First - while I get the point quoted above - I’m going to say “so what?” …does an unmatched impedance lead to inferior performance either audibly or measurably? …or do the other factors in play (eg “cable quality” …on which you can choose your own definition) offset the need for accurately matched impedance.
Second - if it truly is so critical - how can we know the impedance of a cable (I mean REALLY know) without measuring it? …there are lots of cables that are specced to 75 ohm - but then there are lots of exotic cables used for clock cables (I’m thinking the jazzy ChordMusic cables I referred to earlier) that possibly/probably aren’t “certified to 75ohm” and yet “sound better”
The stock cables that come in the clock box are marked as 75ohm - and given the engineering statements made, I expect dCS have carefully matched these. But I’m not hearing anyone saying these are end game performance, so there is (probably) more going on?
I had also asked someone knowledgeable in the field, and he said word clock signal’s power and frequencies are relatively low (he usually deals with frequencies in MHz or GHz ranges), and is transmitted over a very short distance. Cable variations are negligible.
But someone from PS Audio also said that a poorly matched impedance will distort the square wave of word clock signals. That the “square” may become a “trapezium”
Others have also said that an unmatched cable with an unmatched connector may provide a correct overall impedance, but the unmatched connector can give rise to reflections.
We ordinary audiophiles would unlikely be able to verify cable impedances. We need to trust cable companies.
I asked Phil because I like Kondo cables very much and would like to use their Theme 41 RCA interconnects as clock cables by using adapters. Kondo says their cables are NOT 75 Ohms. I actually did try—-clock locked successfully without audible distortions.
Currently I am using Siltech 880d clock cables, and quite satisfied with the results.
Strangely, a cable always carries the same sonic signature regardless whether it is used to transmit analogue or word clock signals.
I think that you may have an incorrect expectation. This is not a case of hearing analogue distortions like superimposed buzzing or breakup. We are looking at accurate timing signals .The circuit discriminating the exact timing point of the waveform requires a known waveform. ( e,g the rising edge of a squarewave). If the choice of incorrect cable (or accessory) distorts the waveform then the timing point may be interpreted incorrectly and therefore you will not be hearing things at their best which defeats the object of having the system clock in the first place.
Though I am not sure if it is just me that I sometimes find using the master clock, which makes the sound more “focused”, can make certain albums sound more stressful. Switching off the clock allows the sound to “relax” a bit and becomes more enjoyable.
I’ve had my own experience of this: back when I owned a Puccini I was foolish enough to buy an MIT digital cable for the clock connection. The cable came with a little box in the middle with a rotary control. This turned out to be what I have described elsewhere as a “variable boominess” control because main the effect was in the bass and clearly affected definition. (dCS later commented that such cables sometimes won’t work at all with their equipment.) Still foolish, I graduated to a Chord Sarum digital cable (which may not even have been 75 Ohm, I can’t recall). Finally, for my current system, I settled on a pair of 75 Ohm coax cables made from cable produced by one of the non-audiophile big companies (Belden). I’m happy enough not to feel the need for any comparisons although, if an opportunity arose to borrow a Transparent cable to try, I’d probably say yes just out of curiosity.
