The Cloud Generator, otherwise known as the e340, is shown in the photo to the left of its sibling, the e350 Morphing Terrarium. The e340 is described by Paul Schreiber:

the synthesis technology e340 contains 8 sine and sawtooth vcos with unique modulation capabilities. the term ‘cloud oscillator’ was first used by ambient musician robert rich when he was recording his ‘bestiary’ cd. he wanted to define a new type of “buzzing, swarming cloud of sine waves” and after some experimentation, was able to create such a timbre using 24 individual motm modules. now, 8 years later, the technology is available to have this new range of sounds in a 14hp wide euro module.

in its basic form, the e340 is a 2-output, wavetable vco that is generating 16 waveforms at once. modular users quickly discover that in order to get the large, fat notes multiple oscillators are needed that are slightly detuned. this can get expensive quickly, and then you have to deal with the tracking differences, additional mults for the cables and mixers for the outputs. the e340 combines all of these, eliminates the tracking errors and adds the added dimension of being able to control just how “buzzy” the cloud can go. if spread and chaos are set to ’0′, the e340 behaves like a standard analog vco, but with a very pure sinewave output (less than 0.3% thd) and a standard sawtooth wave.

simple detuning can sound really good, but the e340 adds 2 controls never seen on any modular: chaos and chaos bandwidth (bw). once you set the degree of detuning using the spread control, you can then add ‘animation’ to the detuning by dialing in chaos. the chaos randomly ‘wiggles’ every vco’s pitch, while the chaos bw controls the ‘speed of the wiggle’. this adds the “swarming of bees” effect at the extreme settings, and in the low settings the subtle pitch changes are similar to a slow-speed leslie effect.

Construction was almost identical to that of the Morphing Terrarium project.  I used some different pots I had around, a bracket I made myself, and 24 gauge wire.  I am glad I added the Spread CV attenuator pot, because that parameter is the most likely of the unusual ones to be getting CV, although both the Chaos and Chaos Bandwidth also have CV inputs.

Here is a Synthtech e350 Morphing Terrarium DIY project.   Paul Schreiber’s description, taken from the AnalogueHaven product page.

the synthesis technology e350 morphing terrarium is a unique wavetable vco with 2 independent waveform outputs. unlike similar designs, the e350 is a fully self-contained, 1v/oct vco. what sets the e350 apart from previous wavetable oscillators is the voltage-controlled morphing.

the module comes shipped with 3 banks of 64 ‘basic’ waveforms (192 total). each bank of 64 waves is arraigned in memory as an 8 x8 array (like a chess board). the ‘rows’ are called ‘the x direction’ and the columns are ‘the y direction’. the 2 panel controls and the 2 external control voltages (morph x and morph y) are used to “point” to where in the array we use for the data that is the xy out. the third control voltage is called ‘z morph’, and it determines the waveshape at the z out. the z control voltage ‘scans’ then wavetable bank from wave #1 (think as row 1, column 1) to wave #64 (row 8, column 8). for example: if x morph is set to 2, and y morph is set to 5, the signal at xy out is the waveform stored at row 2, column 5 (the 13th wavetable). the z out is completely independent of xy out, so if the morph z knob is at 48, then the 48th wavetable ( row 6, column 8 ) is the output.

the wavetables in the 3 banks are very carefully ordered by rows. in general, scanning in the x direction will generate a smooth progression of timbre. each row, however, is different! there are sine banks, pulse width modulations, filtered noise and even male/female vocal formants. so, then you can see that scanning in the y direction (in a column) will be extremely varied. and the beauty is that you can scan in both directions simultaneously if you want.

but we were not content with just indexing through the table 1 wave at a time. instead, the e350 implements a proprietary smoothing/anti-aliasing algorithm that allows the 2 outputs to be a continuous blending of one wave to another. the algorithm calculates 128 “in-between” waveforms, so that the 192 ‘basic’ waveforms are really expanded to over 24 *thousand* individual timbres! so as you adjust the panel controls, or add external modulation (from lfos, eg, etc) the e350′s outputs are “glitch-free” and will provide you with a near infinite range of tonal possibilities. for people that like the glitches of older wavetable vcos, there is a jumper option on the pc board to add these back in.

but, we wanted to do more, so we added a 3-position range switch for using the e350 as the world’s best lfo. at the lowest setting, the e350 will cycle once every 13 minutes and be repeatable within 20usec. the sync signal can be used to reset both outputs to zero (‘hard sync’) like any other vco. the ‘c’ bank of waveforms are specifically designed to be used in lfo settings (although they will output audio timbres as well). the lfo waveshapes are everything from ‘chirps’, sequences of individual notes to noise gates, s&h effects to exponential/log sweeps. like quadrature outputs? the e350 can have variable phase outputs under cv control.

there is nothing like the e350 in any modular format. in many patches a vcf is not needed: the timbres that are generated are already smooth and harmonically “correct”. from the precise tracking to over 24,000 waveforms possible, the e350 sets the standard in modular oscillators.

