|
|
This topic comprises 4 pages: 1 2 3 4
|
|
Author
|
Topic: long interconnect ( balanced ) to amp and short wires to subwoofer or the opposite ?
|
|
|
John Pytlak
Film God
Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000
|
posted 01-01-2001 02:38 PM
Randy --- for DC and AC current, the entire conductor carries the electrons, so it is the total cross-sectional area and the conductivity of the material (e.g., aluminum vs. copper) that determines current carrying capacity / line loss. AFAIK, surface conductivity only starts to occur in the radio frequency spectrum (RF).------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
| IP: Logged
|
|
Steve Guttag
We forgot the crackers Gromit!!!
Posts: 12814
From: Annapolis, MD
Registered: Dec 1999
|
posted 01-01-2001 03:21 PM
John is on the money. Surface resistivity is a function of frequency and for copper, the frequency must be quite large (way beyond hearing) before the current distribution comes into effect (the skin effect). The advantage of using stranded wire is in the connection and flexibility (included in that is the less likely to break). Increasing the number of strands helps out the installer on the pull/dress, and in the connection plus the long term reliability of the connection. In strict current carrying capacity, the solid conductor will work as well. Gordon: Presuming your twisting jig is fixed and someone is pulling the twisted cable through, what is keeping the conductors from twisting together before they "go in?" If it requires that someone feed the jig as well...that is cut the conductors to length and have someone at the end keeping up with the drill so they don't pre-twist, that method would work. Please explain. Steve ------------------
"Old projectionists never die, they just changeover!"
| IP: Logged
|
|
|
|
|
|
John Walsh
Film God
Posts: 2490
From: Connecticut, USA, Earth, Milky Way
Registered: Oct 1999
|
posted 01-01-2001 08:13 PM
Everyone has different experinces, of course. But, I've been just stuffing wire ends into a drill chuck and twisting away, and never had any problems. Usually, the end closest to the drill gets twisted the most. I twist until I get about 1 twist per 6in.I mean, I didn't strip back the entire length to check, but I've striped back short sections at the ends, and didn't see any breaking. I didn't see anything on twisting wire after a quick look through my NEC book. Only size of pipe and how many (of what gauge) wires can be used.
| IP: Logged
|
|
John Eickhof
Jedi Master Film Handler
Posts: 588
From: Wendell, ID USA
Registered: Jan 2000
|
posted 01-01-2001 11:34 PM
I'm with you Paul! First, we must consider the purpose of this wire! Mainly it carries low amperage signals of A.C. origin and is generally laid inside a conduit or is supported well, thus, strength / integrity of conductors is not an issue as the wire is basically way over rated for this application, and the individule strands are carrying the signal anyway, (whether they are tightly wound or not.)as compared to: max. current @max. volts continuously! Next, 'Skin effect' comes into play at high A.C. voltages ie: 2500 V. A.C. or greater, with high current passing. ie: long distance A.C. transmission lines that are 5kv or more, the conductors for these are in fact HOLLOW!(Aluminum outer structure, with steel strand inside structure for strength, Generally filled with an inert gas to help prevent ionization and deterioration of these conductors) In these cases, 85-90% of current is travelling on the outside skin of the wire! This is NOT a factor in low voltage A.C. lines. Of course, RF energy is even more severe! so don't hook up that 1kw linear HF amplifier to you're loudspeaker lines! And if you do, dont touch the conductors! Happy new year to all! & Happy B-Day Film Tech!
| IP: Logged
|
|
|
|
|
|
Bruce McGee
Phenomenal Film Handler
Posts: 1776
From: Asheville, NC USA... Nowhere in Particular.
Registered: Aug 1999
|
posted 01-02-2001 02:38 PM
OK. I wish I had a real theater!This set-up using the 10ga solid UF cables is going to be at the most 15-18 feet, and have terminal boxes at each end. I'm doing this because my house has a crawl-space under the theater/booth, and is a major pain to get into due to my large stomach! (Thank you, Michelob!  ) I'd rather pull the one heavy wire rather than a group of lamp cords. As I said before, the wire can be run so that there will be no twists, and since the wire is flat, I can use the two outer wires as the hots, and the inner two as grounds. My amp is a 100 watt Sony Pro Logic and will be hooked to a pair of Advent speakers.
I think that non-sync CD music will be the best quality that these wires will ever carry. My Holmes projectors are mono! As for interference, there are radio stations nearby, but these have never caused any trouble for me in the past. I wont try this if you brains think it is a bad idea. I've never doubted you before... Thanks!
| IP: Logged
|
|
|
|
|
|
|
|
|
|
|
|
|
|
All times are Central (GMT -6:00)
|
This topic comprises 4 pages: 1 2 3 4
|
Powered by Infopop Corporation
UBB.classicTM
6.3.1.2
The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion
and agrees to release the authors from any and all liability.
|
Home
Printer-friendly view of this topic