Hum Isolation Suggestions.

I recently change my amp from ARC tube amp to a Classe solid state amp because the tube amp stopped working and need some repair. The table after reconnecting to the pre amp has a slight hum, and after connecting the ac power cord of the table to ac source, the hum is even more severe. (The table has a ground lead to the pre amp, and is connected.)

Any suggesions would be greatly appreciated!

I would try calling Classe and asking them if you could lift the ground on the amp. Seems to me you have a ground loop.

hope this helps,

I really struggled with this issue as well. Are you using different circuits? Doing a quick web search listed a coupl eof informative links:

I ended up installing dedicated 20 amp circuits and used Shunyata Hydra units as well as Shunyata cords. My hum issue is gone now, and I had it pretty bad!
Cheater plugs.
Or try disconnecting the ground between TT and Pre.
Or try grounding the pre to the Amp (unscrew a chasis screw from amp and attach wire from Pre to Amp).

Good luck!
Check your headshell connections to see if any have loosened, the same with all other connections from the RCA cabling and DIN connectors should they be present. A cheater plug on the tables power cord may also help. If you have TV cable connected to your system this may also be the culprit. If that is the case you can try calling the cable company (I doubt they'll do anything, as they didn't in my case) but Mondial makes an isolation device that is very effective called the Mondial Magic, selling for around $75 (at least that's what I paid for mine about 6 years ago). I hope this advise helps. Happy listening.