Philco Radio Upgrade
Last year for Christmas, I purchased an old Philco radio for my girlfriend. Now before you jump to assuming how terrible of a Christmas present that is, let me say that I had bought one for myself the year before which she really liked. They make really cool pieces of furniture, and are better yet if you actually can get them back to working condition.
When I purchased mine, I had no intention to completely restore the amp. I simply wanted a cool jukebox. I don’t really listen to much AM radio, so the original circuitry wasn’t that important to me. Instead, I added an auxiliary input to it for an iPod, and summed it down to one mono signal using some resistors. This worked great. I’m able to turn it up to a decent volume despite the fact that it has a 2W tube amp inside it. The original speaker has a great rustic sound that goes great with some easy listening music. I had the hopes of doing the same thing to my girlfriend’s radio; however, after completing the same modification, I still received no sound. Instead of trying to fix what might be wrong with the tube amp, I decided to gut it and replace it with a more modern amp/speaker combination.
Above shows the simple circuit design I had for the radio. I added a fuse and used a knob as the power switch. This cycled power to the end of an extension cord, in which I connected all the devices (amplifier, Bluetooth receiver, and future turntable). The audio circuit involves a selector switch between the two stereo inputs and a volume knob for the chosen audio signal. Then this signal is carried to a LP-2020A+ amplifier and out to a PolkAudio single stereo speaker (RC6s). I wish I had known about the single stereo speaker when I upgraded mine. This made it very easy to have a stereo speaker setup in a single speaker cutout. Her radio also has a 78 rpm turntable featured above the speaker. Even though I knew I wanted to have the compatibility for an iPhone/iPod, I plan to eventually add a modern turntable. The second aux input will allow this, and so will the last receptacle on the extension cord.
