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?
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The Codex, as you know, is a really nice DAC.  Moved up to the QX5/20 to better it’s performance. I’m sure you have reviewed the manual but again you may want to ensure it has not been set into the volume controlled mode as opposed to straight through “DAC” mode. And if you have used any headphones try plugging them in and unplugging again.  The if the Codex erroneously senses the headphones to be still plugged in it reduces output significantly. Rick
If @drrsutliff advice doesn’t work, you should call Ayre next. It does seem like something you can reset rather than something broken.
Ayre is super easy to get hold of.  Very responsive bunch.  I think you should buy the Topping and do a shootout!  Where is the Topping made?
Thanks for the advice.  I've printed out the setup instructions and plan to sit in front of the Codex with them.  My other Roon endpoint is a QX-5/20 that takes Ethernet in and outputs balanced analog to the KX-5/20 preamp.
@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.
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. 
Hopefully you can figure out what's going on with your codex but if you need a new DAC the D90 is an incredible bargain.  I know it seems to rankle some feathers that something that costs $700 can deliver but if you want transparency in a DAC it's hard to better the D90. That's my 2 cents and yes I've heard it and looked at the measurements. 
Ayre Codex is way better than a Topping. Whoever tells you Topping is great, either (1) never tried anything other than a Topping, or a similar chi-fi DAC, or (2) believes all DACs sound the same, bits are bits, etc.
You might want to consider Schitt's Bifrost 2 Multibit. Same price as the D90 but fully user upgradable, both in firmware and software. DAC obsolescence is almost guaranteed given the pace of development in DACs. It is generally acknowledged that the D90 measures exceptionally well but the BF2 has a better sound. Let your ears (and only your ears) be the judge of course but for me, upgradability is important in DACs.

Ayre offers upgrades, too.
But, I agree that Schiit DAC's are very good. Though you would need to get a Gungnir or Yggy to compete with the Codex.

@dbphd, Let us start over, again. My assumption is the problem is NOT the Codex DAC (gut feeling). Any chance of borrowing another DAC from a friend and see what happens? This test will confirm the Codex DAC works or does not work.

Let us also assume, for minute, the issue is the Mini or Roon. What do you mean by inaudible audio? Does that mean NO sound or just a little sound? I had a similar issue when streaming from my iPad to my Aurender and had to turn the iPad volume control way up. Does your Mini, Roon, or anything else have a volume control that needs to increased? Please double check again, all setting on these devices to ensure their volume control is set high. I am not a Roon user but does Roon have a volume control setting that need increasing? Any comments from ROON Users?

Of course, if none of the above works, please call Aye on Monday.

I previously owned the Ayre CODEX DAC and thought it sounded terrific. The other DAC’s mentioned above are okay but I feel the Ayre CODEX DAC is a step above. In any case, please contact Ayre Customer Service for repairs, if needed. Thanks. Howard

Yep, my QB-9 started as the second iteration, ie, 192 Hz version. Then I had it upgraded to DSD version (which was much more about improved sonics than ability to play DSD files). And now it’s been upgraded to the Twenty version. The chassis and feet might be the only original parts left, IIRC the power supply was replaced for the DSD version. According to Chris Connaker, the Twenty version “held its own” against $20K+ DACs from dCS, EMM Labs, and Berkeley. If that’s obsolescence then put me down in favor!
Roon does have a volume level but I always leave it at 100 and use my AX-5 to set the volume. Worth it for @dbphd to check!
That happened to me with Roon once.  The volume is on the bottom right if you use the iPhone app.