A modular analog synthesizer that surpasses all expectations.Lately I've been asking myself, "What madness would induce a musician to invest thousands

A modular analog synthesizer that surpasses all expectations.

Lately I've been asking myself, "What madness would induce a musician to invest thousands of dollars in an analog modular synthesizer when everyone is moving toward software emulations?" Software synthesizers offer more features at a lower cost and don't take up the space of hardware synths. However, they lack the immediacy and physicality of a real instrument.

When I first encountered Synthesis Technology's MOTM system and its wall of conservative black faceplates covered with large gleaming knobs, I recalled the excitement I felt before the days of MIDI. Creating electronic music then was a tactile and visceral experience, and the instruments were big and messy. MOTM stands for "MOTher of all Modulars," and though that's quite a claim, the exceptional quality of Synthesis Technology's system might validate such hyperbole. The MOTM system balances modern audiophile standards with some of the more desired quirks of retro analog synth design.

BACK TO THE FUTUREWhereas a MIDI-controlled synthesizer, by its nature, operates in terms of discrete note events, a modular synth works from a continuum: sound is created by complex swings in voltage and the interacting patterns of clocks and switches. A patch on a modular synth is an environment for inflection and nuance: a living and changing entity far removed from the preset mentality brought on by recent keyboard developments.

The physical accessibility of each function in the various components of a modular synthesizer makes it easy to explore new sound possibilities. Anything that creates a voltage can become a controller, and anything that makes a sound can become part of a patch.

A modular synth can be integrated into the modern studio in ways that were not possible during the instrument's heyday. A MIDI-to-CV converter and sequencer software give substantial control over the modules through MIDI. The recording and sampling capabilities of a digital audio workstation further increase the usefulness of an instrument that requires repatching to get new sounds.

Although the idea of programming with patch cords is primitive by today's standards, it's more direct than programming a preconfigured synthesizer. You don't have to spend hours fussing with routing assignments, SysEx parameters, and device IDs as you do when you set up a hardware controller for a soft synth. Using a modular hardware synthesizer is a truly satisfying plug-and-play experience.

SELF-SERVICEA modular synth might even inspire you to grab a soldering iron. Although preassembled and tested MOTM modules are available, Synthesis Technology also offers each module in kit form. The kit versions are about 30 percent cheaper than the preassembled ones. Besides the satisfaction you will gain from creating a system by hand, you might have enough money left over to buy a few extra modules. For those new to DIY, the Synthesis Technology Web site has a regularly updated tutorial page that includes a list of supplies and books for getting started, as well as MP3 demos of each module.

Synthesis Technology grades most modules by difficulty (1 is the easiest, 5 the most difficult) and, in some cases, indicates the amount of time it will take to build the module. For this review, I built the MOTM-110 VCA/Ring Modulator module, which has a difficulty rating of 2. It took me about four hours to build.

The documentation that comes with the modules is clear and precise, featuring thorough assembly and testing instructions, schematics, and calibration procedures. The kit includes everything except a soldering iron, tools, and a voltmeter. The wires are even precut, stripped, and tinned. The module worked perfectly the first time I plugged it in, and I calibrated it in a few minutes to within a millivolt of specification. Now I have a deeper respect for the thought and precision that goes into the design of this high-quality system.

Perhaps you don't want this kind of intimacy with your instrument. Even if you choose to buy your modules completely assembled, you could find yourself getting your hands dirty: the MOTM system encourages hands-on interaction, and you'll get better mileage from it if you have a knack for DIY (see Fig. 1).

KICKING THE TIRESThe various modules' components - 1/8-inch-thick aluminum faceplates, large instrument-grade knobs, high-quality Switchcraft 1/4-inch jacks, sealed Bourns pots, and low-leakage capacitors - show attention to detail throughout. The circuit boards have solid ground planes and mount to a steel backplate that helps shield against unwanted hum and noise (see Fig. 2).

Through its care in the design process, Synthesis Technology has overcome the problems that plague most modular systems. One interesting and useful design feature is the placement of the I/O jacks in the module's lower section, which keeps the patch cords away from the controls. Synthesis Technology's modules have a high signal-to-noise ratio, impressive thermal stability, and low leakage and hum. The sound is neither dry nor clinical; you can easily saturate the filters and make them growl, just as you can with an old Minimoog or a Sequential Circuits Prophet-5.

