Coaxial Digital-Can RCA Interconnect be used?

[Andy D]

:steve

Hi all,

I'm looking to hook up a Sonos ZP90 to Arcam rDAC via Digital Coaxial, which is a cable I don't have unfortunately.

I was wondering if I could use 1 of my Cambridge Audio Studio Reference RCA Cables for this duty, and whether there would be any downsides to using this connection.

I've looked at the QED SR75 Coaxial Digital if I must buy one, but I'm trying to keep the budget relatively reasonable & would appreciate any feedback....

Thanks in anticipation...

Andy D

 

[Anonymous]

You can use an RCA 'analogue' inter connect cable in that it will work although a digital coax cable has a 75 ohm impedance which is the optimum rating for this type of signal transmission.

I think an analogue cable has a different rating hence digital ones are categorised as such.

I've certainly used an analogue one before I bought a specific digital coax cable and it seem to work well enough but I'm not sure of the downsides as to sound quality.

 

[CustomCable]

You should definately be able to use an RCA lead so long as it conforms near to 75ohm impedance, ideally a coaxial cable would be best in order to get a correct impedance on the cable.

 

[aliEnRIK]

You should definately be able to use an RCA lead so long as it conforms near to 75ohm impedance, ideally a coaxial cable would be best in order to get a correct impedance on the cable.

Id be willing to bet the majority of these '75ohm' cables dont actually measure as such

 

[CnoEvil]

Id be willing to bet the majority of these '75ohm' cables dont actually measure as such

I agree.

A lot of leads do not maintain 75 Ohms, as they often use connectors that compress the cable, and alter its impedance characteristics.

 

[CustomCable]

Completely agree, many are +/-1.5ohms if not more. Trouble is you get a cable with near 75ohm impedance and then connect it with an RCA plug instead of a BNC and you are back at 50ohm.

 

[fayeanddavid]

Completely agree, many are +/-1.5ohms if not more. Trouble is you get a cable with near 75ohm impedance and then connect it with an RCA plug instead of a BNC and you are back at 50ohm.

Must be my day for being dense....................

Are you saying that you can have a piece of cable that has an impedance of 75 ohms and by fitting an RCA plug at either end you have reduced the impedance possibly to 50 ohms

How..............the cable impedance hasn't changed has it??

 

[RobGardner]

In my opinion it's definitely worth getting a digtal cable. However, while I can say from experience there is a clear difference in the sound quality between a 50p and a £1600 digital cable, it's no where near as much as you might like it to be. I am convinced a properly constructed 75ohm cable will sound better than the most expensive analogue cable when utilised in a digital connection. I spent a very entertaining afternoon with 5 different digital cables and a couple of analogue cables connecting my Cyrus cd transport and DAC. All of the digital cables sounded better than the Chord Indigo analogue and Chord Sarum analogue cable placed between the cd transport and DAC (even the 50p one!).

The thing is use what you've got for now. Check out ebay and the bargain bins at various on-line shops or your local dealer and see if you can pick up a bargain. I've said before on this forum, the best value digital cable I have used was a Van den Hul videolink cable I got on ebay.

 

[aliEnRIK]

In my opinion it's definitely worth getting a digtal cable. However, while I can say from experience there is a clear difference in the sound quality between a 50p and a £1600 digital cable, it's no where near as much as you might like it to be. I am convinced a properly constructed 75ohm cable will sound better than the most expensive analogue cable when utilised in a digital connection. I spent a very entertaining afternoon with 5 different digital cables and a couple of analogue cables connecting my Cyrus cd transport and DAC. All of the digital cables sounded better than the Chord Indigo analogue and Chord Sarum analogue cable placed between the cd transport and DAC (even the 50p one!).

Standard analogue cables could measure anything on the impedance scale, which is why you shouldnt use them in a digital set up. The closer a cable is to 75ohms, the less 'reflections' you get in the cable and so I fully understand why the cheapie cable would sound better than the very expensive chord as the chords impedance is probably WAY off 75ohms whilst the cheapie cable probably wasnt that close to 75ohms, but certainly far closer than the chord. Impedance really is the most important feature of any digital cable before looking into shielding etc.

Cheers for posting anyways. Its always interesting to hear of these 'home' tests

 

[datay]

Completely agree, many are +/-1.5ohms if not more. Trouble is you get a cable with near 75ohm impedance and then connect it with an RCA plug instead of a BNC and you are back at 50ohm.

But is that true for all RCA plugs? Mark Grant (for example) claims the Canare connectors he uses are 75 Ohm - in fact he makes a point of this - 75Ohm crimped phono plugs with 75Ohm cable.

Surely if all RCA plugs immediately put you "back at 50Ohm", the thousands of people using CD players with RCA (not BNC) and DACs with the same input are working at less than optimal level. What do you advise people to use when you're selling a DAC for example, and they have a CD player they are wanting to connect to it? Optical?

 

[CustomCable]

I was being a little too over zealous with the figures. However when introducing an RCA connector to a near 75ohm cable the impedance load to the devices its connected to will never be 75ohm due to the way RCA connectors are designed.The canare is the best plug for the job due to its semi coaxial design and crimp and therefore is the best to use if you cannot use BNC, however in digital applications to be near the 75ohm mark BNC is prefered, thats why the dual data stream on Chord Electronics Blu/QBD is BNC, the Naim DAC etc etc, they all have BNC connection.this is only to my knowledge anyhow.

 

[aliEnRIK]

Mark Grant (for example) claims the Canare connectors he uses are 75 Ohm - in fact he makes a point of this - 75Ohm crimped phono plugs with 75Ohm cable.

The Canares are supposed to be one of the best to use, but your still going to get an impedance drop (it certainly wont be 75ohm)

 

[Anonymous]

In addition to the original question, how would a component video cable compare when used in the place of digital coax?