Adapting an Old AM Tube Radio to Play MP3s September 08 2014, 0 Comments
These old radios are woefully behind the times in their design. But, they can be easily adapted to play MP3 using your iDevice, SmartPhone, or other MP3 player.
All you need is:
1. 3.5mm jack mono
2. 2 or 3 position toggle switch DPDT
3. 3.5mm to mono RCA cable
1. Solder iron
3. About 24” wire 18-24 AWG solid or braided
4. wire snippers
Here’s a Magnavox AM tube radio that will be converted to play MP3.
This Magnavox model R5 was made in 1957. Right now, it only plays AM radio. It has duel speakers and features vacuum tube amplification that sounds great. Your iDevice, MP3 player, smartphone plays your favorite music but its audio fidelity is passable at best.
How about getting the best of both worlds? Plus, the Magnavox retro looks isn’t too harsh on the eyes either!
Here is the Mag opened up to reveal all the lovely tubes that glow orange when it’s turned on. Isn’t that sweet?
The painful part is cutting into the radio original back panel to fit the toggle switch and 3.5 mm jack. This is not a reversible modification so be sure it’s what you really want.
Here it is with switch and RCA plug.
Here’s the back side:
Cut into the circuit before the signal goes into the volume potentiometer. This way you can use the Am radio’s original volume knob to change the loudness. You also have the volume setting on your player device to vary the loudness.
Here is where you cut into the circuit with switch and auxiliary input.
Here’s what it looks like applied to this radio’s circuit board.
It’s important ground the lead from RCA jack to the radio circuit ground or chassis. Most of these old radios did not feature a third plug or negative plug to differentiate positive from negative.
Here is an old original plug next to a modern polarity keyed plug.
Here’s the modern plug cord hard wired to the radio circuit board.
Here’s the finished product with MP3 conversion:
Hear it play on my channel on You Tube. https://www.youtube.com/watch?v=wb6yuy8gkX0&list=UUNXdUWfWZHpaDdrOyesz1Cw