Digital vs RCA Cables

Is there any advantage, disadvantage to using digital cables instead of RCA?

You mean connecting the players digitally to the digital mixer with SPDIF connections vs analog?

On short runs of cable, using the RCAs for the digital connections is even fine, if that was what you were asking.

As for digital vs analog, usually it’s better to connect using the digital connections. In the case of Denon, I think there are pluses and minuses, as I suspect (but I’m not sure) that there may be some sample rate and bitrate conversion happening prior to the SPDIF in the digital domain. If the work rates were 32bit/384hz, for instance, the SPDIF out on the players is limited to a max of 24/96. Pioneers, in contrast, just crunch the DSP math on their CDJs in the bit rate of the track. And the SPDIF CDJ output changes to match that. Since the Prime sample rate conversion right now is probably not great (you can see issues in RMAA results and with a tone sweep on a scope) and their work bit rates don’t seem to change to match the track bit rate, there seems to be some advantage to using the players with a good analog mixer since that would mean (if previously mentioned stuff is true) that there’s another rate conversion stage prior to the Prime players’ SPDIF outputs. At the very least, glass half full, a good analog mixer might simply not be as ruthlessly revealing. Now, if you’re using a digital mixer, the advantages of SPDIF might outweigh the disadvantages even with the Prime players’ not-great sample rate conversion. So with an X1800 mixer, for instance, you probably will still hear better sound with the digital connection.

With Pioneer CDJs going into a true fully-digital mixer (as opposed to, say, the Denon DN-X900 or Tascam X-9) that has SPDIF inputs, it’s always better sounding when using the SPDIFs than analog connections. With Pioneer digital DJMs, there’s also the added benefit of the digital connections bypassing the analog inputs that can be clipped. Rane, Denon, and Numark, however, have fixed gain/trim inputs on their digital mixers, so you don’t get such an added benefit on them regarding not clipping… you’re unlikely to ever clip their line inputs, anyway.

As a side note, Pioneer DJM SPDIF out sample rate converters (the ability to switch from 96 to 48) are really cheap, simple implimentations people should probably avoid using. People going into an outboard DSP that only supports 48khz digital input might be better off using the DJM analog output connections with how good a lot of ADC and DAC stages are now. If the house DSP can do 96khz, then definitely use the DJM’s digital output connection at that rate, as the Pioneer digital DJMs all run in that internally. In contrast, the Denon digital mixers can be changed to completely run in whatever bitrate you want to use: 44.1, 48, or 96 to match what you’re inputting into it or outputting. The old Denon SHARC-based sample rate conversion, however, was excellent.

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Thanks Reticuli, nice in depth explanation.

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Thanks for the very detailed response. I was talking about using actual digital coax cable to the spdif inputs of the 1800 mixer.

A dedicated digital coax cable would have more margin of operation in adverse conditions (interference, long distance). It certainly has no disadvantages.

But a quality audio cable (like the ones packed with the player) has no drawbacks under normal operation over short distances like player to mixer. I never got any kind of dropouts using audio cables up to 6m of length.

SPDIF is spec’ed for coax terminated with 75 ohm RCA.

Most cables marketed as SPDIF are not exactly 75 ohm.

Video RCA composite (yellow) and video RCA component (three colors) are also spec’ed the same. With yellow, red, white, they all tend to be close enough, too, except for those with a thicker yellow that probably is very close to 75 ohm on-the-money.

Most cheap audio RCAs are coax and not twisted pair audiophile stuff.

Unbalanced RCA line level is highly tolerant of interconnect impedance until you get to massive amounts (you can get that from long runs), when it starts to attenuate the high frequencies, among other things.

SPDIF is surprisingly tolerant of impedance on short runs.

So you do the math on the likelihood your cheap line-level audio RCA cables deviate that much from SPDIF specs to matter. Economies of scale for making RCA cables of all types means that most of them are close enough for going player to mixer.

Now, phono cables and capacitance… that’s another can of worms. Beware of people trying to rewire your Technics, for instance.

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I’m running digital to a Xone DB2, with great results, on some gold plated ‘digital’ Vention 1M cables.

I confirm that with digital cables above all the highs I feel them a little clearer, moreover a problem that I found in one of the two SC5000M decks seems to have disappeared which when starting with an active engine especially on vocal felt as if it slowed down.