Vintage Philco Radio Looks Stock, Contains Modern Secret: A Raspberry Pi

Antique radio receivers retain a significant charm, and though they do not carry huge value today they were often extremely high quality items that would have represented a significant investment for their original owners. [CodeMakesItGo] acquired just such a radio, a Philco 37-11 made in 1937, and since it was it a bit of a state he set about giving it some updated electronics. Vintage radio purists, look away from the video below the break.

Stripping away the original electronics, he gave it a modern amplifier with Bluetooth capabilities, and a Raspberry Pi. Vintage radio enthusiasts will wince at his treatment of those classic parts, but what else he’s put into it makes up for the laying waste to a bit of ’30s high-tech.The original tuning dial was degraded so he’s given it a reproduction version, and behind that is an optical encoder and two optical sensors. This is used to simulate “tuning” the radio between different period music “stations” being played by the PI, and for an authentic feel he’s filled the gaps with static. The result is a functional and unusual device, which is probably better suited than the original to a 2019 in which AM radio is in decline.

If you think of a high-end set like this Philco as being the ’30s equivalent of perhaps an 8K TV set, you can imagine the impact of AM radio in those early days of broadcasting. We recently took a look at some of the directional antenna tricks that made so many AM stations sharing the band a possibility.

68 thoughts on “Vintage Philco Radio Looks Stock, Contains Modern Secret: A Raspberry Pi

    1. As it happens, yes I have. A beautifully restored working example, yes. A non-working dusty hulk, generally still no. THat said, it’s a long time since I encountered a prewar set.

      And yes on your final sentiment.

    2. unrestored radios regularly sell for 80-100 bucks. fully restored radios (not counting the few very popular ones) go on the order of 250-300. there is no money to be made restoring these things, and most people restoring them cannot do a full restore of the cabinet and electronics if they wanted to. as a result, this particular restore is certainly better than tossing the radio in the trash, which is what happens to the majority of them.

          1. There is not really “high” demand for anything inside this set. Probably the most valuable thing would be the big variable capacitor – and the demand would be not from people restoring a similar Philco, but from people making a Depression-era homebrew receiver or crystal set of some sort. And even there – maybe ten bucks at most for the cap in good condition.

            With these kinds of radios, the most in-demand parts are some of the tubes (typically the audio output tubes) and the knobs.


            Will

    3. Have you tried to sell an antique radio lately??

      Guess what – these big floor standing consoles simply do not move. Nobody wants them. The collectors have their fill of superbly restored sets, and there is a seemingly endless supply of these on the market, as large established collections are broken up as the collector demographic slides up in age. The buying public also generally does not want them – they want small tabletop radios, or radios that can go on shelf.

      In fact, at the Kutztown radio show, twice a year, lower condition consoles are gutted and burned in a big bonfire – and these are the established radio collectors doing this!


      Will

      1. Thanks, uniservo.
        I bought an empty cabinet from a guy who’d noted that “either it sells here or it goes to Kutztown”. I didn’t know what that meant – a bonfire(!).
        I gave it some ‘TLC’, placed (however non-destructively, sans any alteration of the cabinet integrity) some BT electronics to make it a “BT speaker” and basically caught hell for this “sacrilege”, calumny of calumies, from hackaday reactors.
        [If possible, please post a photo of the Kutztown bonfire.]

        1. I didn’t know about Kutztown, but a dozen years or so ago, after some flea markets for antique woodworking tools, they would have a bonfire for “transitional planes”. Those planes were a transition from the wooden block planes to the all metal planes. The collectors had no (not much) interest in preserving those.

  1. I’m planning to do something similar with a radio from a 41 Buick, as a gift for my mom. My parents drove a car like that when they got married in the 50s, so I thought it’d be a nice gift. 1941 car radios are a bit pricey though, especially if they include the nice fascia, so I’m going to do a practice run on a 1953 Mopar radio.

    1. Just fix the radio and give it an aux cord. That’s easy and can be made undone if wanted. If necessary, with a bluetooth receiver.
      Or, for extra authenticity, use a AM stransmitter.

      1. I want to have the push button tuning select “stations” of my mom’s favorite music. I’m thinking of maybe doing something with Hall effect sensors on the button mechanisms, which I think could be done without damaging the stock tuner operation. But wouldn’t be compatible with an AM transmitter because pushing the buttons would still change the tuning.

        Then I’d figure out where to inject a signal into the audio path, and put in a switch to toggle between aux and AM.

