still there. Now this amp stock is very quiet but I was going for something more. All tubes were replaced. NOS Mullard 12at7's for the driver and signal tubes. Siemens and Winged C's for the power tubes. Great tubes sound great, buy NOS whenever you can!
But I wanted more..
My friend went to work on the power supply.. WOW!!!
He replaced the diodes with Fairchild stealth Freds, resistors with Caddock 231's
and replaced a few caps with blackgates and bypassed the big electrolytic with Auricaps. WOW!!
Much quieter, much more detail, much more texture.
It now has the ability to resolve complex passages and multiple voices with such ease, it sounds SO refined, fast and Delicious. I've had a few goosebump moments.
Bass is less boomy, hell there is no boom at all , just fast textured, resolved bass, so fast that it makes my little 5 inch woofers now seem inadequate. I need a sub! A fast one

to keep up with the system. I may be excited by all the newness of it all, just like we get when a new piece of equipment arrives, but I am very glad I did this. No mods, just better, newer parts made a very big difference. It definitely took this amp to the next level. If I want more I will have to look elsewhere.
Pics to follow
mike