(still under construction, additional patches will follow)
|We hope that the
following patch examples will help for a better understanding of your
A-100 system and stimulate you to search for new unusual patches.
This is a minimal patch to understand the
absolute basic function of an analog synthesizer. The audio output of the VCO
(saw output of an A-110-2 in this example) is
followed by a VCA (A-130 in this example). The VCA is
controlled by an envelope signal that is generated by an ADSR generator (A-140
in this example). The pitch of the VCO is controlled by the CV output of an
USB/Midi-to-CV interface (A-190-3 in this example).
The gate signal for the ADSR is also generated by the interface module. The
patch can be expanded by a VCF that is inserted between the VCO an the VCA and
the filter frequency can be controlled manually and/or by the second output of
the ADSR. One can play around with different control settings, other waveform
outputs of the VCO. The patch works also with other VCOs, other VCAs, other
envelope generators and other CV interfaces. The modules shown in this patch are
just deputies for the functions VCO, VCA, Envelope generator and USB/Midi-to-CV
Basic Patch A-100 Mini System
This is a basic patch for the A-100 miniature
system (A-100BSM) and can be used as a starting point for other patches. The
patch forms a classical synthesizer voice: Two VCOs (A-110), the colored noise
output of the noise module (A-118) and the lower ring modulator output (A-114)
are mixed together in the mixer module (A-138). The output of the mixer module
is processed by the VCF (A-120) and VCA (A-131). The envelope outputs of the
ADSR (A-140) are used to control both the filter frequency and loudness. The
triangle output of the LFO (A-145) is used to control the pulsewidth of the
second VCO. Therefore the rectangle output of the second VCO is used. The sine
outputs of both VCOs are the inputs of the ring modulator (A-114).
It is not necessary to patch CV and Gate at the front side as these signals are
available at the internal A-100 bus. The Midi interface (A-190)
"sends" CV and Gate to the bus and the VCOs (A-110) and ADSR (A-140)
"pick up" CV and Gate from the bus.
Try these modifications:
- Other usage of the LFO (e.g. controlling the
pitch of a VCO or the frequency of the VCF or the loudness of the VCA or to
trigger the ADSR)
- Use the output of a VCO to modulate the
frequency of the second VCO (FM sounds)
- Use the output of a VCO to modulate the
frequency of the VCF (FM sounds)
- Use the output of a VCO to modulate the
loudness of the VCA (FM sounds)
- Use the output of the ADSR to control the
pitch or Pulsewidth of a VCO
- Use the random output of the noise module to
control other parameters (e.g. VCO pitch, VCO pulsewidth, VCF frequency, VCA
- Use the second audio input of the VCA for a
audio signal that is not processed by the VCF (e.g. connecting a VCO or
noise or ring modulator directly to the VCA)
- Use the VCA before the VCFand mixer, in this
case the VCF is used as the last module in the audio chain and the VCA can
be used e.g. to process one of the VCOs or noise or ring modulator before
the signal is added to the mixer
This patch creates an automaticially random melody.
The sound source is a VCO (A-110) that is processed by a VCF (A-108 in this
example but each VCF or VCA will work). The quantized random control voltage for
the VCO is generated by the A-118 random output that is processed by one of the
A-129/3 Attenuator/Offset Generator and the lower section of the A-156
Quantizer. The rate of change is controlled by the Rate control of the A-118.
The basic tone/note is adjusted by the offset control of the A-129/3 and the spread
(distance between high and low notes) by the attenuator control of the A-129/3.
The setting of the three switches of the A-156 define the type of the random
melody (all semitones, only minor or major scale, only tones from chords and so
on). The trigger output of the A-156 is used to trigger the A-140 envelope
generator for the filter. It is possible to synchronize the patch e.g. with a
sequencer. For this the trigger input of the A-156 has to connected to the main
In this patch the two potentiometer rows of the
A-155 sequencer are used to control the pitch (upper row) and the momentary
wavetable (lower low) of an A-112 Sampler/Wavetable Oscillator. And this is how it works:
The rectangle output of the A-145 LFO generates the Clock for the A-155
sequencer (any other clock source will work as well) . The A-155 CV output of
the upper potentiometer row is connected to the pitch CV input of the A-112. The
A-155 CV output of the lower potentiometer row is connected to the CV input of
the A-112 that is used to address the wavetable. The A-112 has to be in the
wavetable play mode (the picture above does not show the correct settings of the
three switches, the upper switch has to be in the S1 or S2 position, the middle
in the Play position, the lower in the Wav Position). The Gate-Input has to be
connected to as positive signal (e.g. an unused output of an A-165 or A-176) so
that the A-112 is permanently triggered (not shown). The audio output of the
sampler is processed by a filter (the A-124 Wasp filter in this example, but any
other VCF or VCA will work too). The envelope for the VCF is generated by a
A-142 Voltage Controlled Decay (any other envelope generator will work too). The
trigger for the A-142 comes from the upper Trigger section of the A-155. The
Decay is modulated with the Gate row of the A-155 so that shorter or longer
longer decays can be controlled with the gate switches. It is not necessary to
load the A-112 sampler with wavetables. One obtains very interesting sounds even
with a normal sample (e.g. a recorded human voice) that is chopped by the A-112
in the wavetable mode. For each step of the sequence another section of the
sample (defined by the lower sequencer row) is cutted out and looped. With the
scaling control the spread of the addressed wavetables can be limited. The patch
can be expanded e.g. by an A-129/3 to define the position (offset) and spread
(attenuation) of the wavetables.