        I definitely intend to use the existing tube amplification stage.

        1. Tap off the local oscillator (probably by using a piece of wire next to the oscillator tube or coil) to get the dial setting, then adjust the AM frequency to match. Or since the front end is going to vary also, it would probably be possible to make a single transistor micropower oscillator that uses a pair of coils placed on opposite sides of the antenna coil so that it always tracks the dial setting.

          Or go about it the brute force way by simply generating several AM signals – AM does not take very much compute power.

  2. Please don’t destroy any more real vintage radios. You can generally get tubes and capacitors for them to make them cherry restorations. Wouldn’t it be a much more enlightening exercise to craft a vintage look case, perhaps out of rosewood, oak or walnut? I think back on all the old model As and model Ts that were destroyed making teenagers hotrods and just can’t believe it. Let’s not do the same with vintage radios.

    1. Agree. Vintage radios (at least the amplifier bits) are very easy to get working again. Aside from that, many have line inputs. You can easily connect a bluetooth receiver to it, and stick the bluetooth receiver to the inside of the cabinet with some velcro.

    2. It is a really odd aspect of electrical engineering hobbyists. A good amouint have no respect for the past or heritage. Gut it and put a Blutooth on it! (For Grandma – who will subsequently place it on a shelf to rot).

    3. So what? Model Ts are worthless on todays road, kids used them to learn how to work on cars and improve things. Today we call it hacking. Sure, we need to keep some old things around to know how things were made. But we dont need to leave old things unimproved and useless just because nostalgia. Progress cant happen without change.

      1. The house next door sold to a get-rich-quick house flipper who was going to cut down a beautiful 35 year old oak tree because it would brighten up the yard. I sat down and talked him out of it. It wouldn’t have hurt anyone to cut it down and he’d not lose money and probably could have sold it a week or two sooner. The radio stayed intact for 82 years until it was stripped and sandblasted and it is now (insert char$ variable here), but good news: it now looks really old-timey. Maybe it’s best to procrastinate this type of project and let the next guy who knows why a tetrode isn’t a pentode get ahold of it.

  3. All that work just to maintain the look of the old radio? It would have been a lot less work to actually restore the radio to working condition.

    The spring loaded split gears are an antibacklash mechanism so that stations show up on the dial at the same place regardless of the direction you spin the tuning knob.

      1. Same here. It definitely wouldn’t have been my path. I might have wired an amp direct to the speaker and left the original works for a future custodian, but never strip everything and sandblast like that.

  4. I would like to use some very strong words to describe what I think of people doing these kinds of things. It is NOT cool. Please stop it. You can get the same functionality by restoring it to its original state and then build/buy an AM transmitter to connect your raspberry to.

    Again, please stop doing this.

    1. People nowadays don’t know how tubes electronics works. It’s more dangerous of a 5V Arduino, but it’s way way easier to solder and replace components due the construction.
      A vintage prewar radio or a vintage end of war TV set could be restored in working condition.
      http://www.museoradiotv.rai.it/dl/portali/site/page/Page-e79849ae-d58e-4afe-9fd4-8dd9a55d9866.html
      In this museum they have sometimes on exibit an homebrew TV recever made in the 50’s able to receive onli the C chammel (channel 6 in NTSC) they restored it and built a little TV modulator for VHF and hooked to a cheap DVB receiver. For am Radio they’re still operating a 100 kW AM transmitter nearby. And have a plenty of open reel recorder, and various videotape recorders.

    2. Coming from the world of amateur radio and seeing so many great units disappear into the ether, I completely agree. This piece deserved to be restored to original function and belongs in a museum or at least a proud space in the study of someone who can appreciate it better.

      Having said that, there are a ton of reproduction “vintage” radios in thrift shops all around the world; I’ve got a 1980s remake of a 1940s style tabletop FM/AM radio that I’m planning to turn in to an internet radio while maintaining its original analog functions. Not because it’s “vintage” or worth anything, but because the original sound is excellent and it picks up remote stations surprisingly well for a cheap radio from the 80s.

  5. This radio lacks of all the love that is deserved. This build was never supposed to be done,and takes quite literally the word “hacking”.
    Things that I hate about it, is the complete ripping out of the original electronics, because of the “lack of space”. There was absolutely no need to do that, in fact he should have simply restored the amplifier functionality to work, and tapped in the audio from the BT into it; not that hard to do. Schematics for antique radios were usually made available by the manufacturers, so that the user could repair it at home. Has this guy even heard what a 7W tube amplifier sound like?

