23
[audio cassette player] Are both or only one "axis" supposed to drive the tape? (piefed.cdn.blahaj.zone)
submitted 1 month ago by to c/techsupport@lemmy.world
22 comments fedilink hide all child comments
 

I finally bought myself and old audio cassette player. The insides look crazy clean and the drive belts seem neither loose nor dried out.

But!

It's only the left "axis" - or whatever it's called - that's spinning and thus "driving/forwarding" the tape. With "left", I mean the one that rolls up the tape as it's being played. Looking inside, the right axis is not even actuated. It's just a "dead"/unmoving part. Is this how they all work?

you are viewing a single comment's thread
view the rest of the comments
[–] 22 points 1 month ago* (7 children)

I don't have a cassette player around, but I'd think that it'd be extremely difficult to have a motor drive the unspooling side concurrently, because the ratio at which you'd need to drive the two gears would change over the span of the tape due to the size of each spooled-up tape radius changing. And tapes aren't standardized in length, so it's not like the tape player—even if it had a way to know where it was in a tape when you inserted it, which it doesn't—would really have a way of knowing that ratio.

  • permalink
  • fedilink
  • source
  • hideshow 7 child comments
    •
  • [–] [S] 4 points 1 month ago (6 children)

    Sic! I had never thought of that! Does the winding/spooling speed of the driving side change to account for the change in radius?! How is that solved mechanically? Pressure plates that "feel" the size of the spool? 🤯 Or is that just the case if it had two drives?

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 6 child comments
    •
  • [–] 10 points 1 month ago* (5 children)

    There's no need to fix it since the tape is recorded the same way it's played.

    Like a vinyl record, the grooves towards the outside of the platter are moving faster than the grooves on the inside yet it spins at a constant RPM.

    One advantage of analog is that there's no constant "bitrate" that has to be maintained though faster moving analog media generally translates to higher fidelity.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 5 child comments
    •
  • [–] 2 points 1 month ago (1 child)

    So, I guess that that means that the fidelity of audio near the end of the cassette would be higher than that near the beginning. Huh. Never thought about that. Neat!

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 1 child comment
    •
  • [–] 5 points 1 month ago

    Yes. In very rare cases, vinyl records will be cut with tracks running inside to outside. In the one example I've seen, it's to accommodate the building crescendo of the classical piece recorded. The louder more dynamic portion at the end benefits from the faster vinyl.

    https://m.youtube.com/watch?v=5Afikv6k1-c

    Edison's original phonograph used cylinders which offer constant speed playback.

  • permalink
  • fedilink
  • source
  • parent