Upgrade from Ayre QB9 DAC

Am thinking about upgrading my Ayre QB9? Would like something with MQA. Have considered the Aurender a10, Mytek Brooklyn and Bryston. Any suggestions? Trying to keep < $4,500. Thanks. 
The Ayre Codex DAC is in current production while the Ayre QB-9 DSD DAC is not. 

The sound quality of my Codex DAC is excellent and I suggest you give it listen.  I have used my Codex DAC as a DAC and its sound quality was excellent.  In addition, I also have used the Codex DAC as a pre-amp with great results.   I am currently using my Ayre Codex DAC in my 2 channel home theatre system with the Ayre AX-7e integrated amplifier.  

Several years ago I had the Ayre QB-9 DSD DAC and believe the Ayre Codex DAC sounds better but, of course, everyone has a different opinion on this.  I suggest you audition the Ayre Codex DAC.