I'm the OP and have been in constant contact with Pat for the past 1+ year. We just exchanged 8 emails today. So I can pretty much answer all the questions raised in here.
- There have been different revisions of the original Legato. The jitter on the latest Legato is about 10 times lower than that of the very first revision, but Pat never mention this on the website. The original specs call for <5ps RMS jitter measured from 1Hz - 1KHz. The very last revision of Legato I has <0.6ps. This is less than 600 Femto Seconds. I happened to have the last two units of the Legato production run. So yes, you can say the Legato and Legato II have Femto Second clocks. Pat likes to look at phase noise measurement at 1Hz. In my particular Legato II unit, the phase noise is measured at about -90dBc @ 1Hz.
- MSB's Femto Galaxy clock is pretty much measured the same way (from 1Hz up) and it does 0.077ps or 77 Femto Seconds. In phase noise terms, it measures at -99dBc @ 1Hz. But MSB is using a clock with higher carrier freq (I believe that is 24.576MHz). Legato I/II is using a 11.2896MHz clock. In order to equate the phase noise measurements of the two clocks, one needs to subtract 6db from the MSB clock. That puts it at -93dBC @ 1Hz. So you can see, the Legato II clock is not far away from the MSB FemtoGalaxy clock!
- Whether one hears the improvement of the Legato II highly depends on the downstream gear. One of Pat's references was the Berkeley Alpha DAC series 2. The BADA dealer near him was amazed by how much the Legato II improves compared to the Legato. Legato II is actually a very high-end USB SPDIF transport in disguise. This is why when you feed the output to a high-end DAC, you'll hear more improvements. If you do not hear much of any improvements, that means you have some bottlenecks downstream. I run a bi-amp setup with active crossovers and room correction DSP engines. I can discern the improvements brought forth by the Legato II vs the Legato I.
- Use the coax cable Pat supplied for the Legato II. The length is 8' and its length has been calculated to avoid reflections on impedance mismatch, which happens in most people's gear as they have RCA SPDIF input instead of BNC. That particular coax cable Pat used is a made by Belden.
- Legato I/II have a very large return loss to combat signal reflections in case you choose not to use Pat's cable. The return loss is so large that the reflection is less than a few percent.
- So far I found that the Legato II blows away high-res transports even when the high-res files are downsampled in realtime and played as 44.1 (I use Squeezebox Touch to drive my Legato II).
- As for DIRECT or XFMR outputs, try both and see which one sounds better to you. The DIRECT output should sound better in most cases. But in my case, the XFMR output is better. It sounds more relaxed and more emotional. My downstream gear has pulse transformer on the input too. So it is hard to say which output is better. You just have to try both.
Edited by Viper2001 - 1/22/13 at 6:40am
