What cable are we using on location?

Posted: Mon Feb 14, 2005 12:12 pm

Sonarerec wrote:

HF roll-off as a fundtion of capacitance is a fact of electrical life-- I think it was on the Belden site.

I don't doubt that for a second - my question was can I hear it? Does it matter to me under real-world conditions?

Posted: Mon Feb 14, 2005 12:27 pm

Does it matter to me under real-world conditions?

Great thread, Karl! I've stayed out of this thread for lack of any additional useful input on my part. (I like all the major players, with no serious problems to report.) I'm glad to see such a sane approach for cables here. Thumbs Up

In general, I think all the basic rules apply: Use good connectors and soldering techniques if you're going to roll your own, and buy from any of the big three (or four) when getting off-the-shelf stuff.

The talent in FRONT of the mics (and the space they're in) will determine the sound moreso than anything else in the chain, the rest is just details. (Oversimplifying, of course!)

I'm old fashioned: I take care of my stuff, but I STILL don't gaff-tape down any wires until we've powered up the mics and know they work. Sooner or later, no matter what the brand, something's gonna break, somewhere. Not just the "Sound" of the cable (as such) I'm just as impressed with the reliability of it.

Posted: Mon Feb 14, 2005 1:06 pm

Got it Karl.

Posted: Sat Mar 05, 2005 11:37 pm

Hey Zemlin,,

i was doing a s earch on cables etc and saw your test,,,

anyway of doing a test comparing cable brands as apposed to lenths?

say the same 50' Conaire, against whatever brands that you have in your studio that we may know? Nogami, Belden etc,,

just curious,,

thanks for the info

SI

Posted: Sun Mar 06, 2005 5:30 am

I suppose it would be possible, but I don't have a lot to choose from. I have a couple of PRO-CO 50' cables - the only identifier on the cable says "Professional Low-Noise" and I have some Connectronics Musiflex cables I picked up from a guy who used to do SR work. The most noteable feature of this stuff is the shield which is conductive plastic.
http://www.louisgrace.com/gfx/thumbs/Musiflex.pdf

Last I have my ho-made snake - 100' of General Cable 19-pair cable. The cable is fairly old but it might still be a current product for them. I think the specs are still available.

The work is stacked up pretty high right now, so I don't know when I'll get around to doing this again. Tests like this are best performed when my wife isn't around wondering why I'm comparing cables rather than installing baseboard and trim in the Kitchen. Wink

Posted: Sun Mar 06, 2005 8:10 am

Hey Zemlin

I sure don't want to get in the way of house work on ya Smile

)

thanks for the quick reply,,,

just think it would help us with runs of 75' or less to see if spending $$ on big brands is worth it ..

if anyone else has input, thanks

SI

Posted: Fri Mar 11, 2005 9:17 pm

I bought gobs of connectors a few years ago while working a big wiring project at the station. I happen to like the Gepco multi-pair cables and asked them about connectors. They sell lots of connectors - think about it, they sell a load of cable and cables need connectors.

Bought 100 pc qty of Switchcraft metal TS and TRS, and a few dozen each of Neutrik XLR-M and XLR-F from them when I ordered my cables. Their connector prices were quite good (at that time).

There are two things about cable capacitance that pop into my mind:

1) the higher the C, the more the cable can roll off the high frequencies (f = 1 / 2*pi*R*C). Moral #1: make sure the cable driver has very low series resistance to keep the roll off frequency as high as possible. Some amplifiers can literally go unstable driving highly capacitive loads - especially feedback type amplifiers (op-amps). Moral #2: minimal C, minimal series R yields happier driver amplifiers.

2) the higher the cable capacitance, the more current is required to drive it. (i = C * dV/dt). Higher drive current can cause slew-rate limiting in amplifiers of limited bandwidth and loss of level under large-signal conditions and is exaggerated at high frequencies . Both cause distortion. Moral: you want good current drive at max signal level across the frequency spectrum

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