Speakers Wiring

There is a risk when adding dual speakers - wiring them in parallel and achieving a impedance [resistance] below the minimum recommended by the decoder manufacturer.

The impedianced is the tap or restrictor on a amplifier that prevent the amplifier from destroying itself so must be taken seriously.

Parallel wired speakers

The effect of wiring the speakers as shown above is to reduce the impedance from the recommended minimum of 4 ohms to just 2 ohms and was causing the amplifier to shut down. ESU are unique in using 4 ohms most other manufacturers are 8 ohms minimum so read the attached documents with the decoder.

Series wired speakers

The speakers must be wired in series to give a total of 8 ohms using two [2] 4 ohm ESU speakers. If two 8 ohms speakers were used these could be wired in parallel for a ESU decoder because the total resistance would be 4 ohms - OK for ESU but not most others.


If in doubt use the resistance measurement on the meter as shown above.