Amp for series wired speakers

[Sheridan]

We have what seems to be a crusty old audio system in one of our halls - 6 speakers wired in what I think is series but in two sections, as there is a wire in and out of each. At the amp end only a two core wire emerges (black/red) which goes into the Left channel of the amp. This is working but is buzzy/distorted and I think the amp is broken. It looks like the speakers are wired in two seperate channels which are then merged at a wall point at which the single pair wire emerges:

 

 

So at the AMP point I have 1 wire (pair black/red) to use!

 

With just one pair of wires though I'm not sure which type of amp is suited for this? Normally you'd have a L/R pair - this is the first set I've seen with the speakers apparently in series!

Edited March 15, 2017 by Sheridan

[localzuk]

That looks extremely odd. I personally would look at re-wiring from the WS part, and splitting into 2 channels! Then you can just get an appropriately sized AMP.

[Sheridan]

That looks extremely odd. I personally would look at re-wiring from the WS part, and splitting into 2 channels! Then you can just get an appropriately sized AMP.

 

Thats sort of my thought, as they seem like passive speakers, converted into a single cable! Very odd!

[Chris_Cook]

It could be several things, either a 100 volt parallel system, or a combination of series and parallel wired speakers. If the total resistance of speakers is about 8 ohms, then a normal amp of suitable power would be ok. It could also just be a bodge.

 

You might be better off replacing it all if its crusty. Probably easier that figuring it out. Its possible the amp thats there isn't the correct one.

 

https://geoffthegreygeek.com/calculator-speakers-in-parallel/

 

To recommend an amp, you would need to work out how the speakers are wired, and what size/rating they are.

 

If you wire 3 speakers in parallel, you might not be able to find a suitable amp, as the total resistance would be 2.7 ohms. Most amps would want at least a 4 ohm load.

Edited March 15, 2017 by Chris_Cook

[Andrew_C]

Sounds like 100V to me. Or, as Chris says, "A bodge".

[Sheridan]

Oh it's definitely a bodge alright [emoji3]!

 

I might try and get one of the speakers off the wall to see what rating it is.

 

I'd love to rip it all out but that would be on next years budget!

[Sheridan]

And the correct answer is: Its a 100V system, and a replacement 100V amp works fine!