I just got my CARY SLI-80 back from repairs (done by Stereo Surgeon in East Hartford Ct.--great service, price and advice). I had a cap blow, and it made blew out two of my KT 77 tubes. So I had to replace the tubes. I replaced them with KT 120 tubes.
There is a significant improvement in the power and openness. While I don't necessarily hear more bass, I can feel it. Nothing overpowering, but just more "right."
Associated equipment REGA Apollo-R; Merlin VSM speakers with latest BAM modifications and R-DAC for Logitech duet server.