6 volt horn in 12 volt vehicle
 

I don't know if this questions belongs here or in the newer fords, but here goes. I have a 1928 Ames horn that was on my dads 28 Tudor that is all of it that is left. I would like to mount it on my 65 mustang. What kind of resistor do I need to make it sound right? I know it works on 12 volts but it runs so fast that it doesn't sound right. I want a cheap resistor, so was wondering if an ignition coil resistor would work, as it will not be used but for a couple seconds at a time.

Re: 6 volt horn in 12 volt vehicle
 

The Ahooguh horn draws a lot of current and the dropping resisters on the market do not handle it well, they burn out. The best option is to rewind the field windings. It is not difficult to do. The attached article explains how to do it.

Tom Endy

Re: 6 volt horn in 12 volt vehicle
 

Bought mine from one of the vendors 14 years of trouble free service.

Re: 6 volt horn in 12 volt vehicle
 

buy a voltage regulator off of ebay. Hook it up to a 6 volt battery with an ammeter inline and check the current requirements, times it by two, and get that size or larger regulator. Very cheap on ebay. Here's a 10 amp version: https://www.ebay.com/itm/12V-24V-to-...kAAOSwPJhd~v5E

Re: 6 volt horn in 12 volt vehicle
 

Hate to disagree with Tom Endy, but the resistors that the vendors sell for this purpose work just fine. They are completely contained in the horn "can" so they do not affect the Model A "look". (Of course, this is probably immaterial for you.)


Yes, the resistor gets hot when you honk the horn, but unless you sit there and blow it for minutes at a time, they work o.k. The brief time you sound the horn is handled by the resistor.

Re: 6 volt horn in 12 volt vehicle
 

I agree. I have been using this bad boy from Bratton's for years now. Not cheap but gets the job done.

https://www.brattons.com/horn-resistor.html

Re: 6 volt horn in 12 volt vehicle
 

Tom,
Do you mean the resistors sized specifically for horns and sold by places like Bratton's or are you just talking about generic voltage dropping resistors?

Charlie Stephens

Re: 6 volt horn in 12 volt vehicle
 

The resisters sold by the suppliers is what I was referring to. They work fine as long as you do not blow the horn a lot. There is a photo of one burned out in the article I attached.

Tom Endy

Re: 6 volt horn in 12 volt vehicle
 

A good one from Speedway Motors; finned, etc. $$ Mounted external to the horn under frame rail, etc..

Re: 6 volt horn in 12 volt vehicle
 

I got good results from a 1-ohm, 100 watt wirewound resistor from eBay.

Re: 6 volt horn in 12 volt vehicle
 

Best results will be obtained by following Tom's post on rewinding the field coils (post #2).
That is what I did.

Re: 6 volt horn in 12 volt vehicle
 

I am sure that rewinding the coils would be best, but I really would like to keep the horn original, as someday, I will probably put it up for sale. Especially seeing what people are selling horns for now days. I can probably get 1/2 as much for the horn as we sold the whole car for in 1964. And it was running!

Re: 6 volt horn in 12 volt vehicle
 

I once saw a 28 with a repo 12v horn and it looked fine so I went to ebay and purchased what looked like same. what I got was a shitty plastic horn including a plastic trumpet which was just too far from original. think I'll give it to my grandkids to use on their go cart.

Re: 6 volt horn in 12 volt vehicle
 

I agree with Tom. With the resistor it started slower because of the higher starting current and when it got running it sped up as the running current is lower. It only took me about one hour to rewind the field with 24 gauge magnet wire.

Re: 6 volt horn in 12 volt vehicle
 

Exactly what I was going to recommend.
It worked fine for the 6 volt horn I sold to someone to use on a 12 volt system.

Re: 6 volt horn in 12 volt vehicle
 

I can get one of those 1 ohm 100 watt resistors really cheap from eBay, so I think that is what I will do. Thanks all.

Re: 6 volt horn in 12 volt vehicle
 

Since the cost is low I would suggest getting a couple different values so you can fine tune the sound you want. For example you can get a 1/2, a 1, and a 2, and using them singly or in series you can get values from 1/2 to 3 ohms in 1/2 ohm increments. I did this and a single 1 ohm resistor sounded best with my horn.

Re: 6 volt horn in 12 volt vehicle
 

Just finished rewinding the field coils on my horn as per Tom Endy's instructions. Works great on12 volts and never sounded better.

Re: 6 volt horn in 12 volt vehicle
 

I don't know the ohms value or wattage but there are 12 volt to 6 volt drop down resistors made for this kind of purpose.