Cable Budget Guidelines

gene

gene

Audioholics Master Chief
Administrator
<font color='#000000'>Cable Budget Guidelines by Gene DellaSala (gds@audioholics.com)
Date:  9/30/02

I have been receiving numerous emails about how one should budget their spending on interconnects and speaker cables.

As a rule of thumb, I recommend investing about 5-7% of your total system cost into cables and interconnects, with the following priorities:
1) Video Interconnects
2) Analog interconnects
3) Speaker Cables
4) Digital Interconnects

1) Video cables:
Video cables are the most important cables in your system as the signals that are being passed thru these cables (especially when dealing with HDTV) are in the Megahertz range.  The higher in frequency your transport, the more critical it is to use cables that have a proper characteristic impedance (usually 75ohm for video), adequate shielding, and solid terminations.
Applications:  TV, DVD, HDTV Decoder, Monitor Output of Receiver/Preamp.


2) Analog Interconnects:
Analog interconnects are also important since they interface high impedance connections, usually greater than 10kohms for amplifiers, CD players, preamps, etc.  It is important to choose cables that provide low capacitance, good shielding, and solid terminations.  IF we assume the input impedance to your power amp is 10kohms (usually power amplifiers are designed with a much higher input impedance), then you can get away with an interconnect with up to 150pF of capacitance and still yield a 3dB point above 100kHz based on the relationship of:  
f= 1 / (2*pi*R*C).  It should be relatively easy to find low capacitance interconnects for a reasonable price that will provide frequency response beyond the limits of your hearing and equipment abilities.
Applications: Preamp, Power Amp, CD Player, Subwoofer.


3) Speaker Cables
Despite all the myths and engineering fallacies surrounding speaker cables, these cables are not as critical as many cable companies would have you believe.  In fact, many of these cable companies are simply marketing Snake Oil in fancy packages, and selling them to you for outrageous prices.  The truth of the matter is, standard 12 AWG Oxygen Free Multistranded Cable (OFMC) is fine for most applications.  It has low enough DCR for runs in excess of 100ft to not cause any deleterious effects on system performance. Dealing with relatively low frequencies (IE. 20kHz bandwidth) into low impedance loads (typically 8 ohms), it is very difficult for RF to ingress in your speaker cables.  In addition, the inductance and capacitance of these cables is insignificant for runs up to even 100ft or so, compared to the actual impedance properties of your loudspeakers and the 20kHz bandwidth in question.  

If you consider that even most high end loudspeakers are internally wired with 14-16 AWG copper wire, and the terminations of most power amps / Receivers and Loudspeakers are soldered onto binding posts, then ask yourself, how could these &quot;exotic&quot; cables make an audible difference?  

What is important in speaker cables is how you terminate them.  You want to ensure that you have the tightest connection of the cable to your amp and loudspeaker.  For that, I recommend either spades or bannana plugs.

If you feel there may be a potential problem with RF in your system (IE. You live close to a radio station), you can always try running multiple pairs of Belden Twisted cables with shielding to your loudspeakers.  I will be writing an article about this shortly.  Stay tuned…
Applications:  Loudspeakers.


4) Digital Cables  
Digital cables, particularly toslink, are not that critical since they are tasked to pass a 44.1-48kHz bitstream for PCM, DD/DTS.  Since these are fiber optic cables, they do not get disturbed by adjacent cables carrying digital, analog, or power signals.  Should you choose to use coax cables for your digital connections, I recommend using 75ohm shielded RCA type cables to minimize coupling issues from adjacent cabling on long runs and/or potential RF ingress.
Applications:  CD/DVD Player, Cable Box.


Bottom Line:
Use common sense when purchasing cables and interconnects for your system.  Don't run out and spend $1000 on a pair of &quot;exotic&quot; speaker cables for your $500 loudspeakers.  The $1000 wasted on those &quot;so called&quot; exotic speaker cables may be better utilized on upgrading your $500 loudspeakers to a better set of $1500 speakers, with all things being equal.  Choose cables that are durable and built well while providing solid mechanical connections (terminations) with your hardware.  Most importantly, arrange your cables in a logical and neat fashion to minimize any potential interference issues.  For more details about this, please refer to:
http://www.audioholics.com/techtip....101.php


Enjoy the music!

