New Russian Vacuum Tube Synthesizer, Apparatus

Eternal Engine Electronic Music Instruments shared this video demo of the Apparatus – described as “the first Russian duophonic synthesizer based on vacuum and gas-filled radio tubes.”

The audio path of the instrument is based on vacuum and gas-filled radio tubes, using circuitry solutions that Eternal Engine says are “in the spirit of the first half of the 20th century.”


  • Kenoton rectifier power supply
  • Audio path based entirely on radio tubes
  • Two independent thyratron oscillators with quartz frequency stabilization, which ensures frequency accuracy throughout the entire operating range
  • Voltage-controlled second order vactrol filter with the possibility of self-oscillation and overdrive
  • Voltage-controlled amplifier, based on the traditional schematic of tube opto compressors
  • Triode asymmetric overdrive
  • Velocity-sensitive ADSR envelope generator with two trigger modes
  • MIDI Clock synchronizable low-frequency oscillator with retrigger option and smooth waveform morphing: saw-triangle-reverse saw in triangle mode or pulse width modulation in square wave mode, sample & hold
  • Auto and continuous modes of portamento / legato
  • Monophonic and duophonic mode
  • Powerful headphone amplifier, compatible with low impedance load
  • Analogue VU meter

Audio Demos:

Pricing and Availability

The Eternal Engine is priced at $1,899 USD. See the Apparatus site for details.

23 thoughts on “New Russian Vacuum Tube Synthesizer, Apparatus

  1. As usual with a lot of boutique machines , very little synth for lots of money, great if you are into that kind of looks over music 😐 , for my part I’ll take erica fusion II any day

    1. It’s the other way around, with large-scale multinational companies you get a lot of synth for little money, in part due to cheap and abysmal production methods by underpaying the people putting it together and ramping up production to massive scales.

      Boutique companies get the reputation they’re expensive, but they’re actually just priced at prices where the people working on these products can earn a normal living where they operate.

      Fusion II does seem like a better deal, but they’re also not all that similar.

  2. Ah, the pains of making less than $13,000 a year. I would love to have one of these too. It’s like the 303s grandpa.

Leave a Reply

Your email address will not be published. Required fields are marked *