Which DAC as a preamp?

SPL Director, dcs Elgar Plus, dcs Delius, NAD M51

Cary 600.  Friggin awesome as a stand-alone with a 3 volt outputDoes it all and sounds fantastic.   Based on AKM 4497 Dac set. 28 lb beast. All sorts of digital ins and outs. Roon , Mqa, integrated SD card reader. It is sweet  and you will never tire of listening to it 

just never worked for me without a pre. that said the mytek manhattan has an analog pre and is a very good dac. 

@shadorne , @transience, I too expected my very mellow balanced tube preamp to tame the highly analytical M6S for a perfect match. On SOME recordings -- notably those originally analog mastered -- it works splendidly despite subsequent remastering. (Example: Keith Olson's 1975 "Fleetwood Mac" eponymous album remastered in 2017). But on more recent, digitally mastered material with substantial high-frequency content, the M6S's 768 upsampling screams like a banshee, cackling right past the tubes when coupled with RCA-terminal coax. Have not yet tried using USB or optical (M6S has no AES input), but if those don't tame it, I've got serious trouble. 

Any hints? Maybe I will start a new thread if a different coupling doesn't help. 

@hicksmore 

RCA coax is intended for digital signals. I suggest to try the M6S RCA analog output with simple analog RCA cables.