GDS



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J

Jon Risch

Audiophyte
<font color='#000000'>The cabling guidelines posted here seem very much skewed toward video cables, perhaps due to a distinct Home Theater predisposition on the part of the author?

However, some of the statements made do not jibe with what is actuallly going on with cabling.
For instance:
&quot;Video cables are the most important cables in your system as the signals that are being passed thru these cables (especially when dealing with HDTV) are in the Megahertz range.&quot;

This makes a very simplistic assumption that sheer frequency range is somehow the most important issue, and perhaps the author believes that it is the only issue.

Most video cables use a form of coaxial cable. &nbsp;Most coaxial cables, be they RG-59 types, or RG-6 types, will pass signals up to around 1 GHz, that's one gigahertz.

Most RF video signals are in the TV band, or cable TV range, and these are well below this range. &nbsp; There is a very important factor that often gets overlooked about RF video signals, and that is, they are isolated from direct interactions with the cables, due to the fact that they are carried as a &quot;coded&quot; sideband of energy within the RF carrier. &nbsp;The RF signal it self is not the TV video signal, but rather is a vehicle for it. &nbsp;As such, any minor distortions that occur to the video signal when it is in RF form are pretty much glossed over when the video signal is demodulated down to baseband video.

How far up in frequency does baseband video extend? &nbsp;Not quite 4 MHz for NTSC TV, and about 10 MHz for HDTV. &nbsp;Now if we extrapolate that a bandwidth of over 10 times the highest frequency will suffice to keep cable related phase shifts and problems down to a minimum for the video baseband signal, a frequency range of 100MHz will cover even HDTV baseband component signals.

How much loss is there in even a cheap RG-59 cable at 100 MHz? &nbsp;About 3.4 dB (or less) for a 100 foot run. &nbsp;For a 10 foot run, or approx. 3M, this would be - 0.3 dB down at 100 MHz.
So much for the need for sheer frequency response, and any concerns regarding typical coax video cables carrying these MHz frequencies.

As far as any cable distortions, and what would be seen on the TV screen, I think that you will be in for a shocker. &nbsp;Even in a dimly lit room, with the TV optimally set up, the absolute maximum signal dynamic range that can be seen on a CRT is less than 40 dB. &nbsp;The blackest black is approx. 22.5 dB down from full white (100 IRE down to 7.5 IRE).

This means that cable distortions that would be an audible problem on an audio cable, will not ever be seen on a video cable.

Most of the issues that exist with cables are well below 22.5 dB, and in most cases, below 40 dB down.

Audio signals on the other hand, have a much wider dynamic range, and given that digital audio dither algorithms that live down at -90 dB can be heard to differ, it is clear that analog audio has cable requirements far in excess of those of a video signal.

The differing impedances of video vs. analog audio also give more of an advantage to video in terms of keeping the signal free from cable related issues.

There are two key issues for video cables:
Shielding, to avoid picking up noise or spurious signals that might be capable of intruding into the picture, and Impedance matching.

In my opinion, the impedance matching is the main factor that influences what you see on the TV screen with different video cables, as the freedom from impedance mismatch ghosts is what can be seen as a sharper and more deliniated picture. &nbsp;Noise pickup is pretty obvious as such, but impedance mismatch can make one cable look blurred and dull, while another looks overly sharp and crisp due to edge distortions less spread out than the first cable.

