If/once you have an external clock connect it to both. Reason is to give the DAC the benefit of better timing too (but trust your ears as to whether it is in fact better as there’s many potential points of signal degradation with external clocks, cable quality - shielding and terminations, power quality, impedance matching etc etc), not because you want to ‘synchronise’ the internal oscillators of the two devices.
Cheers for the feedback. This one was recently acquired second hand so assume well burned in.
Not enough. It must be synchronised with GPS for the best effect. .LOL.
Same observations here. When I was trying out different external power supplies of the streamers USB output with a dedicated 5V in, which was further connected to the PhoenixUSB and then to the DAC, I observed some palpable changes to character of the sound mainly regarding its density, flow and liveliness. It was very controversial at first as per description the reclocker shall regenerate the signal from scratch with no respect of what happens upstream. But the reality appears to be different...
Someone with a lot more knowledge than me has pointed out that the internal clock in the UIP is 10 MHz and in the Phoenix it is 24 MHz clock.Here’s some impressions adding the LHYUIP (+OCK2) in front of the Phoenix:
Removing the OCK-2 and running off the UIP (INT) the sound smooths over a fair bit, a touch warmer, bass more generous and flowing with less absolute command and speed, less dynamic weight and scale. Soundstage less expansive, closer to Phoenix alone. Vocals smoother/fuller so more forgiving with less than perfect recordings - the one area I’m not sure about with the EXT clocked UIP as definitely a touch leaner than the super lush baseline of the Phoenix.
- cavernous soundstage depth with extended decay, amazing layering and instrument placement.. so much space between soundstage elements
- Very busy multilayered music sections are a little more coherent, easier to follow the threads/laterals
- Electronic music bass notes’ leading edges hit like a hammer, but still nicely textured, a little less of the Phoenix’s default generous bass quantity and warmth
- Remarkable resolution, speed and dynamic agility
- The extra precision means more delicacy and fine texture in vocals, if a touch less warmth and body, but still good relatively speaking
OK, after adding back the OCK-2 to confirm the above impressions then removing the UIP entirely and listening to the Phoenix alone impressions - vocals definitely sweeter and more palpable than even the UIP (INT), a lovely effortless flow if a less obviously layered soundstage or as much dynamic scale. Hmm confusing… darn, far from clear cut.
More listening required I guess..
That correct re their oscillator frequencies, I understand the LHY UIP and a similar SoTM USB regenerator use an internal clock sythesiser to convert the 10Mhz reference to the 24Mhz frequency needed for USB. Higher frequency isn’t automatically better but all things equal (incl assuming oscillator quality equal) it’s better to have an internal one operating at the native 24Mhz frequency and not require synthesis which introduces another variable, another potential source of jitter on top of the extra connections and cables needed for an external clock. Same logic holds for DACs and switches, if all things equal. Here of course it’s not equal, v likely the Phoenix has a higher precision oscillator AND it is operating at the native frequency. While the OCK-2 OCXO > UIP internal, even with all the potential sources of jitter of going external.
But as 
