My transport doesn't like my DAC. Help!

I'm using my old Nakamichi CD Player 2 as a transport in conjunction with a Bel Canto DAC-1. I'm getting popping noises (along with the music) that seem to be generated from imperfections on the disc. A new disc plays fine, most of my collection has a few isolated pops, and my less pristine CD's are unlistenable. I never had this problem when using the Nak by itself. I've also used this player as a transport with other DAC's and didn't have this problem. The Nak just doesn't seem to like the Bel Canto. I've tried my usual disc cleaning tricks with no success. Should I try cleaning the laser in the CD-2, or am I going to have to buy a better transport? (Now I'm wondering if THIS is why Bel Canto recommends using DVD player with a Toslink connection). Any suggestions would be appreciated.