Will a new Dac improve the sound?

@garypick 

I just came out the other end of what you're asking. I used players as transports, the best was the Pioneer PD65, but it was quite old and the only output was toslink, a low resolution data transfer medium. When it died I replaced it with a Marantz HD CD-1 to use as a transport, but, have as a back up player. It too died. Ultimately a CD players transport will not live up to even a relatively inexpensive Audiolab CDT 6000, which I bought and am shocked at how good it is even though the MSRP is "ONLY" $600 (Audio Advisor). There's a GREAT written review on line where he used very inexpensive dacs and worked his way up to ~ $2500 dacs. Each upgrade was readily heard, SO, you could get it, and start with a dac you can afford and work your way up

HTH

In decades past I used transports with outboard DACs. Being retired for 5+ years living on SS, I streamlined my front end , making due using my Oppo 105 (with aftermarket power supply). The following worked out for me because I have an Audio Alchemy DDP-1 + PS 5, a dac/pre. So, then I used an old Pioneer PD65 with level 3 Musical Concept mod as a transport (but it only had toslink out) for redbook, and used that until it died. I replaced it with a Marantz HD CD-1 player, used as a transport but with coax out, but like the PD65, the laser mechanism died, parts are no longer available, BUT, I could buy a laser assembly for $150 + shipping from Asia. However, I came across a fantastic review of the Audiolab CDT 6000, and found a slightly used one on AG at a price I could afford. The level of improved musical enjoyment jumped quantum levels, still surprising me months after the purchase. From my experience, unless you have an exotic ($$$$$) player, it likely has an average laser mechanism and circuit

hth