I have recently been introduced to the art of tape looping. It’s hard to Google for tape loops and not come across the name AMULETS.
If you never heard of him, please take a min and check him out:
He has a few tutorials floating around on the net on making a 5 second tape loop that was really easy to follow.
I had an older/cheap GE portable tape recorder that I wanted to do a pitch mod to. This would give me the ability to slow down the playback speed with a potentiometer. I played around with a few different pot values and found for this player a B25K pot was perfect to get a complete stand still just at 100% of the pot.
Look at the case of your player and see where the best place is to mount the knob at. With the case off the player you will be able to see if you have clearance for the pot/knob. I found a nice little cubby hole right behind the battery compartment that gave me access to the top of the player without obstruction from the PCB or internal speaker.
When you have your tape player open, look for a hole in the PCB that has access to a trimmer. This trimmer is used to set/calibrate the motor speed from the factory. We are going to add a pot to it to add control from the outside of the player.
Now make your hole for your pot in the plastic enclosure. If your careful about it you can do all this while the PCB is still mounted. Seeing all the motors and belts I decided to not take it completely apart. If I did I am confident that it would no longer work LOL.
End results: (Cassette tape courtesy of my wife)
I also wanted to add a MONO 3.5mm jack so I can output it to my modular system. More to come on this later.