Connect mixer to surround sound receiver, it's 10 metres away

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Connect mixer to surround sound receiver, it's 10 metres away

2007-05-23 11:33:14

Hi everyone

I've got a rather specific problem... I want to connect my Pioneer DJ mixer to my surround sound receiver, to save having a separate hi fi amp.
Obviously the hifi quality of surround sound receivers is often a concern, but I've been using mine for a while to play CDs and music from my computer and I'm willing to give it a go.

My question is... what's the best way to do it?
The mixer is about 10 metres away from the inputs of the surround sound receiver.

As I see it, these are the options...

1) Buy a 10m 2-phono lead to run round the room...
http://www.cablenet.org.uk/catalogue/phono_hq.htm or http://www.universaluk.com/acatalog/2_x_Ph...e__Premium.html

Is it worth going for the more expensive one (search for UNI37524 on the 2nd link)
Also this is the most likely to be affected by interference, and the only way I will know is by trying it.

2) Buy 2 of these and use ethernet cable to span the room...
http://www.mcminone.com/product.asp?catalo...%5Fid=50%2D7725
Then it's back to phono to go in to the receiver

3) Buy a DAC and convert the signal to digital just after the mixer and buy a pair of these to span the room using ethernet...
http://www.mcminone.com/product.asp?catalo...%5Fid=50%2D7755
I believe there's a maximum length that SPDIF can be used over and I think 10m might be too far. Can anyone confirm this?

Then the digital coax just goes straight into the back of the receiver.

Anyone have any other suggestions, or ideas on which one will result in the best quality signal?

Thanks
Ben

Connect mixer to surround sound receiver, it's 10 metres away

Reply #1 – 2007-05-23 14:22:20

Go with a good 10m phono cable unless you have a digital source. I cant see why you would want to ADC then DAC the signal

Connect mixer to surround sound receiver, it's 10 metres away

Reply #2 – 2007-05-23 14:37:31

How about a pair of the 2 phono baluns then ethernet cable making the 10m distance?
Using those devices it seems you can get transmission of 500 feet over ethernet cable which would imply that it would be less-prone to interference that way.

My only concern is obviously there are 2 breaks in the signal path going with the baluns in option 2, and that's where you're more likely to get signal loss... rather than just one complete cable with option 1.

In terms of perceived audio quality, will I get a decent result with a 10m phono cable?
Or will it start to get a bit crackly and rubbish?

Connect mixer to surround sound receiver, it's 10 metres away

Reply #3 – 2007-05-23 15:35:20

Quote

I believe there's a maximum length that SPDIF can be used over and I think 10m might be too far. Can anyone confirm this?

Are you referring to S/PDIF over coaxial or optical cables? Not sure about coaxials, but I have a 100ft TOSLINK cable (optical) and I use it to connect my computer to a receiver via S/PDIF. Bought the cable from Lifatec. Works fine.

Connect mixer to surround sound receiver, it's 10 metres away

Reply #4 – 2007-05-23 16:16:34

I read up on some previous threads and this seems to suggest there is a maximum...
http://www.hydrogenaudio.org/forums/lofive...php/t48533.html

Also this wikipedia entry suggests a 10m max run for Toslink... http://en.wikipedia.org/wiki/TOSLINK

But I've not found much more information than that.

Connect mixer to surround sound receiver, it's 10 metres away

Reply #5 – 2007-05-23 16:50:45

Quote from: sergeymen on 2007-05-23 15:35:20

Quote
I believe there's a maximum length that SPDIF can be used over and I think 10m might be too far. Can anyone confirm this?

Are you referring to S/PDIF over coaxial or optical cables? Not sure about coaxials, but I have a 100ft TOSLINK cable (optical) and I use it to connect my computer to a receiver via S/PDIF. Bought the cable from Lifatec. Works fine.

100' over TOSLink? Wow, you're pushing it...I looked at Lifatec's website, and it seems that they know what they're doing, but even with very good quality fiber and connectors, I still wouldn't be comfortable with TOSLink at that distance.

Signal loss in fiber is exactly the opposite of copper: the larger the diameter of the fiber, the greater the loss, as the light is able to diffract more and more as it travels down the fiber. This is why the lowest-loss fiber - single-mode - is also the smallest: ~9 micrometers in diameter, compared to TOSLink's 900 micrometers (using a laser light source also helps ).

The 10 meter length limitation so often quoted for S/PDIF is for TOSLink, not coaxial (although very good-quality TOSLink cables can obviously make a difference) - I've sent S/PDIF through ~500' of RG/6 coax with no problems whatsoever, and I'm sure it could go much further. The minimum distance spec for professional unbalanced digital audio, AES-3id (the data format of which S/PDIF copies nearly exactly), is 1,000 meters - yes, one thousand - over RG/59. The only differences in terms of signal strength and transmission distance between AES-3id and S/PDIF is that AES-3id uses a higher signal level - 1.0V peak-to-peak as opposed to S/PDIF's ~0.5V - and specifies tigher tolerances on the equalization of inputs.

So, while S/PDIF probably couldn't make it 1,000 meters, a few hundred should be no problem with good-quality RG/6 coax and good, true 75 ohm connectors (this is probably where coaxial S/PDIF encounters the biggest loss as consumer-grade RCA connectors are by no means guaranteed to have sufficiently high return loss out into the 10-20 MHz range as required by S/PDIF).

Regarding the OP's question of which method to use to run unbalanced audio 10 meters: The only reason that the 10-meter RCA cable shouldn't work just fine would be ground loops or strong RF interference. In my experience, outside interference in residential environments that is strong enough to be clearly audible is quite rare - ground loops, or noise on the ground from such things as switching power supplies, are more common. If you're really concerned about signal loss, build your own interconnects out of a couple chunks of decent video coax and Switchcraft 3502A RCA connectors. RG/59 coax is usually around $0.10-$0.15/foot, and the 3502A's are usually less than $2/each. This would cost quite a bit more than the 10-meter cable from Cablenet (which should work just fine - again, barring any ground issues or severe interference), but you'd have a very sturdy, well-shielded interconnect (most video coax intended for installation - as opposed to stage or field use - uses 100% foil + 95% braid).

If you do have ground issues, the CAT5 baluns could solve that IF they use good-quality transformers and lift the ground on the balanced link...but that's a big "if" at that price...

Connect mixer to surround sound receiver, it's 10 metres away

Reply #6 – 2007-05-30 14:16:41

Wow thanks for all the info. That is invaluable.

So if I was going to do it digitally, digital coax would be the way to go then.

From all the advice given I think it's beginning to make sense to just use a 10m phono cable.

The cable will be running around the edge of the room, in a 2nd floor flat.
There will probably be a power extension cable running parallel, but this will literally just be for a spotlight. So I'm not expecting too much interference - though there's a microwave, wireless router and cordless phones in our flat.

The 10m phono cable sounds like the cheapest and simplest option to be honest.

Anyone have any recommendations for a decent 10m phono cable?
I don't really want to spend £150 on an audiophile QED custom one, but I'd be prepared to spend £30-£40 ($80) on something if it was decent.

Thanks for all your help!
Ben

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