As for audio interconnects, they need to be much more than just adequate or OK, if you want SOTA audio peformance, and your system is capable of delivering it, then OEM patch cords, or RS Gold is not going to cut it. &nbsp;Note that I do not advocate super expensive audio cable, far from it. &nbsp; In point of fact, I personally encourage folks to try DIY audo cables, as they can be made for pennies on the dollar, and outperform all but the very finest aftermarket retail cables.
( See: http://www.geocities.com/jonrisch/i1.htm and http://www.geocities.com/jonrisch/s1.htm )

Then you make some statements regarding speaker cables that are just plain wrong.
You state:
&quot;In addition, the inductance and capacitance of these cables is insignificant for runs up to even 100ft or so, compared to the actual impedance properties of your loudspeakers and the 20kHz bandwidth in question.&quot;

Well, how does a HF loss of -3 dB into a 4 ohm load, for a 100 foot run of 12 ga. zip cord grab ya? &nbsp;If you can also stand the damping factor to be reduced to less than 16 with that much resistance from even 12 ga., then OK.

But it is not quite as harmless as it is made out to be, and simple frequencye response errors are not the only issue.

There are material quaity issues, geometry issues (which relate to the speaker cable inductance), and all the other more subtle aspects involved.
See: &nbsp;http://www.geocities.com/jonrisch/c4.htm

RE digital audio interconnects, there are issues with the signal that go beyond mere zero's and one's. bits and words, and one of the major factors is jitter.
See:
http://www.geocities.com/jonrisch/jitter.htm
for more on this subject.

Jitter is insidious, and can arise due to the most seemingly unrelated issues of system/circuit behavior.

Once again, one need not spend a fortune, there are several DIY recipes out there for very high performance digital interconnects that don't cost a fortune. &nbsp;You can even get Belden to send you a free 3-6 foot piece of cable suitable for a high performance DIY digital IC, call:
1-765-983-5200 and ask for a free sample of either 1695A or 1506A. &nbsp;Then some decent RCA plugs and some soldering, and replace that cheap video cable used as a digital IC, and listen for yourself.

Jon Risch</font>
 
gene

gene

Audioholics Master Chief
Administrator
<font color='#000000'>Jon;

I appreciate your detailed and thorough analysis and the thought you put into your post.  However, your conclusions are loaded with engineering fallacies.

First off, if you look at the RLC lumped parameters of 12AWG wire, say &quot;Original Monstercable products,  you will find that the DCR is about  .002ohms/ft, Inductance is about .17uH/ft, Capacitance is about 22.2pF/ft.  Take 100ft, which would be a worst case figure for someone who is running speaker wires to their surround sound speakers in their home theater room and multiply all of these metrics by a factor of 100, you will have:
DCR = .2ohms
L = 17uH
C = 2220pF

I recommend reading this link for a better  understanding of cable metrics:
http://www.epanorama.net/documents/wiring/wire_resistance.html

If you model the L in series with the 4 ohm speaker load and the C in shunt with it, you will notice that the 3dB point is greater than 40kHz !!! I can live with that loss considering that the bandwidth of most normal humans hearing is about 1/2 half of that and almost no speaker on the planet in a typical living room can extend beyond 20kHz on/off axis.  

As for Damping factor, your way off on that one.  I cannot explain this concept any better than it already has been explained by a John Murphy (Physicist/Audio Engineer) as listed below:
http://www.trueaudio.com/post_013.htm

However, John basically explains that the DCR from the woofer is far greater than from the speaker cables for a resultantly lowered system damping factor, thus the cable DCR is a wash.  In addition, almost all modern day solid state amplifiers have a high enough damping factor to handle a few hundred mohms of cable DCR.  

Subject:   Effect on Loudspeakers of Amplifier Damping Factor
          (posted 2May01  to Bass List)

          Chris asked:

          &gt; I realized after thinking about slew rate and damping factor that I
          &gt; wasn't sure what the damping factor in an amp really meant.
          &gt; Would somebody be kind enough to explain damping factor.
          &gt; Also, does damping factor relate to slew rate in any way?


          The damping factor of an audio amplifier is unrelated to the slew rate of the amplifier.
An audio power amplifier's damping factor is defined as the ratio of the load impedance to the
          output impedance of the amplifier.

