What would be an upgrade over the NAD M51 Direct Digital D/A Converter?


I am looking for some advice as to an upgrade over the NAD M51 DAC.  The objective would be to get my digital end to be more engaging so that there's less of a gap between it and my vinyl front end (Manley Chinook pre, Technics 1200 GAE).  

Would this necessarily require me to spend >$2k?  I'd be fine going used.  I have a Primaluna Dialogue HP integrated, so the replacement DAC doesn't need to have an independent volume control.  

128x128jbhiller
Of course every component may not mesh with you gear, but that is a tough dac to beat.....prepare to spend $$$

I use one for and number of sources and it sounds pretty good given its price....
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You know you're right. It may be tough to beat this DAC without dropping a fortune. I may just need to realize that my analog front end is just better and my digital is very listenable just not going to be as good. 
Try a stand alone preamplifier. after trying the Auralic Taurus pre i couldnt go back to using the M51 as a preamplifier
I upgraded from an M51 to a PS Audio DirectStream DAC when it first became available and haven't looked back.
The DirectStream DAC does not use a conventional DAC chipset, instead uses an FPGA, so once or twice a year PS Audio makes firmware updates, once installed, improves the performance of the DAC, something that is not typically possible with a DAC with a conventional DAC chipset.
No plans to replace the DAC, from someone who tries stuff out and does lots of upgrades.