The Hard Way of Cassette Tape Auto-Reverse

The audio cassette is an audio format that presented a variety of engineering challenges during its tenure. One of the biggest at the time was that listeners had to physically remove the cassette and flip it over to listen to the full recording. Over the years, manufacturers developed a variety of “auto-reverse” systems that allowed a cassette deck to play a full tape without user intervention. This video covers how Akai did it – the hard way.

Towards the end of the cassette era, most manufacturers had decided on a relatively simple system of having the head assembly rotate while reversing the motor direction. Many years prior to this, however, Akai’s system involved a shuttle which carried the tape up to a rotating arm that flipped the cassette, before shuttling it back down and reinserting it into the deck.

Even a regular cassette player has an astounding level of complexity using simple electromechanical components — the humble cassette precedes the widespread introduction of integrated circuits, so things were done with motors, cams, levers, and switches instead. This device takes it to another level, and [Techmoan] does a great job of showing it in close-up detail. This is certainly a formidable design from an era that’s beginning to fade into history.

The video (found after the break) also does a great job of showing glimpses of other creative auto-reverse solutions — including one from Phillips that appears to rely on bouncing tapes through something vaguely resembling a playground slide. We’d love to see that one in action, too.

One thing you should never do with a cassette deck like this is use it with a cassette audio adapter like this one.

69 thoughts on “The Hard Way of Cassette Tape Auto-Reverse

    1. Nakamichi coreccttly stated that their system was superior, since the head alignment was fixed (but of cours adjustable) all the time, while other autoreverse either had a head that moved, or a fourtrack head where you could adjust the whole head, but adjusting for best audio on one side made the other side misaligned.

      He was dead serious about his audio equipment and got an reference tape and an instrument to align the head of his Naka.

      He also owned every high end Walkman that Sony ever made, he had uther brands too, but he was totalt sold on the Sonys.

      Recently he payed hundreds of $ on flebay for a Sony Walkman of his favourite model.

    2. Back in the 1980s when I was but a poor high school student the local hifi salon had a Nakamichi RX-505 demo unit that showed off the mechanism. It may have had a cutaway to show all the gears and belts but I don’t remember. It was way out of my price range so the idea of my owning it was out of the question.

      A few years ago I was at a local thrift store when they were putting out fresh meat in electronics when I saw the back of what appeared to be a tape deck. I couldn’t see the front until the employee set it on the shelf right in front of me. I recognized it as Nakamichi but I couldn’t tell if what model. I grabbed it and ran off to the testing area. Found a tape and plugged it in. Hit eject but nothing happened. Slapped it on the top of the case and the tape area popped open. Inserted a tape and hit eject again to close it. Surprisingly it worked. Ran to the checkout and they charged me five bucks!

      I need to replace all the belts to get it up to scratch but after looking at an Audiokarma how-to I can honestly say this is a nutbuster of a repair.

    3. Loved the 505, when Nakamichi was high up the totem pole. Their ZX series tapes were the best Metal tapes I have ever used. Now those cassettes are getting $50 on eBay

  1. This reminds me of some of those “how many _____ does it take to change a light bulb?” jokes; why try revolving the smallest part of the mechanism when you can turn something bigger?

    1. There some issues that weren’t mentioned. Most auto-reverse decks didn’t record on earlier machines.

      The speed of the tape is regulated by a capstan post and roller and if a tape has to turn both ways then 2 of the three openings at the top of the cassette needed to have a capstan post and roller so there was nowhere left to put the erase head needed for recording.

      Later on they made a micro small erase head that sat beside the flip head.

      1. I used to work on car stereos while in high school. From what I recall most simply had a dual head (separate coils for both directions). It made the mechanics far simpler.

  2. My older brother had one of these that we spent a lot of time marveling at. I think he picked it up in Japan while he was in the service…I don’t remember seeing one at the local stereo store. I had a “simple” Pioneer deck that had a double set of heads or something that was supposed to be better….it wasn’t and ultimately busted down. The real audiophile cassette decks (there’s an interesting statement) had no such gimmicks….

  3. “Towards the end of the cassette era, most manufacturers had decided on a relatively simple system of having the head assembly rotate while reversing the motor direction.”

    No, they had dual stereo pickups on the head, and just reversed the motor direction.

    1. Phillips had one system that reverse the direction of the tape and flips the head to read the 2 tracks in the other side,maybe it’s done that way to allow recording in both sides (one at the time of course)

    1. indeed, this has nothing to do with hackaday in the sense of hacking.
      BUT… it is such a marvelous hypnotic sight that made it earn it’s place on this website.
      I love it! And it was fun to see that the maker of the video has the same appreciation.

    1. Every time someone comments about a GIF, several others respond either in defense or agreement with said comment. More page views and and comments. More incentive to insert GIFs.

      “The only winning move is not to play.”

      1. I seem to be an ignorant SOB; so what’s wrong with more page views? In the event it means a bit of minuscule income for HAD, that’s some of life’s small stuff not to sweat.

    1. I suspect early on Japanese companies might had a Cassette head cartel going on, just like most Hard drive platters in the nineties used to come from one Japanese manufacturer – Hoya.

