Replace Ayre Codex with Topping D90 DAC

@dbphd ,
Are you sure you are using the DAC out and not the Pre out?
That would explain the low volume. 
Whoops, @hgeifman  beat me to it.
If not, then I would pursue an Ayre QB 9. Ayre just offered an upgrade to Twenty status for $1500, so if you found a used one (like I did), you can get a sweet DAC for a lot less than buying new.
The upgraded QB 9 is a significant improvement over the Codex.
Even Ayre says so (which is why I made the move), and they rarely blow their own horns.
Bob

I love Ayre but the D90 is an insanely good DAC. The AK4499 chip is the best Chip on the market and the D90 is, so far, the best implementation. It will, however, hide absolutely nothing from you. If the recording has flaws, you’ll hear ever one of them crystal clear. 

@furiouslyadrift is that an Audio Science Review verdict or just your own 2 cents? If that is your 2 cents fair enough, if it is courtesy of the ASR crew then it is a measurements verdict, nothing to do with the sound.

I set the Codex input to USB and output to DAC, but no audio.  I'll check cabling for the ultraRendu setup.  I may have screwed that up after I substituted the microRendu when trying to find the fault.

I’m in the “any distortion is just noise” camp. For DAC chips, I tend to favor AKM for their VelvetSound profile (no ESS distortion hump) and the AK4499 truly is an excellent implantation. It’s AKMs first current drive chip and it’s a huge step up. It’s also a pain to implement into a functional DAC. They really nailed it with this chip.