          Example 1:

          Amp output impedance at 1k Hz is known to be: 0.25 Ohms

          Impedance of the test load is 8 Ohms (at 1k Hz)

          Damping Factor = (Load Impedance) / (Output Impedance) = 8 / 0.25 = 32 (dimensionless ratio)


          Now, add a 0.25 Ohm speaker cable between the amp and the speaker and measure the
          damping factor at the speaker terminals and you would get: Damping Factor = 16
          (Note that damping factor varies with frequency)


          Example 2:

          What if you started with an amp with output impedance of 0.0025 Ohms?

          DF = 8 / 0.0025 = 3200             WOW!, what a spec!

          Now, add your .25 Ohm speaker cable and evaluate the damping factor at the speaker terminals:
         
New source impedance = 0.0025 + 0.25 = 0.2525 Ohms (at spkr terminals)

          DF = 8 / .2525 = 31.7                Where did the DF=3000 go! I paid extra for that number!


       
  Example 3:

          Now determine the damping factor at the actual woofer terminals:

          ( Hint: Internally the speaker has a 0.5 Ohm inductor in series with the woofer)

          Source Impedance = 0.0025 + 0.25 + 0.5 = 0.7525 Ohms (amp+cable+inductor)

          DF = 8 / .7525 = 10.6


          The point I'm trying to make is that the actual amplifier damping factor specification has little to do with the damping factor seen by a typical woofer...unless the woofer is welded directly to the output terminals of the amplifier ... there could be a patent here. :)

Many audio engineers are of the opinion that an amplifier damping factor of 10 or greater is
adequate. Those sky high damping factors seen on the spec sheets of some amps are frequently  just inventions of the marketing department and are irrelevant to actual system performance. The effect of higher source impedances (lower damping factors) is the same as adding series resistance in the speaker cable. Ultimately, the effect is a micro equalization of the frequency response as the voltage drive to the speaker becomes non-flat due to the frequency dependant impedance of the speaker. (adding series resistance creates a small peak at the speaker's own impedance peak...often on the order of 0.25 dB or so) The effect of the series resistance of the &quot;damping&quot; of  the speaker is difficult to see when the problem is viewed this way.

          The Q(tc) of a closed box speaker is increased by the addition of a series resistance. Here is the formula for this increase in system Q:

          Q(tc) = Q(tco) ( (Re + Rg)/ Re )

          where:
          Q(tc) is the final Q of the speaker system
          Q(tco) is the Q of the speaker with zero Ohms source impedance
          Re is the DC resistance of the speaker
          Rg is the added series resistance


          Example 4:

          Say we have a speaker system with Q(tco) = 0.707 and DC resistance Re = 6.5 Ohms.
          We add 0.25 Ohms of series resistance by way of our amp, speaker cable and crossover.
          The net Q of the speaker then becomes:

          Q(tc) = 0.707 ( (6.5 + .25) / 6.5 ) = .707 (6.75/6.5) = .734

So the effect of 0.25 Ohms series resistance is really to raise the Q of the speaker from .707 to
 .734. We could calculate the damping factor...but who cares! We are really only concerned with
 our net system response. Yes, you could say the &quot;lower damping factor&quot; has affected the transient response of the speaker for the worse. We've all heard the mysterious explanation that &quot;the cone keeps moving after the signal has stopped&quot;. But I prefer to look at the problem in terms of the speaker's Q(tc). We can all relate to the speaker Q much better than &quot;the cone keeps moving...&quot;.
 So I prefer to move any discussion of amplifier damping factor away from the mysterious &quot;cone
     keeps moving...&quot; and into the much better understood arena of speaker system Q.

          As you can see there is much more to the issue of &quot;speaker damping&quot; than just the amplifier's damping factor. In many systems the amp's DF will be irrelevant to the final system response because of the series resistance added by the speaker cable and the passive crossover components (see Example 3 above). Speaker designers should always be aware of the source impedance from which their speakers will be driven so that they can compensate for the source impedance in their design. If in fact your goal is to design a speaker system that will have a net response Q(tc) = .707 then you will need to anticipate the Rg (source impedance) the driver will &quot;see&quot; and design the enclosure for some lower Q(tco) such that the Rg will raise the NET Q(tc) to the targeted 0.707.

