SONOS drives dCS stack - Say it ain't so
I love my SONOS system. I have 6 zones. Bathrooms, garage, kitchen and… my high-end, dCS-driven stereo? Blasphemy! How can this be?
The SONOS system has a wonderful user interface, works with cell phones, iPads, etc. Connects to NAS drives. Internet radio is seamless… but the DAC in the Connect is horrible and its clock is even worse. So how does one mate this wonderful user interface with a dCS Verona master clock and Purcell/Elgar DAC system?
The first step is to modify the SONOS Connect (‘SC’) to remove both its internal CPU clock and its warranty. Don’t worry – the clock will be replaced. The warranty? Not so much so… but anyway… I had this done to my SC to use with an Emperical Audio Pace Car 2 (now discontinued). The mod was done by Cullen circuits, now diseased, but the mod is still available through Wyerd4Sound. Basically, a coax cable is soldered to where the clock chip was on the main board and brought to a SMC terminal on the rear of the SC. If you do this, be sure to specify the SC mod should be done with 75 Ohm coax.
The next step is to get a clock to drive the SONOS that is phase-locked to the dCS Verona master clock. The problem is that the Verona outputs a 44.1kHz and the SONOS CPU needs a ~11.3MHz to drive the CPU…. Aka a ‘super clock’.
Enter the magic box – the Mutec MC-3 + Super Clock (‘MC+’). This device can take the 44.1kHz Verona clock and multiply it by 256 to get an 11.3MHz clock for the SC. It works with a phase-locked loop (PLL) so the output of the SC becomes phase-locked with the dCS stack. As an added bonus, the MC+ has an extremely good clock with less than 1ps of jitter, vastly improving the clocking of the SC’s digital outputs. Connect the MC+ output to the SONOS and go!
Or not. It turns out that the stock MC+’s output amplitude at 11.3MHz was too low drive the SC CPU. But it turns out the folks at Mutec and their US rep. Bob Reardon at SonicUS(.net) are great folks. Working with Chris Peters (CEO of Mutec) we found a simple resistor swap in the Mutec to boost its output. Chris is thinking that this mod might be done with jumpers in future MC+s, but in any case the mod is easy if you do electronics – I did it at home. If you don’t even know what solder is, I think Bob and Chris can probably make the mod happen for you…
And it works!!! My SC digital outputs are now phase-locked to the dCS Verona and working happily with my Purcell & Elgar. The other nice thing here is that the Purcell effectively re-clocks the SC’s output so what is going to the Elgar is top-notch clock wise. The sound is spectacular. This is my system. I have no intent whatsoever to go to a different digital server.
Thought folks might be amused/interested. I wouldn’t hesitate to recommend this setup. Of course it can be adapted to other world clock systems. I’m happy to answer questions.