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Posted (edited)

LOL @ 'bit'.

They (digital cables) need to meet the minimum criteria, but after that, MHO is that further improvement is nonexistent, whereas with audio cables, I think there is still an asymptotic curve (I.E. the usual lip service to diminishing returns, but no 'threshold' proper).

Edited by Dusty Chalk
Posted

I'm with "SPDIF to spec" but analogue cables get the law of diminishing returns applied strongly (probably most due to the increasing amounts of marketing given to them as they get more expensive).

Posted

so is BNC is the only way to have spdif to spec?

it's much less rare to find BNC than coaxial right?

so what about other digital inputs and outputs... toslink, aes/ebu, are these way off in terms of speC?

Posted
aes/ebu is dead simple to get to spec.

really? if that was the case, then wouldn't it be just as easy to get coaxial to spec? I mean, okay, there's a difference in transmission impedance, a different connector, higher signal level... isn't that it?

Posted

other than an xlr will never achieve 110ohm spec. Also to the OP, BNC and coaxial aren't mutually exclusive. BNC connectors are designed to be used on coaxial cable, most of them on specific coaxial cables. Try to make your spdif cable at least 1.5m... longer won't hurt you here.

Posted

I can't find any PCI cards that have coaxial output with a BNC female connector,

and off the top of my head I can't think of any transports I've seen that have that either.

I'm using a random Philips coax cable from Walmart from my EMU 0404 into my Parasound and I'm having doubts that it's up to spec,

I might have to switch to AES/EBU, and see if I notice a difference

Posted
other than an xlr will never achieve 110ohm spec. Also to the OP, BNC and coaxial aren't mutually exclusive. BNC connectors are designed to be used on coaxial cable, most of them on specific coaxial cables. Try to make your spdif cable at least 1.5m... longer won't hurt you here.

I believe XLR actually does come pretty close to hitting the 110ohm spec, the real problem is that an XLR connector is not in any way an RF connector. Something like a twinax connector would be much more suitable for balanced spdif.

Posted

I guess I have similar questions:

1) What about Toslink? I generally see negative comments about it but I don't really understand why.

2) On a given DAC, is the SQ from the various inputs (setting aside the cable quality for the moment). For example, does coax in generally have some advantageous implentation over toslink that will make it a preferred method of connecting?

Posted

1. Slow rise/fall time, which can influence the decision point (jitter)

2. Yes, different connection types can have different jitter, which may matter to the sound. Depends really how the DAC gets it's clocks. Of course, toslink does have the advantage of complete galvanic isolation. Coax may, depending on the use of pulse transformers.

Posted

  1. Also, Toslink has a transmitter/receiver which introduces noise/jitter as well, so an additional conversion from electrical spdif to optical and back
  2. Good coax implementations should use a good pulse transformer (Newava?) and be terminated correctly. Many (most?) aren't. Many pulse transformers in existing equipment may be there more to pass FCC Part15 testing than their performance as a pulse transformer. Looking at my Rotel 855 for example (yeah, old :palm:), it uses a pulse transformer and then a 2 conductor ribbon cable to the spdif RCA. Nice. Even well done, the clock is embedded in the data bitstream (bad design). Most DACs anymore don't rely on extracting the clock, but people still hear differences in cables when they shouldn't. :rolleyes:
Posted

You figure most DACs use ASRC these days? No idea really. Also, many sources will use a series ferrite bead to suppress EMI for FCC compliance reasons, even though that EMI is really just upper harmonics making the sharp edge of the wave.

Posted
I believe older Parasound and CEC transports have BNC outputs, but I honestly can't think of any soundcards that have BNC anything.

The Transporter has BNC output,

but to send signal to it you've got to be losing some quality because your'e converting music to a wireless frequencies and then back

...also it's 2K

Posted
...

but to send signal to it you've got to be losing some quality because your'e converting music to a wireless frequencies and then back

...

Whiskey Tango Foxtrot!

Posted

C'mon Jim don't be daft. It's just like how when you connect to the internet via a wireless router, websites and such appear in worse quality than when you use a hardwired connection.

Posted
but to send signal to it you've got to be losing some quality because your'e converting music to a wireless frequencies and then back

Warning, does not compute!

Posted

Yeah I think I'm prbly a little too obsessed with this spec stuff,

call it bit perfectionsim

.

But if data is transferred to the the device without any errors I'd be interested in finding out how it works.

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