          Regards,

          John

          /////////////////////////////////////
          John L. Murphy
          Physicist/Audio Engineer
          True Audio
          http://www.trueaudio.com
          Check out my recent book &quot;Introduction to Loudspeaker Design&quot; at Amazon.com

          NP:  Santana, Put Your Lights On

{Reprinted with permission from John L. Murphy  10/02/02)]


As for your theories about video cables, you posted far too many fallacies for me to address at this moment.  I will come back when time permits.

In the meantime, I will allow your links to your website to remain in your original post for anecdotal reading purposes.</font>
 
J

Jon Risch

Audiophyte
<font color='#000000'>GDS,

RE the Original Monster Cable LCR parameters you posted:
&quot;DCR is about &nbsp;.002ohms/ft, Inductance is about .17uH/ft, Capacitance is about 22.2pF/ft.&quot;

While I do not have a sample of Original Monster handy, the measured data that I do have, both my own, and that of Fred Davis, indicate that most 12 gauge zip cords are higher in inductance than this, typically 0.25 to 0.28 uH per foot. &nbsp;Some common hardware store 12 ga. cables run even higher, due to increased spacing between the wires within the cable (fillers, webs, etc).

In addition, a simple calculation will not sufice to show the actual roll-off, due to the interacting factors involved. &nbsp;I measured this amount of roll-off with a hardware store 12 ga. zip cord, into a pure resistive 4 ohm load, accounting for the amp's FR droop of 0.1 dB at 20 kHz.

If you wish to use the very best inductance figure you can find for 12 ga. cables, fine, but I thought the whole point of this was to deal with the real world, and hardware store 12 ga. wires are often cited as &quot;good enough&quot; by many. &nbsp;You did not make any distinction about using Monster Cable instead. &nbsp;

Aside from these side track FR issues, there is more going on here than just a simple FR loss, this hard-core FR roll-off is the tip of the iceberg, the sign that transients will be dulled, not that you would hear the -3 dB at 20 kHz necessarily in a direct manner. &nbsp;Much is made of some folks not being able to actually hear 20 kHz, but as I said, that is not the real issue.

I fail to see the point of your link to epanorama, these raw wire facts have little to do with the more involved issues of using cables for carrying audio signals.
NEC/UL amperage ratings have diddly squat to do with how much sonic finesse a cable has.

RE the damping factor issues, this is not as cut-and-dried as it might seem either.

As a pro loudspeaker design engineer for the past 17 years, I work with loudspeakers everyday, and I have extensive first hand experience with what DF can and can not do for the sound. &nbsp;I do know that the simple formulaes do not tell the whole story, and to write off the speaker cable as a factor is not a good idea.

Besides, I was objecting primarily to your use of 100 feet as a gross example of what was &quot;OK&quot;.
If merely &quot;OK&quot; is all one requires, then by all means, use 12 ga. zip cords. &nbsp;SOTA performance is another matter.

RE video cables and what I posted being fallacies, I will have to &quot;wait until you have time&quot; to see what these objections are, but I have to warn you ahead of time, I did a stint at a video company, and designed an HDTV distribution amp that had to be flat out to 10 MHz, and with phase response within a few degress out to that bandwidth as well. &nbsp;All of this while it was driving hundreds of feet of cable. &nbsp;Having scooted video and video RF around thousand foot spools of cable, and having dealt with a wide variety of video issues, I am not the typical audio enginer who does not know TV.

While I did simplify things a bit for the benefit of those not being working video engineers, what I posted was basically correct.

Regarding the &quot;anecdotal reading purposes&quot; of the website links, all I can say is that a great many DIYers have tried making one or more of my cable designs, and out of literally thousands of folks who did so, there have not been any significant complaints or folks who posted that they did not perform as described.

However, I will be the first to acknowledge that THE most important link at my web site is this one:
http://www.geocities.com/jonrisch/a.htm
the link to the DIY Acoustic Treatment Info I make available.