This patch was inspired by the Buchla 266 Source
of Uncertainty (SOU). It shows how the sample&hold function of the 266 can
be emulated with A-100 modules. And this is how it works:
The incoming trigger signal (rectangle output of an A-145 LFO in this example)
is divided by the A-160 clock divider. The /2 output is used to trigger the
upper section of the A-148 S&H. The /2 output is inverted by the A-165
trigger modifier and the inverted signal triggers the lower S&H. For both
inputs the same voltage source is used (random output of an A-118 in this
example). At the two
S&H outputs of the A-148 the random voltage of the A-118 is
"stored" alternately. This is the same function as the alternating
S&H outputs of the Buchla 266 (the normal CV out of the 266 works as a
normal, non-alternating S&H). Even the alternating pulse outputs of the 266
are available (i.e. the /2 output of the A-160 and the inverted output of the
A-165). Of course another trigger source (instead of the A-145) and/or another
voltage source (instead of the A-118) is possible. We think about a module that
integrates all functions of this patch within one unit - provided that there are
sufficient inquiries for such a module.
Additional "emulations" of the Buchla
265/266 Source of Uncertainty (SOU) will follow soon. The integrator section of the
266 is nothing but the Voltage Controlled Slew Limiter
A-171. Only the
"Quantized Random Voltages with 2n and n+1 states" and the
"Stored Random Voltages with adjustable probability distribution"
could be emulated with already existing A-100 modules (as of December 2003).
This is why the A-149-1 Quantized/Stored Random Voltages
The toggling S&H function can be realized much easier with the new module A-152
Voltage/Clock addressed Switches/S&H (available ~ summer 2004).
Fluctuating Random Voltages
This is another patch inspired by the Buchla 266 Source
of Uncertainty (SOU). It shows how the "Fluctuating Random Voltages" of the 266 can
be emulated with A-100 modules. And this is how it works:
The random output of the A-118 Noise/Random source is used to modulate the
frequency of the A-147 Voltage Controlled LFO. The basic frequency of the A-147
(i.e. without CV coming from the A-118) has to be about 100Hz to emulate the
Buchla 266. The triangle output of the A-147 becomes more or less
"noisy" as the random voltage modulates the frequency. Use short
random rates (Rate control of the A-118 in the left area). The "noisy
triangle" is fed into the lower section of the A-148 Dual S&H. The
S&H is triggered by the rectangle output of a second A-147. The output of
the S&H is smoothed by the A-171 Voltage Controlled Slew Limiter. In the
Buchla 266 the trigger sampling frequency and the slew time are controlled by
only one knob. This is why the A-176 is used to generate one common voltage to
control both the second A-147 and the A-171 simultaneously. If the simultaneous
control of both functions is not necessary the A-176 can be omitted and both the
second A-147 and the A-171 can be replaced by a "normal" A-145 LFO
resp. a "normal" A-170 slew limiter (upper section). Another
modification - if no A-147 is available - is to mix the triangle output of a
normal A-145 LFO with the random voltage of the A-118 and to use this mixed
signal as S&H input. But in this case an additional A-138 mixer is required.
The advantage - or disadvantage (depends upon your point of view) - of this
patch compared to the original 266 is that one has more controls available than
the 266. The disadvantage is that you need six modules. We think about a module
that integrates all functions of this patch within one unit - provided that
there are sufficient inquiries for such a module.
We may develop a separate module (A-149-3 ?) for the "Fluctuating Random
Voltages" if there is sufficient need for such a module. In the meantime
the above patch will solve the problem.
