Tube buffer or tube preamp

I have an expensive system except forthe digital which i have not upgraded in awhile.
I tried a small Chinese tube buffer and it did nothing of any value for me.
So i went and bought a VAC Standard four tube preamp to use as a glorified tube buffer and that made a positive difference.
I still use my main preamp a Bryston Bp-26 and have the digital sources to the VAc then from VAc to Bryston.
Works for me.
I would be very hard to say in advance what would work for the op.
All I can say is a cheap sub$200 buffer did nothing for my setup. The used VAC is wonderful and solved any and all issues I have with digital. So i paid $1,400 to solve my digital issues.

Elizabeth,

Have you ever tried using just your VAC without going through the Bryston preamp? It should sound better.

Thenis, it might be helpful if you would list the equipment in your system, speakers, amp, source, and cables.