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DACs: USB vs. Coax. vs. Optical - Page 3

post #31 of 55
I've read a good bit on this here at HeadFi and I was wondering if this is an accurate conclusion: USB is the hookup of choice for portable based audio, while for home based audio, optical or coaxial are the hookup of choice. Does that sound reasonable for the average HeadFi'er?
post #32 of 55
Quote:
Originally Posted by Penchum View Post
I've read a good bit on this here at HeadFi and I was wondering if this is an accurate conclusion: USB is the hookup of choice for portable based audio, while for home based audio, optical or coaxial are the hookup of choice. Does that sound reasonable for the average HeadFi'er?
Sounds reasonable to me. First time I've heard anybody actually point it out though.
post #33 of 55
Quote:
Originally Posted by manaox2 View Post
Sounds reasonable to me. First time I've heard anybody actually point it out though.
There are always exceptions as well, but this seems to fit the growing majority. Like with my notebook (ASUS A8JS) I got lucky and it has optical out on a combo headphone jack. I can go straight into my Zero DAC/Headphone amp and there is no noise, totally black.
post #34 of 55
Quote:
I'm sure you could find some ultra-cheap $10 product and connect 10+ metres of unshielded USB cable from 1998 wrapped around a motherboard and power supply, and detect some noise that may be attributed to USB.
1. Maximum cable lenght for USB is 5m. After that, you need a repeater. So you can buy a 5m cable, and add a 5m extension cable with built-in repeater. 5 repeaters are allowed, stretching the limit to 30m while fully maintaining integrity.
2. Any decent USB cable is shielded. And no, not foil but braid (or even both).

In any case, USB offers 16bit CRC error detection and correction for it's data payload. For the simple isochronous transfers most audio devices use this means most bit errors will be detected AND corrected. Even better: around 99.998% of all errors can be detected, but not all can be corrected: with a isochronous transfer you're guaranteed bandwith and lowest possible latency, but at the cost of not being able to re-send the data.
For a more advanced USB bulk transfer it means bit error correction, multi-bit detection AND a re-send of data. But since you don't get access to the available bandwidth all the time, you need to buffer things cause you're bound to miss the "bus" every now and then.
No matter what method you choose, USB is one of the best (and cheapest) ways to transfer data from a PC to another device.
post #35 of 55
I like usb.
post #36 of 55
Quote:
Originally Posted by Penchum View Post
There are always exceptions as well, but this seems to fit the growing majority. Like with my notebook (ASUS A8JS) I got lucky and it has optical out on a combo headphone jack. I can go straight into my Zero DAC/Headphone amp and there is no noise, totally black.
Anyone who is worried about the bus noise can typically buy a powered USB hub for cheap and eliminate it.
post #37 of 55
Quote:
Originally Posted by manaox2 View Post
Anyone who is worried about the bus noise can typically buy a powered USB hub for cheap and eliminate it.
Hey, I'm just curious. I can't rememeber what others were worried about some time back...Was there ever an issue with bus noise for USB? Or was it something about the chip that translates USB into SPDIF? Thanks!
post #38 of 55
Some of the devices are picky and don't work well if connected to an external hub, IIRC.

I think the concern is primarily with bus powered USB devices and "dirty grounds" that can cause problems with the analog output from the device...the ground can be modulated by PC noise. Someone please correct me if I am wrong on that one.
post #39 of 55
Alright so basically they are pretty much all on the same playing feild? except for coax can go longer distances, usb has the advantage of compatibilitiy with a possibility of driver/noise problems, and optical (im making an educated assumption that this is the same thing with S/PIDF?) is prone to jitter

so did i sum it up correctly?
post #40 of 55
Can't speak for USB, but as between optical and coax, coax is usually better. S/PDIF is the shorthand reference to the interface for both optical and coax. As someone has already mentioned, the problem with optical is jitter. There are companies that did a fair job of improving optical connections to such a degree that they performed better than coax (like Audio Alchemy l/k/a Camelot Technologies and their I2S connection), but to my knowledge, those companies are dead. If you do decide to go with with coax, just get yourself a purpose-built 75ohm digital link and you should be good to go.
post #41 of 55
i have the trends audio ud-10 (with optional battery supply)for dead quiet listening and jitterless playback on my headroom desktop headphone/dac amp! my source being a macbook!
im extremely happy with the results.
post #42 of 55
I used to have a cheap Optical cable that I got from a Walmart type place for $10'ish.


Recently, I bought a Coaxial cable similarly priced, to compare and see whether there really is a difference between the two technologies. I needed a longer cable anyway, so if it wasn't any better I'd still use it.

I found no difference' between the two cables on my TC-7510 connected to the front panel of my Audigy 2 ZS Platinum. While switching between them via the buttons on the front, there was no change in the sound at all.

Coaxial vs Optical? Either.
post #43 of 55
Quote:
Originally Posted by fraseyboy View Post
I used to have a cheap Optical cable that I got from a Walmart type place for $10'ish.


Recently, I bought a Coaxial cable similarly priced, to compare and see whether there really is a difference between the two technologies. I needed a longer cable anyway, so if it wasn't any better I'd still use it.

I found no difference' between the two cables on my TC-7510 connected to the front panel of my Audigy 2 ZS Platinum. While switching between them via the buttons on the front, there was no change in the sound at all.

Coaxial vs Optical? Either.
You aren't going to hear the differences between the two if you don't have a source that can resolve the differences. I am not saying that to step on your kit, I'm just stating a fact. My home theater rig can resolve the differences, whereas my comp set up probably can't.
post #44 of 55
I personally wouldn't use glass optical because it can easily break.

I'd use USB if I needed the versatility, ie. I may use a computer that doesn't have a coaxial SPDIF out.
post #45 of 55
Quote:
Originally Posted by jtizzle View Post
You aren't going to hear the differences between the two if you don't have a source that can resolve the differences. I am not saying that to step on your kit, I'm just stating a fact. My home theater rig can resolve the differences, whereas my comp set up probably can't.
I guess that makes it a great way to hookup for Notebooks, Desktops and smaller systems then. Sure is nothing wrong with that. I am curious if the better glass cables make any kind of difference for this kind of use though?
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