Hello Gabus,
I and another Agoner have had great results using a Dared SL-2000a tubed preamp with the 585 Adcoms.It has plenty of gain and matches nicely with the impedence.It is extremely quiet no hums or hiss. You also get a RF remote all for around $300.00 new.It has two inputs ..no phono. I have yet to see one put up for sale on the used market since they were released.I have a audiophile friend that has owned hundreds of pieces of Audiophile equipment from speakers,amps.. to preamps (he has albums of pictures to prove it).He is still amazed at how good this preamp is!That should tell you something about the product and the happy audiophiles that own them.
Good Luck!