Panel Design

You can download my

Front Panel Express Morphing Terrarium Panel

Yes, I just had to fit this into a 1U panel with small knobs.  I located all the knobs at the top, the jacks at bottom, and the two switches in the middle.  I admit the downside of the closeness of the knobs, having immediately discovered that fiddling with the MX (Morph X) knob risks nudging the coarse frequency pot to its left.  But I got the 1U sinewave VCO I wanted, plus 24,000 other waveforms!  For this application I used high-quality Bourns potentiometers, Mouser part 652-91A1A-B24-B18.

Construction

The dual PC boards with SMT components fit well on a Bridechamber 3-jack bracket, cut down in length. Wiring was made harder than needed because I was out of thin wire and had to use #22 with rather thick insulation.  This resulted in a bunch of wires running under the bottom board and required that the jack wires be soldered to the top of the board, contrary to instructions.  But it all fits.  Here’s a mid-assembly photo.

And all together.

From the Synthesis Technology website:

The MOTM-730 is used to “divide down” an input signal (usually from a LFO or VCO) to produce multiple square wave outputs.

• Fixed output divisors are simultaneously available and phase-locked.
• Outputs are 0 to +5V square waves.
• Variable output  with divisor under voltage control is independent of the fixed divider outs.
• Has RUN/STOP input for sync or driving all outputs low.
• Can sync to positive or negative edge of input clock.
• Unique ‘Half Divide’ mode where the divisors are 1.5, 2.5, 3.5, etc. on all outputs.
• Stepped CV out is a 8-step rising sawtooth that has 3 fixed step intervals.

The MOTM-730 fixed divisor outputs run independently of the variable (‘/N’) output. The large red LED display shows the divisor for the variable output. This divisor can be set by the INIT DIV panel control or by a control voltage/attenuator. The MOTM-730 does not generate pulses on its own. A CLOCK IN is required, but can be any waveform that is at least 0V to 2V peak. The ‘trip threshold’ for the clock input is ~ +0.75V, so the output of a MOTM-800 EG can be used to clock the module.

Modifications: None

Here’s a photo of the back of the MOTM-730, mounted in one of my portable cabinets:

From the Synthtech website:

The MOTM-820 is used to add slew to an input. The most common use would be to add portamento to a control voltage feeding a VCO. Check out the features:

• Independent voltage control of both rise (UP) and fall (DOWN) times
• Times variable from 500us to 5 minutes
• Ganged UP/DOWN control to emulate standard portamento effects
• A SHAPE control that varies the glide slopes from Linear to Log

From the Oakley website:

The OMS-820 is a companion module to the MOTM-820 voltage controlled lag processor. It adds powerful new features to the superb Synthtech module.

With this module you can make the MOTM-820 into a voltage controlled LFO with variable waveshape. Or you use it to make a powerful voltage controlled envelope generator, with manual set and preset modes. You will be amazed by the uses you can find for this module.

1. LFO

When the mode switch is turned to LFO, the output of the MOTM module will oscillate between +5V and -5V. The rise time of the waveform will be set by the UP control and the fall time will set by the DOWN control. The frequency will change according to the settings of both UP and DOWN. You can also change the rise and fall time together with the UP/DOWN control on the MOTM. You can easily make saw, reverse saw, and triangle type waveforms. The LIN/LOG pot on the MOTM will alter the shape of the waveform by introducing the usual non-linearites of the exponential rise and decay.

2. EG mode

When the mode switch is turned to EG, you get a voltage controlled AD/AR generator and more besides. This section has four sub-modes. These are selected by two switches: AD/AR and Gated/Reset.

The envelope generator is triggered by a GATE input.

When in AD (attack-decay) and gated mode, the output of the MOTM-820 will then rise until +5V is reached, whereupon it will fall back to zero. Rise and fall times are governed by the MOTM-820 of course, and fully voltage controlled. Removal of the gate signal will cause the decay phase to start prematurely. Standard A-D EG behaviour.

