I've recently become interested in the original Teddy Ruxpin that operated by playing 8-track cassette tapes. The 8 channels on the tape were used in a creative way to ensure that Teddy's animation would line up correctly with the audio. This link gives more information on how it's done. It seems like channel 1 is perhaps the channel used for the audio, and the other channels are used for eyes, upper and lower jaw, and whether the audio is supposed to come from Teddy or Grubby (a different toy).

I can find lots of tutorials on hacking Teddy using open-source python libraries, a wi-fi connection, replacing the cassette deck with a microchip, blah blah BLAH. I want to create my own Teddy Ruxpin cassette tape that can be inserted into the toy like one of their own tapes and will animate according to my coding.

I can't find any information on how the animation channels were specifically used to determine the mouth and eye movements, however. What do you guys think? Is there an easy way to find this out? And if not, what's the best way to get to work understanding it myself? What kind of equipment is good for editing individual tracks on an 8-track cassette tape, and where could I get it?

  • 1
    FYI: 8-track tapes used for distributing pre-recorded music were an adaptation of the A-size NAB Cartridges (a.k.a., "A carts") that were ubiquitous in radio stations throughout the 2nd half of the 20th century. I never personally saw an 8-track recorder for sale or blank tapes for sale, but the Wikipedia article seems to show that they were a thing. Mar 16, 2020 at 19:13
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    Teddy Ruxpin did not use 8-track tapes but rather 2-channel cassette tapes similar to standard cassette tapes on the market. The were slightly different so that you could not put them in on "Side B". One channel had the audio and the other had tone-encoded commands that worked the animation. 8-track tape recorders and blank tapes were available in the 60's and 70's but they were not all that popular and were soon replaced by cassette recorders.
    – jwh20
    Mar 16, 2020 at 23:04
  • Oh, okay, I see I mixed those up. So this type of cassette tape should be easier to replicate then because machines to record them were more common? Also: I did see YouTube demos of vintage Teddy Ruxpins that stated the tapes could be put in on Side A or Side B, but one side was the side it was meant to be used with and would be much better.
    – ribs2spare
    Mar 17, 2020 at 14:09
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    FWIW, The wikipedia article for Teddy says that at least three different versions were made by three different companies. The first and the last used ordinary compact cassette tapes. The one in-between (made by Hasbro) supposedly "used cartridges that resemble 8-track tapes." (I found this on e-bay, ebay.com/itm/154298260842 , but that sure doesn't look like an 8-track to me.) Jun 3, 2021 at 20:28
  • @SolomonSlow That's no 8-track but the resemblance is pretty close (at least to my eye). Jun 4, 2021 at 4:56

1 Answer 1


There were many 8-track tape recorders, but they all, to my knowledge, used the same stepping-head arrangement for conventional playback (4 sets of stereo tracks)

It would theoretically be possible to use a single eight-channel head to make an event recorder or eight-track master recorder, but the limited tape length and crappy drive method make these uses nonworthwhile. It is possible to modify the mechanism to have more precise locking of capstan against roller; a better approach would be to use a radio 'cart' machine drive, which raises a pinch roller through a recess in the shell to lock the tape path.

Many four- and six-track "cassette" recorders were made, including the TASCAM Portastudios. Obviously the channels here could be used for any combination of click or tone control data; with simple audio filtering of the type used for slide-projector control, multiple tone or pulse signals can be provided above and below the AF content.

  • Incidentally you may still be able to find endless-tape cassette shells and the metal 'sensor' tape on a source like eBay -- this is the design used in early answering machines, with the same general tape path in the shell used for 8-track, with an enlarged hole over the 'reverse' spool drive head. These can with care be loaded with modern thin audio-quality stock to considerable length, using the metal strips to divide programs on the single long tape run. Jun 3, 2021 at 18:05
  • Quadraphonic 8-track players would move a quad-pickup assembly head between two positions, and electrically switch between two pairs of head for stereo playback. Those would be designed to be suitable for use to output four synchronized channels.
    – supercat
    Nov 2, 2023 at 20:43

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