Finished cassette looper

I got a basic cassette looper put together using the techniques I wrote about earlier. The basic premise revolves around separating the erase head from the engagement of the rest of the record electronics and making each of them momentary so that it’s easy to retry a few times until the loop is just right. The record electronics is triggered by a slide switch that is momentary already so I just added an extension to it so it’s accessible from the outside. Making the erase head momentary involves cutting the detent tab off of the record button action so that pressing the record button becomes momentary.

The basic operation once a loop cassette has been inserted is to hit play and engage the erase head for one full loop to start with a blank tape. Then once the erase head is disengaged, hit the record button starting a little before the beat and ending a little after the last beat. Since there is no erase head it’s not too critical to stop right on time – the sound will be overdubbed so this can be used to figure out if the speed and tempo match up.

Some nice things to have would be monitoring, metronome, better speed control (nudging, vernier). The speed control is pretty touchy since it’s a small trimmer pot with a really wide range. Maybe a BPM meter could be added, I’m not sure.

It was pretty difficult to fit anything else inside the case. I had to dangle the input jack out in the battery compartment and even the little 3D printed part that pushes the record switch didn’t clear without removing the AM antenna. I wonder if I could 3d print a case that would hold the transport and electronics with room to spare for other things like perhaps an Arduino for doing the metronome and speed nudge features.

I disabled auto stop and the record tab prevention thing (not sure what that’s called). If auto stop is still enabled on the deck some loop tapes can cause the deck to stop looping if the tape is a little bit tight. Rule of thumb for making the loop cassettes is that the tape doesn’t have to be tensioned inside the shell. It just needs to be tight enough to stay routed along the tape path.