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On Fri, 06 Feb 2004 16:13:59 GMT, wrote:

Using a toggle switch to suddenly remove the load from the output of
the Stereo probably isn't such a great idea. The problem I've seen in
all the responses so far is that they are trying to switch in the
wrong place. The switching needs to take place at the preamp stage,
not the output stage.

Meanwhile the one really useful comment I saw was that stereo speakers
really aren't ideal for VHF anyway.

BB

Running an amplifier with no load or suddenly disconnecting the
speaker leads will do nothing to harm an amplifier. The only thing
that will harm them is shorting the output leads together or using a
speaker with an impedance that is too low. This will cause the
amplifier to draw excessive current and damage the output transistors.

I think that there is a carryover on this myth from the tube amplifier
days when they had a transformer in the output. Also some of the early
transistor amplifiers had transformers too but those days are long
gone.
If you had no load on an amplifier with an output transformer and
turned up the gain you could get excessive voltages from the kick back
of the transformer winding that could damage the output stage or cause
the output transformer to fail.

As for switching at the preamp stage becomes tricky to avoid problems.
All DC references must be maintained with various inputs or you will
get huge transients in the amp as you switch.

Regards
Gary