[Budgie]

I use mostly DIY interconnects in my system and use small gauge wire, such as magnet wire, most often. I decided to try and see how twisting the wire together would affect the capacitance of the interconnect, as I consider capacitance to be the major factor in interconnect performance.
Using two equal lengths of wire, I pulled them through a 3/16 inch vinyl tube, in a roughly parallel, random arrangement. The capacitance measured 46.3 picofarad. To verify that the vinyl jacket is not adding to the capacitance, I removed it and got the same reading.
Next I removed the wire and twisted them into a twisted pair configuration of approx. 3 turns per inch, reinstalled the pair into the vinyl jacket, and measured again. 200 picofarad. Quite a differance in capacitance from such a simple change.
The addition of the extra capacitance is enough to cause the top end to roll off, using the twisted pair. If your system tends toward brightness, you may like the slight roll off. If your sytem is more balanced, then bright, you may want to try not using twisted cable for your interconnects. Slight spacing between the two condutors decreased the capacitance even further.
Additionally,braiding has the same effect also on the capacitance, as twisting.

Braiding and twisting has very little effect on noise pickup for unbalanced audio connections, such as RF interferance, due to the low common mode rejection of unbalanced input circuits.

I hope this helps those of us who build our own cables to get a little better handle on what we get from a few design choices.

 

[bootman]

You know that this is the real reason that cables sound different.

 

[aeberbach]

Stands to reason, capacitance is the ability of two conductors to hold a charge. If you twist the wires you get more wire in close proximity to the other conductor, and more capacitance.

 

[Budgie]

I should mention that the length of the interconnect tested is 3 1/2 feet, end to end. the tests were done without the rca connectors installed.

 

[rickcr42]

Damn nice post budgie,I had read that several years ago but never really put it to the test.I use parallel magnet wire between preamp and amp but twisted pairs elsewhere.My preamp has a high output impedence and the amp low so capacitance is a real factor here.On componants with low impedance / high output drive current I use the twisted pair or trio.Nice heads up

Rick

 

[Budgie]

Thanks Rick. So are you using a passive pre, or tubes?

 

[crk]

Budgie, Rick
What's the advantage of using small gauge wire (magnet wire)? I would have thought the thicker the better!
crk

 

[Budgie]

For interconnects, gauge is not really an issue, because the current flow is very small, unlike speakers, which need current to operate. Some people believe that "skin effect" is a problem at the upper octaves of the audio band. I don't really have an opinion on that issue, yet, but if it is true, a thinner conductor would help mitigate the effect. Some people report getting better results from thinner gauge wire, when used for interconnects. I have also ran into a few people who insist thin wire also sounds better for speaker cable too. I figure it wont cost much to give it a try, so what the heck.

 

[rickcr42]

Quote:

So are you using a passive pre, or tubes?

Neither.DIY Nelson Pass Bride Of Zen (BOZ) line stage.A single mosfet in single ended class A with no feedback.But the volume control is on the output and it is 5K so the actual impedance is higher than the normal line stage.
And I use the ZEN Amp (also a SE mosfet design) which has a low input impedance of around 5K and you high end attenuation with high capacitance cables.
BTW-I use cat 5 for my speaker cables,single run though most DIY plans on the net use two.Best available ? Nope.But not bad for $0.50 ft,and the color blue looks cool too

Rick

 

[Budgie]

So you built the BOZ/Zen yourself. I keep looking at the Zen amp, but I haven't tried to gather parts yet. What did you use for the Bias resistors in the Zen amp? (Sorry for all the questions), Wow, looks like were hitting Afghanistan -the news just came on. Catch you later.

 

[rickcr42]

mine is a combination of both the zen and return of zen.Mostly zen but (the .33 ohm 2 watt resistors) added the film cap bypasses,feedback resistor (which means changing the trimpot to 25k from 10k and the input resistor from 4.7k to 1k) and the additional filter stage.
My version is also running at reduced power by using a variac.The reason behind this is my use of not enough heatsink area.This baby runs HOT ! If you think you have enough,double it and you may be on target.Fans (run at 1/2 speed for lower noise) are also recommended but in my layout hard to implement.
At some point I plan to build two more and run them as two mono amps (in and out strapped)and move this one to tweeter duty only.

 

[Daniel Pumphrey]

The main reason I braid my solid silver cables is to enhance the strength. Solid silver has the least capacitance anyway. I also keep my cables as short as possible. Headphone gear rarely needs over a foot of interconnect wire between the amp and source.
There are differing opinions on wire gauge and also the use of single conductors as opposed to stranded. (Many conductors). I prefer single conductors but also have made some great mulitstrand cables.
Computer cables are usually multistrand silver plated.
Dan

 

[Daniel Pumphrey]

"The Bigger the Better" is an old outdated solution that does not hold water anymore. Quality of a conductor is more important.
Dan

 

[Audio Redneck]

Quote:

Originally posted by rickcr42 BTW-I use cat 5 for my speaker cables,single run though most DIY plans on the net use two.Best available ? Nope.But not bad for $0.50 ft,and the color blue looks cool too Rick

Rick,
I was curious if you use any special combinations of the +/- wires and what are the results.

 

[rickcr42]

was going to whip out an e-mail to ya but this is probably better,others can read and laugh or read and be impressed

Nothing fancy.there are many elaborate versions floating around the net but i like to keep things simple.

V1.0-decide how long the run is from amp to speakers,measure that amount of cat 5,cut,fold in half and cut at the fold.You now have two pieces of cat 5 cable ,mine are 10 ft each run.Strip aboutfour inches from each end of both cables,the outer jacket only-be careful not to cut through tto the inner wires.I use a coax stripper from radio shack (tip : buy it,save all packaging and receipts,use it,repack carefully and return it).
You now have four twisted pairs of one solid and one striped wire.Connect all the solids together and all stripes together..Slide some heat shrink over the wires,add connectors of choice,spades or banana plugs are fine,slide the heat shrink down and shrink it to make it look professional
DONE DUDE

V2.0-cut FOUR equal lengths of cat 5 cable,strip as above,but THIS TIME connect all the wires in each cable together in each bundle.What you end up with is four "cables",twist them together in pairs of two,not too tight and tape off every two feet or so,whatever works for you,finish off as above.

Which is the better cable ? Got me,I like both so i use both.Single run for the mid-high satellites,double run for the bass bottoms.
YMMV

Rick

BTW-the individual strands make pretty good hookup wire for projects