I'm told that replacing/upgrading the op amps in a good CD player, a Denon 1500 II, for example, helps the sound even more than replacing old caps. But my only use for a CD player is as a transport, used with a truly outstanding DAC that this Forum has heard about from me before. So my question: are the op amps in the CD player's circuit as part of its DAC function? If so, it would seem that replacing them would not help the sound, given the intention to use an external DAC. Does that make sense? And where in the circuit do the op amps serve? I bet someone in this Forum knows, and can advise me on this. As usual, thanks in advance.