Sequential OB-6 Keyboard

The OB-6 takes the classic bold Tom Oberheim sound — with its true voltage-controlled oscillators, 2-pole filter, and amplifiers — and adds modern enhancements such as studio-quality effects, a polyphonic step sequencer, an arpeggiator, and more. No other modern analog poly synth can boast such a pedigree or such a massive, in-your-face sonic signature.

OB-6 Specifications

OSCILLATORS

• Two discrete VCOs per voice
• Continuously variable wave shape (sawtooth and variable-width pulse, plus triangle on oscillator 2) per oscillator
• Pulse width per oscillator
• Hard sync: oscillator 1 syncs to oscillator 2
• Square wave sub-octave generator (oscillator 1) per voice
• Low frequency mode (oscillator 2)
• Keyboard tracking on/off (oscillator 2)
• Oscillator detune amount for increased tuning instability, from subtle to extreme

MIXER

• Oscillator 1 amount
• Oscillator 1 sub-octave amount
• Oscillator 2 amount
• White noise amount

STATE-VARIABLE FILTER

• Two-pole, resonant, filter per voice with low-pass, high-pass, band-pass, and notch functionality inspired by the original Oberheim SEM filter
• Bi-polar filter envelope amount
• Velocity modulation of envelope amount
• Keyboard tracking: off, half, full

FILTER ENVELOPE

• Four-stage (ADSR) envelope generator
• Velocity modulation of envelope amount

AMPLIFIER ENVELOPE

• Four-stage (ADSR) envelope generator
• Velocity modulation of envelope amount

LOW FREQUENCY OSCILLATOR

• Five wave shapes: sine, sawtooth, reverse sawtooth, square, and random (sample and hold)
• Clock sync (internal or external MIDI clock)
• Initial amount
• Mod destinations: oscillator 1 frequency, oscillator 2 frequency, oscillator 1 and 2 pulse width, filter cutoff, filter mode, amp

X-MOD

• Sources: filter envelope (bi-polar) and oscillator 2 (bi-polar)
• Destinations: oscillator 1 frequency, oscillator 1 shape, oscillator 1 pulse width, filter cutoff, filter mode, normal to bandpass filter

AFTERTOUCH

• Source: channel (mono) aftertouch with bi-polar amount
• Destinations: oscillator 1 frequency, oscillator 2 frequency, LFO amount, amplifier envelope amount, filter envelope amount, filter mode

CLOCK

• Master clock with tap tempo
• BPM control and display
• MIDI clock sync

ARPEGGIATOR

• Selectable note value: 16th note, 8th note triplet, 8th note, dotted 8th note, quarter note
• One, two, or three octave range
• Up, down, up/down, random, and assign modes

SEQUENCER

• Polyphonic step sequencer with up to 64 steps and rests

EFFECTS

• Stereo analog distortion
• Dual, 24-bit, 48 kHz digital effects, including: reverb (room, hall, plate, spring), delay (full bandwidth digital delay and emulated bucket brigade), chorus, flanger, phase shifters, and ring modulator
• Delay sync
• True bypass maintains fully analog signal path when digital effects are off

PERFORMANCE CONTROLS

• Full-sized, semi-weighted, 4-octave keyboard with velocity and aftertouch
• Backlit pitch and mod wheels
• Spring-loaded pitch wheel with selectable range per program (1 to 12 semitones up and down)
• Transpose controls for an 8-octave range
• Hold switch latches held notes on
• Polyphonic portamento
• Unison (monophonic) mode with configurable voice count, from one to all six voices, chord memory, and key modes
• Manual switch: when on, the front panel is live; what you see is what you hear

PATCH MEMORY

• 500 user and 500 factory programs in 10 banks of 100 programs each
• Direct program access, including single-button access to the current set of 10 programs

IN/OUT

• Left/mono and right audio outputs (2 x 1/4” phone jack)
• Headphone output (stereo, 1/4” phone jack)
• MIDI in, out, and thru ports
• USB for bidirectional MIDI communication
• Filter cutoff expression pedal input
• Volume expression pedal input
• Sustain footswitch input
• Sequencer start/stop footswitch input

POWER

• IEC AC power inlet for internal power supply
• Operates worldwide on voltages between 100 and 240 volts at 50 to 60 Hz; 30 watts maximum power consumption

PHYSICAL SPECS

• 32” L x 12.7” W x 4.6″ H (81.3 cm x 32.3 cm x 11.7 cm)
• 0 lbs (9.5 kg)

Walnut end panels