Installs Intercom Re-installation

I'm thinking of doing a re-install of the intercom system in the house I work at, and I wanted to get some feedback to see if it's necessary, and if it is, what parts should I look at getting. It was installed sometime between 5 and 10 years ago and it's always given me problems.

The current set-up has a Clear-com MS-702 with 2 ~250' unshielded 3 lead mic cables running up through the attic. The cables come together in a 3 pin terminal block connector with 3 other unshielded 3 lead mic cables that run through conduit to boxes onstage. The beltpacks we have are a combination of Clear-com RS-501's, RS-603's, RS-601's, RS-701's, and PI's BP-1's.

I recently opened up the boxes and re-terminated all the solders (they were atrocious), and that solved some problems. In the last show I used a Clear-com TWC-701 and got a considerable amount of crackle on line B that would come in and out through the whole process.

It's worth noting that there is also a substantial amount of electrical cable (building power as well as the lighting system) in the attic as well. I've tried my best to keep the Intercom cables separate, but I can only do so much with the way the cable is run.

I've thought about replacing the 3 pin terminal block with a patch bay to be able to patch the conduit boxes to either channel.

Any comments/suggestions would be very helpful.

Thanks.

EDIT: The mic cable is shielded with foil. It's 22 AWG.

I don't have much experience from the installations side, but I can tell you that one bad mic cable going to a box can really mess up a clear com system.

If you have always used older cables with the system, I would consider starting there. I have a brand new installation, and everything went funky one night for no apparent reason. It all came back to one older cable I used to connect a pack to the wall.

TheaterEd said:

I don't have much experience from the installations side, but I can tell you that one bad mic cable going to a box can really mess up a clear com system.

If you have always used older cables with the system, I would consider starting there. I have a brand new installation, and everything went funky one night for no apparent reason. It all came back to one older cable I used to connect a pack to the wall.

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I've experienced this before. A cable managed to make the whole system go dead once. The crackle I had sounded different though. Best way to describe it is that it sounded like someone was making a ball out of paper. It would come and go with no pattern or tempo, whether the lights were on or off, and sometimes only some headsets on B would hear it while others couldn't.

Crackles are usually an indication of bad cables.
Disconnect one at a time until the crackles go away.
I have thousands of feet of mic cable in a 4 channel intercom that is 15 years old and still works perfectly.
Cable issues often happen from the beltpack to the wall.

Clear-Com has very specific instructions on design and installation that most people don't follow. If you are planning on re-wiring, talk to Clear-Com to get their design guides.

Do you have any of the two channel wall plates? If so, the switches on those are easily damaged.