3X8 Step Sequential Controller
It’s tempting to compare analogue sequencers to hardware MIDI sequencers, both rackmount and computer-based, if only because they are all capable of producing repetitive sequences and effects that can be modified in real-time. But, while a hardware MIDI sequencer can look like its analogue counterpart, it lacks one important facility inherent to analogue voltage control: you can’t add multiple MIDI controllers or use audio signals as modulators to create new effects.
Unfortunately, vintage analogue sequencers from companies such as ARP and Korg sell for hundreds of pounds, and you’ll be lucky to get change from £1,000 if you want an original Moog sequencer. Worse still, these originals are becoming increasingly rare, and by modern standards they can be rather limited. This is why the RS Integrator has a dedicated analogue sequencer, the RS200. Not only does it eliminate the need for a vintage unit if you want to create sequences with the Integrator itself, the RS200 will (with an RS10 or RS15 case) function as a self-contained unit capable of controlling almost all other analogue monosynths.
of 8-step CV generators with individual CV ranges and CV outputs for each
understanding about each of these we will divide this chapter into four
parts, as follows:
1. QUICK TOUR
If you are impatient to hear some immediate results using your RS200 within a suitably configured RS Integrator the following instructions should have you up and running within a few minutes. If you are using the RS200 to control an external synthesiser please make allowances for the different names and configurations that you might encounter.
2. THE SEQUENCE STEPS
The number of steps in your sequence and the outputs determined by each are defined by the eight columns (called "steps") marked 1 to 8. Each step has five controls and one indicator, as follows:
Switches: (iv) RESET/RUN/SKIP switches
Note: The SKIP position has another function when used together with the SKIP IN input described in the next section. If you want SKIP to function as described here but it is not doing so, check that you do not have a CV connected to SKIP IN.
Note: A trigger is produced at the TRIG 3 OUT on every step regardless of all other settings. Amongst other uses this acts as a 'trigger THRU' socket when the RS200 is clocked from an external source.
3. INPUTS, OUTPUTS, AND OTHER CONTROLS
The RS200's I/O panel offers a total of 13 sockets, of which five are inputs and eight are outputs. There are also five knobs, three buttons, one switch and three LEDs. Together these can control many aspects of a synthesiser’s operation, including but not limited to: pitch control, filter frequency modulation, and the timing of events.
The operation of the knobs, CV inputs, and the switch are closely interrelated, so it is not possible to describe each without referring to the positions/settings of others. Please bear this in mind when you consider the action of each of the controls.
These determine the range of voltages controlled by the CV knobs in each of the three rows. With the RANGE in the 0V position, the positions of the CV knobs are irrelevant, and 0V is output by the row regardless of any other settings.
Note: The notation on the RANGE knobs is approximate, and does not ensure that the maximum frequency will increase in precise octave steps.
Internal Clock Frequency
Pressing RESET will always return the sequence to step 1. This action may be performed whether or not the sequence is running.
Down (INT) The rate at which the sequence moves through the steps is determined by the internal clock.
Up (EXT) The rate at which the sequence moves through the steps is determined by an external clock pulse presented to the EXT CK IN socket.
Centre The sequencer is not clocked, and you must use the STEP button to move through the steps.
These give a visual indication of the triggers generated at each of the three TRIG OUTs. When any of the LEDs is lit a trigger is produced at the appropriate output.
(ix) INT CK
(x) EXT CK
If the input signal is pulse-like, the sequencer will move through the steps according to the timing of this signal. There is no practical limit to the frequency of the input signal. One advantage of this is the ability to clock the RS200 at audio frequencies, making it possible to use each of the three rows in the sequencer as an audio-frequency complex waveform generator.
Normally, the sequencer will ignore any step that has the RESET/RUN/SKIP switch set to SKIP, and jump directly to the next step in the sequence. However, if you apply a CV in the range +1V to +10V to the SKIP IN input, the sequence will not SKIP the step, but hold it until the CV is removed.
The normal 'skipping' action is, therefore, just a special case of this: with no CV applied, the step is not held, and proceeds directly to the next.
The three rows of CVs determined by the LEVEL knobs in each of the steps (as modified by the RANGE controls) are produced at these outputs. The maximum CV range is 0V to +10V.
(xv) The Trigger Output
The three sets of triggers determined by the TRIGGER switches are produced at these outputs. All triggers are +10V pulses.
Remember that Row 3 produces a trigger pulse at the TRIG 3 OUT on every sequence step, regardless of the other controls and switches.
(xvii) INT CK
Inserting a lead at this point does not break the internal circuit, and if the CLOCK SWITCH is set to INT the sequence will continue to operate as before.
4. SOME IDEAS TO GET YOU STARTED
If you are not fully acquainted with analogue sequencers and would like a few ideas to get you started, the following may be of some help. Of course, there’s no room to do more than scratch the surface of the RS200's possibilities in this manual, so remember: an open mind and some free experimentation can yield startling results. Here are some basic ideas:
If you have not already done so, set your RS200 and synthesiser up as described in the QUICK TOUR. Then…
Set up a sequence and apply an LFO to the INT CK CV IN. This modulates the speed at which the sequence runs.
Drive the EXT CLOCK IN at audio frequencies, and use the 8 steps to define a complex waveform. Direct this back to the synth as an independent oscillator. The shape is multi-stage and heavily quantised, so it has a rather 'digital' character quite unlike the standard oscillators in your RS Integrator.
Use the TRIGGER switches creatively. Trigger outputs are used primarily to trigger the synthesiser’s envelopes. You can manipulate your sequence in real-time by switching the trigger switches between trigger ON and OFF whilst the sequence is playing. If triggers are placed at the beginnings of some notes and not others it will give a more human feel to the sequence, analogous to guitarists who pluck or hammer strings at the beginnings of some notes but not others.
Use other RS Integrator modules such as the RS280 Divider module to create complex timing changes within your sequences. For example, connect the INT CK CK OUT to the CK/SIG IN of the RS280, and return the _16 output from the RS280 to the START/STOP EXT input on the sequencer. This will cause the sequence to stop every 16 steps, and then restart after an interval of a further 16 clock pulses. Each time the sequence runs, it will start one step further to the right, creating complex changes in your music.
Use an RS150 Sequential Switch to extend your sequences to 24 steps. You do this by connecting CV A OUT to IN1 on the Sequential Switch, CV B OUT to IN2, and CV C OUT to IN3. Then connect the END PULSE OUT on the sequencer to the CLOCK IN on the Sequential Switch. Now, each time the sequencer reaches step 8 it will send a pulse to the switch advancing the input by 1.
Put all the RESET/RUN/SKIP switches to the SKIP position. Now apply noise from an RS40 Noise Generator at the SKIP IN input. This will make the sequencer step randomly, apparently moving backwards as well as forwards within the sequence. This is truly random note selection, and can be used in a number of ways to create quasi-melodies, generate harmonic structures, or provide sound effects.
Again, put all the RESET/RUN/SKIP switches to the SKIP position. Take noise from the RS40 and band-pass filter it using an RS110 Multimode filter. Apply the resulting signal to the sequencer's EXT CK IN to create random timing effects. You can even modulate the filter to modulate the speed of the randomised clock.
Just as an analogue synthesiser has an infinite number of possibilities, so does an analogue sequencer. The seven ideas above merely give you an idea of the types of sounds and effects you can create with the RS200. The rest is up to you!