    The best this guy could do was print a couple of rubber feet … wow, I am impressed.

    I am currently working on adding BT, internet radio and DAB to an antique radio from the 60s , but my approach is to change the least as possible the radio. The inconvenience of waiting for the RPi to boot up, fits perfectly with the nuisance of the tubes warming up with their gentle hum.

    This is the kind of project that requires time and love.

  6. I think this build is brilliant. I love to do this very thing with integrating new technology and functionality into old electronics. I have a couple examples on my website radiorestomod.net. As far as people being reluctant (or hostile) to modifying these old radios I would say a museum grade original radio that only receives AM radio and is a fire hazard because of cloth wiring doesn’t seem that useful. Would they have the same objections to me having plumbing and electricity in my 1880s built home?

    1. Very cool site. I checked it out. I really like the one with the LCD screen! I know someone that is trying to do something similar. Have you used OSMC? If so, what did you use to connect your external switches and knob input to control the OSMC?
      Thanks for the help, Again good job.

      1. Volume knob is just your standard volume pot that controls a class D amp board. Buttons are made from walnut dowels and hand wired to control adjustments of the LCD (inputs, brightness, contrast, etc.). So the Pi Mini is just another input on the board essentially. I’m using a variant of RetroPie and Kodi on it currently.

  7. The audio interface to an antique radio is always the high side of the volume control potentiometer. Typically requires between 0.1 and 1 volt peak to peak signal with high impedance load. Put in a series 1 k ohm resistor and a 1 mfd capacitor in series with the audio output and you should be fine. Put in a switch to select either radio or micro. But don’t drill out s hole for the switch. Almost all higher end radios came with 6 or 12 volt transformers to run the tube filaments which can be tapped to supply the AC for a small DC power supply. Be really careful if you have a tube lineup with high numbers such as 50C5 instead of like 12AX7, etc. This means there isn’t an isolation transformer and parts of the radio are tied directly to each side of the electrical outlet. I regard these as extremely dangerous to interface external electronics to and a project no go.

  8. I was all ready to defend this build – yes he pulled some vintage components from an old radio and added cheap hobby electronics, but he achieved the intended result.

    Then I watched the video – indeed a little hard to watch that teardown.

  9. It would be cool to make some tube socket passthrough adapters, so you could tap onto various tube connections solderlessly. That way you could do a historically accurate restoration, but also add modern tech which can be removed in seconds at any time.

    1. Be really careful tapping into the tube sockets. Most of the radios have 300 to 500VDC running around in them. A safe interface is the volume control and only on transformer isolated radios. Also be careful of speakers that have field coils with 120 V applied to an electromagnet winding.

      1. Isolation can be added, either signal isolation or an isolation power transformer. But, yes, volume control is a classic point for signal injection.

        My own cabinet radio had a turntable, long gone alas. If I do modify it, I hope to use that selection switch as my own injection point.

  10. I’m split on this one. The woodworker in me is glad to see the case being cleaned up and displayed. The electronics tech says that in addition to the transmitter option, he could have minimally altered the system to allow injecting his signal into the existing amp, retaining the rest of the radio almost unaltered. (I have a more recent cabinet radio (am/fm) waiting for that treatment). The steampunk fan in me says completely replacing the guts is justifiable if the old system was set aside and preserved and a replacement mocked up from scratch… Or, better, built the case too, modelled on this unit… And so on.

    Realistically, my final answer is that the community spoke when he didn’t get a high enough price offered to make him preserve it. Thiink of it as a gut-rehab of an old house; the facade has been preserved and a decent job has been done of preserving the cosmetic aspects while refitting it for today’s needs. It isn’t what I would have done (in several conflicting directions at once), but it deserves more respect than it’s getting.

      1. Yes. Really should replace double cotton covered power cord, tubes and all power supply electrolytic capacitors. The rest of the stuff such as wax and foil capacitors, resistors, tuning capacitors, coils, etc. will probably be ok for another 50 years if cared for.

    1. It’s nothing like rehabbing an old house. It no longer functions as a radio. It’s an MP3 player. If he’d put a transistorized receiver and amp inside I MIGHT be with you but this is an abomination.

  11. Sad and lazy, honestly. I think it has more to do with an unwillingness to restore things or learn ‘old tech’ like tubes. That radio was restorable. Now it is hacked up junk that no one will want in a year. This is like putting a gas turbine in a steam locomotive from 1870. Why?