Till the video cable reply,

Jon Risch</font>
 
G

Guest

Guest
<font color='#000000'>This is familiar territory (yet again) - and although I still don't find cables very interesting, I find it is necessary to post some information, based on some recent simulations I have done on &quot;typical&quot; configurations (among other things).

With respect to the comments on video cable, Jon has pointed out countless times that FR is not the be-all and end-all to cables (especially audio cables) yet this is the sole point addressed. &nbsp;If the cable's impedance is not accurate, this will result in ghost images as the signal is reflected by impedance mismatches, and the other &quot;flaws&quot; that are attributed to audio cables (skin effect, characteristic impedance, dielectric factor, dielectric loss and dielectric absorbtion) will certainly have ramifications at higher frequencies. &nbsp;That a properly constructed video cable (including long distribution cables) should not exhibit any ghosting, phase shift or other degradation is obvious, as the picture is not just light and dark, but has edges and details that will be easily destroyed by cabling faults.

These cannot be expressed as a simple &quot;loss&quot;, nor related to the video dynamic range - they are entirely separate issues, and are very much more complex than a typical audio application. &nbsp;The quality of a viewed image is determined by the bandwidth, phase shift, reflections/ multipath reception (the latter usually not an issue except in distribution systems), and a high quality image is easily degraded by only small amounts of any of these parameters. &nbsp;That the signal may be carried on an RF carrier as &quot;coded sidebands&quot; is immaterial - if there is significant phase shift or other signal modification, the effects will usually be quite visible, as the sidebands represent real bandwidth that must be accomodated (try filtering off the sidebands, and see how much picture is left).

OTOH, there is unlikely to be any percieved difference should silver wire be used, or if the cable has a steel core, if the cable has a Teflon vs. PVC or similar outer sheath, etc.

For interconnects, the only parameter of importance for typical home installations is capacitance - resistance and inductance are generally of a magnitude that will not impact any installation, unless unusually low impedances are used, and the cable has very high resistance and/or inductance. &nbsp;This is rare.

Speaker leads are another matter. &nbsp;The resistance, inductance and capacitance quoted seem reasonable enough, and some simulations were done (after conversion to &quot;real&quot; measurements - the definition of a &quot;foot&quot; is something on the end of a leg, to stop it from fraying
)

DC resistance is quoted (by Gene) as about 6.6 millihoms /metre, inductance .56uH /m and capacitance 73pF /m. Assume a 5 metre length (typical of many installations). &nbsp;Rather than using a simple lumped equivalence, I simulated in 1 metre &quot;blocks&quot;, using a fully balanced configuration for the simulation. &nbsp;Amplifier output impedance is assumed to be constant, and around 0.1 Ohm (not a wonderful figure, but it makes the simulation worse than would otherwise be the case). For the simulation, a 4 ohm resistive load was used, for no reason other than predictability (and repeatability) of the results.

Using the original values as shown above, the loss at 20kHz is 0.036dB into 4 ohms, or 0.12dB into 2 ohms.

So, let's double them all. &nbsp;Using values of 13.2m Ohms, 11.2uH and 146pF (per metre), response into a 4 ohm resistive load is -0.127dB down at 20kHz. Since it is well known that CD players have a nominal 20kHz &quot;brick wall&quot; filter, the small loss at 20kHz is of little consequence (assuming we can even hear that high - I can't) - and remember that this cable has twice as many of all the nasty things that cables have.

Note that these measurements are relative, and only look at the HF response relative to the LF response - damping factor and cable losses at low frequencies have not been included, but these were very adequately covered by John Murphy's comments reproduced in an earlier post. &nbsp;The resistive loss of the original cable at 2 Ohms vs. 4 Ohms is 0.27dB, and may safely be ignored.

The complete details of these simulations and &quot;ponderings&quot; will be on my website shortly (http://sound.au.com), and I will also make the simulator schematics available for anyone who wants to examine the effects more closely.

