CHRT Synthesizer Offers Expressive Vacuum Tube Synthesis

At SynthPlex 2019, CHRT Synthesizer was showing their unique vacuum tube analog synthesizer.

It’s available as a DIY kit or partially pre-built.

We talked with Petr, who gave us a hands on demo and some background on why he chose to create a synth design using tubes.


  • ‘Natural electric, real synth sound’ – no attempts to “sound-like-some-acoustic-instrument”
  • ‘Natural Synthesis’ is a different approach to sound synthesis compared to mainstream subtractive analogs – the wave is shaped in a resonator
  • The whole tone signal path is a pure tube (thermionic valve) circuit, digital circuits are used only for what they are good at – MIDI to CV, tuning, etc.
  • It is designed by a saxophonist to offer expressive dynamics, phrasing, articulation, accents
  • It fully utilizes all MIDI data coming from the wind controller or advanced keyboard controller
  • Proper design in terms of earthing, ground circuit and shielding ensures that the instrument has no hum or noise issues

The CHRT Synthesizer is available now.

12 thoughts on “CHRT Synthesizer Offers Expressive Vacuum Tube Synthesis

    1. Yeah – the only tube synths I’ve heard before were the Metasonix modules, which seem to be focuses on creating noisy, chaotic sounds.

  1. I heard that such tubes fast loose their “mojo” and I could imagine that a tube replacement in this matter will be a nightmare. Looking at the CHRT web-page…it could really use a lift-up…..

    But indeed a nice sounding device. The sound reminds me of Yamaha VL series…

    1. Tubes are usually the last thing to fail on old electronics – when people have guitar amps rebuilt, they don’t change the tubes, it’s stuff like capacitors and pots.

      1. ? ? ? tube amplifiers replace the full set of tubes every few years, or with damage which can come from bumpy car rides or a single fall. Who knows tho, maybe with a solid design and a use of mainly ‘pre-amp’ style tubes (not ones to do the final amplification) it could last long tho. Still a very neat idea indeed.

  2. Beguiling sound, has the richness of an acoustic instrument. Please be within my price range.

    My guitar amp is tubes, my hifi amp is tubes… there’s a transparency and subtlety I don’t hear anywhere else.

  3. Korg should pick up this guy’s expertise to use with those Nu-Tubes they patented hmmm. Definitely a warm sound! He seems very satisfied with the response to the wind controller, very cool.

    Tube LFOs… that’d be wild with the power-sagging and mix of electricity between multiple tubes all lighting up heh.

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