> I have a odd situation where I need to run long audio cables
> between my
> repeater controller and two repeaters. In this case, the
> repeater controller
> will be connected to 2 repeaters in the same cabinette. The other two
> repeaters will connected thru about 140 feet of wiring to the
> other side of a
> building. I am thinking of using balanced audio wires for the
> long runs and
> using Henry Engineeering boxes to convert between
> balanced/un-balanced at each
> end.
I'd definately go balanced, but I'd use transformers rather than active
balanced devices. Decent transformers (even audiofile-grade Jensens) would
still cost less than Henry matchboxes (or anyone else's active converters
most likely), and be more reliable. Back in the old days, Western Electric
111C "repeating coils" were supplied by the telco for program audio lines.
Look around broadcast transmitter sites and old studios, you'll probably
find a few nailed up to the telco backboard that the LEC no longer has an
interest in maintaining ownership of...
The common mode rejection of Henry matchboxes isn't all that great, I've
tested them.
If you can, keep the audio level high on the sending side (I think 111C's
were good up to close to a watt at 600 ohms!), and pad it down on the far
side's secondary as necessary to maximize S/N.
--- Jeff WN3A