Now, it must be said that this particular cable would be quite suitable for a 100 ft (about 30 metres) run. &nbsp;The impedances will have a more noticable effect at 20kHz - in fact, the loss at 20kHz into 4 ohms will be approximately 0.97dB. &nbsp;Naturally, for an 8 ohm load, this is diminished (to 0.26dB), and it is doubtful that this small rolloff would be considered objectionable. &nbsp;I don't know the figures for 12 AWG &quot;zip cord&quot;, since it is not available by that name or size description in Australia, but it is doubtful that it would be much worse than the doubled figures above. &nbsp;Perhaps someone can supply me with the RLC values per metre (or foot if you must) of this apparently ubiquitous (in the US) cable.

The material quality difference and &quot;sonic finesse&quot; is dubious - loudspeakers and amplifiers are low impedance devices, and provided resistance, capacitance and inductance are within tolerable bounds, the actual materials are not highly taxed, and will contribute little or nothing that will be audible. Of course, this cannot be &quot;proven&quot; (to the reality naysayers) any more than the opposing viewpoint can be &quot;proven&quot; - the two sides on this issue are unlikely to ever agree on audibility, test methodology or anything else.

The fact remains that the &quot;subtle&quot; distortions that are claimed to exist at audio frequencies should play absolute havoc with RF or video, but this has not been shown to be the case. Presumably, the &quot;distortions&quot; go away again once one measures beyond the audio band. &nbsp;They can be measured (of course), and there are countless sites on the web that describe the effects of the dielectric, skin effect (etc., etc.). &nbsp;For any distortion to occur, it will require an inherent non-linearity in the materials used, either with amplitude, frequency or current. &nbsp;That dielectrics are non-linear to some degree is well known, but this only shows up at very high frequencies.

As for jitter, it would require some degree of incompetence (or a lack of understanding of the requirements for exact impedance matching) to design a digital interconnect that introduced jitter into the bitstream, yet this very error is intrinsic to the S/PDIF design! &nbsp;A properly made lead should present a constant impedance from the connector through the cable and the connector at the remote end. &nbsp;

The use of RCA connectors for this purpose is lamentable. &nbsp;None can maintain the impedance at the design value of 75 Ohms, since the ratio of inner to outer conductor is not correct. Actual impedance can be anything from less than 40 Ohms to about 60 Ohms, depending on the insulator used in the connector itself. &nbsp;Hardly a good match to a 75 Ohm cable. &nbsp;In case you were wondering, the inner conductor needs to be about 1.45mm diameter to achieve an impedance of 75 Ohms.

Most (if not all) systems use a clock recovery system (typically a phase locked loop), and will generally incorporate a (small) buffer to ensure that the bitstream is fed to the DAC at a constant rate (i.e. hopefully without jitter). &nbsp;That this area is open to further analysis is almost certain - jitter tests have been performed on a number of machines and cables, and variations are common. It is less certain that the variations have a direct effect on the &quot;sonic signature&quot; of digital systems, although there seems to be some correlation from what I have read on the subject.

Cheers, &nbsp; &nbsp;Rod</font>
 
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gene

gene

Audioholics Master Chief
Administrator
<font color='#000000'>Jon;

The last link you sent me to your sight makes good sense.  I agree 100% that budget dollars are better spent on room treatments than exotic cables.  
http://www.trueaudio.com/post_013.htm

However, I feel you generalize too much regarding the importance of good video cables, especially for HDTV.  

While I have not measured the RLC parameters of 12awg wire, I did get that data from whitepapers produced by Audioquest and Nordost where they compared their cables RLC paramters vs their competitors.  In addition, standard 22/24/26 AWG twister pair wire RLC paramters are well documented in ANSI standards for telephony.  One can extrapolate based on that data what the RLC paramters should be for 12awg wire and derive a pretty good estimate.
When time permits, I will take some 12AWG wire into my lab and measure its metrics with an HP LCR Analyzer.  I was using 100ft as an extreme case for mostly surround sound speakers.  Most of the time the listen is off axis to the actual speakers and thus 20kHz signals will never even reach there ears, assuming they can even hear that high. &nbsp; Also, I clearly stated to use 12AWG oxygen free multi stranded cable. &nbsp;Home Depot 12AWG is not oxygen free and the outer service corrodes over time.


