Best Sonos ZP-80 Mod?

Shazam - A USB out does not help things unless you are forced to go to a USB input DAC. Even these are not jitter intolerant. Most use ASRC to reduce but not eliminate jitter.

I2S output to the DAC is superior because it puts the low-jitter clock closer to the D/A chip itself. Usually I2S input DAC's do not have upsamplers in the path either, just the D/A chip. The Pace-Car that Wappinghigh talks about does this. It uses a buffer memory that isolates the input stream from the output stream. There is no other more straightforward way than this technique to get low jitter digital to the D/A chip.

Steve N.
Empirical Audio

The real problem with the ZP-80 is jitter on the digital outs. It is the worst of the WiFi servers I have modded. Replacing the power supply will not fix it. It needs a new clock and redesign of the S/PDIF output path. A reclocker after it will reduce jitter also, even better.

Steve N.
Empirical Audio

Steve - going from a Sonos box to a USB DAC is *exactly* what I want to do. If you were to use an asynchronous USB DAC (like a Wavelenght) that puts all the clock and stream management responsibilities on the DAC, then the Sonos box merely becomes a "digital file pass-through." In this scenario, I've eliminated all transport noise (because I'm not transforming the file in anyway) and laid the actual digital source file at the doorstep of the DAC. At this point, the limitations of the Sonos would no longer matter, correct?

Does this not seem optimal from a sonic and cost perspective or am I mis-understanding the fundamental nature of USB Audio?

No, no, I just said that the Cullen mod is or might be what I am looking for ($ wise). Performence wise - I am just like you - waiting for someone with real exp.

Sorry for misunderstanding

Hi Guys - I have two of the ZP-80 units from Cullen. I went through Underwood HiFi (Wally) and they are great! One unit was set to a 48k output (my Spectral DAC will only take a 48k) and another unit set to a 96k outputfor my Peachtree Decco. The Decco is a great piece gear itself.

These are the mods:
The upgrade consists of installing a new custom Cullen Circuits designed pc board that contains:
1) A high end sample rate converter made by TI
2) A low jitter clock with less than .5ps jitter
3) A low noise power supply for the clock
4) A new micro processor
5) Input & output digital buffers.
6) New upgraded RCA output jacks are added.

I have not tried the analog outputs but direct head to head w/an unmodified ZP-80 gives you a much bigger less compressed sounding soundstage. Bass is much better and fuller and there is more "air" around all the instruments/vocals. It's well worth the cash.