Bridge output for an amplifier.

[Hartley118]

Originally Posted by Michael Maurice

I've been back to it, the DC resistance across the speaker cable is 24 ohms.

There are 6 speakers which I presume are 4 ohm each ceiling mounted. If they are connected in series, that would explain the 24 ohms.

With one channel connected and the inputs to both channels connected to give mono, it is more than loud enough.

Well, there's a surprise!

I suspect that Herald 1360 may be right when he suggested:

'Sounds unlikely, but do check the old setup wasn't 100V line with a transformer at each speaker. Someone may have done a proper PA job.......'

I just checked the primary DC resistance reading on a couple of 100V line speaker transformers and got 110 ohms on one and on another (probably set for a higher power) 72 ohms.

So, just suppose 6 are paralleled and read 24 ohms, that would be 144 ohms for each transformer - not unreasonable if they were set for, say 4W each.

Still, if it's loud enough, then it ain't broke and doesn't need fixing.......

Martin