When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
This is a modification I like to do on all of my cars running original AM or AM/FM radios. Since I just did this one for my hard top, I thought I would shoot some pics in case anyone else was interested. For this car, I am adding the audio input to the AM side of a 71-72 AM/ FM radio. I had already tested the radio and repainted and polished all of the parts on the face.
I have a surplus of audio jacks that I bought from radio shack before they closed, but you can find these parts on Amazon, ebay, etc. I use sub-mini jacks for the for the side of the harness that will attach to the radio and a 5 pin 1/8 jack for the audio input. You will also need a 100 ohm resistor.
Basically, this modification will replace the low voltage signal coming from the tuner board going to volume **** with the audio signal from your newly added jack. In this radio the orange wire (circled in green) is the one feeding the AM signal to the volume ****.
These early AM/FM radios use a 4 pole 2 throw switch to power the various boards and send the tuner signal to the volume ****. It is controlled with a small rod attached to the slider and selects either the AM or FM connections. The 3 pins in the photo below (circled in green) are the part of the switch that select which audio output to send to the volume ****. The orange wire circled in blue is the other end of the one pictured above coming from the AM tuner. This is the wire that gets cut to replace the AM signal with the audio jack signal.
Here you can see the sup-mini female jack soldered to the wire coming from the AM board and the wire going to the slide switch. The threaded part will ground the third lead to the case so a third wire is not required.
Conveniently on this radio there was already a hole in the case the perfect size to mount the jack next to the tuner ****.
It is not necessary to use the sub-mini jack. You can simply have three wires coming out of the case, but I like to make harnesses that allow the radio to be easily removed if necessary. The hardest part of the entire job might be soldering the wires onto the sub-mini male connector. The yellow wire is the signal coming from the AM tuner, the orange wire is the signal going to the slide switch and the brown wire is the ground.
When making these harnesses, I like to braid the wires together and use heat shrink every few inches to keep the braid from unraveling.
The 1/8 inch input on this car will be in the center console, so it will have a two piece harness using these simple connectors that you can get online.
When ever I use any kind of crimped connector, I prefer to solder it as well.
Here is a shot of the 5 pin 1/8 inch jack. When nothing is plugged into it, the slide switch in the radio will still receive the AM tuner signal (the radio will operate exactly as it did before). When the audio jack is plugged in, the AM signal is replaced by the signal coming from the jack.
The way I wire these up, the radio is only receiving 1/2 of the audio signal coming from the MP3 player (mono not stereo). To protect the MP3 player from damage, you need to connect the left and right outputs on the jack with a 100 ohm resistor.
Finally, the three wires can be soldered to the terminals on the connector.
Here is the final result.
Lastly, the jack mounted in the console.
January 17th, 2022, 06:28 PM
