It was suggested I share this in my 57 chevy build thread, so I just thought I’d make a dedicated post for it. This modification replaces the stock AM radio internals that many of our pre ‘65 cars came with. I’m not sure how it is in y’all’s neck of the woods, but around here, the only AM stations still operating are religious talk shows. Hardly my cup of tea! The amplifier kit I purchased for this project is one of several similar offerings. Mine is a stereo board but I believe they also offer a mono board if you just want to run one speaker or retain your original mono speaker. Here’s an eBay link to the exact model I used, though in case the link goes dead, it’s called a Wuzhi Audio model ZK-1002. https://ebay.us/m/W7ThFt This specific amp model has a 3.5mm aux jack if you have an iPod or similar device without bluetooth, but my mobile phone doesn’t even have a 3.5mm jack anymore so I chose to use bluetooth. The amp kit comes with a knob and covering so that it can also be used standalone, if you don’t want to tear apart your factory radio. In my case, I wanted the illusion that the stock radio on my car is fully functional, so I chose to gut my factory 57 Chevy radio. It will be dependent on what specific radio you’re doing this mod to, but in my case, I was able to retain the tuning knob and ****ons, and they do still function to move the tuning needle, again looks like an original fully functional radio. After I gutted the radio, I did some test fitting of the amplifier board to figure out where exactly it would need to be mounted inside the case. Mine needed about a 1/8 inch offset from the side of the radio casing, so I ended up making some spacers out of a piece of 1/8 inch plywood. The important thing is to just be sure the board isn’t actually touching any metal which would cause a short. Next, I had to figure out how to connect the factory volume knob to the volume potentiometer on the new amp. I accomplished this by using a nylon bushing from the hardware drawers at Ace, though I’m sure almost any hardware store should have something you could use. I chose nylon because it friction fits onto the new potentiometer, and is easy to drill through and grind small pieces off of. I originally was going to use the original volume knob shaft, but unfortunately I broke it due to vibrational forces when cutting it down with my angle grinder, and it ended up being too short. So it became a 2-hardware store-trip project… Anyway for my new volume knob shaft, I opted for a 3/16 br*** rod, also available in the hardware section at Ace. They had steel rod of the correct diameter as well, but again I chose br*** for the softer material since I needed to drill a hole through the side of the rod. And now we get to the pictorial part of the post; ***embly time. The nylon bushing is just friction fit to the volume pot, though if you wanted to, you could also add a small machine screw and nut by drilling a hole through the nylon bushing and potentiometer shaft. I actually did drill mine but decided it wasn’t needed due to the tight friction fit. Next, I drilled the hole through the br*** rod and nylon bushing at the same time, making sure there was enough distance from the end of the nylon bushing for it to retain strength, while also making sure I had enough of the br*** rod protruding out of the front of the radio for the knob to attach to. I ground a flat spot on the rod end to make a D-shaped profile since that’s how the factory ‘57 knob is made. Hopefully that all made sense and wasn’t too long-winded. Y’all are good with making pieces fit together so I’m sure you’ll figure it out if I missed something
The finished product, with functioning original dial-lamp and tuning ****ons/knob, in this case playing some Buddy Holly
It's cool to make the attempt and I hope it works great for you. I can understand the reasoning behind this. I mean, I get bored and try things, too. I used to cross wire my car stereos to get the quad sound and for the boost I always added a 40 watt booster and added woofers. And then stereos became advanced with built in boosters and quad sound. It would be easier to keep the stock AM radio and just power the new unit and then hide it, IMO. Keep doing what you're doing. I want to see this work.
neat! I did a similar thing with an amp with a 1/8" phone jack on my 62 Corvette, but since my newer phone doesn't have a dedicated jack, I use an old portable mp3 player. I think I might want to switch to bluetooth, to see how it works. Then I wouldn't have to worry about the battery charge in the mp3 player on long trips. also mine has a weird issue with cutting out, but the power specs for the amp are not like yours, they specify a rather small range around 12v, and I think it's a voltage issue that makes it cut out. I might order the one you used and try it instead.
There are all sorts of cheap amplifier/MP3/Bluetooth/FM radio modules available , most are OK for what you pay for them. The only thing you have to be aware of is that the rated power of these amplifier modules is very "liberal"- they will say "100 W", but the way that is calculated you will actually end up getting about 30 watts per channel (if it's a stereo unit), and they don't consider distortion in their "calculations"- so you might only get 20 watts per channel before distortion. Still OK for a car, etc, but if you want a module that really thumps, you have to get something which is higher powered. And they need airflow around the heatsink, so if you mount them in an old radio housing they are usually OK, as the originals had lots of vent holes.
The Jalopy Journal
