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How to Make an Old-Time Radio Into an Mp3 Player Speaker
Posted By Brett & Kate McKay On September 19, 2011 @ 4:16 pm In Uncategorized | 75 Comments
I love old-time radios. They’re sturdy and good-looking. And there’s a reason for that. Back in the day appliances were considered pieces of home furniture, so a lot of thought and care went into their design. People wanted something that not only played Glenn Miller, but that also went well with their home’s traditional decor. The result was marvelous pieces of technology encased in handsome wood and fabric.
A few months ago, I inherited my grandpa’s old 1940s Philco radio. It’s positively manly looking. It had a few dings in the wood, but it looked fantastic sitting on my desk. It still worked, but only played AM radio. I thought it was a shame that it didn’t get much use except as decoration. So I had a thought.
“Would it be possible to mod my radio so that I could play music from my iPod on it?”
To answer my question, I called up my electrical engineer brother-in-law, Ryan Davis. His response? “Of course!”
I headed over to his electrical engineering laboratory in his house with my radio in tow, and he fixed me up. Now I have an audio device with 1940s charm and 21st century technology.
I figured a lot of AoM readers would want something similar in their home or office, so I asked Ryan if he’d help me create a tutorial so you all could make your own mp3-playing old-time radio too. Ryan was happy to oblige.
There are two ways you can go about modding an old radio so you can connect your iPod to it. One approach is to add an audio input right into the old tube amplifier. This mod is nice because your iPod music gets that warm, vintage tube amp sound, and you can still maintain your radio’s radio capability. This is how Ryan modded my grandpa’s old Philco radio.
The problem with this approach is that it’s really difficult to do for the average Joe. First, you have to find a radio that still has a working tube amp, which can be hard and makes the radio more expensive. You can find plenty of radios with working speakers, just not a working tube amplifier.
Second, you have to do some complex rewiring on the radio to add the audio input. Your first step is to find the radio’s electrical schematic online. That’s the easy part. There’s a great site that has all the schematics for old-time radio s. The hard part is knowing how to read the schematic so you know where to add a new audio input. This takes some skill and know-how. When Ryan worked on my grandpa’s radio, he tried explaining what we needed to do to make the change. It went completely over my head. Of course, I acted like I knew exactly what he was talking about (“Oh, yeah. Of course you need to put a new transistor in the flux capacitor. It’s so obvious…”).
With that said, if there’s enough interest in seeing how to mod an old radio into an iPod speaker this way, Ryan said he’d be happy to demonstrate how to do it in a future post.
The second approach is to bypass the existing tube amp altogether by adding a new, smaller, and more modern amplifier to the radio and connecting it to the radio’s existing speaker. This way is much easier because you don’t need to know how to read complicated electrical schematics. You also don’t need a working radio. As long as your radio has a working speaker, you’re golden. You can even use a radio with a broken speaker. Just buy a new 2″ speaker for $4  and replace the old speaker in a snap.
Today, we’re showing you how to mod your old radio using the easy approach. It took Ryan and I less than 30 minutes to complete this project. If you’re new to electrical tinkering, it may take you a bit longer. But I’m not kidding when I say this: if you’ve never done any type of electrical projects, you can do this. It’s the perfect weekend project to work on with the kiddos.
Ready to get started? Let’s do this!
An Old-time Radio
The most important part! The best place to get them are antique stores, flea markets, or yard sales. You can find them on eBay, but they’re WAY overpriced. Even broken radios on eBay go for about $60-70. And by broken I mean it doesn’t work, and it’s missing half of the wooden cabinet. I went to the local flea market last weekend and spotted several nice cathedral radios in great shape for $20-$30.
I picked up this old Farnsworth radio at a local antique store for about $30. The outside is in pretty good condition, but it doesn’t power up. That’s common with old radios, but it’s okay. The only part we need to work is the speaker. Usually when old radios are burnt out, the speaker still works fine. So if you find a nice-looking vintage radio that doesn’t work, buy it. It will work for our project.
Important Note: Commenter J.W. Koebel brought to our attention that if you want to use the radio’s original speaker like we do in this project , the speaker needs to be a permanent magnet speaker. Radios from about the mid-1940s and on should have permanent magnet speakers. Earlier radios used electrodynamic speakers. Our amp won’t work with electrodynamic speakers.
How do you know if your old-time radio has permanent magnet speakers? Check the back of the speaker. If it has 2 or 3 wires going to the speaker, it’s a permanent magnet speaker.
If you decide to use an older radio that lacks a permanent magnet speaker, you can still do this project. You’ll just need to pull out that speaker and replace it with a permanent magnet speaker. It’s not difficult. Ryan sells a 2″ speaker on his site for $4 . Pick one up when you buy the amp.
Ryan sells these on his site . Ryan used his electrical engineering skills and designed these amps specifically for vintage radio mods. They should work with most types of old radios. You can buy the amps pre-built  for $26. Select “Pre-built kit” when you check out. If you’re feeling particularly handy, you can buy the kit and put the amp together yourself. The unassembled kit is $20. And of course if you’re super handy with electronics, you can experiment with designing your own amp.
12 Volt Power Supply
You might have one lying around the house. If not, pick one up at Radio Shack.
22 Gauge Copper Strand Wire
1/8″ (3.5 mm) Audio Cable
We’ll plug one end into our iPod or other audio source and the other end into our amplifier.
We have our supplies. Time to get to work. Keep in mind that every old-time radio is different. How this Farnsworth radio looks on the inside will be different from how your Philco or Zenith looks on the inside. However, all old radios pretty much work the same way, so the steps below should work for your radio. Just know that you may need to use your noodle a bit to find the analogous parts on your radio.
Remove Radio From Cabinet
Disconnect Old Wire Speakers
Connect New Speaker Wire
Remove Capacitor From Potentiometer
We want to be able to control the volume with the radio’s volume knob. To do that we need to run some new wire from the volume knob to the new amp. Here’s how to do it.
Ryan suggests making the middle wire a little longer than the other two. When we connect the wires into the amp, we need to make sure the wire from the middle soldering terminal on the pot connects with the middle screw terminal on the amp. Making the middle wire longer than the other two wires makes it easier to figure out which wire is the middle wire.
Connect Wires to New Amp
Here’s a video of our old-time radio in action:
Article printed from The Art of Manliness: http://www.artofmanliness.com
URL to article: http://www.artofmanliness.com/2011/09/19/how-to-make-an-old-time-radio-into-an-mp3-player-speaker/
URLs in this post:
 There’s a great site that has all the schematics for old-time radio: http://www.nostalgiaair.org/Resources/
 2″ speaker for $4: http://thingylab.com/speaker-2inch
 Amplifier: http://thingylab.com/audioamp1w
 Image: http://www.artofmanliness.com/2011/09/19/how-to-make-an-old-time-radio-into-an-mp3-player-speaker/removeoldspeakerwires-2/
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