I suggest considering Monarchy Audio. Might be over your $300 budget but giving Mr. Poon a call is definitely worth the time.
FWIW - I'm using a Monarchy Audio M-22A with the NAD 162/272 combo. I should disclose that the DAC I have has been upgraded to the same chip set which is used in the current NM-24. I bought it from Monarchy this way.
FWIW - I'm using a Monarchy Audio M-22A with the NAD 162/272 combo. I should disclose that the DAC I have has been upgraded to the same chip set which is used in the current NM-24. I bought it from Monarchy this way.