peter%versatc.uucp@ames.arc.nasa.gov (Peter Tapscott ) (02/28/91)
Michael from Florida wrote to ask how to build twisted pair shielded interconnects. Since this might be of general interest, a posting seems be appripriate. The cable has three conductors: signal signal return shield Connect the signal to the center pin of the RCA plugs. Connect the signal return to the shell of the RCA plugs. Connect the shield to the shell of the RCA jack at the device receiveing the signal (preamp if this is a interconnect to a CD, amp if this is a preamp-amp interconnect. Insulate the shield near the other end of the cable. Use RTV (room-termperature-vulcanizing rubber) or shrink tubing or whatever. If you want to prevent those dastardly oxygen atoms from attacking your oxygen-free copper, coat the connections in the plugs with RTV. Might help in humid climates also. Someone will ask about cable and connectors. Old Colony has some Magami cable, but there are a lot of other cables that would work fine. Standard microphones that use XLR connectors need this type of cable, so a pro-sound place (musical instruments, amps, etc) might be a good source for reasonable prices on good cable. (high-enders: please post if you find good cable.) I bought my cable in Akihabara (Electronics City) in Tokyo. Besides all the mid-fi vendors, there is a flea market arrangement under the train tracks that sells all manner of small parts. They have at least 6 types of high-end RCA plugs, and cable is available by the foot. I bought Hitachi cable because I wanted two conductor plus shield, but they have all types, even European. Some are coax, some are 2-cond + shield. -- |----------------------------------------------------------------------| | peter@versatc.VERSATEC.COM -OR- {ames|apple|sun}!versatc!peter| | Peter Tapscott - Xerox Engineering Systems, Versatec Products | | 2805 Bowers Avenue, Santa Clara, Calif (408)982-4235 |
rbars@hila.hut.fi (Rainer B{rs) (03/04/91)
In article <9812@uwm.edu> peter%versatc.uucp@ames.arc.nasa.gov (Peter Tapscott ) writes: >Michael from Florida wrote to ask how to build twisted pair >shielded interconnects. Since this might be of general >interest, a posting seems be appripriate. > >The cable has three conductors: > signal > signal return > shield > ** deleted lines *** > >Connect the shield to the shell of the RCA jack at >the device receiveing the signal (preamp if this is >a interconnect to a CD, amp if this is a preamp-amp >interconnect. > ** rest deleted ** Hi net! I might be wrong, but I have read, that the shield should be grounded in the end that has a lower impedance. Usually, I think, it is the signal-feeding end of the equipment. The reason for this I do not know, but maybe someone else does? This should be straightforward grounding techniques without any mysteries. And a question, which possible should be somewhere else: Could somebody tell me what the impedance rating in coaxial cables in theory and practice means, and how is it calculated? The views expressed are my only, and that is a d****d shame. Rainer B{rs Helsinki University of Technology Laboratory of Engineering Geology and Geophysics
jhenders@van-bc.wimsey.bc.ca (John Henders) (03/04/91)
In article <9812@uwm.edu> peter%versatc.uucp@ames.arc.nasa.gov (Peter Tapscott ) writes: > >Someone will ask about cable and connectors. Old >Colony has some Magami cable, but there are a lot of >other cables that would work fine. Standard microphones >that use XLR connectors need this type of cable, so a >pro-sound place (musical instruments, amps, etc) might >be a good source for reasonable prices on good cable. >(high-enders: please post if you find good cable.) > I work in the pro sound industry, and have found the Canari Star-Quad cable to make an audible difference when used as microphone cable. I'd highly recommend trying it. It uses paired conductors for the 2 signal carrying wires and has a niced braided sheild. I recently built 2 24 channel snakes for a local PA company, and the system (Turbo Sound TMS4 and 24" Sub bins) sounded much better than with the previous Belden snakes. Of course a 24 channel Star_Quad snake is about twice the diameter of a normal snake, but thats not relevant to this discussion. Star-Quad also has the added feature of "laying" very nicely, where Magami is much stiffer. Overall, very nice cable. I have no financial involvemnet with Canari, and recommend it merely as a satisfied user. John Henders Vancouver,B.C.