Newbie Question: RCA cable vs. coax connection for DAC

70'sMusic

Well-Known Member
Hi Everyone,

Have a "newbie" question for the collective group's wisdom. I want to connect my CD player to my DAC and I can go "optical" or "coax." Can I use a RCA cable for the "coax" connection?

Thank you in advance for your help, I really appreciate it!
 
If you choose to use an RCA cable for your Coax connection, you need to use one that is labeled for Coaxial Digital use. It should have a 75 Ohm rating if it is designed for Digital hookups.

Thank you. Do you recommend using an optical cable instead?
 
You should be able to switch back and forth from rca to optical on your dac to see which one sounds better. To my ears the rca was slightly better sounding than the optical. I used a decent quality rca for my initial hookup and later "upgraded" to a 75ohm digital rca. I noticed zero difference in that cable swap.
 
Last edited:
Audioraven said:
That cable would not be ideal, as it is not designed for use as a digital signal carrier.

If you're *that* worried about impedance than you should be using BNC for your interconnects because RCA is not exactly 100% accurate in the impedance department.

I've also never heard a difference between a proper impedance cable and rigging something up using twisted pair. Maybe over an extremely long run; but most people don't have runs that long.
 
For your average 6' interconnect the difference between cable impedances is unlikely to cause an issue.

I prefer the coax over the optical when given a choice, except in cases when the source is electrically noisy. Optical was a godsend when using my old laptop as a source as otherwise it injected a ton of noise into the system unless I used a cheater plug.

Optical tends to have higher jitter than coax on most sources. Whether you can hear that is debatable.
 
(...) Do you recommend using an optical cable instead?

Main advantage of optical over electrical (alias coaxial) SPDIF is full galvanic isolation by principle. So optical SPDIF is always a good choice, if one would like to avoid possible hum issues. This can for example be interesting, if one would like to integrate a computer into one's audio or AV system, in which that computer would be the only safety class I device...

Greetings from Munich!

Manfred / lini
 
Main advantage of optical over electrical (alias coaxial) SPDIF is full galvanic isolation by principle. So optical SPDIF is always a good choice, if one would like to avoid possible hum issues. This can for example be interesting, if one would like to integrate a computer into one's audio or AV system, in which that computer would be the only safety class I device...

Greetings from Munich!

Manfred / lini

Yes, my experience is that for certain computers as sources, optical is a great way to eliminate noise. :)
 
EN: Yup, most regular desktop computers are safety class 1 devices, that require a connection to safety ground. So if one integrates such a computer into one's audio or AV system, which happens to consist of safety class II devices and to be connected to an antenna or cable radio/TV wall socket, chances are pretty high, that this will introduce hum due to different ground potentials, so that one will need to provide galvanic isolation, most usually either with an audio transformer/ground loop isolator between the computer and the audio/AV system or with an antenna ground loop isolator between the wall socket and the system. Both of these approaches may be not entirely non-lossy, though - in which case optical SPDIF can be a welcome alternative - especially if the receiving device isn't an older design, which might still derive its clock from the SPDIF input and thus react less benign to the not rarely somewhat increased jitter (compared to electrical SPDIF) than a modern design, that relies on its own master clock...

And of course the same would apply, if a CD transport (or CD player, that's merely used as a transport) would happen to be the only safety class I device in a system that otherwise only consists of safety class II devices.

Greetings from Munich!

Manfred / lini
 
Just ordered a digital optical cable

To toss my experiences onto the group bonfire: I think all your options are acceptable, but probably you're doing the best thing. Optical cable is reliably good at carrying the 44.1khz data rate that comes from a standard CD player, whereas the advantages of wired coax can come more into play at hi bit-rates like 192khz. And as others have mentioned, there are situations where the optical connection prevents ground-loop / hum / noise issues.
 
To toss my experiences onto the group bonfire: I think all your options are acceptable, but probably you're doing the best thing. Optical cable is reliably good at carrying the 44.1khz data rate that comes from a standard CD player, whereas the advantages of wired coax can come more into play at hi bit-rates like 192khz. And as others have mentioned, there are situations where the optical connection prevents ground-loop / hum / noise issues.

Thank you Duncan, I appreciate it!
 
Do any DACs reclock the optical signal internally before converting to analog? Can spdif run asynchronous?
 
Back
Top Bottom