Anyone recognize these speaker cables? Flat, braided . . .

[njcanuck]

Picked up some speaker cables at an estate sale this weekend. They look to be pretty good quality and judging by the rest of the equipment for sale, is possibly expensive stuff.

It is flat, braided, "two conductor" copper wire in a transparent plastic sheath measuring 3/8" wide x 1/8" thick. The two colors are made up of very fine strands, almost like magnet wire, that are then combined and braided into the larger pattern. There are no markings on it anywhere. I'm sure I've seen it before somewhere but darned if I can remember where. Google hasn't helped yet. Anyone recognize it?

Here are the pics:

 

[kfalls]

These look like Polk Cobra speaker cables. They run about $500-$600 /pair depending on length and termination. I saw one reference to them being "Amp Killers". They are very high capacitance and resistive cables with the lowest inductance of any cable making them very fast. Commonly used as several paralleled short lengths together to reduce resistance. Best for tubes and newer solid state amps. As a single long cable can cause your amp to go into oscillation.

 

[njcanuck]

That's them! Thanks kfalls. I came home with three 16 foot lengths for a few dollars (in with a bunch of other stuff). It looks like I have some reading to do before I try them out, though! Maybe on a tube amp . . .

 

[JoeESP9]

I know for a fact that Adcom GFA-545's will produce high frequency oscillation when driving highly capacitive speaker cables. It was very easy to see on a scope.

 

[Chip Chester]

So, the way the pic shows the cable separated and twisted, are those two separate conductors? Or do you use one copper+green braided assembly for +, and another for - ?

I mean, if the green is actually insulated from the bare copper, how does it then make contact with the connector on the green twisted breakout section? (Or was the "remove green insulation" step skipped?) And just how thick is that green "insulation", if that's the case?

Chip

 

[njcanuck]

Pos and neg are both contained in the same cable, one conductor being copper colored and the other green. None of the wires are actually bare. All of the fine strands, even the bare looking ones, are coated with a sort of enamel insulation. This insulation has to be scraped or burned off to attach the terminations / connectors.

 

[BillWojo]

So what are the positive aspects of using a cable made in this manner? Also it would seem really easy for very minor damage to short the outputs in the amp if all the wire has is enamel insulation. I'm not trying to knock it but it seems to have a lot of negatives going for it.

BillWojo

 

[njcanuck]

From what I've read so far, the main advantage is the extremely low inductance making signal transmission almost instantaneous. Disadvantages are high capacitance, high resistance and potential for shorts (although I haven't read any reports of this happening, yet).

They do have a somewhat risky reputation! You can bet that I'll test them carefully before using them.

 

[Lesterbest]

These look like Polk Cobra speaker cables. They run about $500-$600 /pair depending on length and termination. I saw one reference to them being "Amp Killers". They are very high capacitance and resistive cables with the lowest inductance of any cable making them very fast. Commonly used as several paralleled short lengths together to reduce resistance. Best for tubes and newer solid state amps. As a single long cable can cause your amp to go into oscillation.

Polk smartly abandoned the "Cable Biz."

 

[4-2-7]

The wire you have looks like bulk non terminated that was available and or when ordered they would then terminate it for the setup needed..NOS.

If you have a system built for speed, high power, high quality amps you'll get all the benefits. Putting them in a system built around a vintage 80 watt receiver you'll most likely have problems, hell just trying to use them in spring terminals is a problem.

 

[kfalls]

From what I've read, having four runs of the same length wired in parallel provides a cable that is comparable to the best manufactured cables available. Keeping the lengths equal was heavily stressed. I've made speaker cables from CAT5 before with only eight conductors. These would be a nightmare to terminate. Recommendations for removing the insulation was with a soldering iron, or solder pot. Using a solder pot doesn't sound too bad, but if I had to strip/scrape each cable, diminishing returns would come into account very quickly. At the age of 61, I doubt I could hear the finer high-end details these could provide.

 

[njcanuck]

I have two 16' runs of factory terminated (I think) cable and a third run that is only terminated on one end. I don't think I want to cut them up to go massively parallel but I suppose I could parallel all three on one channel just to see . . . err, I mean hear. I bet a propane torch would make quick work of stripping the insulation.

Not sure if my 62 year old ears will hear any difference, either. I'll try them with a tube amp to be on the safe side. It's always fun playing around with stuff like this!

 

[unfairlane]

Do your amp a favor and stay away from these ones

 

[Lesterbest]

It didn't take Polk long to pull the plug on these cables due to amp issues.With the plethora of cables on the mkt today, I fail to see why these are worth persuing. BTW, I owned 2 different pr of Polk spkrs that represented good bang for the buck.

 

[njcanuck]

Deeper reading appears to indicate that the amp issues were due to poorly designed feedback circuits in early SS amps. Well designed amps and tube amps apparently did not suffer any adverse effects with these cables.

They are worth persuing because they are just sitting here looking at me.

 

[Lesterbest]

Fortune favors the brave. Misfortune is the longshot. Hook `em up. Inquiring minds want to know.

 

[RT Fan]

Very interesting, I have a similar pair that I picked up when I bought a full rig from a friend back in '92 or so. At the time he said they were the best speaker cables available from the PX where he bought his stereo, circa early 80's. Nice construction, certainly high quality for it's time.

 

[unfairlane]

Very interesting, I have a similar pair that I picked up when I bought a full rig from a friend back in '92 or so. At the time he said they were the best speaker cables available from the PX where he bought his stereo, circa early 80's. Nice construction, certainly high quality for it's time.

They are still seen as the best for some, like Mr.Arthur Salvatore on his reference-product site. But me I warn people; stay away..

http://www.high-endaudio.com/RC-SpkrCab.html

 

[RT Fan]

Thanks for the link.

 

[Tim D]

I received a set of Polk cables back around 1981 when I bought my Polk 5B's. I remember though that the cables were round and not flat like this, but they otherwise looked similar. Also, I was given some kind of capacitor like thing to put across the speaker terminals. I think that Polk knew they had a problem and were trying to work around it. Oh yeah and I remember that mine were really long. I usually had them wound up because they were longer than I needed.