Synthesis Technology also has a conservative approach to design. MOTM modules will never fulfill the addiction to blinking lights that some analog junkies have; only four of the modules sport LED indicators. According to the designer, each LED adds noise to the system in the form of added current drain and switching transients. By avoiding gratuitous flashing, each module's sonic performance is improved. It seems like a fair trade-off, but I wish a few of the modules (especially the envelope generators) gave a visual indication of activity.

The MOTM modules fit neatly into a 19-inch rack by mounting to steel brackets (available from Synthesis Technology) that horizontally span the rack rails. Each module is 5U high and comes in multiples of the 1 3/4-inch width: single-, double-, and triple-width. Five double-wide modules fit the traditional 19-inch rack.

The modules are less than five inches deep, so they are shallow enough to fit into a 12-space SKB pop-up mixer case. Depending on the configuration, those cases can hold 10 to 12 modules (see opening photo).

The MOTM system is continually evolving, and new modules are due for release every few months. Although the current module selection seems a bit conservative, it provides a strong foundation for a system that will grow into a monster in the near future. (Synthesis Technology says that three new modules will be shipping by the time this goes to press.)

The current module selection includes a VCO, an LFO, a sample and hold with noise, a VCA and ring modulator, an envelope generator, a voltage router, a suboctave multiplexer, and three filters.

OSCILLATORSMOTM-300. The MOTM-300 Ultra Voltage-Controlled Oscillator sports a frequency range of 0.2 Hz to more than 38 kHz, and it exhibits better tracking and thermal stability than any other analog oscillator I have used. In typical Synthesis Technology fashion, this module includes a host of useful features without gimmicks. Each of the VCO's four waveforms - sine, triangle, sawtooth, and pulse - has a dedicated output jack that can be used simultaneously with the others (see Fig. 3). The module also includes a 1V/octave input and two FM inputs. The first FM input has dedicated switches for exponential or linear FM tracking and AC or DC coupling. Control knobs are included for pulse width, pulse-width modulation (PWM) depth, coarse and fine tuning, and depth control for the FM inputs.

The MOTM-300's sync feature is particularly interesting. The sync jack emits a pulse that can drive other VCOs. However, the jack can also accept an external sync signal, depending on the position of the Hard and Soft Sync switch. In Hard Sync, the sync jack acts as an input only. In Soft Sync, it acts as both an input and output simultaneously. The harmonic richness that results from Hard Sync, in which the pitches of the oscillators are locked together, is part of what gives an analog synth its characteristic sound. On the other hand, Soft Sync, a rare innovation that first appeared on the E-mu modular synth, latches two oscillators together when they are close in frequency but allows for drift when the frequencies are farther apart.

MOTM-320. The MOTM-320 Voltage-Controlled LFO has the same high stability as the VCO, as well as sine, triangle, ramp, and pulse outputs that you can use concurrently. The frequency range is from one cycle every 30 minutes to 2.8 kHz. Along with a 1V/octave input, the MOTM-320 has a Hard Sync input, an FM input, a rate control, an FM-scaling control, and a wave-shape control.

The MOTM-320 provides voltage-controllable waveshaping through the Shape input. This feature narrows or widens a pulse wave, makes a sine wave asymmetrical, or morphs a sawtooth from an upward ramp to a downward ramp. However, more sophisticated processing is also possible. For instance, to create syncopation in a particular piece, I synched the LFO to a clock and triggered an envelope generator from the LFO sawtooth. That turned the shape control into a continuous groove control that moved the trigger timing earlier or later in relation to the beat. To hear an example of this, visit

FILTERSThe MOTM system really shines when it comes to filtering. Each of the three filter modules sounds both stunning and unique. For signal processing alone, these filters might inspire an investment in a small MOTM system.

MOTM-420. The MOTM-420 Voltage-Controlled Filter has a 12 dB/octave response and emulates the filter on a Korg MS-20 synthesizer. A switch selects among highpass, notch, and lowpass types of filters. The MOTM-420 has three audio inputs (each with its own level control), two scaleable FM inputs, and cutoff and resonance controls.

