Future Retro XS

via this auction
"This is the Future Retro XS, serial number FRXS025 (the 25th XS to ever be made). It was purchased directly from Future Retro when our number came up on the pre-order list.

"From the Future Retro website:
The XS is a true semi-modular analog synthesizer with a universe of sonic possibilities just waiting to be discovered. Our versatile design allows it to be used as either a rackmount or desktop instrument, and its compact size makes it ideal for musicians on the go.

In its simplest form the XS is an extremely powerful monophonic synthesizer including 46 controls with internal signal routings pre-wired in a way which allow the unit to act similar to traditional synthesizers. The unit also provides 7 inputs and 11 outputs which can be connected in various ways to override the pre-wired signal routings, and interface the unit with other instruments in a modular fashion, and even process external audio.

The XS can be controlled by both MIDI and CV/Gate control signals simultaneously in a variety of ways. And can also act as a MIDI to CV/Gate converter with outputs including CV/Gate/Mod Wheel/Velocity signals for controlling other analog instruments.

With a single unit you can easily create basslines, leads, drones, percussion, and sound effects. Connect multiple units together to form larger systems and the possibilities are endless.

The XS provides 2 ultra stable wide range voltage controlled oscillators, each capable of covering a range of 0.5 Hz to 100 kHz. Oscillator A generates saw tooth, and square waveforms. Oscillator B generates sine, triangle, saw tooth, pulse width/square waveforms, and its own sub oscillator waveform which can be 1/2, 1/4, 1/8, the frequency of the main waveform. The pulse width shape of oscillator B can be set manually or modulated with an internal or external control voltage, and oscillator B can also sync its frequency to oscillator A. Each oscillator can be frequency modulated independently by both internal and external signals to create more complex waveforms. The XS also provides a white noise source, and ring modulator which can be used on the internal oscillators or an external source. Dedicated outputs are provided for the waveform select controls A, B, and C.

A dedicated LFO generates triangle, saw tooth, square, and random waveforms, to modulate internal parameters, or external circuits as well with its dedicated output. The LFO can act in a free-running mode, or sync its rate to divisions of an external MIDI clock. When synced to an external MIDI clock, the LFO can be used to generate analog clock signals at various synced rates for stepping analog sequencers or arpeggiators in time with modern sequencers.

The mixer section sets the levels of the oscillator waveforms, sub oscillator waveforms, white noise source, ring modulator, or any external audio signal to be sent to the input of the filter.

The 2-pole multimode filter provides 4 filter types including low pass, band pass, high pass, and notch settings, each capable of covering a range from 5 Hz to 18 kHz. With high resonance settings the filter will self oscillate allowing it to act as an additional audio source. The cutoff frequency can be modulated by both internal and external signals. And the filter’s input and output can be overdriven independently giving it unique tone characteristics. A dedicated output for the filter is also provided.

The XS includes our unique velocity sensitive ADSR type envelope with additional attack and decay time settings for accented envelopes. It’s like having two envelopes in one, and capable of some truly funky sounds. This is the main modulation envelope internally routed to the modify the oscillators and filter. The envelope can be triggered by internal or external logic signals. Both normal and inverted polarity envelopes are available at the output.

And finally a voltage controlled amplifier is provided to process the amplitude of signals. The amplifier normally affects the filter’s output but can also be used to process external audio signals. The amplifier has it’s own dedicated envelope with 4 selectable shapes, velocity sensitive amplitude, and independent accent times. The amplifier also has a volume control for attenuating signals sent to the main output."