What is the impact of using analog interconnects RCA (instead of the 75 ohm s/pdif ) for moving digital data around?
The S/PDIF format is for handling high speed Digital signals.
Coax is not a balalnced wie configuration. Suggest making a
twisted pair yourself of clear twin-lead for a in-house test.
Also see WWW.Epanorama.net
select article on S/PDIF you will get some more information.
The S/PDIF (Sony/Philips Digital Interface Format) spec calls for an unbalanced connection on coaxial connection. The professional version, AES/EBU (Audio Engineering Society/European Broadcast Union) is the same format, but carried on a balanced line (one other difference: S/PDIF is +0.5V, AES/EBu is +5V).
Although analog and digital interconnects have different design criteria, some interconnects designed for analog work well for carrying digital data.
Something intersting on this subject:
I recently purchased a Monarchy DIP (re-clocker) to go in between my computer and my DAC. The only digital output on the Monarchy that I could use was RCA coax. I did not have an RCA coax at the time I ordered the DIP so I ordered one from Empirical. The DIP arrived 2 days before the coax cable. In the interim, I used an analog RCA cable (an old Transparent Link 100). I was surprised that it worked at all.
The system sounded fine with the analog cable. When the coax digital arrived and I substituted it for the analog, I could hear no difference. The sound was already hugely improved by the DIP so any minor improvements from the digital cable I am probably not hearing.
Note: The analog Transparent cable cost me $120/m back in 2000 and the Empirical coax cost $50/m.
Even though you can use Coax, a balanced line / inter-connect we feel is better.
By using 2- two-conductor cables like Dayton or Standard wire [2009 Parts Express p.96]
24 -26 Awg; glued together to make a four wire bundle then connect opposite
corners together [ an X pattern] you get a very fast inter-connect.
This configuration is very flat to many MHz and with low phase shift.
This configuration also has good noise rejection and
is a balanced cable system.
I am trying to imagine how to put together a cable as per your desciption. [I am looking at p 96 in the PX catalog] If I glue together two 2-conuctor cables, I end up with 4 conductors. Then I connect opposite corners [ how? twisitng, soldering?] and end up with 2 braided conductors. How would I connect 2 conductors to an RCA connector? I thought RCAs take only a single lead. Or would I use a 3 pin XLR connector and just connect 2 pins; and then use an XLR/RCA adaptor?
Also, are you saying a cable thus constructed would conduct analog or digital signals?
Remember too that SPDIF requires a 75 ohm connection.
A connection with a different impedance will cause reflections within the cable, raising jitter.
You can use just about any cable and get audio at the other end. It is the quality of the result that is affected.
I have had very good results using old analog cables. I just get them from my "cable stash". You know the one we likely all have if you have gone through several generations of audio and video gear.
I don't just have a "cable stash" I have a "cable closet." It's like a museum of cable.
My cable "stash" is less like a museum and more like a mausoleum...
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