In article ,
"Meindert Sprang" wrote:

If the horn is 20 Watt and your battery is 12V, you'll need at least a 2 Amp
diode. Ask for a 50V/5A diode and you'll be fine. Higher specs on voltage
and/or current are fine too if that is what is available. The price
difference should be negligent. We're talking about a sub-$ component here.

Meindert

Meindert, What are you thnking, man? Audio is AC.....You can't isolate
AC with diodes....


Me