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SequentialOB-6 6 Voice Analog Synthesizer

Item#
N13-5238-D
$3,499.99 $3,159.99
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Serial Number: #557

Sequential OB-6

The OB-6 features two discrete voltage-controlled oscillators (plus sub-oscillator) per voice, with continuously variable waveshapes (sawtooth and variable-width pulse, with triangle on oscillator 2). There is a classic SEM-inspired state-variable filter (low-pass, high-pass, band-pass, and notch) per voice. Voltage-controlled amplifiers complete the all-analog signal path. “The classic, bold SEM sound is all there,” said Oberheim.

Present also is X-Mod, with filter envelope and oscillator 2 as modulation sources (with bi-polar control). Destinations include oscillator 1 frequency, oscillator 1 shape, oscillator 1 pulse width, filter cutoff, and filter mode.The knob-per-function front panel puts virtually all parameters at a user’s fingertips. Toggling on the Manual switch enables live panel mode, in which the OB-6 switches to the current settings of its knobs and switches. 

A dual effects section provides studio-quality reverbs, delays (including standard and BBD), chorus, and faithful recreations of Tom Oberheim’s acclaimed phase shifter and ring modulator. The effects are digital, with 24-bit, 48 kHz resolution, but a true bypass maintains a full analog signal path. Additionally, the OB-6 features a multimode arpeggiator and a polyphonic step sequencer with up to 64 steps (and up to 6 notes per step) plus rests. It allows polyphonic keyboard input and can sync to external MIDI clock. 

The full-size, four-octave, semi-weighted keyboard is velocity and aftertouch sensitive. Said Dave Smith, “As with the Prophet-6, we made size a primary concern on the OB-6. It’s the right mix of power and portability and it fits right in on-stage or in the studio.” Added Oberheim, “And of course, it’s got that unmistakable SEM sound that’s going to turn a lot of heads. ”

OB-6 Synthesizer Features

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: triangle, 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

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

AFTERTOUCH

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

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 and tape delays), 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 off, 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)
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Sequential OB-6 6 Voice Analog Synthesizer Reviews