Replace Ayre Codex with Topping D90 DAC

My Ayre Codex takes USB from an ultraRendu and sends balanced analog to an Ayre A7e integrated that drives KEF LS50s.  The sound level has become nearly inaudible, and I suspect it's a problem with the Codex -- substituting a microRendu made no difference; the sound level with the Ayre C-5xeMP disc player is fine.  Should I send the Codex to Ayre for service or buy a Topping D90?  Anyone hear the two DACs?
Ag insider logo xs@2xdbphd
@dbphd, I agree with the above posts that the AYRE CODEX DAC is excellent sounding.

The CODEX operates in 2 modes.  One as a preamp and the other as a DAC.   Unfortunately, sometimes the setup for one operation or the other is not easy.  Please confirm your CODEX DAC is set fo DAC only operation.  When the round button is moved, you want the screen to say DAC and not preamp.   Please keep us posted.
@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.
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.