Tandberg instrumentation recorder controlling a synthesizer

video upload by A Radiophonic Shed

"This Tandberg Series 115 instrumentation recorder is a scientific logging device from the 1970s.
Voltage changes detected from scientific instruments are recorded as frequency-modulated signals to four separate tracks on ¼" magnetic tape. When the tape is played back for analysis, those same voltages can be examined - replaying the experiment.
Here we have recorded 1V/octave pitch voltages from a keyboard, and now we're replaying those same voltages into a modular synthesizer - all the sound is coming live from the synthesizer, it isn't an audio tape recording.

More details: https://shedsynth.wordpress.com/2026/..."

And a short video featuring the Tandberg as a VCO along with a full view of the front:

Tandberg 115 as a VCO – electronic music from old test equipment

video upload by A Radiophonic Shed