Help: Music Server to DAC Connection Question

[Lee]

I have a new Mac Mini which is next to my listening chair and I use it for two things: cataloging my somewhat vast CD collection and playing digital music files. Due to the scanning I do of new CDs I want to keep the Mac near my listening chair for convenience.

I want to connect this to a DAC1 and will be buying a Musical Fidelity V-Link soon. I plan to run a long USB run to the DAC1 which sits atop my top-loading Sony SCD-777.

The question is this. Would I be fine just connecting the optical out on the Mini to the DAC1?

In other words is USB to SPDIF better for long runs (around 8 feet) and/or is optical fine at that long a length?

Thanks for any advice.

 

[Bruce B]

optical can go much further than wire without degrading the signal, but at only 8ft, no worries on either part

 

[Lee]

That is good to know Bruce, thanks.

 

[Vincent Kars]

USB
Cable length between full speed devices is limited to 5 meters. For a low speed device (most DACs) the limit is 3 meters.
As the signal degrades proportional to the length of the cable, a short cable is often recommended.

Toslink
Toslink cables are made of plastic or glass.
The plastic ones are cheaper but have a higher attenuation coefficients (1 dB/m or higher).
Due to the high attenuation, reliable transmission distances were limited to 10 meters, in practice often under 5 meters.
Today companies like Lifatec offers length up to 30 m (98 ft) using APF (All Plastic Fiber) with an attenuation (optical loss) less than 0.15dB/m.

Just to spoil your weekend:
Mini – long Toslink – DAC1
Mini – long USB – Vlink – short Toslink – Dac1
Mini – long USB – Vlink – short coax – Dac1
Mini – short USB – Vlink – long Toslink – Dac1
Mini – short USB – Vlink – long coax – Dac1

 

[Bruce B]

Toslink
Toslink cables are made of plastic or glass.
The plastic ones are cheaper but have a higher attenuation coefficients (1 dB/m or higher).
Due to the high attenuation, reliable transmission distances were limited to 10 meters, in practice often under 5 meters.

What about MADI optical?

 

[Vincent Kars]

According to http://www.iis.ee.ethz.ch/~felber/DataSheets/AES-EBU/aes10-2003.pdf

A fibre interface should be used as specified according to ISO/IEC 9314-3. It should be a graded-index fibre
with a core diameter of 62,5 nm, nominal cladding diameter of 125 nm and a numerical aperture of 0,275, at a
wavelength of 1300 nm. This specification can provide a range of up to 2 km.