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Jim Shearer 17th November 2009 07:52 PM

DIY speaker cable question
 
I'm getting ready to build some speaker cables using CAT5e wire. I plan to use 3 CAT5 cables braided together. That should make sufficient gauge. What I wonder about is the need for proper termination to prevent ultra-sonic ringing (and associated catastrophic failure of amp) due to capacitance of the cables. I found a reference to proper termination in an article: Speaker Cables Science or Snake Oil Article by Pass; found near bottom of page at this link:
Technical Papers

Matt Polk used .047 uF cap and 6 ohm R in series placed across the speaker terminals; Nelson Pass used .1 uF cap and 5 ohm R.

I know little about electronics. Should I add this termination to the CAT5 cables? What do you experts think?

Thanks, Jim

memofer 18th November 2009 02:45 PM

I have no answer for you, but hopefully someone knows and will post. I have been using one CAT5e for a while and I have had no issues blowing up my amp. I actually like how they sound. I have blown amps due to other accidents but not by using cat5e.

carlmart 18th November 2009 08:13 PM

Cat 5 based cables sound very good. But you have to be aware they are highly capacitive and some amps may not stand them.

Adding a zobel at both ends, adding the values, might be a good idea. Just remember that parallel resistors are a +b/2 and parallel capacitors add up.

Jim Shearer 19th November 2009 12:12 AM

Thanks. I thought that in the paper they added the zobel (if that's the right name) across the speaker terminals to damp out the reflected energy and prevent ultra sonic oscillation. Are you saying that I should put something at the amp end as well? And is this important for tube amps as well as the SS? (I have only heard of problems with SS, but that may be due to the dominance of SS in the market place.)

Thanks, Jim

Andersonix 19th November 2009 08:59 PM

I'm no expert (on this), but why don't you try it without the 'damper network' before deciding? The way I read 'the problem' is it applies only to some very high bandwidth output stages?

Have you thought of braiding four CAT5 cables together instead of three? I think it looks better....

jleaman 19th November 2009 09:07 PM

Quote:

Originally Posted by Tosh (Post 1986649)
I'm no expert (on this), but why don't you try it without the 'damper network' before deciding? The way I read 'the problem' is it applies only to some very high bandwidth output stages?

Have you thought of braiding four CAT5 cables together instead of three? I think it looks better....

How do you braid 4 ?

http://web.me.com/jason.leaman/audio/twist.jpg
http://web.me.com/jason.leaman/audio/cable.jpg

planet10 19th November 2009 09:19 PM

Jim,

Start out by trying a single pair... you might be surprised.

I just swapped out my single strand Cat 5 cables (dog chewed need repair), for a set of red & white ones Jason sent me to try out (as above).

The connectors are nice (althou 3/4" spaced doubles would not be a hardship), they are breaking in now (in other words i'll let them sit in the system for a while (and fix my known cables) before any serious compares.

dave

jleaman 19th November 2009 09:21 PM

Quote:

Originally Posted by planet10 (Post 1986691)
Jim,

Start out by trying a single pair... you might be surprised.

I just swapped out my single strand Cat 5 cables (dog chewed need repair), for a set of red & white ones Jason sent me to try out (as above).

The connectors are nice (althou 3/4" spaced doubles would not be a hardship), they are breaking in now (in other words i'll let them sit in the system for a while (and fix my known cables) before any serious compares.

dave

:P post pictures or email some to me :) The spades were just a test, they are pretty big, as im looking for other solutions.

BTW U got mail.!

BTW that's orange and white :)

Andersonix 19th November 2009 09:37 PM

1 Attachment(s)
Not the best pic and not the best 4-wire braid as the wires weren't all the same gauge, but it gives you the idea.

I will be braiding two white, one blue, and one red CAT5-type for my speaker cables (some day) which gives 12AWG.

jleaman 19th November 2009 09:42 PM

Quote:

Originally Posted by Tosh (Post 1986715)
Not the best pic and not the best 4-wire braid as the wires weren't all the same gauge, but it gives you the idea.

I will be braiding two white, one blue, and one red CAT5-type for my speaker cables (some day) which gives 12AWG.

cool, looks christmas'Y.

What kind of ends are you thinking about going and using ? Mostly everything on the market now a day's uses a heavy massed connector or something with lots of weight etc etc.


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