The A-155 Analog / Trigger Sequencer is a well-equipped 2 x 8 step sequencer with three trigger tracks, one gate track and two control voltage tracks.
Triggers 1 and 2 are always alternative, as are trigger 3 and the gate signal. Separate settings for “glide” (portamento) can be made for the two control voltages.
In addition, the module can also be used as a luxurious 8:1 switch via the “External CV/Audio Inputs” – both for control voltages and for audio signals.
User interface
Inputs:
EN-CTRL-A155-IN1 EN-CTRL-A155-IN2Outputs:
EN-CTRL-A155-OUTControls:
EN-CTRL-A155-SW1 EN-CTRL-A155-SW2 EN-CTRL-A155-SW3Switching between the two tracks (16 steps)
If the 8 steps are not enough, you can – even without the A-154 – switch between the two control voltage tracks. To do this, the clock signal is split up and sent to an A-160-1 frequency divider (which is way cheaper than the A-154). Here we use the “/8” division to toggle using an A-150-1 switch.
Attention: since the frequency divider “counts up”, i.e. it outputs a gate signal at the 8th step, switches it off again at the 16th step, etc. we first get an asynchronous behavior to the sequencer: The sequencer should actually be switched to the 9th step (instead of the 8th), to the 17th (instead of the 16th), etc. A manual reset of the A-160-1 frequency divider can help here (the reset should be done in step 2 of the A-155).
Oscillator, filter and envelopes controlled by the sequencer
The upper control voltage track is very well suited for controlling the pitch of VCOs, as it can be easily switched between 1, 2 and 4 octaves. In addition, you can e.g. modulate the cutoff-frequency with the lower control voltage track.
“Trig 1” could control an A-140. For special accents, “Trig 2” triggers a second A-140 (with different settings), which also controls VCA and VCF. This allows accents to be generated that go far beyond a mere “louder”, as other sequencers allow. In order to set these accents, simply select “Trig 2” with the toggle switch of this step instead of “Trig 1”.
Useful supplements
Although the basic version of the A-155 offers a wide range of options, far more complex sequences can be implemented in combination with the A-154 Sequencer Controller. With its help you can, for example, combine two A-155s into a 4-track sequencer or (with an additional A-150-1 switch) into a 16-step sequencer.
Another useful add-on module for tonal sequences is the A-156 Dual Quantizer, which can limit the output voltages of the sequencer to semitone steps or major/minor scales.
Technical specifications
| Width | 50 HP |
| Depth | 40 mm |
| Power requirements | 80 mA (+12V) / -20 mA (-12V) |
