Bluetooth 8-Track Adapters Are A Thing

When it comes to classic cars, the entertainment options can be limited. You’re often stuck with an old cassette deck and AM/FM radio, or you can swap it out for some hideous flashy modern head unit. [Jim] had a working 8-track deck in his Corvette, and didn’t want to swap it out. Thus, he set about building himself a simple Bluetooth to 8-track adapter.

The hack is straightforward, with [Jim] grabbing a Bluetooth-to-cassette adapter off the shelf. These simply take in audio over Bluetooth, and pipe the analog audio out to a magnetic head, which is largely similar to the head that reads the cassette. Pumping the audio to the magnetic coils in the adapter’s head creates a changing magnetic field essentially the same as the audio tape moving past the cassette reader head. It doesn’t really matter whether you’re working with an 8-track player or a regular cassette. Get the magnetic field in the right spot, and it’ll work.

The electronics from the cassette adapter are simply placed inside an old 8-track tape, with holes cut in the chassis for the charge port and on switch. Then, all you need to do is pop the adapter into the 8-track deck, pair with it over Bluetooth, and you can get the tunes pumping.

Others have had success with hilarious Rube Goldberg methods, too. [Techmoan] took a classic cassette-to-8-track adapter, which is actually self-powered by the deck, and simply popped a Bluetooth cassette inside. That worked surprisingly well, and it was interesting to see how it all worked on the inside. We even saw a 3D-printed device on TikTok.

Thus, if you’ve got an old Corvette, particularly of that era with the Doug Nash 4+3 transmission, this might just be the hack for you. Alternatively, you can hack Bluetooth in to just about any classic stereo; we’ve got a guide on how to do just that. Video after the break.

31 thoughts on “Bluetooth 8-Track Adapters Are A Thing

    1. Although I’m too young to have had contact with them, we did have 8-track cassette systems here in Australia, particularly in the 70s. One local radio station (now off-air as of Friday morning… their frequency now a 24/7 yappety-yap sports station) used to make frequent references to them and other things of that era (e.g. record selectors).

      A while back, Jenny List also did a deep dive into the inner workings of an 8-track player she had, so clearly they had them in the UK too. https://hackaday.com/2017/04/12/retro-teardown-inside-an-8-track-stereo-player/

      1. 8-track media was a cartridge, not a cassette.
        We certainly did have them here in Oz and the cartridges used to pop up at Salvos, op shops, swap meets that sort of thing but I haven’t seen one in a long while.

    2. Which devices: the 8-track itself, or the adapter to play standard audio cassettes?

      8-track was really common in the mid to late ’70’s in the States. When the technology was supplanted by audio cassettes, a number of those adapters cropped up as well: I recall Radio Shack sold at least one model under their Realistic brand well into the ’90’s.

      Never had a car with an 8-track, and I can’t imagine an adapter sticking four or five inches out of the slot was convenient in a car; I also suspect road vibration would have badly affected playback, and probably damaged the mechanism over time – those slots weren’t designed to support an outboard mass…

      1. Nah, those decks had solid steel chassis. And road vibration was not really an issue. Those adapters, however, I know the one I’m familiar with had a solid MDF body with a plastic shell. Odd engineering choice. Sliding a slab of wood into your stereo.

    3. 8-track sort of lived on until very recently at radio stations.

      They used to use things called Carts which were very similar to 8-track to store and playback ads and repeated announcements.

    1. I thought those things had only 256MB memory. I tried one of the type that Techmoan has in his video, which takes a 2GB SD card, but it’s only useful as a single folder playlist device, as there is no way to navigate folders. Just skip forward or back. and the remote is useless in imbedded transport decks, or shelf units that don’t have mostly transparent doors. The Mixxtape ( https://mistapeboss.com/products/mixtape-1?variant=15312844423211 ) model seems to have gone overboard with feature creep and is priced accordingly.

      1. Yes, 256 + 128Mb MMC card, so about 80 mp3’s which is a good 5 hours before repeats. I’m fine with that as the amount of rides I go on longer than that is very, very few!

  1. Makes me wonder if a CD adapter would be possible. In other words, a mechanism which converts an audio signal into dynamically produced “pits and lands” that would be read by a CD player.

