I got some help from dCS on this one:
"dCS started adding word clock I/O to consumer products in 1999. These features have been on our pro products from 1989.
- 1st Generation 1999 to 2007 – Classic products: Elgar Plus / Delius / Purcell / Verdi / Verona. These have a basic clocking interface where the clock frequency must match the (single wire) sample rate. So, the DAC accepts a 44.1kHz word clock for 44.1 data, or a 96kHz word clock for Dual AES 192kS/s data, for example. Single-wire interfaces are limited to 96 maximum.
- 2nd Generation 2007 to 2015 – Scarlatti / Paganini / Puccini / Debussy. These can multiply the clock frequency by 0.25 / 0.5 / 1 / 2 / 4 to match the sample rate. So, the DAC accepts a clock at 44.1, 88.2 or 176.4kHz for data at 44.1, 88.2, 176.4 or DSD. Similarly with 48, 96 and 192 clock and data rates. More flexible. (This multiplier feature was added to Elgar Plus also.) Computer audio causes a problem here, because the sample rate can change from one file to another. If the sample rate is not an exact multiple of the clock frequency, the DAC will lose lock with the Master Clock. There are ways around this, but they not ideal.
- 3rd Generation 2012 to present – Vivaldi / Rossini / Network Bridge. These have our advanced clocking system, featuring 2 word clock inputs that can each lock to word clock at 44.1, 48, 88.2, 96, 176.4 or 192kHz. Now you can drive the Upsampler and DAC with bothbase clock frequencies simultaneously. Yhey can choose the compatible clock automatically and it is “set & forget”.
We designed the Network Bridge with the intention of serving all 3 generations or products. You can connect both clock inputs to a Vivaldi or Rossini Master Clock and drive it with both 44.1 and 48kHz. The asynchronous USB interface regulates the delivery of data from the network to match the Clock frequency, or a multiple, changing clocks inputs as needed.
With a 3rd Generation DAC and Upsampler, lock them to both frequencies also. For the earlier DACs and Upsamplers, slave to the Bridge’s word clock output instead. The 96kHz limit here ensures even a 1stGeneration system can keep more of the benefit from locking the Bridge to the Master Clock.
So, in ToD’s system, you can play a 24/192 file with the Bridge locked to the Master Clock – it will select the 48kHz Clock output. The data output can be single-wire or Dual AES into the Paganini DAC. Connect the Bridge’s clock output (96kHz) to the DAC and set the Sync Source to WClk. The DAC locks and the system is happy.
If you play a 24/88.2 file, the Bridge will swap to the 44.1kHz clock input, change its clock output to 88.2kHz, the DAC will re-lock and play.
This setup will also work very nicely with our Classic Elgar Plus or Delius DACs, as intended. You can use the NB app to set the Bridge to match the lower data rate capabilities of these older designs.
Clocking can become fiendishly complicated, but the new system definitely cuts a lot of this out."