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BMC022 - Auto-Seq PCB | Barton Musical Circuits

BMC022 - Auto-Seq PCB | Barton Musical Circuits


"Auto-Seq" is shorthand for "Automated Sequencer." It is a unique step sequencer which programs it's own sequences. There is a small selection of controls to help refine it's sequences to the taste of the composer. There is no way of storing and recalling the sequences which it writes, Auto-Seq is an improviser. If you're interested in random composition, or if you're just tired of the hand cramps that come with programming traditional step sequencers, then this is a module that you might find useful.

This is for a PCB (including programmed microcontroller) only suitable for multiple formats.

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Availability:In stock


  • Mode - The Auto-Seq has a built in quantizer, this knob selects what musical mode it will quantize to. From least clockwise knob position to most clockwise, the modes are Major, Minor, Major Pentatonic, Minor Pentatonic, Fifths and Chromatic.
  • Length - This knob controls the length of the sequence. This is measured by the number of input clock pulses before the sequence resets itself. The range of pulses before reset is 1 to 256.
  • Rhythm Subdivision - The input clock pulses are run into a 4x clock multiplier and then through a divider. This control selects what division of output is used by the sequencer for functions other than Length. The range is from 4x input to 1/8 input. This knob is only read at the start of a new sequence.
  • Range - This selects the range of pitches that Auto-Seq can output. It selects by octave, ranging from one to five octaves. When the sequencer is choosing notes, it will check to see if a note is in range, and if not it transposes the note down an octave. So when increasing range, you will hear the same notes, just in different octaves.
  • The "One" Switch - When activated this switch will make sure that a note is played on the first note of the sequence (the "one" of the sequence) and that the note will be the root note of the scale being played (the "one" of the scale).
  • Portamento - This switch will turn on portamento or glide between notes. Not all notes will be played with portamento. The effect becomes more noticable as the range of pitches is increased.
  • Keychange - This switch sets whether or not the next sequence to be written will be in a new key. When this switch is disengaged, all sequences will be in the key of 0V as their root note.
  • Straight Rhythm - This switch, when engaged, sets the sequencer to play a note on every beat. There will be a minor variation on the note length from the gate output. This switch is only read at the start of a new sequence.
  • New Sequence - This pushbutton tells the sequencer to write a new sequence. The new sequence will be played when the current sequence finishes.


  • Clock - A series of timing pulses should be input here.
  • Reset - This tells the sequencer to play the first note of the sequence on the next incoming clock pulse. It's used to help syncronize with other timing devices.
  • New - This input has the same effect as the New Sequence button, but can be activated by a gate or trigger.


  • Control Voltage - This is a 0 to 6V CV output to be used with 1v/oct calibrated oscillators and VCFs.
  • Trigger - This is a short timing pulse that is sent out at the start of every new note. It's range is 0 to 5V
  • Gate - This is a timing pulse that is sent out for the duration of a note's length.
  • End of Sequence - This is a timing pulse sent out on the last note of a sequence.
Additional Information
More Information
Brand Barton Musical Instruments
Additional Resources Build Guide

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