ARC LS25 mkII noise level

Yeah, it has been a challenge. This is my first foray into tube gear. Maybe I am used to dead quiet solid state amps.

I think the culprit here is the LS25 MKII. The VS60 with a solid state preamp is very quiet. So the LS25 might need repair but I'll try getting new tubes for it first. It has 2 6H30 tubes.

Perhaps my expectations are skewed as I am probably looking for the dead silence my solid state gear provided. However, these 2 amps sound really good to my ears.

The noise can't be heard over music. If the room is dead quiet, I do hear the hum and noise very slightly from 3 meters away. With a solid state preamp, the noise is gone.

Maybe a pointless question, but do you have tube dampers on the LS25? I have a LS26 and hear no noise. Maybe the tubes need replaced, take small steps to solve the issue.
Possibly vibration dampers under the componet. Mine is on AQ Feet. Contact ARC they are very helpful on the phone, the challenge is reaching someone on the phone as they are very busy. If you are buying new tubes look for the 6H30-DR, I have found them to sound better than the ARC OEM tube.

If you are listening intently from three feet away and worry about the noise. You are not having any problem. Tubes ALWAYS make a little noise.
Anyway if you can't stand the thought that your preamp has a very slight hiss that you have to get right up near the speakers with no music on. The agree tubes are not for you.
Tubes make noise. Good tubes make less noise. Bad tubes make a lot of noise, more than yours are doing.

Yes, there are tube dampers on the 2 6h30s. They are the UltraSonic Hal-o dampers. I will work with ARC to resolve this. It might just need some service.

@Elizabeth I wish it was 3 feet. 3 meters which is about 10 feet away from my listening seat.

It's more of a hum with some hiss and a slight buzzing. I've ordered new tubes. And I'll disconnect all the sources one by one to see if that helps. The spec sheet says 14uV IHF weighted so on paper, it should be nearly dead silent.

Also, try to float the AC ground on the LS25 temporarily. See if the hum/noise go away.

The guy you need to talk to at ARC is Chris Ossana. Helpful and technical Guru.

I have a pair of Classic 120's and Ref3 LE both with many upgraded parts in the critical signal path and power supplies. When the amps are on and the Ref3 is off, there is absolutely no noise or hum coming out of the speakers.
When the Ref3 is turned on and i select any source (except phono) with no signal and turned the volume to the max, there is only a very faith hiss that i hear when i put my ears to the speakers. Selecting the phono input while the phono stage is turned on with no signal, i can hear hiss or what they call "tube rush". However, that is to be expected from tube phono stage. Mine is a Ref2 Phono.
Tube amplification nowadays CAN BE quiet although no quite to the level of a good solid state design.
Good Luck.