Dave Plowman (News) wrote:


** The simple solution is to add a DPDT relay to mute both inputs of the
405 whenever there is no AC power.

Ideally, a miniature sealed type with gold contacts powered by rectified
AC from the secondary of the transformer - plus a suitable series
resistor.

You can use the contacts to either ground the two signals or open
circuit them.

Snag is this squawk happens immediately at switch off. So the relay would
have to operate extremely quickly.



** With the relay powered with rectified AC only, the switch off time is less than 15mS.

That I why I suggested it.

Why not actually try it ?



..... Phil