Re: Problems going from stereo to mono

[Jim Noble <yahoo-groups@xxxxxxxxxxxxxxxxxx>]

Gareth Cook wrote:

> Thing is, the dining room works fine - but the kitchen and games room
> only
> have one channel coming out of them (easily tested by shifting the
output
> balance to left or right).
> So, assuming the amp inside doesnt like me doing this - is there a
simple
> addon i could use to correctly merge left and right into one channel ?


...and rightly so.

Imagine you're listening to some slightly unusual, minimalist music. Out
of the left channel you have a nice pure sinewave, and out of the right
channel you have the same sinewave but 180 degrees out of phase (such
that when the voltage on one channel is high, the other channel is low,
and vice versa)...

<waits for penny to drop> :-)

Presumably one channel is seeing the short and is shutting down (and
thus going high impedance). The other channel is then free to wobbly the
speaker as intended. I'd suggest disconnecting at the earliest
opportunity though, because if there's no short circuit protection you
might blow/have blown the amplifier in one of the channels.

You need to feed it a mono signal on the input side (possible on both
left and right channels) and then connect each speaker to only one
output. Maplin do line level mixers IIRC, or you could cobble something
together with a few resistors (or if you're lucky, mono input is
supported by the amps?).

Jim