Mark Levinson 390S Question

I have the 390S processor, and I was wondering what is the best way to make it stay on 44.1K instead of 48k. 
It works ok with an older Accuphase transport, but when I switch to blu ray or Apple TV, it goes to 48k. To my aging ears, it sounds better with 44.1k.

Also, has anyone compared it's built-in preamp with other Levinson preamps, such as 38s and 380S? Shall I buy those if it will improve its SQ, or in your opinion, it sounds better on its own going directly to a power amplifier?

I did have the Ayre preamp, K5XE MP for a couple of days to try in my system, I wasn't impressed with it, so it was returned.

I appreciate you all for your time to read my post and responding to it.

Going direct into an amp is the best way. Your 390S has enough voltage output to suffice. No need to add another active stage! Regarding the 44.1/48K issue, the processor will automatically lock onto whatever the incoming digital signal's native frequency is. No way to change it!
Post removed 
Many Thanks for your reply roberjerman. Much appreciated.