Need Help Trouble shooting


I Have a hum coming from my right speaker
I tried swapping speaker leads and the hum moves to the other speaker
i'm thinking it's a tube and i'ts my amp that is the issue
If it is a tube not sure if it's the output or input tubes I should be looking at
The pre when in operate mode without Amps on the hum is gone

Help me trouble shoot further
musicfile
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Any tube recommendations for the Exemplar that works well
I belive I have standard 5965 tubes in mine.
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Further update I swapped out cdp and put in the tuner and the hum is gone !!!!
The source is definitely the issue.. would tubes in the CD Player be the only culprit or should I get the cdp in for a check up as well

You guys have made my day

Cheers