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

Shazam - I understand what you are trying to do. There is just no solution out there for this. Also, there are no USB converter or DAC solutions that are completely jitter insensitive IME.

What you could do is use the S/PDIF or AES input on the USB DAC driven from a reclocker like the Pace-Car sourced from the Sonos. This will match or beat the quality that you get with straight USB. This would be driven by Superclock4 rather than an inexpensive oscillator.

Steve N.

http://forum.audiogon.com/cgi-bin/fr.pl?ddgtl&1204503359&openflup&9&4#9

http://www.audiocircle.com/circles/index.php?topic=42526.30

http://www.audiocircle.com/circles/index.php?topic=47245.new#new

"Is a basic difference between the Empirical and Cullen mods is that in the Empirical mod the reclocker is an external unit (pace-car), where in the Cullen mod the reclocker is a board which replaces a board inside the ZP-80?"

No, there is HUGE difference between the Cullen reclocker and my Pace-Car. The Cullen is an asynchronous sample-rate converter (ASRC) with a better oscillator than the stock Sonos. This is just like an upsampling DAC or a Monarchy DIP. It will improve the jitter by resampling the data, but nothing like the Pace-Car, which does not change the data.

The Pace-Car is a true reclocker with a FIFO memory that is clocked by a Superclock4. It offers superior isolation, jitter rejection and superior clock. It does not resample the data stream like the Cullen reclocker. The Pace-Car also has a separate power supply from the Sonos and many voltage regulators. It contains probably 30X the parts count as the Cullen board, even more parts than a typical DAC. This is a very complex circuit and designed to test equipment standards, using GHz coaxial cable and connectors. It can also drive I2S input DAC's directly, as well as standard DAC's using S/PDIF or AES/EBU. The jitter levels from the Pace-Car will be lower than ANY CD transport. The Pace-Car was recently compared in a shootout (I was not present) to 2 new Meridian $8K and $14K CD players and there was no contest. The participants told me that the Pace-Car was clearly better at a fraction of the price. I believe it was driven in this case by an Apple TV and an AirPort Express, but can be driven by virtually any PCM digital source.

Steve N.
Empirical Audio

Some feedbacks I have read:

http://forum.audiogon.com/cgi-bin/fr.pl?ddgtl&1204503359&openflup&9&4#9

http://www.audiocircle.com/circles/index.php?topic=42526.30

Steve N.
Empirical Audio