I need an Audio Detective

@erik_squires 

Erik has it right, disregard my first post.

I don’t keep the DAC on but you will have to admit this is a head scratcher

Um, no it isn't!!

Anything with a computer or DAC generates some RF.  Your particular situation is just more noisy than others.   I'm not sure why this is a puzzle, really. What's probably happening is that the RF from the DAC is broadly across the channels you are trying to tune, and it's lowering the quality of the signal lock.

Follow up all 4 of my tuners are behaving in the same way and the other two are on the left side of preamp nowhere near the DAC and it’s interconnects or power cable. The interconnects only get close where they connect to preamp. Thanks for all your thoughts. Like I said not really a problem I don,t leave DAC on but the curiosity factor was quite interesting 

erik_squires

Sounds like RF interference. 

I want to point out though that this isn't much of a problem unless you like to keep your gear warmed up.  Distance, shielded interconnects and shielded power cables are the usual solutions.

Awhile back I read a lot of claims that equipment sounds best when left permanently powered on. 

Could it be the opposite is true and powering off after each listening session and then powering on 30 minutes before the next is the best option?
 

 If I may ask,

Denafrips recommends you leave your DAC on all the time. Why do you turn it off?