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gold

Platinum Blonde

Posts: 1,468 Member Since:27/01/2011

#41 [url]

Mar 17 14 2:58 PM

dcollins wrote:
I’ve been meaning to try some of the Grimm cable I have as a guitar cord.  Could even be better than the George L?

DC

I just saw very interesting cable. It was sold by Canford. It's coaxial cable about the size of RG59. The distinguishing feature is that the shield is made from conductive plastic. I'm told that this goes a long way towards making the cable non microphonic. I've never seen anything like it.

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ssltech

Aqua Marine

Posts: 4,034 Member Since:22/01/2011

#42 [url]

Mar 17 14 4:38 PM

I've seen guitar cables made using conductive plastic for some long time...

One of the most microphonic cables I ever encountered was a 'conductive plastic and drain wire' construction. -It was just awful. -Truly dreadful. -That's not to say that all are of course, but I have significant doubts that it offers a particular benefit. -I shudder to think what this cable might have been like otherwise.

Unless they can get conductive plastic with a SERIOUSLY low resistance, the ground resistance per unit length would be unacceptable without a drain wire, so I'm led to somewhat cynically suspect that the REAL benefit would be in the area of reduction in the cost of manufacturing process (extruding con-plas at lower temperatures and pressures) and cost of raw material. -Whether these cost savings are passed on may well depend on how good a job the marketing does of making the product seem appealing.

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gold

Platinum Blonde

Posts: 1,468 Member Since:27/01/2011

#43 [url]

Mar 17 14 9:09 PM

ssltech wrote:
One of the most microphonic cables I ever encountered was a 'conductive plastic and drain wire' construction. -It was just awful. -Truly dreadful. -That's not to say that all are of course, but I have significant doubts that it offers a particular benefit. -I shudder to think what this cable might have been like otherwise.
 

 
I don't doubt it. I was just spitting out what I was told. I had never heard of such a thing so I thought it was cool. It was in a pile at Leeds Radio. I got two really nice matching GE ammeters for a bipolar bench supply I'm building.

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soapfoot

Ruby Baby

Posts: 7,041 Member Since:04/02/2011

#44 [url]

Mar 18 14 7:23 AM

I have to swing by Leeds today, so I'll ask Richard about it. I have an 0A2 regulator I have to swap out, and I want to pick up some new tubes for an AM864/U that's acting funny.

brad allen williams

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gold

Platinum Blonde

Posts: 1,468 Member Since:27/01/2011

#45 [url]

Jul 22 15 4:31 PM

He got rid of a lot of stuff. I didn't see any cable around. He said he only brought the stuff that was worth selling. Bulk resistors and caps, gone. oscilioscope CRT's, gone, anything that costs $0.02 and you only need one, gone.

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Mickeyrouse

Silverado

Posts: 127 Member Since:05/11/2015

#47 [url]

