[Audio Redneck]

Thanks. I got a box of CAT5 (and Cat4 and Cat3) scraps that are looking for a purpose in this life and I think you've just given it to them.

You recommended the scraps to me for hook-ups on a CMOY/switch box project (that I still haven't gotten around to building - unintened job changes made life a bit hectic this summer)

Speaking of which, my backups done so back to work.......

Too bad Jude doesn't have a yawn symbol.

YAWN

 

[rickcr42]

Got that right .....YAWN

The rickster is outta here

 

[jteef]

What do you guys think about rod elliotts articles on cables ?

He thinks that the speaker cables (or in our case, headphone cables) have a much greater impact on the sound than any other set of cables. And that low inductance designs might be better as long as the amplifier can handle the increased capacitance in an inductance minimized cable.

The only thing I have seen that makes reasonable sense in interconnect lines is using a higher voltage over the longer runs because the induced noises in the line will be a lower % of the overall signal in an unbalanced system.

RE also says that capacitance in interconnects should be avoided. So then should twisted lines be avoided completely in unbalanced setups ?

I have doubts to whether any of this makes any audible difference since i've never seen any double blind AB test that shows otherwise. Still, as an engineer and an audio lover, I'd like to know the right way to do it.

jt

 

[rickcr42]

Talk to two "experts" and you will get two different opinions.My take is-use what works for you and don't worry about what others say SHOULD sound good.How many out there use Kimber Kable PBJs and love them ? And one mans great cable is another mans turkey.Can be very system specific at times,kinda like a tone control to either accentuate or attenuate certain freaquencies.

 

[Budgie]

I don't think I have read his opinion. (Its Kinda counter to mybeliefs, by I will readly admit to a degree of dip****tedness. ) I will take a look at his comments, maybe it will change my mind.

 

[sneared]

Seems like this is a lesson that has to be learned over and over.

Back before electricity (early '70s) we were experimenting with instrumentation cabeling. And DUH, we found that noise on the cable was a function of impedance matching, cable capacitance, and termination. We were mostly interested in noise, but it was also obvious that these factors affected the dynamic response of the cable.

Check out the article "Speaker-Cable Impedance Concerns-Real or Imaginary?" by Dennis Colin in the March 2001 Audioxpress.

His conclusion:

You can hear the differences in cables because of:

1. Signal loss differences

2. Response deviations due to cable inductance or capacitance interacting with speaker impedance or amplifier stability.

and

3. Interference pickup.

 

[Budgie]

Thanks for the input, sneared, but I don't see how that relates to my attempt to determine the effect of twisting conductors. My understanding is that twisting is valid and neccesary for differential circuits to perform correctly, but is pointless or even detrimental for unbalanced, non-differential circuits.

 

[Daniel Pumphrey]

Budgie, I can't tell a difference between wisted pairs or parallal pairs. As far as this affecting speaker cables I just hear that certain newer cable designs can cause problems when older Class A amp designs are used. This would cause problems when using longer cable runs maybe.
I tried one DIY speaker cable using cable TV wire and didn't like it at all. It didn't sound as good as my standard lamp wire.
I have not tried the CAT 5 cables yet but do like this wire for audio. In fact I buy the more expensive RS Cat 5 and remove the insulation which is teflon. I use this insulation as a cover for my .999 solid silver wire for interconnects and amp wiring. I get the pure silver wire from a Jewelry supply company.
This wire should make a nice speaker cable.
Dan

 

[Budgie]

Yes, it may not have any effect on certain systems ( the extra capacitance) and maybe desirable or detrimental to others. But it is helpful to have an idea of what the results of twisting the conductors together will be.
Glad to hear your "rolling your own" interconnects. It is one of the fun parts of this hobby.

