Petteri Mäkiniemi sent in this video that demonstrates the Ginette, a DIY instrument, based on the Ondes Martenot.
Here’s what Mäkiniemi has to say about the Ginette.
I designed and built this instrument during 2010-2011. The idea is based on the ondes Martenot that was invented by Maurice Martenot in 1928.
My instrument is named ‘Ginette’ after Ginette Martenot – an ondist and the sister of Maurice Martenot. She played ondes Martenot at the premiere of Olivier Messiaen’s Turangalîla-Symphonie.
The heart of the instrument is a voltage-controlled oscillator (VCO) that produces the sound. I found great VCO design from Music From Outer Space website. The VCO produces four waveforms or timbres – sine, triangle, ramp and square – which can be selected on the panel. The range of the fingerboard is four octaves and on the panel there is an octave selection knob, so the total pitch range is nine octaves. In practice the tracking isn’t so accurate in very high and low registers.
There are connectors for an external CV and a gate, so the instrument can also be controlled using external device like a keyboard or a sequencer, which both are my future DIY projects. I am going to improve the instrument by adding a voltage-controlled amplifier (VCA). This would fix the problem with the volume control button that leaks some signal when it’s supposed to be mute.
The background noise in the video is due to the tube amplifier.
Mäkiniemi notes he was inspired by Dana Countryman’s take on the Ondes Martenot.