  12. There was enough room in the speaker compartment to put the Pi, the amp, a power supply, a CD player, an 8 track player, and a collection of reel to reel 7 inch tapes, so I don’t know why he needed to remove the tuner sections. Tack the connections on to the volume control, etc. and you can snip them off to make it stock again.

  13. Is there a formula when its acceptable to gut something old to make it usable/functional with modern technology? age of product, operational state, rarity, coolness factor, usability after restore vs usability after replacing with new technology, cost and effort necessay to repair to original state, and general technical capabilities of the owner.

    I feel it really has to do with the group you ask, if you ask most non-tech and non-retro, person (id say 90%+ (random guess) of the population) they would feel the remade radio to a usable state with modern technology (Can easily be modded to play streaming services if need be) is a much better and more awesome finished product than a radio restored which can only catch AM channels.

    Does the fictional 10% group who would cry foul (most of hackaday apparently) actually make it ‘wrong’ to do so?

    I was mulling this conundrum recently as I came into possession of a broken 1970s Lear Siegler ADM-31 Dumb terminal, although it wouldve been cool to use it as a serial terminal, I would think the novelty would have worn of pretty quickly of seeing text based information scroll, I am considering gutting it and pi’ing it, much to the horror of most people here Im assuming. I think the dumb terminal would be much more usable and possibly more ‘wife friendly’ to have around the house if it was actually capable of doing something other than connecting to text based information services. (local or otherwise)

    1. It’s all a question of value, and that can be person-specific. For me, for instance, I _definitely_ think that this old radio is cool, but I can also understand that it’s a piece of mass-produced consumer gear from days gone by. I don’t insist that my vintage 2000 water-cooled Athlon box persist for all eternity either.

      I’m American, but live in Europe. In my neighborhood, currently, the debate is what to do with the Derzbachhof, currently the oldest farmhouse in Munich, built just before the American revolution. https://www.denkmalnetzbayern.de/index.php/menueeintrag/index/id/10/seite_id/1756 It’s been empty and essentially derelict for over 20 years. Architects want to build new apartments (seemingly respectfully) around the old building. https://www.euroboden.de/projekte/derzbachhof There’s naturally a kerfuffle about preservation of the unity of the old farmstead in a now urban city with a crazy housing shortage.

      Next door is the Alter Wirt, a restaurant and inn dating back to the 1400’s, and apparently in reasonably continuous service. The menu isn’t the same as it was in 1523, and it’s received more than one coat of paint since then. But at least some of the old timbers are pretty much ancient.

      Just south of here, in Italy, you see paintings, if not by Caravaggio, by masters who worked in his studio, sitting moldy in basements because they’re minor works and restoration funds are tight. And honestly, they’re out of style and nobody wants to have it on their wall.

      Is this radio (terminal) unique? Is it the last of its kind? How many are worth preserving? Will it still be useful/beautiful/treasured in the future? Can the parts of it that capture its essence be preserved, while making it useful, and thus possibly valuable, in the future?

      There’s certainly no clear-cut answer.

  14. I think there is a fine line to walk with all antiques like this. I restore old wood working tools and to some collectors I’m a monster for it. Take a hand plane for example. I clean them up, save all finishes that I can, and set them up user ready just like Stanley or Sargent intended. To some people this is perfect and to others you ruined its patina.

    I want to do a build like this for a radio but instead of just buying any old radio and gutting it, I’ve talked with a couple restorers I’ve met during my tool dealings. I’m in no hurry so one of them agreed to do the tear down and keep the internals for himself when he finds a good candidate for me. Just like with old tools I assume not all radios can be saved. I hope the internals from the cabinet I receive are put to use restoring another radio.

    1. I have a modest “collection” of hand braces (the original cordless drill), as well as a number of old woodworking tools in my shop.
      I guess, if one is to make a replica part/tool it should be clearly identified as a replica/reproduction. (I’m not accusing you of that, just expressing my own opinion, as in making a new handle for an old classic Disston, one should have some engraving/indelible mark that can’t be removed by a future person to pass off as genuine.
      I have an old coffee grinder that the original wood is bad. When I get around to replacing that I’m pretty sure no one will accuse me of trying to pass off a counterfeit (my skill level precludes that from happening B^).