Switch the unit to AR (attack-release) and gated mode, and the output will rise to +7V or so, and stay there until the gate is released. Standard A-R EG behaviour. The RESET input has NO effect in this mode.

Switch to AD and reset mode. The MOTM output will now rise to a +5V peak when the gate input goes high. It will then fall back to zero automatically. Removing the gate has no effect on the output. This is ‘one shot’ mode. However, the output may be forced to decay prematurely by use of the RESET input. A positive signal of above 1V or so will activate reset.

Switch to AR and reset mode. The MOTM output will rise until +7V is reached whereby it will stay there until the RESET input is activated.

Remember that all rise and fall times are controlled by the pots on the MOTM820 and OMS820. And can be varied from 1mS to well over two minutes.

Four LEDs are included on the front panel. Two of these will indicate the status of the gate and reset inputs. Another will show the EG’s status. A fourth LED, a bicolour type, will give visual indication of the final output signal.

The OMS-820′s two pots pots together with the MOTM’s own pots, control the rise and fall time. This will enable you to set a time of say, 1 sec with the OMS-820′s pots and then introduce a modulation signal. The depth of which is controlled by the MOTM’s pots.

Richard Brewster modifications:

• Front-Panel-Express MOTM style panel combines the MOTM-820 and Oakley OMS-820 modules into a single 2U-wide integrated unit.
• The GATE and RESET pushbuttons were omitted because of panel space.
• Added end-of-cycle comparator PULSE output
• Patching PULSE out back into GATE obtains a new LFO mode that cycles 0 to +5V. This works much like the old Serge Universal Slope Generator.

From the Synthtech website:

The MOTM-800 provides the standard ADSR (Attack, Decay, Sustain, and Release) envelope for controlling VCAs, filters, and other CV inputs. Both positive-going (0V to +5V) and negative-going (0V to -5V) envelopes are simultaneously available.

Attack, Decay, and Release times can be set from 1ms to over 14 seconds using the smooth feel, conductive-plastic Bourns log pots.

The MOTM-800 actually can be operated in one of 3 modes:

GATE & TRIGGER: a full ADSR (Attack-Decay-Sustain-Release) cycle, with re-triggerable AD portion with GATE on and a new TRIGGER. GATE only: A-D-S-R using Roland “drop GATE” synths (SH-101, etc). MOTM-800s generate full ADSR cycles with GATE only. TRIGGER only: A-D cycle, useful for “stretching” drum pad envelopes.

DIY Modifications:
Added gate comparator with Schmitt function
Output limited to 5V max with clipping circuit
Output level LED

My modifications are similar to the DB-800 Daughterboard from Scott Juskiw.

Here is what my DIY perfboard modifications look like:

The DB-800 version before final assembly:

The DB-800 after final assembly.  I soldered all the wires, rather than use connectors.

From the Synthtech website:

The MOTM-700 is a dual, bi-directional SPDT switch that is “toggled” when an input control voltage exceeds a trip-point set by a panel knob. Special circuitry handles routing of audio (cross-fading VCAs) or control voltage (fast, low-offset switches). The MOTM-700 has two identical, totally independent sections.

Think of a SPDT (single-pole, double-throw) mechanical switch. When the switch is ‘up’, signal A is is routed to X. If the switch is ‘down’, then signal B is routed to X. There are two ways of viewing this: two inputs are routed to one output, or one input is routed to two outputs; it’s truly bi-directional. This is exactly how the MOTM-700 works. What makes it useful is that you control the selection with a control voltage! The MOTM-700 uses a circuit that compares the input control voltage with another voltage, set by the panel pot SWITCH. The SWITCH control is adjustable from -5V to +5V.

• If the CV IN voltage is less than the SWITCH setting, then A and X are connected.
• If the CV IN voltage is greater than the SWITCH setting, then B and X are connected.

A MODE switch selects if audio or control voltages are being routed. In the AUDIO mode, a special circuit switches by a very fast cross-fading between channels. This eliminates pops and clicks. If the MODE is voltage, then a high-speed, low resistance CMOS switch is used that is good enough for switching VCO control voltages without adding drift or offsets! It can also switch at audio rates as well! This can result in some very bizarre timbres.

