Few months back I posted a thread asking for advice on upgrading my cheapo setup. I've since upgraded both my speakers and turntable to a pair of Wharfedale Diamond 225s and an AR-XB. I'm now looking to finalize my setup by replacing my receiver (Yamaha RX-497) and get a DAC. So far I've been mainly considering either a used NAD C316BEE or Yamaha A-S500 paired with an external DAC, or a new Yamaha A-S501 with internal DAC on a budget of $400. I already own a preamp (TCC-TC 750) so that's not required. How is the internal DAC on the A-S501 and is it equal or better to some of the external DACs on the market in the $100-150 range? Also wondering what other new/used modern amplifiers in this range I should be considering.