USB printer cable VS USB audiophile grade cable?

While I haven't tried different audio grade USB cables, their impact on sound is well documented by users on other fora. exaSound might be the exception and their DACs indeed neutralize what is going on upstream - be it at the computer or the cable - by using a buffer inside the DAC from where data is retrieved exactly at the DAC's clock pace.

Lewinskih01,

True for synchronous older DACs, better USB cable will not contribute to additional jitter from incoming PC. However, the majority of newer DACs like Benchmark DAC2 HGC and probably exaSound which you mentionned, use asynchronous clocking device which get rid of jitter from incoming PC. The audio impact of USB cables is not well that documented IMHO, for these asynchronous DACs which are more recent. The majority of USB cable reviews that I've seen in audio trade magazines are 2-3 years old, and performed on sychronous DACs variety.

So I am suggesting that jitter is not part of the equation here when using asynchronous DACs. The audiophile variety of USB cables are doing something rigth to the incoming streaming data, but at which level exactly?

The audio improvement is very noticeable, very similar to replacing a middle range to top of the line interconnect from same manufacturer line.

Any suggestions?

There are a number of possible explanations that occur to me:

1)Electrical noise that may be transmitted from the computer to the DAC via the cable could to some degree couple "around" the DAC's buffer memory and jitter rejection circuitry (via grounds, stray capacitances in the circuits, etc.), and thereby affect jitter at the point of D/A conversion. The bandwidth and impedance characteristics of the cable will affect the amount and the frequency content of that noise.

2)Some of that noise may result from groundloop effects between the computer and the DAC, which in turn will be affected by the resistance and inductance of the ground conductor within the cable.

3)USB signals have substantial content at RF frequencies. The quality and characteristics of the shielding in different cables may result in differences in radiation of electrical noise from the cable into unrelated parts of the system (including cables and power cords as well as components), which may be sensitive to that noise to varying degrees at various frequencies. The sonic consequences of that can be expected to be arbitrary and unpredictable. The fact that your cable, or at least the previous Belden cable, is or was 12 feet long perhaps increases the likelihood of those effects.

4)Earlier Benchmark DAC's employed an Asynchronous Sample Rate Conversion (ASRC) approach to jitter reduction, which I understand is a technology that is not always 100% bit perfect when faced with significant amounts of jitter on the incoming signal. I suspect that is not applicable to the more recent DAC2 HGC model you are using, but perhaps it too is not 100% bit perfect under some circumstances?

I would add, however, that IMO none of this necessarily suggests that a high degree of correlation between performance and price should be expected among the various audiophile-oriented cables that are available. It also does not suggest any reason to expect a high degree of consistency between the sonic results provided by a given upgraded cable when used in different systems.

Regards,
-- Al

Hi Al,

I think we are getting somewhere. The overall resistance of the individual cables composing the Furutech USB should far less than the printer cable which are probably run of the mill copper cables with high impurity levels.

The Furutech cables are silver plated OCC conductors for minimal resistance and connectors are 24K gold plated. They also have 3 layer shield construction. They aslo use special damping and isolation materials for best frequency extension and tonal balance.

I'm with you on the pricing aspect of the audiophile grade USB cable pricing. For me, manufacturing a decent USB data cable is somewhat less challenging than building a good quality XLR interconect cable in the analog domain. While I have invested some decent money on my XLR interconnects ($2K), I was not ready to put more than a few hundred bucks on an audiophile grade USB.

I've been using Furutech products (wall plates, connectors, cable,etc.) for a few years with great satisfaction and was surprisingly pleased with my recent USB cable purchase.

Digital audio was less than perfect when it started in the 80's but have come along way since then. It is so convenient to change CDs directly from my seat using Jriver's JRemote. Cymbals are just starting to sound rigth :-)

Al,

Excellent post!

There certainly is *not* a direct correlation between price and performance
and I also concur that USB cables may not produce the same results from
system to system. That said, there are a few well-designed USB cables out
there that mange to intelligently address some of the challenges you cite
and, as a rule, these cables perform better than stock USB cables and
more consistently so when it comes to delivering music files.

Nonetheless, the wide variety of computer systems and the noise they
create does pose a significant challenge to designers of the USB interface.