I know they have a pre of their own. They come up used,time to time.---My personal rec. would be the Placette Passive---in a proper set-up.Used; under 1k. I had this amp back in '86,and kept it for 7/8 years. I had the Audio Re. sp9 and then the Encore 201--- (something). While there are many pre's out there, the passive would be my choice.---One would have to have the pre close to the amp---and then a strong voltage out of the cd player--or dac.--The be amazed.