The MOTM-700 patches below were contributed by John Loffink
The Microtonal Synthesis Web Site

Full wave rectifier

Modules:
Signal source
MOTM-700 Dual VC Router
Oakley Multimix (need gain of -1), or
Mixer Comparator (using the inverting output)
Connections:
Signal source to MOTM-700 CV IN (A/B/X) and to MOTM-700 IO B and
Signal source to Multimix IN1(or Mix-Comp MIX 1)
Multimix OUT1 (or Mix-Comp INV OUT) to MOTM-700 IO A
MOTM-700 IO X is full wave rectified waveform
Settings:
Multimix IN 1 knob at -5 (or Mix-Comp INV switch up)
MOTM-700 switch knob at 0
MOTM-700 mode switch to voltage

Pulse Divide by Two

This divides a square wave frequency by two. Good for clocking/gate applications or suboctave square waveforms.

Modules:
MOTM-320 VCLFO or MOTM-390 uLFO or MOTM-300 VCO
MOTM-700 VC Router
Oakley Multimix (need gain of -1), or
Mixer Comparator (using the inverting output)
Connections:
300/320/390 TRIANGLE to MOTM-700 CV IN (A/B/X)
300/320/390 SQUARE/PULSE (set pulse at 50%) to Multimix IN1 (or Mix-Comp MIX 1) and to MOTM-700 IO A (This needs to be the same oscillator as the triangle wave.)
Multimix OUT1 (or Mix-Comp INV OUT) to MOTM-700 IO B
MOTM-700 IO X is divided square out

Settings:
MOTM-300/320/390 Rate/Frequency = any
MOTM-700 Mode = voltage
MOTM-700 Switch = 0 for square wave, any other setting for uneven pulses
Multimix IN 1 knob at -5 (or Mix-Comp INV switch up)
For modulation of pulse width, mix the TRIANGLE wave with a second LFO sine or triangle, then feed that to the MOTM-700 CV IN.

Syncopated Clock with Random Probability

This gives a nice syncopated, semi-random clock, but always on the beat. Good for triggering envelope generators.

Modules:
MOTM-100 or MOTM-101 Noise/S&H
MOTM-320 VCLFO or MOTM-390 uLFO
MOTM-700 VC Router
MOTM-830 Dual Mode Mixer, or
Mixer Comparator (using the bias control)
Connections:
MOTM-320 PULSE or MOTM-390 SQR to MOTM-100/101 EXT CLK and to MOTM-830 IN 3 (or Mix-Comp MIX 1) and to MOTM-700 IO A
MOTM-100/101 S&H OUT to MOTM-830 IN 2 (or Mix-Comp MIX 2)
MOTM-830 OUT1 (or Mix-Comp MIX OUT) to MOTM-700 CV IN (A/B/X)
MOTM-700 IO X is syncopated clock

Settings:
MOTM-100 LEVEL = 10, SLEW = 0
MOTM-320 or MOTM-390 RATE = about 8
MOTM-700 SWITCH = +0.5 to +3.5
MOTM-830 (or Mix-Comp) IN 2, IN 3, BIAS (optional) = set to taste

Semi-random patch

Modules:
Any 2 LFOs
MOTM-700 Dual VC Router
MOTM-820 VC Lag

Connections:
Any LFO 1 waveform to MOTM-700 IO A
Any LFO 2 waveform to MOTM-700 IO B
MOTM-700 IO X to MOTM- 820 IN
MOTM-820 OUT1 to MOTM-700 CV (A/B/X)
MOTM-820 OUT2 to any control voltage input, VCO pitch, VCF cutoff, etc.

Settings:
LFO rate, Router switch, and Lag Up, Down and Up/Down will cause significant change to the semi-random pattern. Adjusting the Lag control too far to the right may cause the Router to stay pegged to one side. The patch creates a feedback path so that lagged versions of LFO 1 and LFO 2 alternate control of the router switching.

From the Synthtech website:

The MOTM-650 is a 2U wide, full-featured 4-channel MIDI-CV converter. Features include:

