My cat tore up my Virtual Dynamics Power 3...

[Budgie]

This is about power cords, but that being said, a few nanoseconds of jitter is not audible.

Quote-
Eric Benjamin and Benjamin Gannon, "Theoretical and Audible Effects of Jitter on Digital Audio Quality", Pre-print 4826 of the 105th AES Convention, San Francisco, September 1998. This paper concluded that the threshold of audibility of jitter on normal music signals is around 20ns.

Thats just one conclusion. I find many sources that have tested listeners and found much higher rates of jitter to be effectivley inaudible-

Artifact Audibility Comparisons

http://www.jstage.jst.go.jp/article/ast/26/1/50/_pdf

AST : Vol. 26 (2005) , No. 1 pp.50-54

That last one even included audio critics! If they can't hear it, what chance do us mere mortals have?
Jitter is really a non issue for any reasonably designed gear.

Oh ya, back to power cables- I never thought I would quote a cable seller on anything, but one company seems to be bucking the power cable snake oil and B.S. trend -
Blue Jeans Cable--Does Wire Matter?

Qoute-
Absent some sort of known malfunction, there's very little reason to think that replacement of control or power cables will improve your system's performance at all. There have been a lot of strange claims made in recent years about power cords, and people paying hundreds or even thousands of dollars for them; but the fact is that a power cord, so long as it's well-constructed and undamaged, correctly sized for the load, and driving a reasonably well-designed power supply, should make no difference whatsoever to the sound of your system. The same goes for these other non-signal cables. If they seem to be working, don't mess with them.

If I couldn't solder, I would buy my cables from Blue Jeans. At least they have reasonable explanations for what they build-
Blue Jeans Cable--Index of Informational Articles

[nick_charles]

Originally Posted by Budgie

Eric Benjamin and Benjamin Gannon, "Theoretical and Audible Effects of Jitter on Digital Audio Quality", Pre-print 4826 of the 105th AES Convention, San Francisco, September 1998. This paper concluded that the threshold of audibility of jitter on normal music signals is around 20ns.

Thats just one conclusion. I find many sources that have tested listeners and found much higher rates of jitter to be effectivley inaudible-

Two things are worth mentioning here. In the B&G study only one subject was able to hear jitter at 20ns, and that on only one of the four test tracks. These tracks were chosen from McGill University Music Samples specifically to have the highest possible audibility for jitter. The average for even this best subject was 60ns , other subjects ran from ~ 100 to 175ns.

Secondly the B & G test was for music-correlated sidebands, the worst case , the Ashihara et al study used random jitter which is much more benign hence the much higher thresholds.

[nick_charles]

Originally Posted by Budgie

Oh ya, back to power cables- I never thought I would quote a cable seller on anything, but one company seems to be bucking the power cable snake oil and B.S. trend -
Blue Jeans Cable--Does Wire Matter?

Qoute-
Absent some sort of known malfunction, there's very little reason to think that replacement of control or power cables will improve your system's performance at all. There have been a lot of strange claims made in recent years about power cords, and people paying hundreds or even thousands of dollars for them; but the fact is that a power cord, so long as it's well-constructed and undamaged, correctly sized for the load, and driving a reasonably well-designed power supply, should make no difference whatsoever to the sound of your system. The same goes for these other non-signal cables. If they seem to be working, don't mess with them.

I trust BJC can back this assertion up with properly proctored blind listening tests

This really should be less about who you believe, despite their experience and credentials, but more about who can provide the best evidence for their case.

[mojo]

[quote=Budgie;4364789]Eric Benjamin and Benjamin Gannon, "Theoretical and Audible Effects of Jitter on Digital Audio Quality", Pre-print 4826 of the 105th AES Convention, San Francisco, September 1998. This paper concluded that the threshold of audibility of jitter on normal music signals is around 20ns./QUOTE]

Um, yeah, okay, but... any DAC worth it's salt uses it's own internal clock, i.e. it re-clocks the data so you would have to have an incredibly bad cable to affect it.

As a test I connected two sound cards together with an expensive glass optical cable and a cheap eBay plastic one. I then played back an audio sample that alternates between sine waves of various frequencies and random noise, and recorded it on the other PC. I then wrote a program to check the recording and it was bit-for-fit identical the original on both cables. Thus, data was transferred perfected and re-clocked (during recording) perfectly, so at least as far as digital optical cables go they make no difference at all.

[Uncle Erik]

Originally Posted by mojo

As a test I connected two sound cards together with an expensive glass optical cable and a cheap eBay plastic one. I then played back an audio sample that alternates between sine waves of various frequencies and random noise, and recorded it on the other PC. I then wrote a program to check the recording and it was bit-for-fit identical the original on both cables. Thus, data was transferred perfected and re-clocked (during recording) perfectly, so at least as far as digital optical cables go they make no difference at all.

Yeah, but which one of the two has a higher profit margin?

There's your difference.

[Budgie]

It's not that I "believe" BJC, it's that I agree.
There is nothing magical or mystical (or even difficult) about understanding how to get 120/220 vac at one frequency (50 or 60 hz usually) to travel up three or four feet (one or two meters) of copper wire. It's all very basic electrical principals, that I learned back in the 70's during the educational process of getting my technicians liscense.

I am still waiting for anything like a realistic plausible explanation as to why a power cord might make a difference (especially after not finding an audible differance in my own "listening tests"). Till that happens, I will consider the case to be allready proven. Power cables are only for decoration.

[Terminus Est 23]

Originally Posted by Budgie

It's not that I "believe" BJC, it's that I agree.
There is nothing magical or mystical (or even difficult) about understanding how to get 120/220 vac at one frequency (50 or 60 hz usually) to travel up three or four feet (one or two meters) of copper wire. It's all very basic electrical principals, that I learned back in the 70's during the educational process of getting my technicians liscense.

I am still waiting for anything like a realistic plausible explanation as to why a power cord might make a difference (especially after not finding an audible differance in my own "listening tests"). Till that happens, I will consider the case to be allready proven. Power cables are only for decoration.

Keep your newfangled scientifical stuff away from my ears! Unless you're selling me something, then science me up.

[Happy Camper]

Background : LessLoss Audio Devices Store

High frequency energy filtering. There's more than 50-60 cycle energy in the transmission feed. The more that enters your device, the more the device is reduced in performing to it's full potential. Cable companies use passive filtering vs active filtering to minimize this effect.

Read through Why Less/Loss? I don't and am not trying to hawk a product. It helps to understand a bit better, the science of a power cable.

[pompon]

This cat got Virtual Dynamic.
They not sponsor anymore ... good job to not permit us anymore to have samples and contest to win cables.

[bigshot]

virtual dynamic no good any way. no loss. free junk no good.

See ya
Steve