You can push the MOTM-420 into full resonance, causing it to cross-modulate with the incoming audio signals in fun and nasty ways. At maximum input levels, the filter sounds good and fat as it begins to distort. The 2-pole response lets some of the harmonics leak through, so the MOTM-420 tends to sound more open and cutting than the MOTM-440 filter.

MOTM-440. The MOTM-440 Discrete OTA Voltage-Controlled Lowpass Filter (with VC Resonance) has a 4-pole response that emulates the old SSM filter chips. Filters designed with SSM chips gave the Octave-Plateau Voyetra 8 and the Rev 1 and 2 versions of the Sequential Circuits Prophet-5 their thick, meaty sound. Those filters got their famous growl from subtle overmodulation within the filter itself, and the MOTM-440 manages to improve on that sound with a better signal-to-noise ratio.

Synthesis Technology considers the MOTM-440 to be its signature filter, and I can see why: it is one of the best-sounding filters I have ever heard. Like the MOTM-420 filter, the MOTM-440 has three audio inputs and two FM inputs, and, of course, you can push the filter into full resonance. You can also make it distort, and the resulting overdriven sound differs significantly from that of the MOTM-420. The MOTM-440 also includes a Bass Enhance switch that increases the bass frequencies for an absolutely huge, throbbing low end.

MOTM-410. Based on the Korg PS-3100 filter, the MOTM-410 Triple Resonant Filter complements the other two filters with its interesting formant-shaping abilities. The MOTM-410 contains three sweepable bandpass filters and two asynchronous sine-wave LFOs (one of the LFOs runs 20 percent slower than the other). The filters have a fixed resonance that lets them evoke the vowels of the human voice or impart shifting articulations to the source sound. Each frequency band has a dedicated tuning control and output, so you can pan a sweeping signal across several speakers or sum the output to mono.

The MOTM-410 allows voltage control over the LFO rate (from 0.02 Hz to 100 Hz), modulation depth, and Sweep. Sweep controls all three frequency bands simultaneously. Also, a Mix control varies the amount of unprocessed signal in the output.

A three-position LFO Mode switch determines how each filter tracks with the LFOs. When the switch is in the Single position, LFO 1 controls all three filters. In Dual mode, LFO 1 controls Filter 1, and LFO 2 controls Filters 2 and 3. In Dual Reverse mode, LFO 1 sweeps Filter 1 upward, while LFO 2 sweeps Filter 2 upward and Filter 3 downward.

I wish the module provided an output for each LFO. It would give me two free LFOs to use elsewhere. I also wish I could control the filters' resonance. The circuit's topology doesn't allow for that, but that's okay. As it is, the MOTM-410 sounds fresh and unique; I would need five simpler modules to get the speechlike formant shifts this module provides.

SOUNDS AND PROCESSINGMOTM-101. The MOTM-101 Noise/S&H module performs several duties at once. The noise and the sample-and-hold sections are internally patched together, but you can use them independently, as well.

White, pink, and randomized noise are available simultaneously from the lower row of jacks. The module also includes a randomized vibrato output, created from band-filtered noise centered at 7 Hz. A vibrato control adjusts the filter's Q, which creates a random signal, more or less. Although you can't adjust the frequency of this random LFO, it's useful as it stands.

The sample-and-hold part of the module has an internal clock and a rate control. It can also lock to an external pulse, and a control knob scales the output. A unique feature of the MOTM-101 is the Track/Hold switch. In the Hold position, the module steps to a new voltage every time it gets a trigger. In the Track position, it mirrors the moving input voltage while the gate is low (below 1.5V) but freezes that output when the gate is high. It's like the child's game of red light, green light played with voltages.

MOTM-110. Another dual-function module, the MOTM-110 VCA/Ring Modulator has a simple but high-quality VCA with audio input and output jacks, a gain control, CV input, and a corresponding sensitivity knob. Like the other modules, the MOTM-110 sounds impeccably clean and punchy. The gain knob boosts the signal above unity, which lets you use negative control voltages for attenuation. With two VCAs, you can crossfade between timbres - a nice touch, though confusing at first.