      1. It is possible and done very often in smaller (car stereo or walkman type) devices. Azimuth issiue is not very plausible, as azimuth has to be perpendicular to tape transport direction for any of the 4 tracks.

        Possible is, that crosstalk is difficult to overcome with the 4 small head coils in one case.

  4. I was just thinking about cassettes just the other day. Are they going to be the next thing to be retro-cool like vinyl? Should I be buying up all the old crusty cassette decks from the local thrift shops and hunting Amazon for a book about their repair and tuning? Should I be tinkering with them in my ‘spare’ time getting them all tuned up like new so I can make a fortune selling them to hipsters a few years from now?

    Then I remembered that my home already is a big techno-trash warehouse and I am trying to get away from that, not make it worse.

    1. Oh though believe it or not, there does seem to be a market established…. for 80s original “Ghetto Blaster” type machines. What you couldn’t give away for a a buck at a yard sale 5 years ago are now changing hands for $100.

    2. National Audio Company. The last manufacturer of Compact Cassettes in the USA. Established in 1969, their sales volume has almost always increased year to year. In recent times that’s been mostly due to their competition going out of business. They’ve bought most of the equipment from the other companies. Originally founded to produce audiobooks and sermons and other religious tapes, they saw an opportunity to get into music as the other companies folded. One of their more popular recent products was the “Awesome Mix #1” compilation tape of the “Guardians of the Galaxy” soundtrack.

      https://www.youtube.com/watch?v=CMTpvr9HXeI When this video was made, 2015 was NAC’s highest sales volume year.

      The Compact Cassette has never had a “revival”, it’s never been down and out!

      1. “mostly due to their competition going out of business” for me this is the same as “the compact cassette goes down and out”. It had it’s time, it was a thing of my youth, it was fine theses days as it was the only possibility for recording, but for me it had already more than one successor: First the Mini-Disk, then the recordable CD and now MP3 and other HD or chip based storage of music.
        I still have my old and expensive cassette deck from the 90ies (quite good Sony autoreverse), but it stopped working long ago. Unfortunately it was designed in a way, that the capstan was running all the time it was powered on. Some years ago when I used it after already some years of non-use, it started to make horrible squeaking noises and the last time I tried it, it did not transport the tape any more. probably the belts disintegrated.
        But I have no real need to repair it. Modern digital storage is so much more comfortable and offers better quality. Analog was good when it had its time, but these times are GONE.

  5. Hmm…

    Cool thing about this method… look through the window and the label you see is the one for the side you are listening to. That’s why this beats both the spinning head method and the 4-track head method.

    How about a method for the Arduino generation?
    – Tape deck includes a Raspberry Pi. When it detects the insertion of a tape it rewinds to the beginning. Then it plays the whole tape at high speed, not out loud but recording as it goes. The digital recording is now analyzed for silences, uses them to split the recording into tracks and finally presents the ‘tracks’ to the user for selection and playback (digitally slowed to normal speed) via a touch screen menu supplied by an Arduino connected via BLE. The Arduino of course is powered by a USB cable ran to a laptop computer.

    1. how about an Pee with a camera sitting inside the deck, insert tape and camera reads the label, googles the album for you, opens up YT and starts streaming higher quality music
      or a shortcut – just google the album yourself

  6. Back in the mid/late 80s when the whole “backwards masking” thing was about to peak, I found a cassette deck(a Realistic, IIRC) that had a head that was supposed to be static but had screws to hold the head to its mount instead of being tack welded on. I managed to pull the head mount, unscrew the head and reverse it and then replace it. Once I got the alignment done properly I was able to listen to music in reverse, and I actually found some “backwards masked” songs that nobody else knew about, though they’d have had no reason to suspect them. For example, Art of Noise’s “Paranomia” has something that sounds like someone saying “Buh-bu-buuuuyaaaah” come to find out that’s “Paranomia” in reverse. If you know anything about AoN, you know they were huge into samples and making crazy sounds, apparently playing it backwards was in their tool set. Of course these days nobody thinks a thing of this but back then it was huge.

    Anyway, I got the whole idea from auto reverse decks and just happened to luck upon the one I had. It saved me many a rekkid.

    1. That was kinda normal through the 70s, adjustable head so you could manually fix tracking when it went off…. obviously from the screws on the adjustable head creeping…. handy in early 8 bit days when you needed to “tune in” your tape player so you could load software.

  7. 1972… I have a Dual (that’s the Brand name) C901 Cassette deck that was made in ’74 (some say ’73) and is one of those simple 4 track dual capstan type like most autoreverse walkmen work. Impressive. Even more impressive is the amount of noise it makes when it switches – barely any. It makes less noise switching sides than the average autoreverse walkman.

    1. Right, some went CLACKATACKCLACK like there was mechanical damage happening every time. Don’t forget though compact cassette stuff was at first exactingly engineered, then beancountered for mass market portables in the mid 70s, then de-perfected and simplified to fit in the first actual wear on your belt portables. Then as CD got invented, they just seemed to go “screw it” and knock out the same crappy plastic mech for everything.

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