Hooking up 2 sets of speakers from one amp- series/parallel?

[AudioLancelot]

I wish to hook up more than 1 set of speakers on the rear or B speakers.

I need direction as to how these must be connected in series or parallel and how to do it

Do I wire direct from my amplifier ( B Speakers ) to each set of speakers discretely from the same amp connection

or

do I wire i.e. rear left positive from amp to left speaker positive of 1st set of speakers and from there to positive left speaker on 2nd set

 

[The Quadfather]

You need to wire them in series. Let's look at one channel. This means that you will wire the positive of one speaker to the positive on the amp, then the positive of speaker #2 to the negative of speaker #1. The negative of speaker #2 goes to the negative on the amp. This makes 16 ohms load to the amp, and will not overload the amp. However, if your amp is designed for a 4 ohm load, (most are designed for 8 ohms) you can wire them in parallel. This assumes that you are using 8 ohm speakers. (there are a few 4 ohm models around, or at least there used to be. You can make a selector for the series arrangement by using a double throw switch. the switch must have a center off position which will be the "both speakers on" position. to do this, connect the center pole (common) to the line that goes between the two speakers. connect one of the side poles to speaker #1 positive. Connect the other side pole to speaker #2 negative pole. throwing the switch either way shunts one of the speakers out of the circuit and as a result, turns it off. throw the other way and that speaker comes on and the other goes off. The center position leaves no speakers shunted, and therefore both speakers play. A four pole double throw switch will handle a quad arrangement for two rooms. Good luck

The Quadfather

 

[AudioLancelot]

I am indebted Quadfather.

I like the straight forward series solution.

The operating instructions of the amp state that it handles speakers from 6 to 16 ohm so the series route is ok as all my speakers are 8 ohms.

Just one further query . Am I correct assuming there would be no problem to the amp running just the straight 8 ohm set of speakers I have on the fronts and the 16 ohm series arrangement of 2 sets speaker of speakers on the rears?

Thanks

Dennis

 

[The Quadfather]

It would be OK. The amp probably has an arrangement like I described in it's own speaker setup. When playing all three sets of speakers, you will have a situation where the total impedance is higher than 16 ohms. This is not harmful to the amp. Even if the internal amp switch was wired in the parallel, it would not be harmful. You could hang one of these circuits on both the A and the B outputs. Note that as the impedance is raised, the power being output by the amp is reduced. But I have never seen an amp blow because it's speaker load was too high in impedance. On the other hand, getting it too low will fry it in a heartbeat. Lower the impedance, and the current goes up.

The Quadfather