  15. I have old radios in everything from pristine awful condition. I just got an old Atwater Kent 39 if I recall correctly. Good tubes and the case is in nice shape but mice set up shop inside the unit and nothing is as corrosive and nasty as mouse piss. I need to get it all the way apart and the use the case for something or restore question will probably hinge on the condition of the two transformers. In any event it is not going to be an easy road. I side with the folks on the restore side, and if I do not restore this, I will recycle as many of the parts as I can into other old sets. I have the same thing going on with old tractors. An awful lot of them were scrapped so even if you have one that is hopeless, some of the parts will be of use to somebody else.

    One of the current projects I am mulling is a crystal set. I have some beautiful antique variometers and variable caps and vintage coils, and old knobs and dials. I am envisioning a new oak case with vintage hardware and 3D printed pieces to adapt the knobs to the dials and devices, and perhaps a laser cut black acrylic top to simulate Bakelite. The idea is to marry new and old tech, but to try and retain an authentic old tech look. And I will probably try making a cats whisker from scratch. Have you seen what they are going for these days? If I saved the ones I had when I was a kid I would be sitting on a mint!

  16. You could have done this using the actual, original tube based electronics instead of gutting it. How? The radio, just like any other made at the time has a volume pot. The pot has three “legs”. Ground, center, and top of tap, the top being where the AM signal comes in. Any audio signal, whether it be from a bluetooth device, a phone plugged in via a 3.5mm jack, or whatever can easily be directed through the same pot. The AM signal’s lead can be switched on and off via a small micro switch mounted in the back. The chassis on these can be easily restored if you have decent soldering skills: The electrolytic and paper caps are all common values and new ones are dirt cheap. Also, putting modern speakers in something like this seldom delivers the same warm tonal qualities of the original. The old field coil speakers were sized and fitted for the cabinets, which themselves acted like a resonating body like that of a guitar.

    Anyway, I’ve done a LOT of radios, restoring them to their original electronic, tube powered condition and added bluetooth to them: the best of both worlds, a classic radio restored to original with a modern touch that can easily be removed and doesn’t alter the set. Here’s a bunch of my projects.

    https://antiqueradios.com/forums/viewtopic.php?f=1&t=323758&start=500

    1. I’ve been looking into 60s and 70s big record/stereo cabinets today. It might be an alternate solution to the video here considering i just bought an all original 1965 ranch. Judging by prices of all furniture in that style I may be building a clone of one with restored radio and record player instead. My goal is to wall mount my TV and use a big bench style stereo cabinet as my entertainment stand with room for things like an intel NUC, nvidia shield, small network switch, and UPS. With a quality DAC off of the shield I should be able to switch over to music on the stereo if I stick with something of a later vintage with an AUX in or do as you suggested and add bluetooth.

      Anyway just wanted to say thanks for the link you shared. When it comes time to either build my own cabinet or restore an original I will be signing up to the forums to research and ask questions.

  17. My family has a old german tube radio. Tried fixing it and was succesfull, but something went wrong during transport and it broke again. It also isn’t that great as it’s reception just ain’t cutting it in the modern age with FM reception up to 99mhz while over half the local radios inhabit frequencies above 100mhz.

    I identified where i can latch on a standard line signal (It has an old broken DIN-3 R2R tape-recorder input) that gets amplified and fed through a EL-84 Pentode to the speakers and when i fed a signal on it the radio sounded pretty good. so if i where to get the radio back eventually i figured with a small AC/DC power-supply module, RPi and a DAC for said Pi. i can enable the old device to be a Internet Radio / BT speaker. That way i can augment the radio, without having to gut it in any way.

  18. It’s not the value of the radio or skills of the radio dealer that has the value of radios low. For economic survival in an FM market, AM radio turned their programming over to political nutcases, which is interesting because it is what happened to radio in the McCarthy 50’s before rock and country dominated the radio formats. In any case, the type of person who would appreciate a fine antique radio would be very unlikely to be listening to today’s AM radio content. Hard to sell.

    CodeMakesItGo actually had it right that it would be really cool to have something like an antique radio that plays music, feeds, Pandora, etc. Maybe I could suggest a build project with a little gentler footprint of the following:
    Keep the radio intact and restore it to work or at least restore the three audio stages. Have a switch to select an audio input from a Pi or equivalent on the volume control. Program the Pi with an HTML server accessible over the local network to select with your cellphone what music or feed to play. I think it would be spectacular to have a podcast playing on an antique radio. That could be a nice project.
    An easier project is to simply connect Bluetooth to the volume pot and play content on the radio from a cellphone B/T connection.

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