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Old October 16th 04, 08:56 PM posted to uk.rec.audio
Christopher Hill
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Posts: 4
Default Volume controls for 100V sound system

D'oh. I hate Outlook Express. It sent the message before I asked it to. Not
like this is the first time I've used newsgroups either. The rest of the
message is coming!

"Christopher Hill" wrote in message
...
Hi!

I'm a complete PA system novice, but I've been trying to work out how to
upgrade my church's sound system to include some volume controls. Done a
lot of reading/researching on Google, and I've got the hang of some of the
concepts. I'm hoping you guys can help me with the rest!

Currently, we have what seems to be a 100V constant voltage sound system
that's set up like this:

The amplifier (no model, no make at all, helpfully) is directly connected
to:

1) 2x 'Bouyer Type RC15' speakers.
At the back panel of these is the specifications which says that for a
100V system:
Tap 1: 20W, 500 ohm
Tap 2: 7W, 14 ohm
Tap 3: 2.5W, 4000 ohm
I'm not sure which tap is actually in use, but I'll take a look next time
I see it.

2) A box which contains a 100V 'Line Matching Transformer', which is in
turn connected to 2 fairly ordinary hifi style speakers. This transfomer
has a number of taps, and I can't remember which one the 100V side is
connected to, but the speaker side is connected to the 4 ohm connector. I
also don't know what impedance the speakers are, but I would guess that
they should be 8 ohm speakers... as they are connected in parallel...

3) An individual speaker which has another 100V 'Line Matching
Transformer' inside it, with a volume control which connects the speaker
to the different taps on the 100V side depending on where it's set.