Powerhouse with unique modulation matrix

The Pro-One is one of the most versatile monophonic synthesizers in the world. Essentially, its layout is based on the same architecture as Sequential's legendary five-voice polyphonic synth, the Prophet-5. In terms of sound, the Pro-One more or less resembles a later-generation Prophet-5 since the Prophet-5 as well as the Pro-One are based on the same set of Curtis ICs.

• Sound generation
  The instrument is equipped with the usual sound-generating and sound-shaping component parts (two oscillators, a noise source, voltage-controlled filter, LFO, and two envelope generators) but their feature set leaves nothing to be desired: waveforms can be activated simultaneously, oscillators can be synced to each other, VCO 2 can function as an optional second LFO, there are three LFO waveshapes, filter tracking is continuously variable etc.
  The heart and soul of the Pro-One is its extremely rewarding modulation matrix which turns the Pro-One into a universal tool for any musician who wants to go astray and indulge in a little bit of experimentalism: Three sources (filter envelope generator, VCO B, LFO) can be assigned to five destinations (VCO A, VCO A pulse-width, VCO B, VCO B pulse-width, VCF frequency) – going the direct way, or controlled by the setting of the Modulation wheel to the left of the keyboard.
   
• Performance Tools
  This synthesizer is equipped with some excellent performance tools: For starters, there is a sequencer (which can store up to 40 notes), an arpeggiator, pitch and modulation wheels (the works), adjustable glide, and single or multiple triggering. The keyboard of this very example – the Achilles heel of all Pro-Ones – was completely refurbished and plays nicely.
   
• Sound
  The character of the Pro-One is harsh, raw, and aggressive, and its scope is fairly wide: From punchy bass (at least at low resonance settings), screaming leads, biting brass, and far-out effects (thanks to the two LFOs on board) to snappy electronic percussion sounds, everything is available at the flick of a switch (or two).
  Due to its inherent complexity and its purely electronic timbral character, the Pro-One recommends itself for applications within thoroughbred electronic music.
   
• Unusual features
  The external audio input with preamp is highly interesting for running guitar, keyboards, vocals and other audio signals into the Pro-One. The internal Gate Generator triggers filter and amplifier envelope generators as soon as external audio signals exceed a set threshold value.
   
• manufacturing period: 1981-1984
• weight (with/without case): 14/6,5 kg