The Ring Modulator works independently from the VCA, with separate carrier and modulation inputs and associated level knobs (marked X and Y), modulation output, and two AC/DC switches to pass or remove DC offsets. An extra control lets you unbalance the modulator, which has the sonic effect of adding grunge and saturation to the sound while letting the carrier signal bleed through. That adds an extra timbre-shaping twist to the familiar clangorous tones of ring modulation.

MOTM-800. The MOTM-800 envelope generator is the simplest MOTM module. Just as expected, you have front panel control over attack, decay, and release times, along with sustain level. The module has gate and trigger inputs and positive and inverted outputs. The time values are on the fast side and allow some snappy attack transients. Techno mavens will love it.

I wish the MOTM-800 had an LED so I could see when it triggers. I also think Synthesis Technology needs a full-featured envelope module with voltage-controllable durations. In the meantime, the MOTM-800 is affordable and functional.

MOTM-120. The MOTM-120 SubOctave Multiplexer includes two digital counters, a digital multiplexer, and four digital ring modulators. The module converts an input signal to a square wave and then divides the frequency by 2, 4, 8, and 16. You can mix the octaves with the original, but that's only the beginning.

The MOTM-120 works with both audio and ultra-low frequencies, and it lets you modulate the first input with a second input. In the Cross mode, the module acts as a ring modulator when A and B inputs are audio. If A is audio and B is an LFO, you hear rhythmic, sequenced pulsing among the four suboctave pitches. When a clock is sent to both A and B inputs, strange syncopation occurs. Things can get wacky fast with this module.

MOTM-700. The MOTM-700 Dual 2:1 Voltage Controller Router allows you to assign one input to two outputs (or vice versa) and use control voltages to flip between the two. The module has two routing sections that can be used independently. The MOTM-700 accepts any frequency, so you can route control voltages or audio signals. You can even force the switches to flip at certain audio frequencies, which creates composite waveforms with some bizarre and messy modulation artifacts. The MOTM-700, by design, invites creative misuse.

POWER AND VERSATILITYThe two remaining MOTM modules are utilitarian in design. The MOTM-900 power supply uses a medical-grade, low-ripple power block with enough juice to drive about 30 modules. The power cord plugs into the front of the power supply module, which makes cabinet mounting easier. The power switch has a mechanical indicator for the on position, though no lighted switch.

For systems using more than 30 modules, Synthesis Technology sells a larger power block that doesn't quite fit behind the front panel. Some drilling and soldering is necessary to mount it into a cabinet.

The MOTM-940 Patch Panel includes eight rows of three jack types - 1/4-inch, 3.5 mm, and banana jacks - so you can integrate voltage and audio signals from modular synths (such as Buchla, Serge, Modcan, and Wiard) or other instruments that don't use 1/4-inch cords. The 3.5 mm jacks accept 1/8-inch plugs, and each of the banana jacks has a second banana jack next to it for grounding purposes.

Also, the bottom of the MOTM-940 panel includes two handy 4-way mults using 1/4-inch jacks. Each mult group gives you as many as three output signals from one input. The MOTM-940 is the only panel that doesn't come in kit form. However, it is a panel that you could use in other parts of the studio, wherever there's a need to convert from one plug type to another.

A DREAM COME TRUELike most analog modular synthesizer manufacturers, Synthesis Technology is a small company, and its size has certain advantages and disadvantages. On the one hand, it means that a certain clarity permeates the modules and few compromises creep into the design. On the other hand, you might experience delays when ordering modules, and the price won't drop if a large quantity of modules are produced. The MOTM system is a boutique product aimed at open-minded electronic musicians, audiophile sound designers, and serious DIY tweakers. Such a select market doesn't lend itself to mass production, and I suspect these modules will remain a specialty item.

Yet for the high standards they meet, the Synthesis Technology MOTM modules are quite a value. Each module costs less than a comparable Moog or Buchla module did in 1970, which makes this system a bargain after 30 years of inflation. In addition, Synthesis Technology has updated seemingly retro analog gear into an audiophile 21st-century sound designer's dream. The MOTM system is the real deal. There's nothing virtual about it.