Soundcard vs. Soundcard + external DAC
Jul 11, 2004 at 1:13 PM Post #46 of 83
Well it does sound very close to, if not identical to what I'm getting from a DMX 6Fire - Waveterminal U24 gives you 2-in/2-out analog, coax and optical digital inputs and outputs complete with real-time sample-rate convertor between then should you ever need them. Quite flexible if you ask me - can even use it as an external DAC for your old CD player?
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ESI Waveterminal U24
 
Jul 11, 2004 at 1:48 PM Post #47 of 83
Quote:

Originally Posted by 3lusiv3
Ok. So if all sound card digital outs are not equal, which USB or Firewire soundcards are considered better or worth buying for decent digital output?


Hard to say because nobody's done those kind of comparisions. I've tried Sonica and Audiophile USB and they are just ok. I actually preferred the Audiophile 24/96 over the USB version.

I'd try one of the newer firewire solutions but they are all $$.
 
Jul 11, 2004 at 2:24 PM Post #48 of 83
It is starting to appear to me that USB solutions may be dependant on a few things being right; these being driver software, processor's ability to keep up with the work and bandwidth of the USB interface, plus whether that interface is doing something else at the same time. If these three things are right then USB should be fine, but these variables may be causing some people to have problems with their particular USB setup.
 
Jul 11, 2004 at 5:57 PM Post #49 of 83
I've never had a problem with using USB-based audio interfaces - but that's driven by an Intel I/O subsystem - my experience with lesser chipset makers like VIA and SiS hasn't been totally pleasant ...
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Jul 16, 2004 at 11:45 PM Post #50 of 83
Quote:

Originally Posted by Budley007
Edwood already pointed this out. My definition of bit-perfect was meant to include inherent jitter that a good quality DAC could reject. Thanks for the info, I'll be sure and check it out.


I may not an expert on jitter, but I will offer my 2 cents here. Due to the design of AES/EBU and S/PDIF specs, the operation of the DAC is phase-locked to the clock signal from the digital input. The clock signals inevitably have timing errors (jitter), which will cause distortions or artifacts during D/A conversion. Most DACs use single level phase lock loop (PLL) to reduce, but not eleiminate incoming jitter. Theoretically, a well-implemented two-stage PLL and eleiminate all incoming jitter, but this is rarely the case. According to John Atkinson's and Bob Katz's measurements, at least one company has successfully achieved this, Weiss. According to the same measurements, Bencmark's DAC1 also achieved total jitter rejection with their propietary circuit design called ultralock. Still, the internal clock of Weiss and Benchmark DACs have inaccuracies (jitters), so their D/A conversion is not perfect either. But they are totally immune to input jitter of AES/EBU and S/PDIF, so the quality of discs, transport and cables should not make any difference, unless the bits themselves are read incorrectly even after error correction algorithms.

Because every kind of clock and interface is im perfect, there is never jitterless digital output in AES/EBU and S/PDIF formats. There are better digital audio interfaces that does not carry clock signals, but I don't think consumer products accept these formats. Does this matter? JVC XRCD team sure does think so. They use SDIF-2 digital interface which does not carry clock signals and use a single rubidium atomic clock (super accurate) to feed off to all D/A and A/D devices in the chain. What an amzing effort to attack jitter!!!
 
Jul 17, 2004 at 3:37 AM Post #53 of 83
Quote:

Originally Posted by Adriel
Soundcards that support bit-perfect digital output start at $200. Generally the kind of person to spend $250-$500 on an entry-level DAC will spend the $200 necessary for error free soundcard digital output. Optimally, a jitter buster goes between the soundcard and DAC. That runs an additional $250 or so.


I have sound onboard a motherboard I paid about $100 bucks for that does bit-perfect digital out at 44.1K. Also, all my other cards, onboard and not, are bit-perfect at 48K**. Its not actually more expensive to do at either rate, though the math is easier at 48K. The most common cause of not getting bit-perfectness is the drivers. This is rarely a problem in Linux if there are drivers in the first place
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I'm currently on a quest for a bit-perfect, Linux compatible, coax-out, bus-or-battery-powered, usb card for a reasonable price.
Also, a "jitter buster" or reclocker can be had for well under $250. You can find a Monarchy DIP Classic used for <$100 and I got a Monarchy SuperDrive (BNC out) for $160 with a couple nice digital cables.
Save on the card; buy a reclocker and a nicer dac (like a dAck!)

**note: I mean, of course, they're bit-perfect when the source is 48K to begin with, ie DVDs.
 
Jul 17, 2004 at 4:02 AM Post #54 of 83
Quote:

Originally Posted by commando
Lets hope your guys take it easy this evening
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Oh, I get it. That took me a while to figure out, not being the sport type. We'll beat the cheats.
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Just kidding.

You know, most people here will have no idea what we're talking about.
 
Jul 17, 2004 at 8:48 AM Post #56 of 83
Quote:

Originally Posted by Ferbose
According to the same measurements, Bencmark's DAC1 also achieved total jitter rejection with their propietary circuit design called ultralock. !!!


It works!
I've just borrowed a 1 meter( 3 feet) 240$ Toslink cable and tested it against a cheap 10 meter (33 feet) cable (25 $).
No audible difference.
To my ears, indeed.
 
Jul 17, 2004 at 9:15 AM Post #57 of 83
Quote:

Originally Posted by cosmopragma
It works!
I've just borrowed a 1 meter( 3 feet) 240$ Toslink cable and tested it against a cheap 10 meter (33 feet) cable (25 $).
No audible difference.
To my ears, indeed.


Thank God, hehehe... I've been tempted to get a "better" optical cable to feed my DAC.
 
Jul 17, 2004 at 1:20 PM Post #58 of 83
Quote:

Originally Posted by Zoide
Thank God, hehehe... I've been tempted to get a "better" optical cable to feed my DAC.


That's because of the Benchmark not because there was no difference in the optical cables.

You can get a good optical cable cheap anyhow. Search for glass toslink. Here's the guy on ebay:
http://cgi6.ebay.com/ws/eBayISAPI.dl...sort=3&rows=50

So upgrading isn't that costly.
 
Jul 17, 2004 at 4:40 PM Post #59 of 83
Quote:

Originally Posted by lan
That's because of the Benchmark not because there was no difference in the optical cables.


The expensive cable is made of a special glass quality, extreme purity. This quality was originally developed for long distance telecom connections up to 90 miles.
The cheap cable is made of ordinary plastic fiber, maximum length is 500 feet.
The latter tends to smear the signal to a much higher degree, thereby inducing more jitter.
No problem for the jitter proof Benchmark.
 
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