In article ,
Phil Allison wrote:
They can also include a circuit to make them drop out if they detect a
large DC offset. Very good way of protecting speakers in event of a
fault.



** Few speaker relay systems provide reliable protection if that happens
- nor do they claim to.

I'm talking about those which do.

The simple fact being that the kind of relays used are only capable of
switching *off* DC voltages to a maximum of 30V at rated current. IOW,
their current breaking capacity is very limited for DC voltages.

Then use a relay fit for purpose. Fraction of the cost of a speaker repair.

--
*Why don't sheep shrink when it rains?

Dave Plowman London SW
To e-mail, change noise into sound.