Groovetube

After experimenting with a different way to control audio signals from a plasma, Telmatronics have developed Groovetube, a proto-instrument that can produce a wide range of sounds from ordinary fluorescent tubes. Different types of tubes can make very different sounds, this is an machine for experimental noise-making.

This page has demos and details of specification and performance, and will be updated regularly.

The Groovetube audio fluorescent driver

This machine shown here is still the working prototype, with a load more controls added and one less valve. We are working on a smarter box for it all to go in, that will have to remain mysterious for now...

This is the demo video made for our Kickstarter campaign:

Audio was recorded with neutral EQ, only volume levels adjusted.

The fluorescent tubes used by this machine are due to be phased out in the near future, and we will secure some supplies to keep machines running. We intend to develop our own tubes, and will make these compatible with the driver.

Working Spec

Telmatron:
The machine drives a cold cathode discharge inside 9" T5 fluorescent tubes, with a nominal system voltage of around 350 VDC and using RF coils for excitation. These systems are regulated by preamp valves as they are well-suited for handling high voltages and generating an RF signal, and are also used for the audio circuit. Control signals are coupled in optically for isolation, and the RF system has an additional slide control which allows the plasma stability to be set.

Control system:
The telmatron's systems for regulating tube voltage and excitation are controlled by voltage signals which can be separately modulated. Onboard control has ranges of preset CV sequences and gate patterns, with two harmonic signals generated by digitally-controlled LFOs for modulation. This allows control over frequency and phase relation, which can significantly affect the sounds produced. This system also generates a timing signal for synchronising with other equipment. External inputs allow control by two modulation signals and CV/gate signals.

Release details

Our machine was initially available to order in complete and kit form as part of a Kickstarter campaign, which ran until March 23rd 2023.

Later this year we will open for further orders. You can register interest in the meantime on our contact page.

We have promised to post schematics and construction notes, this will happen in in due course when finalised and time allows.