My issue with the 07x was documented here on A’gon a few years ago. I will repeat.
When I first got the 07x I found it a lot noisier than the Benchmark LA4 which I had. The 07x was supposed to an upgrade from that. I used the 07x with the CODA #8. Both were upgrades from the CSiB.
I spoke with Doug about the noise issue, and he initially thought it was my DAC. A Benchmark DAC3B and/or the AufioMagic Tubadour (do no remember). After about a month my dealer asked me to bring it to the Los Angeles store. We put my 07x on top of this 07x and compared. Mine was noisier. We sent my 07x to Doug to diagnose and fix.
Now the dealers 07x was noisier than the Benchmark LA4 I owned. After a few weeks Doug got back to me and said he could not find the issue but could hear the noise. He said he replaced every part except the casework, great service in my opinion. When I got it back the 07x was much quieter but still not silent and I could hear it. I lost $2k selling it but all I could hear from that point forward was the hiss.
Drove me batty, maybe to match the ears.