• Voice allocations settable as four 1 voice, two 2 voice, or one 4 voice group – each voice group separately addressable via MIDI
• Voice assignment modes on a per voice configuration: Poly 1, Poly 1 steal, Poly 2, Poly 2 steal, Unison, Solo Unison, Solo, Solo Rotate.
• Dual arpeggiators, each arpeggiator assignable to any active voice group – one arpeggiator per voice group
• Arpeggiator clock sources – MIDI IN Clock, internal clock (60-238BPM weighted), or external
• Arpeggiator clock divisors /4, /3, /2, /1.5, 1X, 1.5X, 2X and 4X the clock rate
• Arpeggiator note order as up, down, up/down, and down/up
• Arpeggiator modes are normal, ordered, ping pong, and random
• Portamento – per voice group configurable as constant rate or constant time
• Each voice group is independently configurable
• Firmware updateable via MIDI (Windows and Mac OS 9 update utilities provided)
• All MOTM-650 options settable via MIDI CCs or MIDI System Exclusive commands as well as the front panel user interface
• MOTM-650 Settings and state are remembered across power cycles
• Patch storage for MOTM-650 settings (up to 32) – recallable via MIDI patch change command
• Microtuning per MIDI spec
• Pitch bend adjustable from +/- 0 to 24 to be added to note CV on all voices
• Each of 4 AUX outputs assignable to pitch bend, channel aftertouch, or any MIDI CC.
• Velocity jack on each voice can be configured to be velocity or a trigger – providing a 5ms pulse when the voice is retriggered
• LEDs to monitor MIDI IN activity, internal/external/MIDI clock, and voice gate operation
• 8X2 LCD with variable backlight and 4 buttons for the user interface
• External clock in jack
• Transmits MIDI clock if set to external or internal clock

The MOTM-650 packs all these features into a 2U wide module, using the latest SMT data converters, low-drift op amps and precision voltage references. Most MIDI-CV converters use 12-bit DACs: the MOTM-650 uses a true 16-bit DAC, and an octal 10-bit DAC for the Velocity/Aux outputs. No other MIDI-CV converter has as many features in a small space.

From the Synthtech website:

The MOTM-510 is a new kind of analog signal processing module. It’s not easy to describe what it does, but I’ll try.

Let’s start with the well-known Ring Modulator (like the MOTM-190). A Ring Modulator is a multiplier: the output can be written as Out = X * Y, where X and Y are the 2 input signals (sometimes referred to as the modulator and the carrier). X and/or Y can be audio or DC signals. The output is simply the voltage X times the voltage Y. This produces the sum of X and Y (X+Y) and the difference of X and Y (X-Y).

The traditional RM has no ‘control voltage’ inputs: you just feed 2 signals in, and get 1 signal out. The MOTM-510 takes this concept and generates entire new types of waveforms.

Instead of the 2 RM inputs, the basic WaveWarper has 3: X, Y and Z. These are audio inputs. The transfer function is OUT = X * (Y/Z)^m, where:

• X is the GAIN signal. It controls the overall amplitude of the signal
• Y is the ‘main audio’ signal, the one that is getting ‘warped’
• Z is the DIVISOR signal. This is acts to modulate the amplitude of the main audio signal before it gets warped
• m is the Warp Factor. This is a fixed exponential factor, which is what is doing the ‘warping’. No, it’s not voltage controlled.
• m varies (by the FACTOR control) from 0.2 to 0.6 (ROOT mode), 1 (UNITY, which makes it similar to a RM), to 2 to 5 (POWER mode)
• each input (X, Y and Z) has attenuators
• the AUDIO OUT is AC-coupled and band-limited to 18Khz. The FULL OUT is DC-coupled and can go as high as 200Khz!

But wait, there’s more! There are 3 DC-coupled inputs called OFFSET. These can be DC control voltages (LFOs, EGs, etc) that add to the audio signals. In this manner, the WaveWarper can respond to 6 different modulation sources simultaneously.

From the Synthtech website:

The classic tone of the ’70s, the low pass ladder filter defined “the synthesizer sound”. The MOTM-490 captures all of the subtle characteristics of the original; growling bass, searing leads and overdrive. Can be used as a VCO above A440. Filters any external audio signal.

• Classic 24dB/Oct LPF Ladder Filter
• Based on the Moog 904A modular sound
• Three Audio Inputs
• Distinctive Overdrive Sound
• Can Self-Resonate (Sine Out)
• Low Power Operation

The MOTM-480 CS-80 Resonant Filter consists of two identical state-variable Voltage Controlled Filters. Each filter features:

1V/Octave frequency control input
FM input with reversible attenuator
VC resonance input
High pass, band pass, and low pass outputs

In conjunction with Larry Hendry, I designed a 3U-wide panel with complete features for both filters, so that they can be used independently. Each filter has a two-input mixer and simultaneous high pass, band pass and low pass outputs. Each filter has its own three VC inputs. Four buffer circuits are needed for the four new outputs, and these buffers were built on a MUUB-4 board (see parts list). Visit the PROJECT PAGE.