Cary rocket 88 vs dynaco st70

I currently have a completely rebuilt and upgraded dynaco st70 that sounds very nice in my system.

Classe dr6 pre
Quad 11L monitors
Denon dvd/sacd

I am having some low level hum from my dynaco, and am considering a used Cary rocket 88.
If you have a rocket 88,how quiet are they,and would this be an overall sound quality upgrade over the dynaco?
Speakers are 6ohm, 86db and have plenty of volume with the dynaco.

I had a pair of 96db klipsch kg4 in the system and the hum was unbearable.

There are no groundloop issues since my bryston 3b at has no hum in the system.
????
dave