For Vivaldi Clock and the connections to the DAC and Upsampler:
Should both pairs be the same brand and model (quality) level?
If one has differing brands, or the same brand but different model/quality levels, where should the “better” pair of clock cables go? To the DAC or to the Upsampler?
Should both pairs be the same length ie 1m or 1.5m - or does it not make a difference?
If the two sets of clock cables are of differing lengths, ie 1m and 1.5m, where should the shorter or longer length be deployed. This assumes one believes there is a difference between 1m and 1.5m lengths (not saying I do or don’t)
Of course the clock cables referred to above will be high quality and fully 75 ohm compliant - as I believe clock cables make a difference.
Assuming that the better cables sound preferable to the less good ones you have a choice of upsampling an inferior input or downgrading the result of the optimum upsample. There is , of course, no obvious correct answer so my advice is to ensure that all are of comparable quality.
In theory and as a rule of thumb, digital cables under 1.5m could be subject to failing to adequately attenuate reflected signals due to impedance mismatches at the connectors. However , theory does not guarantee that the event actually occurs nor, more importantly, that it is audible. I would however err on the side of caution and buy 1.5m lengths.
I had an interesting conversation with the Siltech distributor, and another with a forum member.
Siltech has sophisticated measuring devices in the factory and went through the exercise of measuring a 1m, 1.5m, and 2m cable. The equipment showed the best to be 1.5m. On the flip side, as you mentioned, they questioned whether it is audible or not.
The forum member stated, if I understood correctly, the most important factor is for the cable to measure a proper 75 ohms. This attribute trumps (sorry ) length
Deviating from my original question (clock cables) I assume the theoretical “ideal” 1.5m is also applicable to the AES/EBU cable as well? Obviously 110 ohms being the required impedance.
Assuming for a moment you are using different cables (be it brand, model, length etc.), your preferred clock cables should be connected to the DAC - that’s the connection that is most directly correlated to the resultant sound quality. From a purely technical perspective, the jitter on the DAC’s internal clocks being output to the Ring DAC is the mission critical bit, so reducing the DAC’s jitter is more important than anything else here. If you find you have a preference for the sonics of one type of cable, use that into the DAC instead of the Upsampler.
There isn’t any need to match the lengths of cables used across the Upsampler and DAC. As long as each of the cables in isolation doesn’t cause any issues (such as any of the cables being out of spec), there’s no inherent need to have the cables matched.
Thank you for the reply. Definitive and to the point.
Do you care to weigh in on this question -
does length matter (1m vs 1.5m) for either clock or AES/EBU cables?
My sleuthing had me run across the topic of reflections however it seems meeting impedance standards is more important than length, and reflections would more readily occur with a cable out of spec rather than with one too short.
When I purchased my prized Rossini (in the middle of the pandemic) I decided to go all out for Transparent analogue cabling of reference standard (having upgraded from plus through super). Having tested used older model Reference cables against new I really could’nt hear a difference. So I obtained through both UK dealers and eBay used Reference interconnect and speaker cabling. But what about my new Rossini clock to Rossini DAC? Of course (for me) it had to be Transparent. So I purchased (through a dealer) a second hand (3m) Transparent 75-Ohm BNC to RCA digital cable. I cut two 1m lengths and reterminated with Furutech BNC connectors, using Furutech branded silver solder. That’s my Rossini sorted, sounds great but is it truly 75Ohms still? I did cut the rest of the cable in half making two 500mm cables with Cinch BNC connectors (silver soldered) both of which were succesfully sold. I really do need my cables tested but am reluctant to spend money on test equipment to be assured they are still 75 Ohm impedence. Anyway my transparent (modified) digital clock cables look great anyway. Also they are directional (Transparent cabling is directional as arrows are in place visable beneath the cables mesh covering). Can I hear a difference wrt to the direction I have connected them? - no way, but good branding and marketing I’m sure.
Gregg, the cable length is not so much concerned with creating reflections but that it is long enough to attenuate the reflection has it passes along the length. The rule of thumb that has been calculated is a minimum of 1.5m. However any degree to which this has significance in a practical system is difficult to to predict.