Can I just use the “Speaker B” connection on my amp for the extra speakers?

Generally no, but with some speakers you can.

Many Hi-Fi stereo amplifiers have connections for Speaker A and Speaker B. These connections are **normally in parallel, so it is the same as connecting two speakers in parallel – but the amp provides switches to turn each set on or off.

These are designed to allow easy connections of 2 sets of speakers. Normally these amp have a warning notice. This notice is saying that when connecting to either A or B, then the speaker should have an impedance of 4-16 ohms. But when connecting to both A+B, then each individual speaker should be 8-16 ohms.

So if you have 2 sets of your speakers which are 8 ohms or more, then you can safely use these connections.  This is because two 8 ohm speakers in parallel gives a total impedance of 4 ohms – the minimum impedance the amp is designed for.

However if your are connecting speakers with an impedance less than 8 ohms, or you have more than 2 sets of speakers, then you should not use these connections as the total impedance will be below the minimum 4 ohms.

For these speakers you could connect them in series to Speaker A only. Or you can use a speaker selector switch connected to Speaker A only.

** Most amplifiers with an A/B switch connect both outputs in parallel, but there are the occasional exception where they connect both outputs in series.

 

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2 COMMENTS

  1. As far as I’ve seen, you’re the only resource that has finally clarified that the A and B speaker outputs will split the power from the amplifier.

    Before this, I was under the impression that I’d get the full power output through both the a and b outputs. Mega noob!

    Quick question though – I have a nice pair of speakers (JR149s 60-80w 8ohms) in one room, and some basic warfedales (20-100w 6ohms) in a different room, one set on speaker A and the other on B.

    I get that the power is split between the 2 sets of speakers. But when I switch off one of the sets, so I’m just hearing speakers A, does that mean I’m getting the full power output through those speakers now? Or is the power still halved even though speakers B aren’t playing?

    Apologies if this is a stupid question…

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