For plenty of media center PCs, home theaters, and people with a simple TV and a decent audio system, the standard speaker setup now is 5.1 surround sound. Left and right speakers in the front and back, with a center speaker and a subwoofer. But the 5.1 setup wasn’t always the standard (and still isn’t the only standard); after stereo was adopted mid-century, audio engineers wanted more than just two channels and briefly attempted a four-channel system called quadrophonic sound. There’s still some media from the 70s that can be found that is built for this system, such as [Alan]’s collection of 8-track tapes. These tapes are getting along in years, so he built a quadrophonic 8-track replica to keep the experience alive.
The first thing needed for a replica system like this is digital quadrophonic audio files themselves. Since the format died in the late 70s, there’s not a lot available in modern times so [Alan] has a dedicated 8-track player connected to a four-channel audio-to-USB device to digitize his own collection of quadrophonic 8-track tapes. This process is destructive for the decades-old tapes so it is very much necessary.
With the audio files captured, he now needs something to play them back with. A Raspberry Pi is put to the task, but it needs a special sound card in order to play back the four channels simultaneously. To preserve the feel of an antique 8-track player he’s cannibalized parts from three broken players to keep the cassette loading mechanism and track indicator display along with four VU meters for each of the channels. A QR code reader inside the device reads a QR code on the replica 8-track cassettes when they are inserted which prompts the Pi to play the correct audio file, and a series of buttons along with a screen on the front can be used to fast forward, rewind and pause. A solenoid inside the device preserves the “clunk” sound typical of real 8-track players.
As a replica, this player goes to great lengths to preserve the essence of not only the 8-track era, but the brief quadrophonic frenzy of the early and mid 70s. There’s not a lot of activity around quadrophonic sound anymore, but 8-tracks are popular targets for builds and restorations, and a few that go beyond audio including this project that uses one for computer memory instead.
In the 1970s, 8-track audio players were very popular, especially in cars. For a couple of bucks, you could have the latest album, and you didn’t have to flip the tape in the middle of a drive like you did with a cassette. We’ve seen plenty of 8-tracks and most of us a certain age have even owned a few players. But we couldn’t find anyone who would admit to owning the Bearcat 8 Track Scanner, as seen in the 1979 Popular Electronics ad below.
For reasons still unclear, [Techmoan] has procured an RCA 8-track changer that holds five tape cartridges in a custom carrier. It somewhat works, but had a bit of mechanical issues here and there which needed some maintenance. Additionally, the player is designed for the US market and 60 Hz mains, but [Techmoan] is in the UK with 50 Hz.
Although electronics are used for the basic tape player portion, everything else is operated by mechanical gears, levers, and motors. The system plays both sides of each tape cartridge through to completion, and then switches automatically to the next one in the stack. Cartridges could be up to 90 minutes each, making for over seven hours of playing time. Oddly, the system does not repeat automatically after the fifth tape ends –operator intervention is required. It’s not entirely clear whether these carousels were primarily intended to play background music inside businesses, or built for niche consumer applications.
After discovering there was no setting to adjust the tape’s speed for 50/60 Hz operation, [Techmoan] could have ordered or fabricated a larger-diameter pulley for the motor drive shaft. But in true hacker style, he instead solves the problem with cellophane packing tape. By trial and error, he builds up the pulley diameter by winding lengths of tape until the music sounds just “good enough” to his ear. Then he pulls out the wow and flutter meter to really zero in — and gets it bang on. He says that this changer is needed for a future video, so we’re looking forward to see how it will be employed.
If you like these old mechanical logic controls, check out the video below the break. If you want dig into the workings of an 8-track player, check out Jenny List’s retro teardown from 2017. Does anyone still use 8-track tapes any more?
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.
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.
On the outside chance that we ever encounter a space probe from an alien civilization, the degree to which the world will change cannot be overestimated. Not only will it prove that we’re not alone, or more likely weren’t, depending on how long said probe has been traveling through space, but we’ll have a bonanza of super-cool new technology to analyze. Just think of the fancy alloys, the advanced biomimetic thingamajigs, the poly-godknowswhat composites. We’ll take a huge leap forward by mimicking the alien technology; the mind boggles.
Sadly, we won’t be returning the favor. If aliens ever snag one of our interstellar envoys, like one of the Voyager spacecraft, they’ll see that we sent them some really old school stuff. While one team of alien researchers will be puzzling over why we’d encode images on a phonograph record, another team will be tearing apart – an 8-track tape recorder?
Following time backward, for portable music we’ve had iPods, CDs, and cassette tapes which we played using small Walkmans around the size of a cigarette box. And for a brief time before that, in the 1960s and 1970s, we had 8-track tapes. These were magnetic tapes housed in cases around the size of a large slice of bread. Car dashboards housed players, and they also came in a carry-around format like the one [Todd Harrison] recently bought at a Hamfest for $5 and made more portable by machining clips for a strap and adding a headphone jack.
But before hacking it, he wanted to try it out. Luckily his sister had hung onto her old tapes and after plugging it in and sliding in a tape, it worked! Opening it up he found that the contacts for the batteries were rusted but the mechanical components and electronics inside were very clean. Though he did add glue to a crack in the plastic read-head support, cleaned out some grease, did some lubricating, and cleaned the contacts in the volume control’s potentiometer. Check out his teardown video below for those details or if you just want to see how it all works.
Then came making it portable so that he could embarrass his kids by carrying it around the mall. The shoulder strap didn’t come with it, so he machined some clips out of steel and snapped on a strap. It didn’t have a headphone jack and he didn’t want to embarrass his kids too much, so he added one. You can see that hack in the second video below, including how his repurposed jack automatically disconnects the speaker when the headphone plug is inserted. Personally, we think he looks pretty spiffy carrying it around wearing his Hackaday T-shirt.
If you are a connoisseur of analogue audio, it’s probable you might have a turntable and a stack of records at home somewhere. If you are of a certain age you may even have a cassette deck, though you’re more likely to have abandoned that format some time in the 1990s. If you are old enough to have been around in the 1960s or 1970s though, you may have owned another analogue audio format. One of several that you might have found in a well-equipped home of that period was the 8-track stereo cartridge, a self-contained tape cassette format that fit four stereo tracks onto a single quarter-inch tape loop as eight parallel tracks, four each of left and right. A triumph of marketing, really, it should more accurately have been called 4-track stereo.
8-track cartridges were developed from earlier tape cartridge formats, largely to satisfy the demands of the automotive industry for interchangeable in-car entertainment. Thus if you owned an 8-track player it was most likely to have been found in your car, but it was not uncommon to find them also incorporated into home hi-fi systems. Thus we come to our subject today. Our retrotechtacular series usually highlights a video showing a bygone technology, but today we’re going to get a little more hands-on.
Some time in the early 1990s, I acquired an 8-track player, a BSR McDonald unit manufactured in the UK and dating from the early 1970s. BSR were much more well-known for their turntables, so this is something of an oddity. Where I found it has disappeared into the mists of time, but it was probably at a radio rally or junk sale. I certainly didn’t buy it because I wanted it to play 8-track tapes, instead I wanted a talking point for my hi-fi, something quirky to set it apart from everyone else’s. So every incarnation of listening enjoyment chez List for the last quarter century has had an 8-track player nestling within it, even if it has never played a tape while in my ownership. Thus we have a unique opportunity for this retro teardown.