[byteme]

I ran across an interesting question that I hadn't really thought of before.  I've always used a relatively cheap MIT Terminator 3 digital cable between my DVD player and Pre/Pro.  Tonight I'm chatting via PM with someone who is using a rather highly regarded (in the 2 channel world) digital cable for HT use and swears it makes a very noticable difference.

So the question is, what do you use, and if it's "higher end" do you notice a big benefit or no?

Thanks!

[jswallac]

First let me qualify this with the statement that I do not hear differences in power cords, so many can dismiss what comes next.  I believe ICs and video cables do make a difference as can speaker cables.  But digital cables are simply suppose to pass 0's and 1's.  As long as they get that correct it seems the cable has done its job.  I have heard all sorts of opinions why it does matter, but I sure cannot hear it.  So I simply use the Focus coaxial cable from Revelation Audio (purchased from AV123).  $20 for 1 meter.  It does a good job of getting the 1's and 0's correct to my ears.  You did not ask, but I prefer coaxial cables to optical for practical reasons.  They connect easier and you do not need to be as careful about bending them.

[bubba966]

So the question is, what do you use, and if it's "higher end" do you notice a big benefit or no?

Yes, I have noticed a big difference on digitals in HT use. More so than in 2 ch use (but my system is setup more for HT than 2 ch).

I've only listened to one coax that I really couldn't stand. After 30 minutes or so, the Stereovox HDXV was too physically painful to listen to anymore. I finally learned firsthand what "listener fatigue" was as I'd not experienced that before. Which is kinda too bad as that cable did some things rather well...

Currently I'm using a custom Bolder Cables digital coax. It's a Cryo'd Napalm Ultra. Meaning that it's got Silver Eichmann Bullet Plugs, two Bybee Purifiers, full ERS wrap, and Cryogenic treatment. At some point I'll probably uprgrade it to the "current equivelent" from Bolder as it does sound better for HT use. But as an Ultra "Bubba" ICE digital is nearly twice the $ as my Cryo'd Napalm Ultra, it'll have to wait a short bit (like when I'm working again... )

[Double Ugly]

A lot of digital cables have been through my system, including a couple of really expensive cables from a manufacturer I beta test for.  Some are sonically very similar and some are very different, but in every instance I've been able to discern differences.  

That doesn't mean everyone will, or even should, hear a difference.  Nor does it mean that every system will reveal the differences.  Some say there can't be a difference, that it's all in my head.  That's fine; they're entitled to their opinion.  But it's clear to me that digital cables do make a difference, and I use the cable that sounds best to my - and my wife's - ears.

FWIW, the cable I'm using is not the most expensive I've had in my system.  It's just the best sounding.

Jim

[lonewolfny42]

I've only listened to one coax that I really couldn't stand. After 30 minutes or so, the Stereovox HDXV was too physically painful to listen to anymore. I finally learned firsthand what "listener fatigue" was as I'd not experienced that before.

Hmmm, I remember that....

[satfrat]

Byteme, use the Pulsar for both 2 channel AND HT applications, for the price you can't go wrong. The only thing you could do is get the standard bullet plugs for HT. Plus don't forget the Slipstream for slamming dynamic scenes. Regards, Robin

[StevenACNJ]

I use 3 digital cables in my HT system. About 3 weeks ago went with all VH Audio Pulsars, 1.5M, terminated with silver Bullet plugs. Still breaking in but so far they made a big difference.

On my digital cable that runs between my Motorolla 6200 digital cable box and my Lex MC12 pre/pro I installed a new small Bybee on the center conductor and it made a very nice improvement to the sound quality. Tried with & without bybee and cable with Bybee was much better.

Just my $.02.

[byteme]

hmmpf.  Well, I shoulda known.  Looks like another call to Chris and another slipstream from Ryan!

Thanks gang!

But digital cables are simply suppose to pass 0's and 1's. As long as they get that correct it seems the cable has done its job.

js, my only suggestion to you is to grab a few used digital cable (or borrow them) and put them in your system, listen for a while.  If you don't hear a difference I'd be astounded.  I've had probably 20+ digital cables through my system and each of them have made some kind of difference, good or bad.

[PhilNYC]

But digital cables are simply suppose to pass 0's and 1's.  As long as they get that correct it seems the cable has done its job....

Not quite true.  Yes, a digital cable is supposed to pass 0's and 1's.  But at the end of the day, a "digital system" still uses an electrical/analog signal to represent that data.  Those voltages only need to be within a certain tolerance (magnitude and length) to accurately represent a 0 or 1, but when it is passed to the DAC (or even a data buffer), those 0's and 1's are analog voltages that are being passed into a series of resistors/transistors to be transformed into another set of voltages.  If there are variations in the magnitude of those voltages ("data jitter") or length ("timing jitter"), those variances at the input of the DAC will affect the output of the DAC.

So a digital IC does need to pass 0's and 1's, but it also needs to maintain the proper magnitude and length of the square wave that represents that data.

[JoshK]

Not quite true.  Yes, a digital cable is supposed to pass 0's and 1's.  But at the end of the day, a "digital system" still uses an electrical/analog signal to represent that data.  Those voltages only need to be within a certain tolerance (magnitude and length) to accurately represent a 0 or 1, but when it is passed to the DAC (or even a data buffer), those 0's and 1's are analog voltages that are being passed into a series of resistors/transistors to be transformed into another set of voltages.  If there  ...

Well said and often overlooked fact.

