Looking for a good DAC under $500

There's not one.   
Don't play around
Get the most expensive 
One you can buy 
So in one year your
Not buying another one
Taking a hit on the $500
One. This hobby is a MF
  Buy a  used expensive 
One Eddie

I have owned both these DACs with impressive sound and within your budget, new or used: 1) Resonessence Concero HD/HP; 2) Meridian Director DAC
Worth an audition.

Maybe consider a MusicHall 25.3. I got one used and it's a good performer for the buck and is well within your budget. There are reviews out there saying it's most impressive with MP3's. Having said that I'm a Tidal HiFi subscriber.I'm about to try rolling Opamps which this unit is great for as no soldering is required. This can also be achieved within your budget. Put a search in Hifishark.com. Good luck.

I also have an original DacMagic.  I got it because it was an inexpensive solution with 2 digital inputs (plus USB) and balanced outputs.  Sounds fine to me.  If you don't need DSD and MQA, I can't see anything wrong wit it for the price.  That being said, I am looking to upgrade in the near future.

I have an essence hdacc and have been been very pleased with its versatility. Currently hooked up to an old Adcom 535 amp and KEF LS50's surprisingly good sound out of an older pc. Bought OPPO Sonica Dac and do not hear much difference between the two. Good value with HDMI.