DAC purchase:new or used?


Hello. Getting in the digital realm.My budget is 1000 dollars for a DAC. Should I buy new or used? Looking more towards simpler DAC with less bells and whistles, but better components! if that makes sense. My system is very modest.
DAC will be used with Mac Book pro or Sony CDP-707 ESD , Yamaha AS-801 , Focal 836 W. 
Also, could someone explain the "burn in " time factor?
Thanks for taking the time.

rockanroller
Get a Meridian Explorer 2 and a trial subscription to Roon and Tidal. All for well under $1000. Enjoy Tidal huge catalog of high resolution files and even decode their fancy MQA.

Burn-in? Huh? What Burn-in? Forget about that issue.
Your budget is right in the sweet spot for my great DACs, new or used. If your source is limited to playing only Redbook CDs, the general opinion, with some exceptions, is to use an R2R (resistor ladder) design DAC. Schiit multibit type DACs seem to be a very popular option but there are many others out there. Denafrip Ares is another choice and should be within your budget. I'm using a DACmagic Plus with an external aftermarket power supply to improve the SQ of my old CDP and the total cost was around $500. By the way, your system is more than modest and is quite good. A good Good luck.

Gustard X20 Pro with USB - $869

Audio-GD NFB-1.38 (ES9038 Pro, Amanero & TCXO built in.).  Around $800-850 shipped to USA.

Audio-GD R2R 2 (if you want resistor ladder DAC) - Around $800-850 shipped to USA.

If the DAC is bought new, then you may have to run the DAC for about 100hours to burn in components (such as wire, capacitors, etc.).  This is a controversial subject (see shadorne's comment), but I have experienced burn-in many time.  The sound can change over the initial 100 hours until it settles.  The changes could be bad sounding at times (could be bright/harsh/messy).  It's up to you to decide on whether this is a real thing or not.