Jan 5 16 11:59 AM

Re cable and construction:
Ready-made cables are iffy at best. I have never seen published specifications on ready mades. Molded-on connectors are repair-proof.
Learn how to use a soldering gun or iron. Use good connectors and cable. Be careful, don't get in a rush, and your cables will be as good and reliable, if not more so, as any you can buy, and cheaper.
Learn how to check for continuity on a suspect cable. Somebody other than you will at some point be unplugging cables, and will be unconcerned or unaware of the time it takes to make and repair them. The problems are always at the connectors. In over 50 years of playing music and being in studios I have NEVER seen a failure any other place- (though it must surely be possible.)
In choosing cable, the better manufacturers- Canare, Mogami, Gotham, Belden, and others- publish specs on their offerings. Depending on grade, there is little difference between the better grades. In comparing, it will be necessary to do metric conversions. Impedance per foot indicates signal loss per foot, not necessarily linearly. Capacitance per foot indicates filtering per foot, starting at the highest frequencies. (Think of a long skinny crossover, or low-pass filter.) It is likely that there are roll-off and attenuation variations between brands, but considering the tiny capacitance per foot differences, it is difficult to imagine this outside the lab realm. Available ratings on this are typically found at less than 60 picofarads per foot. That's micro micro farads. On studio lengths, likely indiscernible without lab test gear.
Interestingly, Canare publishes a decibel loss of .9 per 1000 feet. If the typical studio cable is about 25 feet long, excluding rack, patch bay, console, and fixed runs, that signal loss in that cable is .0225 dB. My ears can't hear that at my age, and considering the logarithmic nature of the decibel, I doubt ears 50 years younger can either.
Some manufacturers also publish RF rejection data. I have never found this meaningful. Out side of particular problem locations (location live recording, for example) balanced Lo Z cables have never been a discernible source of RF interference in my experience.
Neumann, in literature for some of their mics, claim that cable runs up to 1000 ft. can be made without degradation of loss of signal. Granted, that may be dependent on mic output level and the cable they are using, but it sure seems to hint that "normal" ears couldn't tell the difference between a 15 ft cable and a 25 ft cable of the same type and brand using the same mic, and comparable signal, of course holding all other variables the same.

Last Edited By: Mickeyrouse Jan 5 16 12:03 PM. Edited 2 times.

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waltzingbear

Platinum Blonde

Posts: 1,203 Member Since:16/07/2012

#52 [url]

Jan 6 16 3:33 AM

the output impedance of something like a condensor mic is in the range of 20 to 50 ohms, much lower than dynamic mic. Therefore (even) less loss on long runs.

there are devices that you can use to help identify where an internal break is in a cable, usually not cost effective however. They are meant for long cables like phone lines.

Alan

Alan Garren
Waltzing Bear Audio

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barry hufker

Diamond Forever

Posts: 11,893 Member Since:26/01/2011

#53 [url]

Jan 6 16 3:37 AM

compasspnt wrote:
I have had failures in the middle of long cables…but they were sometimes placed through doorways, with the doors rubbing against them.

Doing mostly location recording, I've had a million odd things happen to my cables and have had to run in them in weird places, for instance when recording operas.  I've had the usual failures but I've also had my cables painted by the stage crew (without asking or telling).  I used Canare starquad for a while but the capacitance is very high.  These days I prefer Gotham and Accusound.  I keep my Accusound cables safe and only use them for my "hi-fi" projects.

Talking about cables with faults in the middle, the phone company uses some method for finding faults where they send a signal down a line and can determine by how soon it bounces back that it has reached the end of the cable or a fault in between.  Even tho' audio lines aren't run in miles (that I know of) for gigs, I always wondered why no one developed the phone company method the average audio engineer could readily find the fault in a (long) bad cable and not have to guess.

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drknob

Gold Finger

Posts: 788 Member Since:02/02/2011

#54 [url]

Jan 6 16 8:48 AM

Fluke has had a Cat5/6 distance-to-fault identifier for years. Much cheaper now: Fluke.
This one claims it's good for audio cables here.
Just open your wallet.....

Harold Kilianski

Music Industry Arts
Fanshawe College

Last Edited By: drknob Jan 6 16 8:54 AM. Edited 2 times.

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waltzingbear

Platinum Blonde

Posts: 1,203 Member Since:16/07/2012

#55 [url]

Jan 6 16 12:20 PM

variations on a TDR time domain reflectometer

its also what you use to look at the characteristic impedance of a line over distance, mostly used at rf. (where it can really matter)

Alan

Alan Garren
Waltzing Bear Audio

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barry hufker

Diamond Forever

Posts: 11,893 Member Since:26/01/2011

#57 [url]

Jan 7 16 4:11 AM

"Fluke has had a Cat5/6 distance-to-fault identifier for years. Much cheaper now: Fluke.
This one claims it's good for audio cables here.
Just open your wallet....."

Ouch!  Maybe when it becomes cheaper... some day...

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