Tubbutec CeeS Hardware Upgrade (Yamaha CS 5/10/15)

Manufacturer's description

CeeS is a hardware upgrade for the Yamaha CS5, CS10, CS15, CS15D, CS30 and CS30L synthesizers. It adds MIDI input and output, along with additional filter modulation sources, while remaining fully additive to the original instrument.

Features

• MIDI input and output
• MIDI CC control of cutoff and resonance — independent control of both filters on CS15 and CS30
• Additional LFO for each filter, with multiple waveforms and optional MIDI clock sync
• Velocity and aftertouch can be linked to cutoff, LFO amount or LFO frequency
• CS30: sequencer can be clocked via MIDI clock or a MIDI note, with an adjustable MIDI clock divider offering many options
• CS30: extended note range for MIDI input
• MIDI CC control of all additional parameters
• Built-in configuration menu for quickly setting additional parameters
• Easy to install: requires soldering, but no traces need to be cut
• Fully additive: does not change the behaviour or sound of the synthesizer unless desired
• Low latency: ~1ms
• Optional for hands-on control of the additional parameters
• Firmware update via MIDI Sysex

MIDI Note Control

CeeS adds MIDI input and output, with the MIDI channel independently configurable (or switched off) for each. On the CS30, the MIDI input has an extended note range, adding 5 additional notes below the lowest F.

The MIDI input is monophonic and behaves exactly like playing on the keyboard, preserving 'highest note' priority. The MIDI output is polyphonic to an extent — in certain situations, the CSxx keyboard IC stops reading low notes (more detail on this below).

Filter Control

CeeS provides MIDI CC control of filter cutoff and resonance — for the single filter on CS10, or both filters on CS15 and CS30. MIDI cutoff control is additive to the existing cutoff setting, while MIDI resonance control is subtractive to the existing resonance setting.

Additional LFOs

Two additional LFOs are implemented, one for each filter. Features include:

• MIDI control of all parameters
• Multiple waveforms: triangle, rising sawtooth, falling sawtooth, square and S/H
• Free-running mode, with frequency adjustable between 0.13Hz (8s period) and 750Hz on a logarithmic scale
• Sync to MIDI clock, with 18 different dividers available
• Adjustable LFO delay and optional phase reset
• Velocity and aftertouch can be linked to LFO depth and speed

CS30 Sequencer Sync

CeeS allows the CS30 sequencer to be synced to MIDI in two ways:

• Synced to MIDI clock, with an adjustable clock divider
• Triggered by MIDI note 0 — each time the note is played, the sequencer advances one step

The sequencer clock source can be set via MIDI CC or in the configuration menu. By default, the clock source is the CS's internal clock, and the sequencer can be used with the START/STOP button and CLOCK SPEED knob as normal.

Velocity and Aftertouch Link

MIDI velocity and aftertouch can each be linked to one of the following parameters:

• Filter 1/2 cutoff
• Depth of the additional filter LFO (1 or 2)
• Speed or clock divider of the additional filter LFO (1 or 2)

These controls are additive to the existing filter cutoff or LFO parameters, with an additional depth control available for both the velocity and aftertouch link.

Configuration Menu

Pressing a special key combination on the keyboard (all notes from F0 to C1) opens a configuration menu, where most additional parameters can be adjusted on the fly:

• MIDI input and output channels
• Velocity and aftertouch link and depth
• Sequencer clock source and clock divider

Settings are saved automatically and recalled the next time the synth is powered on.