legg wrote:



Surprised you need DPDT. DPST should seve this purpose, if the amp has
internal Zobel termination.



** Some amps use all the contacts on a change-over relay.

The speaker output connects to the moving contact and is grounded when unpowered. On power up, the speakers connect to the amp output.

This arrangement is far better at protecting speakers from DC faults as few relays can break the arc that forms when opening under load at high DC voltage.

Most relays are rated at 24VDC max and that is where thee begin to arc badly.


..... Phil