Toslink Digital Audio vs. USB

[NeckBeard]

I just bought a DAC Magic. I need a 30' cable to go from my iMac to my the DAC Magic which is sitting under my Rega Mira integrated amp. So I am thinking of a 30' Toslink Digital audio cable.

 

Should I just get one of these?

 

http://www.bhphotovideo.com/c/product/297010-REG/Hosa_Technology_OPM_330...

 

With a miniplug adapter for my iMac?

 

Or is USB the way to go?

 

Please advise. Thanks.

NeckBeard

 

 

[John]

Sounds like a bad move IMO. Unlike most here, I prefer toslink as an interface. 30 ft though is stretching things too far. I prefer to stay with 3 ft. In your scenario I would go for an apple TV and stream wirelessly.

 

[NeckBeard]

Should I get long RCAs then?

 

[bottlerocket]

30 ft will work fine. I have a 40 foot toslink going from my Imac to my DacMagic and it works fine and I have lots of 24/96 material. Toslink is better than USB for distance and is also better sonically on this particular DAC.

 

Don't get a mini-adapter plug. They are crap. Get a mini to Toslink cable. The place below has quick delivery and a good product at a reasonable price.

 

http://www.lifatec.com/toslink2.html

 

 

 

[bottlerocket]

Nick, I also got some good responses on a similar question here at the link below. Another option is to put your DAC near your Imac, get a short Toslink and then a long balanced XLR cable if your amp has balanced inputs. (the DacMagic does have balanced XLR outputs) I am thinking Toslink handles distance well though, since it is optical. I am not a cable expert, but I can vouch for the long toslink working just fine.

 

http://www.computeraudiophile.com/content/Long-Cable-Run

 

[Panelhead]

I have not tried 30' of Toslink, but I cannot think 3', 30', or 300' will make a difference in a fiber optic cable. Capacitance, resistance, phase shift are all non-issues.

I like glass and not plastic cables. But people say today's plastic are just as good as glass.

 

George

 

[airdronian]

Optical is cool stuff. I remember when we were having a fibre run installed in a data centre I worked at. The cable tech would be terminating the glass multi-mode fibre cable, and then testing it to check for acceptable signal loss.

 

If the loss was above a certain level, then the termination wasn't good and would need to be done again.

 

If it was a shorter run of fibre they would connect the tester to an additional length carried in the tester case, and then connect to our length of fibre. The reason I was told for this was if the fibre was short (not sure the length, 20m?) then they could not test accurately for loss when they terminated the cable.

 

So they had to add length to get an accurate reading with the tester to judge the quality of the termination.

 

As for me I am taking the plunge and moving from a plastic toslink to glass, and look forward to trying it out.

 

[Erwin S]

http://www.hometheaterhifi.com/blu-ray-players/756-oppo-bdp-83se-special-edition-universal-blu-ray-player.html?showall=1

 

There's more Jitter in optical (Toslink). There's a test in the link above about halfway through the article of the Oppo BDP-83SE Blu-ray player.

I presume that longer runs are worse than short ones. So you are depending on the DAC to deal with the Jitter.

 

I have been told that a Toslink output is very cheap to do. But a Toslink input is much more difficult.

 

[bottlerocket]

The gentleman who posed the question already has this DAC, so he has three basic choices - USB, Toslink or SPDIF. I think he is better off using Toslink, first because it is better sonically (on this DAC) and second because Toslink handles his other problem of distance better than USB (regardless of DAC).

 

From Stereophile: The DacMagic obviously features superb jitter rejection via its conventional data inputs (read SPDIF/Toslink). The USB input, however, performed significantly worse on this test, with both a raised noise floor and significant sidebands apparent (fig.12)......Although its USB input is really of only utility quality and shouldn't be used for serious listening, the Cambridge Azur DacMagic otherwise offers superb measured performance. In fact, considering its street price of $400, this level of performance is astonishing.

 

http://www.stereophile.com/digitalprocessors/cambridge_audio_azur_dacmagic_da_converter/index2.html

 

[Erwin S]

Thanks for the info. I have no idea whether the difference in Jitter level is consistent when using other devices. But the Oppo review showed that optical was 10x more prone to Jitter than coaxial. And the DacMagic review shows a lot more Jitter for USB than for optical. I only used optical with my DacMagic and have no complaints about it.

 

OT: For the moment my Weiss DAC2 is also feeded via optical from the same AE as the DacMagic was. Also no complaints! Will try coax from CD with it later and FireWire from Mac mini....

 

Of course, there's asynchronous USB now, but that's not what the DacMagic offers.

 

[barrows]

One must consider that the optical (toslink) digital output from Macs is very high in jitter. I believe I remember Gordon Rankin from Wavelength Audio measuring Mac toslink outputs and reporting over 2 nS of jitter or so (that's 2000 pS). The Dac Magic has pretty good "jitter rejection", but it uses an asynchronous sample rate converter to achieve said "rejection" and it has been mentioned in these forums that ASRCs really just turn jitter into other forms of artifacts that still obscure sonic detail. For best performance from a computer with the Dac Magic, one would need to use a better interface: M2 Tech Hiface, ar-t Legato, Wavelength Wavelink, or similar.

That being said, with the current setup, and considering a long run, you are best off going with an optical cable (vs. USB). Just understand that the perfromance of your DAC is going to be limited by both the toslink interface with the computer, and the length of the run.

 

[bottlerocket]

Not trying to beat a dead horse here, but does a longer Toslink run add jitter? It makes sense to me that perhaps the Mac digital output is jitter prone, but once past that will there be added jitter when comparing a 1 meter toslink cable to a 10 meter cable? I have no idea myself. Interested in responses....

 

[Erwin S]

Light weakens over longer runs.

 

[One and a half]

The days in winter get colder...really a bit more techo explanation would de-mystify light weakens over longer runs.

 

For example the Ruby Electronics 30' fibre cable has a stated loss of 5dbm. OK, if your transmitter outputs as an even number, +20dbm, add in losses for the connectors say 1db x 2 = 13dbm at the other end.

If your receiver is capable of say -65dbm, then you have no issue, as the receiver has enough headroom to keep the signal maintained. This also allows for a few kinks and bends along the way.

 

http://www.ruby-electronics.com/store_item/NEW_30FT_Glass_DIGITAL_AUDIO_OPTICAL_TOSLINK_CABLE_30'

 

 

 

[ar-t]

If it has SPDIF, you can easily run that 30'.

 

TOSLINK.........I wouldn't use that, if you paid me. I don't think it will work at that distance, but since I hate it with a passion, I have never tried it. So, I could be wrong.

 

Trying to equate multi-mode glass to a cheap plastic fiber is disingenuous. More so with single-mode glass. Which is not intended to work at distances under 1km.