I created this cable to serve a very specific function - to connect an MP3 player to a car radio that came with an A/V port rather than an auxiliary audio port. This process is almost identical to my Retro stereo patch cable, the only difference being this has an a/v plug at one end.
My wife and I purchased a used car a few months back, and one of the known problems was that the radio had a busted auxiliary audio port. I thought about trying to replace the port, but since I wanted to install a rearview license plate camera anyway, I decided to replace the whole radio.
I made the mistake of purchasing a Boss BV7320, which has a whole slew of features, including an LCD screen, a DVD/CD player, an SD card slot, and front and back USB ports. But the main feature I was looking for was being able to play podcasts and music from my iPod. Since this product claimed to be "iPod compatible," I decided it was worth a shot since it was less than $100 bucks.
Turns out the USB ports only charge the iPod, and what I thought was a front auxiliary audio port is actually an a/v port. This is great if I wanted to plug my old VCR into my dash board, or watch my 1990s vacation videos from my cam corder on my car radio's LCD screen, but other that, I can't figure out why a car radio needs an a/v port? And when I plugged a standard audio plug into the a/v, audio only plays out one side of the car.
After searching more than a dozen stores, and too many websites to count, my research would seem to indicate that there is no such thing as an a/v to auxiliary audio cable.
So here's how I made my own.
• Soldering iron
• Wire cutters
• Hot glue gun
• a/v to RCA cable
• silver stereo plug
• shoe lace
• heat shrink wire insulator
Step 1: Alternatives?
Before I built this cable, I tried a variety of solutions, including the one pictured above. I attached the a/v cable that came with the radio to an RCA to 3.5mm stereo female adapter, and then plugged in a male to male 3.5mm stereo cable.
Theoretically this should have worked. But all it did was switch the signal I was getting from the driver's side to the passenger side - still no stereo! Plus I had more than a dozen feet of cable hanging from my dash board - Not exactly elegant!
I did find that I could listen to podcasts and MP3 if I copied them onto a USB memory stick or SD car, but this wasn't exactly a convenient solution.
Step 2: What's the difference between "a/v" and "aux"?
As the abbreviation indicates, an a/v plug is designed to carry both audio and video. While an a/v plug can be easily mistaken for a 3.5mm stereo plug, there's actually an additional band around the tip, and it's a bit longer, whereas an auxiliary audio port, (commonly abbreviated as "AUX") is designed to accommodate a 3.5mm stereo plug. This is the type of plug most common on modern headphones.
While a 3.5mm stereo plug will fit into an a/v port, it won't make all the necessary contacts, and the result will not be stereo output.
Step 3: Prepare a/v cable
Fortunately the radio came with an a/v to RCA cable. (In case you want to connect your VCR to your car radio;-) While the a/v plug looks a lot like a 3.5mm stereo cable, its actually a bit longer, and designed to carry not just audio but video. But all I wanted this cable to do was carry a stereo audio signal from my iPod to my car stereo.
Pull the yellow RCA plug and attached cable down to the base of the a/v plug and cut the cable (as close to the plug as possible). Then cut off the red and white plugs.
Step 4: Lace cable
Cut the ends from the shoelace, and if it has a center thread, remove it. Put a piece of heatshrink over the tip of the cable where the RCA plugs were removed, to make it easier to thread.
Now lace the cable through a shoelace.
This process is a time consuming and annoying one, but I found from previous projects that lacing a plain wire or cable really adds wuite a bit of flare to the final product.
Once the lace is in place, heat the frayed edges with a lighter to clean them up a bit if necessary.
Step 5: Heatshrink a/v end
Once the cable is pushed through the lace, add a small piece of heatshrink tubing, to seal the lace.
Step 6: Prepare wires
In a standard stereo plug there are three wires - right audio, left audio and common or ground. On this cable what looks like insulation wrapped around each wire is actually the ground.
If you are using a retro-style metal 3.5mm stereo plug, like I used, now is the time to insert the barrel and spring over the tip of the cable.
Expose the wires from the tip of the shoelace and spring.
Unwrap the copper wires from what were the red and white plugs, and wrap them together to create a third wire. Insert a small piece of heatshrink over this new third wire.
Step 7: Attach plug
This is the delicate part of this build. If you're not used to soldering, this can be a bit tricky. But basically what you need to do is solder one wire to one of the posts on you plug, the other to the other side, and the common or ground to the middle.
Before you attach the plug, make sure to slide the barrel of the plug onto the cable, to tighten later.
It's very important that the wires don't touch each other, or you will have a short in your cable. Once the wires are soldered, this is a good time to test your cable. If it works, congratulations, and heat up the hot glue gun to celebrate.
While the hot glue gun is not required, I find the helps to strengthen the plug and the connections of the wires.
Step 8: Finished!
Here's a photo of my new retro-style A/V to audio cable in action... And it works! In stereo! I hope this instructable helps someone who finds themself in the same situation I was in. And better yet, if you're looking ot buy a new car radio, make sure you get one with an audio port and not an a/v port if you want to listen to your iPod while you're driving, and not watch your VCR;-)