Chaotic patch based on
the so-called logistic equation Xn+1 = k*(Xn - Xn2)
with k = 3.57 ....4.00. The Xn2 term is
realized with the first VCA (A-130) by feeding both the CV and signal input with
the same signal coming from the S&H output (A-148). The subtraction is made
with the voltage inverter (A-175). The S&H is used to sample the last
voltage Xn that is used to create the new voltage Xn+1.
It is triggered by a voltage controlled LFO (A-147) that determines the rate of
the system (controlled by the external Rate CV). The second VCA is used in
combination with the A-136 to create the factor k (3.57 ... 4). As the max.
amplification if ~1 for the VCA an additional amplifier has to be used (A-136
with a fixed amplification ~ 4). Even a modified VCA (with modified max.
amplification >4) or a VC polarizer (with modified max. amplification >4)
could be used. The graphs below show the results for 3 different settings of k.
(attention: so far the patch is theory only,
i.e. we did not yet try this patch, comments are welcome to firstname.lastname@example.org)
In the meantime the patch has been testet
sucessfully by one of our customers. We want to thank Willi Sauter for these
additional comments (so far in German languge only):
Bevor man das Patch nachvollzieht muss folgendes beachtet werden: Man benötigt
einen Verstärker der mindestens x 4 verstärkt. Ich habe einen lin. Mixer
(anstatt des A 136) dafür modifiziert. Wie das geht steht in den DIY Seiten.
Man kann einen der 100 k Eingangswiderstände (R 1-4) mit einem 22 k Widerstand
überbrücken, dann erhält man eine Spannungsverstärkungsfaktor von fast x 5,
das reicht. Die beiden VCA´s müssen auf Entkoppelungskondensatoren überprüft
werden. Die neueren Modelle der 130iger VCA mit dem Platinenaufdruck „V3
2005“ können so benutzt werden. Falls man noch ältere Modelle hat ist der
Kondensator C 1 mit einem Draht zu überbrücken (die anderen C´s in Umgebung
des Bussteckers bitte nicht antasten!). Nun kann es losgehen. Als Chaos CV benötigt
man eine Spannung die sich im Bereich um 3 – 5 Volt regeln lässt, z.B. von
einem Sequenzer oder ein A-176 (Manual CV Source).
Wenn man das Patch gesteckt hat ist eine gute Ausgangsposition der Regler etwa
um 1 Uhr. Die Einstellung des 1. VCA ist unproblematisch. Besonders interessant
ist die Chaos CV Spannung und der Verstärkungsfaktor des Mixers. Die drei
Einstellungen des 2. VCA haben auch größeren Einfluss auf das Ergebnis. Also
bitte nicht gleich aufgeben falls das Patch nicht sofort funktioniert.
Die Logistische Gleichung ist eine Funktion. Das jeweilige Ergebnis der Funktion
wird wieder zur Neuberechung eingesetzt. Sie ist also rückgekoppelt. Diese Rückkoppelung
wird über das S/H und den LFO kontrolliert gesteuert. Das Patch liefert kurze
oder lange Pattern, die sich unendlich wiederholen oder plötzlich ausbrechen können.
Es gibt auch Bereich die unvorhersagbar werden, was man dann chaotisch nennt.
Kleinste Veränderungen an einem Regler können drastische Änderung hervorrufen
(Schmetterlingseffekt). Das besondere Kennzeichen dieser Gleichung ist die
Selbstähnlichkeit der chaotischen Muster und daher musikalisch interessant.
Tipp: 2 VCO die über Kreuz gekoppelt werden erzeugen in bestimmten Bereichen
Wellenformen die sich laufend ändern, dies ist eine Variation des hier
Literatur: z.B. James Gleick „Chaos Die Ordnung des Universums“
Vocoder with triggered vocal freezing, coming
|If you want to create your own patch
examples you could use the A-100 Corel Draw file we have available on
our web site. This file contains all A-100 front panels and all you need
to create your own patches is Corel Draw (V7 or higher) that is
available for a few bugs. You could arrange all front panels at the
desired positions (use the "magnetic grid function") and draw
in the patch leads. We will be happy to publish your patch at this place
(please send us the corresponding Corel Draw file or the pixel file with
440 pixels in height and some explaining
words). If you do not have available Corel Draw you could also use the
pixel files of the A-100 front panels on our web site to create your own
patches (e.g. the pictures in the A-100 module descriptions) with any
pixel program (e.g. Photoshop, Paint Shop, Coral Paint). Simply position
the mouse above the desired picture and use the right mouse button to
save the picture to your computer.