My '39 has a modern 12 volt alternator. Will 12 volts hurt my wonderful sounding trumpet horns? I would hate to toast them. Everything else in the car had switched to 12 volts before I bought it. Also, I added a 10 amp fuse to the horns and it prompt blew. What is the current draw on these things? Obviously more than 10 amps. I think the car only has one fuse, so I am slowing going to add them in for safety. Thanks
A voltage drop resistor is the easiest fix. This is the type used in the ignition systems on chevy and plymouth . They drop the 12 to 9 volts for running to insure a even current to the coil. this type of ceramic resistor is available at some electronic suppliers or look in MSC or Grainger . I see your listed as delaware. Iam in Townsend.
Sounds like you're referring to a standard ballast resister. I have one that I'm not using. Can they take the current load of dual horns? I blew a 10A fuse with the horns, but have had no trouble with 20A fuse. I guess the current is somewhere in between 10 and 20 amps. I don't think my ears could stand a blast long enough to put a ammeter to them. I'm in New Castle. I'm not going anywhere in this weather, but I'm sure our paths will cross when it gets warmer. The beast is mighty hard to steer in 20 degrees, but it runs very well. Thanks for responding.
They make some very heavy duty ones so the load should not be an issue. I will be in a 1952 Concord fastback Maroon and grey,hope to see you in the spring. I always do Hagley. Amazon sells a part a110824000 ux0196 UNSC code 32131000 this is a adjustable wire wound resistor which would allow you the be easy only need to put inline and turn up the resistor to lower current to horns since they are only used for short blast this would be a good unit. This is a $15.00 part look up amazon ceramic power resistors this is a round wire wound unit.
6 volt horns running on 12 volts, especially the trumpets found on some 39s are REALLY LOUD !
they will draw close to 30 amps but very briefly so if you do use them , a circuit breaker such as the self closing type will be more reliable than a fuse. A ballast resistor for ignition use will not likely carry the load.