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THE SERGE MODULES - Applications and Comments   
Control Voltage & Trigger Generators & Modifiers

Analog Shift Register (ASR)
(and Dual Analog Shift Register, 2ASR)

From the catalog:
The ANALOG SHIFT REGISTER is a sequential sample and hold module for producing arabesque-like forms in musical space.  Whenever pulsed, the previously held voltage is sent down the line to three consecutive outputs to produce the electrical equivalent of a canonic musical structure.  A pulse output permits linking two or more Analog Shift Registers together to form longer patterns.  The DUAL ANALOG SHIFT REGISTER is available for high-density systems.


Divide by 'N' Comparator  (NCOM)

Pro: This is a gem of a module!  It does several functions: comparator, voltage-controlled pulse divider, and voltage-controlled staircase generator.  It has two knobs: one to vary the comparator's internal DC offset to change the trigger point, and a 'divisor' knob that changes the division number from 1 to 32.

Con: This is one of  few modules which don't have any CV attenuation.  The divider control knob is added to the CV input.

Wizardry: With feedback, this can be patch-programmed to oscillate.  And you can vary the frequency by turning the divider control knob. Using this module to divide clock pulses is an obvious application; it is also useful for dividing high-frequency audio.

From Chris MacDonald:
Since I only have PCOs in my system I often use the bottom section of the NCOM to get a pulse wave and/or PWM.  Plug a sine into one input and feed a bit of LFO into the other, then fiddle with the knob and the scaling of the LFO signal to control the PWM.


Schmitt Triggers (STR)
From the catalog:
"The DUAL SCHMITT TRIGGER is similar to the Dual Comparator, except that it has been optimized for squaring up audio signals.  The Schmitt Trigger is a single-input comparator with hysteresis.  Hysteresis means that the switching thresholds are different for an input signal depending upon whether it is going up or down.  This feature can be used with an envelope and VCA functioning as a noise gate to reject low-level background noise in audio applications.

The Schmitt Triggers can be used for level detection, plus they have a function unique to the module: both sections of the module can be used as a "set-reset flip-flop".  Essentially, this is a memory element.  A pulse or level into the SET input sets the R/S output high.  This output will stay high independently of the activity at the SET input.  It is reset to zero when the RESET input receives a pulse or sufficient level."


Dual Universal Slope Generator  (DSG)

Pro: Insanely versatile module; there's very little it can't do.  Two independent slew generators (positive and negative) are combined to make a Universal Slope Generator.  This Dual module give you two of them.  Trigger it with a pulse and you get a single AR type envelope waveform.  When the cycle starts a gate trigger output goes low.  When the cycle is finished, it goes high.  So to make it cycle repetitively, connect the GATE to TRIGGER.  Rise and Fall times are settable by knob and two voltage control inputs, one attenuated, the other calibrated at 1v/oct. 

Here's a short list of things you can do with this module: AR transient generator, VC slew limiter, VC LFO (variable slope triangle and rectangular waveforms),  VC audio oscillator, VC trigger delay, VC clock, VCLPF, VC pulse divider, Envelope Follower.  Talk about wide range - cycle times go from hours to microseconds, without range switching.  You can almost make an entire synthesizer with nothing but this module, used in its various ways.

Con: The 1v/oct is most useful when you're patching it as an audio oscillator, but this is at the top of the Slope Generator's range.  Tracking starts to go, then the oscillations die out completely at the top end.  This module, versatile as it is, is not a substitute for a Precision Oscillator or New Timbral Oscillator.

Wizardry:  The Slope Generator's output is linear, but by patching the output back into the attenuated VC input you can create exponential waveforms (with the attenuator knob set after 12 o'clock) or log waveforms (with the knob set before 12 noon).

How can this module act as a filter?  It slew-limits the high frequency components of the incoming signal, at a rate set by rise and fall knobs, and VC.  If the rise and fall knobs are set fully clockwise (fastest rate), filtering will be audibly minimal, seeing as the Slope Generator is responding rapidly to input.  Turning rise and fall knobs counterclockwise increases the response time, and high frequency content at the output will decrease.  Turn them fully counterclockwise and audio output will be minimal.  So feed this thing a low harmonic content waveform like a sine or triangle, and you've got a rough equivalent VCA!

