Is it Parallel or Series?

[Corvette6769]

If a 2-channel 220-watt/channel stereo power amplifier has two sets of speaker terminals for A, B, or A+B operation and a person has four speakers hooked up, when switched to A+B (all four speakers on) am I correct to assume that would be 110 watts available to each speaker?......and are the output terminals wired in parallel or series?

[edwinr]

PARALLEL:
In a parallel setup, If you want to run two speakers from an amplifier, run the positive cable from the amplifier's output and connect it to the positive terminals of both speakers. Do the same for the negative terminals. If both speakers are a nominal 8 ohms, the amplifer will see a load of 4 ohms.

SERIES:
To run two speakers in series, the positive output from the amplifier is conneced to the positive terminal of the one speaker, The negative terminal from this first speaker is then connected to the positive terminal of the second speaker. Finally the negative terminal of the second speaker is connected back to the amplifier. The amplifer then 'sees' a nominal 16 ohm load if the two speakers are 8 ohms.

The output terminals of the amplifier could be wired in series because this presents an easier load for some amplifiers - unless your amp is a high current design and able to run low impedance loads without problems.

Edit: I reckon anyone hooking up two pairs of speakers to any amplifier would need to find out whether the A/B facility was parallel. In that case if someone was to hook up two pairs of speakers with nominal 4 ohm loads, there wouild be times when the amplifier would see a 2 ohm load. I think that's why some amplifiers have warnings about hooking up two pairs of sub 4 ohm speakers.

[Marvel]

They would be in parallel. With 8 ohm speakers, you would then be presenting a 4 ohm load to each amp channel. See if the rating is listed for a 4 ohm load. Usually the power goes up, but some amps can't handle it as well. Most amp manufacturers state that the two speaker setup is in parallel. Although series is an easier load, you don't want the reactance of each cabinet to affect the other cabinet.

This is assuming the impedance doesn't drop lower at some freq. Crossover networks like the ALKs are a constant impedance, so there isn't the fluctuation you get on most crossovers.

Bruce

[oldtimer]

If you can run the B set independently of the A set then you have parallel. If the A set must be on for the B set to work, then the out put is in series. I once bought a receiver that was in series and it made me so mad I took it back. Others will know better than I about the specs issue.

[DrWho]

If a

2-channel 220-watt/channel stereo power amplifier has two sets of

speaker terminals for A, B, or A+B operation and a person has four

speakers hooked up, when switched to A+B (all four speakers

on) am I correct to assume that would be 110 watts available

to each speaker?......and are the output terminals wired in

parallel or series?

We need more information. Specifically what is the impedance of your

speakers and for what impedance is that 220watt spec rated at? Assuming

the answer is 8 ohms for both...

When going into A+B mode, each channel of the amplifier is seeing a 4

ohm load which means the output increases to 440 watts. The current in

the wire now sees two equal paths to travel down and thus splits in

half (parallel connection), so each speaker is seeing 220W. This is of

course assuming your amplifier "doubles down with impedance" (you're

probably getting more like 400W total or 200W per speaker, not the full

doubling to 440W in an ideal world).

If the A+B mode was in series (which it probably isn't) then the

amplifier now sees a 16ohm load and the output is reduced 110 watts per

channel. Again, conservation of power (each speaker uses up half of the

power) so each speaker will be seeing 55 watts

(that's 6dB less than the parallel configuration!)

[Corvette6769]

You assumed correctly - In this example I am referring to a Kenwood Basic M2A which is rated 220 watts per channel RMS, both channels driven at 8 ohms from 20 Hz to 20,000 Hz with no more than 0.004% total harmonic distortion and the speakers are presumed to be 8 ohms (Klipschorn, Cornwall, Chorus II, etc).

[CaptnBob]

It's most likely parallel, although I have seen some receivers with rather baroque switching which would do three sets of speakers in series-parallel.