[Eric]

I was using a Monster 1.5 meter digital cable and switched to an I2digital cable (x-60). I noticed immediate improvements in bass response (I had to adjust the settings on my LFM's because I was getting more bass) and soundstaging (especially width)

[brj]

But at the end of the day, a "digital system" still uses an electrical/analog signal to represent that data. Those voltages only need to be within a certain tolerance (magnitude and length) to accurately represent a 0 or 1, but when it is passed to the DAC (or even a data buffer), those 0's and 1's are analog voltages that are being passed into a series of resistors/transistors to be transformed into another set of voltages. If there are variations in the magnitude of those voltages ("data jitter") or length ("timing jitter"), those variances at the input of the DAC will affect the output of the DAC.

Will a (true) digital amp will react in the same manner?

So a digital IC does need to pass 0's and 1's, but it also needs to maintain the proper magnitude and length of the square wave that represents that data.

Well explained!  Thank you!

Ok, so when coming from a digital source (CD/DVD/SACD/etc) why don't we avoid the problem entirely... go to an error correcting, packet based data encapsulation scheme?  TCP/IP comes to mind as a well used example.  Heck, Ethernet NICs and cable are dirt cheap these days, and could handle the bandwidth without a problem.  For a full digital system, this would appear to be both cheap and ideal.  So what have I missed that prevents this from happening at a technical level?

[jswallac]

PhilNYC, thanks for the explanation.  That does make sense and I appreciate you letting me know.  Not to head the dicsussion into a completely new direction, but will a coaxial cable or an optical cable do a better job at this?  I have heard that it makes little difference in short runs, but to stay away from optical in longer runs.  Thanks again.

[PhilNYC]

Well explained!  Thank you!

Ok, so when coming from a digital source (CD/DVD/SACD/etc) why don't we avoid the problem entirely... go to an error correcting, packet based data encapsulation scheme?  TCP/IP comes to mind as a well used example.  Heck, Ethernet NICs and cable are dirt cheap these days, and could handle the bandwidth without a problem.  For a full digital system, this would appear to be both cheap and ideal.  So what have I missed that prevents this from happening at a technical level?

You'd still have the same issues in that all of this data still needs to be represented as an analog voltage.  Using error-correcting, packet based data encapsulation will ensure that your 0's and 1's are accurate (and are good for math calculations), but the tolerances for ensuring accurate 0's and 1's are well below potential jitter issues.

For example (and I'm not using real numbers here...just using numbers to make the example easy to read); let's say that a single datapoint (a "1") is supposed to be represented by a 5mv voltage sustained for 10nanoseconds.  If the voltage is sustained for 9ns at 6mv, it will still be read correctly as a "1".  But 6mv for 9ns represents a 20% voltage variation and a 10% timing variation from the 5mv and 10ns that the DAC chip/circuit is expecting.  Most computer hardware guys get a little mixed up here...it's not like there's a data register that says "01001100" = 76mv, and somehow magically 76mv are produced.  Instead, there are a set of input voltages that pass thru resisters and transisters, and get transformed to an output voltage.  ...when that hits the DAC, the DAC doesn't actually care if it's a 1 or 0...it cares what the input voltages are and how long they are.

[PhilNYC]

Not to head the dicsussion into a completely new direction, but will a coaxial cable or an optical cable do a better job at this?  I have heard that it makes little difference in short runs, but to stay away from optical in longer runs.  Thanks again.

Yeah, sorry if the thread is getting hijacked, but I think it's relevant to the topic...!
 
Regarding coax vs. optical, the main reason most people will say that coax is better is because optical requires two conversion processes (electical to optical at the transport out, then optical to electrical at the DAC input), and any time you have a conversion process there is danger of introducing jitter.  I haven't done a lot of research on this particular topic, so it's hard to say, but I would also assert that with coax, you also need to be conscious of cable length and whether or not the cable and spdif inputs/outputs are all with matching impedances (75ohm, or 110ohm for AES/EBU), or else you will have jitter and reflection issues with coax...

[ctviggen]

Theoretically, optical should be better, as it's immune to electromagnetic interference.  Also, telecos communicate a lot of information over long optical cables at very high data rates with very few errors (we're talking one error in millions of bits).  So, if it works there, it should work in consumer electronics.  However, I wouldn't doubt that consumer stuff is cheesed out and doesn't work that well.  I'm putting a nice (glass) optical cable on my system; maybe I'll compare my fancy coax with my new optical cable.

[brj]

Thanks for the additional comments, Phil!

Instead, there are a set of input voltages that pass thru resisters and transisters, and get transformed to an output voltage. ...when that hits the DAC, the DAC doesn't actually care if it's a 1 or 0...it cares what the input voltages are and how long they are.

Any idea if true digital amps show the same sensitivity in the same manner?

[PhilNYC]

Thanks for the additional comments, Phil!

Any idea if true digital amps show the same sensitivity in the same manner?

Honestly, I have not done any kind of homework on digital amps, so I can't say one way or the other.  But I would assume that any device that converts a digital signal to an analog signal would have the same issues...to what extent it is audible, I don't know.

[byteme]

Yeah, sorry if the thread is getting hijacked, but I think it's relevant to the topic...!

Are you kidding?  This is way more interesting than "should Brian use a better quality digital cable for home theater"  

Keep up the good work!  Very informative.

[dave_c]

Thanks for the additional comments, Phil!

Instead, there are a set of input voltages that pass thru resisters and transisters, and get transformed to an output voltage. ...when that hits the DAC, the DAC doesn't actually care if it's a 1 or 0...it cares what the input voltages are and how long they are.

Any idea if true digital amps show the same sensitivity in the same manner?

I believe they do.  My experience is limited to the XR45, but the sound definitely changed when using different cable and when using a Monarchy DIP to reduce jitter.