This sort of filtering action is more subtle than the regular VCFs, though a bit more obvious than a 'tone control.'  Good for mellowing out raspy and buzzy tones.

Cross-connecting two Slope Generators together generates interesting 'chaotic' waveforms.  Connect the output of one to the attenuated VC input of the other, then take the output of the second and patch it to the input of the first.  Play with the attenuator settings.

The DSG has a 'Rise-Both-Fall' switch.  This determines whether the control voltage coming in at the 'VC IN' jack controls the rise time, the fall time, or both.  Since you can use feedback to create output exponential or logarithmic output curves, you can use this switch to create combination curves where the rise is linear (set the switch to FALL) and the fall is exponential or logarithmic, or the rise is curved and the fall linear, etc.  The 1V/OCT jack is not affected by the switch.

The LED's on this module and a few others act as a level indicator, dark=off, bright=full on, or in-between.

Tweaks: The panel layout of this module has been changed around, and now it includes a bipolar jack.  This AC-couples the output so you can do nice vibrato (which needs bipolar FM).


Dual Transient Generator (DTG)

Pro: This module is 95% of the usefulness of the DSG  packaged in a smaller and less expensive format.  It gives up a switch and a couple of banana jacks, but that's about all. It doesn't have the 1v/oct calibrated VC input.  Its compact size and versatility make this another gem - one of my absolute favorites.

Con: Same complaints as DSG.

Wizardry: Pretty much the same as applies to DSG.  You can order this module with one of a few stock modifications:

1. A switch to connect Gate and Trigger together to use as a clock.  This is done a lot with the DTG or DSG, so it's handy and saves you a patchcord.
2. Signal In jack.  This lets you use this module as a slew limiter, filter, envelope follower or AR envelope with sustain.  The DSG has this jack, the 'normal' DTG does not. 
3. Bipolar output jack.  This is another feature that the DSG has that's normally omitted from the DTG to save room.  It AC couples the output so you can use the LFO setup for nice vibrato. My choice of the bunch was to have the 'signal-in' jacks put in.

Tweaks: The panel layout and labeling has been changed around a little bit so it makes more sense.


Smooth and Stepped Generator (SSG)

Pro: Weird.  What the hell is this thing???  It is two complementary modules, one is an elaborate slew limiter, the other an elaborate sample-and-hold.  That however is like trying to describe a camel as 'kind of like a horse'.  It's easy to see these functions from the comfortable perspective of the known, but they go into strange territory.  The Stepped generator has extremely low drift, less than 1% per minute from what I've seen.  Slew limiting rate is set by both knob and attenuated VC, as is a 'rate' for the Stepped generator.  Very versatile, whatever it is.   The Coupler output compares the Smooth output with the stepped output.  It is HIGH (+10v) when Stepped is greater, and LOW(-10v) when Smooth is greater.  Be careful of this voltage swing when using this with other modules!  A trigger input won't care, but audio and control voltage inputs will see an extreme amplitude.

Con:  When used as an audio oscillator, the Smooth generator drifts a fair bit.

Wizardry:  Where do you begin??  Both modules can be internally patch programmed.  The Smooth generator can serve as a VC wide-range triangle or square wave generator, which means it can also serve as a VC clock.
Actually, the Smooth module can serve as a sample and hold also.  Put your control source into the usual input, and clock the Hold input with a 99% duty cycle pulse (that is, mostly on).  The Smooth takes a sample whenever the pulse goes momentarily LOW, then HOLDs it while HIGH. Presto, now you've got a dual s/h. Go ape.

Tweaks: The panel layout of this module has been updated from a 3-unit space to 2 units, with the same capability.

Dual Voltage Controlled Clock (CLK)
This is a relatively new module, similar to the DTG.  Here the cycle switches are standard and in place of separate rise/fall knobs there is a single frequency knob.  The VC input is routed through a rise/both/fall switch like the one on the DSG.

Random Source

Pro: Noise.  Usually it's that thing you want to get rid of, but here we're inviting it to the party.  This module offers white and pink noise audio, plus smooth and stepped random control voltages and trigger pulses, the rate being voltage controlled.  As if that were not enough, s/h source and output  are offered, plus a trigger input for the internal s/h and a manual push button s/h trigger.