 

[Daniel Pumphrey]

I am aware of the concern with capacitance of cables and configurations. Much of this has caused the return to smaller diameter wires and less complicated configurations.
My own use of pure silver wire is in part because of capacitance especially capacitance at amp inputs.
For years I was critical of audiophile cable designs mainly because of the high cost of the same. Now that I make my own cost is not a consideration. I can make a cable for a few dollars that is every bit as good as a 500.00 Kimber pure silver. This really saves money in Audio.
Now we are beginning to see that the super high performance opamps absolutely need careful low capacitance ground planes, so the configuration and physical properties of wire and other metal conductors becomes even more important.
If these opamps need low capacitance ground planes then low capacitance cable to and from them are a must also.
I can hear an improvement in my amps when they have a real circuit board as well as silver wiring inside. I do use the braided configuration when using silver wire but maybe this too needs to be changed. Maybe there is a reason also for these ribbon cables used in high speed computers as all conductors are parallel.
My brother swears by these new flat ribbon speaker cables he uses too. Again, very low capacitance.
Dan

 

[rickcr42]

it is my opinion that cable capicitance really is a non issue with short cables, 1 meter or less.It is when you get into long runs that attenuation of high frequencies becomes a reality.Of course,hook up a high capacitance speaker cable to an amp with stability problems and you get a big ass oscillator,bye bye tweeters

 

[Budgie]

A good reason to avoid long cables. (at least for imterconnects)

 

[kwkarth]

General rules of thumb:
Quote:

The main reason I braid my solid silver cables is to enhance the strength. Solid silver has the least capacitance anyway.

Solid silver or any other conductor has no capacitance in and of itself. As was posted here earlier, capacitance is determined by the effective distance between and total surface area of two conductors in proximity to one another.

Quote:

...My understanding is that twisting is valid and neccesary for differential circuits to perform correctly, but is pointless or even detrimental for unbalanced, non-differential circuits.

All other things being equal, a twisted pair will have higher capacitance per foot than two non-twisted conductors. This is because they'll be in closer proximity to one another. However as a twisted pair, they'll also reject RFI much better because with each twist you invert the phase of any induced signal which then self-cancels as a result.

A low impedance circuit will be less affected by capacitance than a high impedance circuit. So typically, line level "inputs" which normally have a characteristic impedance of 10k ohms can be affected by capacitive loading from cables.

Obviously the typical input will be very sensitive to RFI so normally, mic and line level interconnects should be shielded unless you live in a Faraday cage.

Typically, speaker level outputs being very low impedance will not be affected by nominal cable capacitance. Since most of us live in an industrial/urban environment, even speaker cabling should be shielded (i.e. twisted) in some way if there is any length involved because RFI can get back in to the amp through that route. Some amps are sensitive to this, some are not. Typically depends upon things like the degree of negative feedback unsed in the design, whether or not loading coils are used in the output, which tend to act like RF choaks, etc. My .02...

Cheers

 

[Audio Redneck]

Quote:

Originally posted by kwkarth General rules of thumb: <snip> All other things being equal, a twisted pair will have higher capacitance per foot than two non-twisted conductors. This is because they'll be in closer proximity to one another. However as a twisted pair, they'll also reject RFI much better because with each twist you invert the phase of any induced signal which then self-cancels as a result. <snip> My .02... Cheers

Excellet explaination! I was going through some cable guides for this.

Moving on....

Budgie,
While I agree that it is best to avoid long interconnects, because of shielding, RFI, and the like: if you have to choose, long interconnects are "often" the lesser of the two evils between long interconnects and long speaker runs.

YMMV

 

[Budgie]

I know that is the standard take on the "if you need to go long" issue- longer interconnects are better then longer speaker wires, but I wonder if that should be considered to be a situation dependant rule. I think the chance to pick up noise and interferance is much greater in an interconnect. And one of the problems with unbalanced interconnection is that the shield is actually part of the signal path. (one of the reasons balanced connections are used in pro gear).
If you need to go longer for your speaker leads you can always use a heavier gauge cable.

kwkarth- You are right about the feedback issue. I attended a talk at the VSAC show, put on by Linn Olsen, regarding the amplifier/speaker interface, and noise, and back emf getting into the feedback loop is a real problem for high feedback designs, and may contribute significantly to the sound of an amp. One reason why high feedback designs may not sound so good, compared to the low/no fdeedback designs. It was a path I had not really thought about before. Interesting stuff.

Twisting will cause phase changes in the recived signal? I have a hard time visualizing that. Is it wave length dependent? Seems a long wave length would not see the twist and it would become more apparent as the freq gets higher. My understanding is that the reason for the twisting was to get equal noise pickup in both conductors, so the high cmrr of the differential input could ignore it. (the twisting converts the recieved nosie to common mode noise)