I appreciate your follow-up and will comment further about your cable articles as time permits me to read them.</font>
 
G

Guest

Guest
<font color='#000000'>GDS,

Mr. Risch raises a good poing when he talks about subtlty in audio cables.  High-end audio is all about subtlty.  Jon has pointed out that silver plating gives wire a sound akin to needles in ones ears, and often points to the importance of using Teflon as the dielectric in audio cables.  Please explain why silver plating makes wire sound so awful, and why Teflon is so criticl to the proper performance of audio cables.

Thanks,

Thumper</font>
 
Clint DeBoer

Clint DeBoer

Banned
<font color='#000000'>Thumper,

You addressed GDS, but are you really addressing Jon? Rod Elliot made mention of silver and teflon not GDS...
And he stated that it wasn't critical whereas you are asking why it is - presumably a question Jon would need to answer.

Just clarifying...</font>
 
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G

Guest

Guest
<font color='#000000'><table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>
hawke : Thumper,

You addressed GDS, but are you really addressing Jon? Rod Elliot made mention of silver and teflon not GDS... ??? And he stated that it wasn't critical whereas you are asking why it is - presumably a question Jon would need to answer.

Just clarifying...
Hawke,

GDS didn't mention silver or Teflon, which is why I addressed my question to him.  I know what Jon claims for the materials, and I have read what Rod had to say.  GDS explains things very well, and I'd like to understand *why* silver and Teflon make such a big difference in sound quality.  Jon has done extensive testing in this area, and has even presented an AES paper on the topic.  Lots of people follow his advice and are pleased with the results.  Is it possible that GDS is handing out bad advice when he recommends &quot;standard&quot; audio cables?

Thanks,

Thumper</font>
 
gene

gene

Audioholics Master Chief
Administrator
<font color='#000000'>Thumper;

GDS didn't mention silver or Teflon, which is why I addressed my question to him. &nbsp;I know what Jon claims for the materials, and I have read what Rod had to say. &nbsp;GDS explains things very well, and I'd like to understand *why* silver and Teflon make such a big difference in sound quality. &nbsp;Jon has done extensive testing in this area, and has even presented an AES paper on the topic. &nbsp;Lots of people follow his advice and are pleased with the results. &nbsp;Is it possible that GDS is handing out bad advice when he recommends &quot;standard&quot; audio cables?


I am not familiar with Jon's theories about silver plating wires. &nbsp;However, my minimum recommendation for speaker cables is for Oxygen Free Multistranded Copper Cables.

Nor do I subscribe to his claims you mentioned. &nbsp;Speaker cables cannot make your speakers sound bright. &nbsp;They cannot introduce distortion or boost certain frequencies. &nbsp;They can only yield loss in frequency response from their additive RLC lumped parameters. &nbsp;Some of those exotic bi-wire &nbsp;speaker cables out there that are fatter than a garden hose, tend to be higher in capacitance than say standard 12AWG OFC. &nbsp;I have seen cables with capacitance as high as 2000pF for an 8ft set! &nbsp;This can have a tendency to cause some power amplifiers (usually tube based) to go into parasitic oscillation.


If you desire to go out and spend a fortune on speaker cables, than by all means do so.
However, you could alternatively take the money you would have spent on exotic cables and apply it towards:
1) Room Treatment
2) Upgraded Speakers
3) Upgraded Power Amplifier
4) Upgraded CD Player or DAC
5) Buy an identical power amplifier that you are using &nbsp;for two channel and Bi-Amp, not Bi-Wire your speakers, assuming they can accommodate bi-wiring.

I feel that any of the 5 options I listed as an alternative to costly exotic speaker cables would offer more bang for the buck. &nbsp;However to Jon's defense, it does look like the DIY cables he recommends are cost effective and thus you may wish to experiment with some of his receipts to determine for yourself if they make any audible improvements in your system over the cables you are currently using.

Stay tuned for a series of new article we are currently writing to further elaborate on these topics...



</font>
 
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