    Perhaps something based on DLP mirrors.

    1. I think an LED could do it if you always knew where the laser was. Make a whole normal CD of some pseudo random sequence that lets you always know where you are just by seeing a tiny part. Intercept the light returning from the laser, somehow, decode it, send your own signal with the LED.

      1. Yah, you just have to emulate the light that comes back. If you had it shining into a long prism, arranged along the path of the head, then wherever it moved the head to it would get it. In theory, it would work in machines with blown lasers… if the machine didn’t check laser function by a method other than “hey I can see it”

        In tray players, I think you have a bit of height up front, that you can use for a battery or bulky stuff… because you’re gonna make this thing with a too large hole to engage and rotate of course. So could go maybe 4mm or 5mm high on a slice about a thrid the width of the CD… For slot loads, you’d have to have it all outside the hole, but you’d be able to feed the edge of it still. Maybe you can do a twofer, works in both by having a hinge, flip out for slot load, flip on top for tray load. But top loaders may like neither, depending on exact construction, but on the other hand usually have easily fooled lid close switches you can stuff a matchstick in or something…. Then your only real, real problem is multidisk changers (never gonna happen.) and the tray slide top loaders (mostly seen in early CDROM drives)

      2. Technically, you would have too many hurdles to overcome to make a CD adapter a possibility seems impractical. Not only would you have to figure out how to emulate the reflected light, but you have software issues where you would have to know the internal state of the CD player to properly handle seeking, track information, time codes, etc. Most of this is unknowable without physically tapping into the CD circuitry, and at that point financially it makes little sense to do that instead of buying new hardware that can handle Bluetooth, AUX, or other newer technology. AUX input was pretty common with CD players, and cassette players lived on long enough to almost make it into the MP3 and Bluetooth ages, and FM transmitters were a thing too, so really any adapter using CD technology would have made little business or financial sense. Cassette adapters were pretty good for what they were.

    2. It is much more difficult to make since the optical disks are very thin and therefore you cannot put a battery inside them. It could work by inserting an RFID antenna into the disc that powers an LCD similar to those used in active 3D glasses, i.e. a layer that becomes dark when a voltage is applied.
      https://en.m.wikipedia.org/wiki/Active_shutter_3D_system
      This system would obviously require a source to be attached to the outside of the CD player.

  2. That current electronic Compact Cassette is terrible. Try finding an old Mobi-Blu or others from its time. They take standard “gumstick” batteries. The first MP3 player cassette had only built in storage but that was quickly followed by a revised version with an SD slot. Mobi-Blu and others were copies, but good copies.

    1. How’s the Armor-All branded Bluetooh one? PIcked one up very cheap NOS clearance but the battery was already bloated. Keep meaning to source one, just wondering if it’s worth the effort, or just stick with the wired editions.

  3. Interesting trivia about that excellent 1st Boston album:

    “Epic [the record label] wanted the band to record in Los Angeles with a record producer, but Scholz was unwilling and wanted to record the album in his basement studio, so he hired Boylan to run interference with the label. In an elaborate ruse, Scholz tricked the label into thinking the band was recording on the West Coast, when in reality, the bulk was being tracked solely by Scholz at his Massachusetts home. The album’s contents are a complete recreation of the band’s demo tape, and contain songs written and composed many years prior.”

    1. Is it like those new wave and synthpop recordings from the late 70s and 80s where they layered the tracks on reel to reel tape and you play it and get the tsssssss of the analog medium then TSSSSS as the multicopy noise comes through from their tape?

  4. Sadly the condition of a little rubber belt or tire inside will make or break weather that classic in-dash unit will “play”, and continue to work. Only most 8 tracks would keep on till the now beltless motor screams for oil. I have a wired adapter, It sounded great now the cassette reverses over and over. Take-up anti-tangle has failed and it reverses. Chrysler-Infinity with amps in the trunk, stock. If I have to open it up I’d wire into the audio control chip. There is bluetooth 5.0 which is decent but why bother, wired never drops out.

  5. About 20 years ago I used an AUX out to cassette adapter from a CD player inserted into a cassette to eight track adapter to play CDs on an 8-track stereo system. This is not much different than that it just replaces the aux cable with Bluetooth.

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