Preamp suggestion for Quicksilver M120 amps

The amps hum with the rest of the gear off.
I did try lifting the ground with no success.

@argranttz

1) Are your preamplifier and amplifier plugged into the same plug/circuit? If not, try plugging both into the same circuit too.

2) Does it change removing and replacing all small tubes back to originals?

3) Disconnect the RCA cables between amp/preamp and see if it still occurs. A buddy had same issues with a different pair of amps. His new/vintage replacement tubes were bad, but not the entire issue. Turned out to be his preamp causing the hum, had to send it back. He confirmed this trying different preamps

4) Can you plug the amp(s) into a completely different location somewhere else (away from your neighborhood) to isolate if it’s some kind of local electrical induction from power lines that are too close to audio lines. Often referred to as “60-cycle hum.”

Preamp:
Update: heard back from a few friends with the QS Linestage preamp and a few members here pairing QS preamps with QS Mono amps.
ALL much prefer the sound after installing quality vintage or better boutique 12AT7s in the preamps. ALL required 80+ hrs burn-in on pre, caps, tubes to settle in. Better quality RCA interconnects helped show what the better Input-signal tubes can offer in the QS preamp.

Same results when applied to my other-brand 6SN7 based tube preamp to really bring out the potential of the QS Mono tube amps.