Pulse Divider

I think this is one of Rex's creations. Looks simple enough: feed a pulse train in, get multiple simultaneous divided outputs.  Other pulse dividers I've seen from other manufacturers provide outputs that are powers of two (2,4,8,16...) but don't provide 5,6, or 7 or any odd-numbered divisors.  Providing the odd divisors aids greatly in creating polyrythms.


Boolean Logic

This is the best way to combine triggers together in various ways.  Of course, can be used for making audio too.  One guy says he uses it as a blinky-lite indicator to show the status of signals in his system.  This is one of Rex's ideas, offering two inverters, and OR, AND, and XOR gates.



Usually used in conjunction with a sequencer, these modules take a continuously varying voltage and constrain it to equally-tempered steps.  Four scales are available depending on the setting of switches and the state of scale select trigger inputs.  There are 3 quantizers available: the TKB quantizer, a sequencer quantizer, and a standalone quantizer.  The standalone quantizer has seven available independent channels, in other words, you can quantize up to seven sources independently.  The TKB quantizer has four independent channels and four channels dedicated to the A-B-C-D layers of the TKB.  Also, the standalone and TKB quantizers take up 2 inches of panel width, whereas the sequencer quantizers need only one inch.


Active Processor
 From Chris Macdonald:

While it certainly isn't very glamorous, I end up using it in just about every patch in one way or another so it's quite a workhorse. :)  Since my system is a bit short on CV scaling capabilities I often patch a CV into one input and use the VC knob to scale down the output.  I also often use it as a crude audio mixer with the VC knob acting to adjust the level of one or the other signal.  The VC input can act to automatically fade between the inputs as well.  The bottom voltage knob gets a lot of use for manually sweeping multiple filters simultaneously and the inverted input is useful for, well, inverting inputs!  I don't think any of this qualifies as wizardry, but my AP certainly gets lots of use!  :)

Control Module

Very simple, and I think, the cheapest module in the catalog.  It's a 2-way toggle trigger switch, one way provides a continuous gate, the other way is spring-loaded for momentary triggers.  The two pots let you do audio or CV attenuating.


Dual Processor

Pro: Deceptively simple.  It's two 3-input DC mixers,  each input having an inverting attenuator, and with a master DC offset knob, -5 to +5 volts.

Con:  Would be nice if maximum setting on the attenuators corresponded to exactly unity gain, but I think it's actually a little greater than unity.  This would be handier to keep oscillators tracking.

Wizardry:  Can also be used as a spare audio mixer.  Hey, why not?
You can use this module as a voltage multiplier.  Put your incoming voltage at one of the inputs, then multiple off that input to the next processor input to double it.
Keep in mind that you can use this module with no input voltages.  The offset knob is handy for driving one or more modules together as a group, or for using negative bias to VC an oscillator into extra-low territory.  Since several of the Serge modules have no VC processing input, it's handy to have one of these to trim the output of a DSG, Random Source, or TKB Pressure into a more subtle range.


Extended ADSR  

Finally, a familiar module in this sea of seeming Martian weirdness.  Superlative DADSR, with voltage controllable delay, attack, sustain, release. The VC ALL input controls all VC time parameters simultaneously.  The little switch at the bottom selects between exponential and linear output curves.  Hey, hook it up to a keyboard and play notes like everyone else on the block!

Con:  None of the control voltage inputs has an attenuator.


Scaling Buffers

From the catalog:
The SCALING BUFFER is useful for controlling two or more modules from the same control voltage.  A single knob and an offset voltage allows a change in the settings and response of modules simultaneously.  The pitch and tracking of two or more oscillator or filters can be changed without readjusting the individual processing inputs or frequency knobs for each module.

Scaling Processor

From the catalog:
The SCALING PROCESSOR is similar to the Dual Processor except it has three sections.  The top two sections have one fixed gain input and one input with full processing.  The bottom  section has two inputs with full processing control (scaling and inverting) as well as an offset control.  A fixed +5 volts is available at all times for use as an offset bias for the above sections or to change the range of a module or set of modules.

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