Rossum TRIDENT User manual

TRIDENT
Multi-Synchronic
Oscillator Ensemble
Copyright 2019 Rossum Electro-Music LLC
www.rossum-electro.com
Operation Manual
_042419_v5

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Contents
1. Introduction 3
2. Module Installation 4
3. Overview 5
4. Basic Functionality 7
5. Make Some Noise! 9
6. The Carrier Oscillator in Detail 10
7. The Modulation Oscillators in Detail 12
8. Specifications 16
9. From Dave’s Lab 18
10. Acknowledgements 21

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1. Introduction
Thanks for purchasing (or otherwise
acquiring) the Rossum Electro-Music Trident
Multi-Synchronic Oscillator Ensemble. This
manual will give you the information you
need to get the most out of Trident. The
manual assumes you already have a basic
understanding of synthesis and synthesizers.
If you’re just starting out, there are a number
of good reference and tutorial resources
available to get you up to speed. One that we
highly recommend is:
Power Tools for Synthesizer Programming
(2nd Edition)
By Jim Aikin
Published by Hal Leonard
HL00131064
Support
In the unlikely event that you have a problem
with your Trident, tell us about it here:
http://www.rossum-electro.com/support/
support-request-form/
…and we’ll get you sorted out.
If you have any questions, comments, or just
want to say “Hi!,” you can always get in touch
here:
http://www.rossum-electro.com/about-2/
contact-us/
…and we’ll get back to you.
Happy music making!

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2. Module Installation
As you will have no doubt noticed, the rear of
Trident is a circuit board with exposed parts
and connections. When handling Trident, it’s
best that you hold it by the edges of the front
panel or circuit board. It’s not particularly
easy to blow up, but why take chances?
More specifically, the biggest risk (to the
extent that there’s a risk), is damage by static
electricity. Particularly on dry, cold days (or if
you’ve just shued across your shag carpet
in fuzzy slippers), make a point of touching
the metal panel first, before touching any
other part of the module.
While all Rossum Electro-Music modules are
protected against reverse polarity damage,
both to your module and your system, care
should still be taken to connect the power
cable correctly. (For more detail on our
unique protection method, check out Dave’s
discussion of Circuit Protection in Chapter 9.)
Plug the included 16-pin connector into the
header on the rear of the module such that
the red stripe on the cable (the -12V side) is
on the same end of the header as the “Red
Stripe” text on the PCB.
Trident requires, at most, 290mA of +12V and
270mA of -12V.
We have included both M3 and M2.5 (for
vector rails) mounting screws. Use what fits
your system.
If rack rash is of concern to you, use the
included nylon washers when mounting
Trident in your case.

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3. Overview
What is Trident?
The latest brainchild of synth pioneer Dave
Rossum, Trident is a 100% analog, triple
oscillator module that opens up a universe of
dynamic timbral textures.
At its most basic level, Trident is three
precision audio VCOs, each sporting a
unique variety of control voltage inputs.
The main or “Carrier” oscillator provides
its three waveforms simultaneously. The
two Modulation Oscillators each have a
single output and a waveform selector. The
Modulation Oscillators also have a voltage
controlled Symmetry parameter which
varies the duty cycle of the triangle wave
output from sawtooth to triangle back to
time reversed sawtooth, and also varies

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the sawtooth output to have an upward
or downward kink in the middle, as well
as controlling pulse width when the pulse
waveform is selected.
And while each oscillator can be used
independently if desired, it’s when they’re
combined into a synchronous ensemble that
the real sonic magic happens.
That magic is what we call “Zing”
modulation. Each of the Modulation
Oscillators can modulate each of the
Carrier outputs in an amount controlled
by the Zing parameter. Zing modulation is
mathematically akin to ring modulation, but
due to the synchronization of the oscillators
(when an oscillator’s Sync button on), the
aharmonic sum and dierence sidetones of
ring modulation transform into complex but
purely harmonic overtone spectra, which
vary dynamically and dramatically with the
frequency and waveshape modulations of
the modulation oscillators. Each change
in the Modulation Oscillator parameters —
Frequency, Symmetry, Waveshape, Zing, and
(in the case of Modulation Oscillator 2) Phase
— will have a dierent eect on the timbre of
each of the three Carrier waveshape outputs.
When the modulation oscillators are set to
track the carrier oscillator, the waveshape
will remain constant as the carrier frequency
changes. In this case the overtone structure
is determined by the settings and CV
modulations of the modulation oscillators.
If instead the modulation oscillators do
not track the carrier, some of the overtone
structure will vary relative to the carrier
frequency.
What all this means is that whether you take
advantage of Trident’s unique synchronous
modulation capabilities (which you, of
course, should), or just treat it as three
superb, wide-range analog oscillators,
Trident oers a vast variety of dramatic sonic
textures.
Trident features include:
> Three precision analog oscillators with
dedicated 1V/Octave inputs and coarse
control ranges of 20Hz to 20kHz and
modulated ranges of 0.01Hz to 25 kHz.
> Main Carrier Oscillator with simultaneous
triangle, sawtooth and pulse waveforms,
with exponential and linear frequency
modulation and pulse width modulation.
> Main Carrier Oscillator hard sync input.
> Modulation Oscillator 1 with selectable
triangle, sawtooth and pulse waveforms
with exponential frequency modulation,
variable symmetry and symmetry
modulation, and variable Zing level and
Zing level modulation.
> Modulation Oscillator 2 with selectable
triangle, sawtooth and pulse waveforms
with exponential frequency modulation,
variable symmetry and symmetry
modulation, variable Zing level and Zing
level modulation, and variable phase and
phase modulation.
> Both Modulation Oscillators with
independently selectable options to sync
to the main oscillator and track the main
oscillator.
> Trident, like all Rossum Electro-Music
modules, features solid construction,
with thick aluminum panels, solid
aluminum knobs, and quality components
throughout.
For a substantially more in-depth exploration
of Trident’s technology, be sure to check out
“From Dave’s Lab” in Chapter 9.

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4. Basic Functionality
Before we jump into individual functions
in detail, let’s take a quick look at Trident’s
controls.
Coarse and Fine Frequency
Controls an oscillator’s initial frequency over
a range of 20Hz to 20kHz. Modulated ranges
are from 0.01Hz to 25kHz.
1V/Oct Input
Calibrated 1 volt per octave Frequency CV
inputs (accurate over 10 octaves).
Exponential and Linear (Carrier
Oscillator only) Frequency
Modulation
CV inputs into attenuverters (exponential) or
an attenuator (linear).
Pulse Width and PW Modulation
Sets the Carrier Oscillator’s initial pulse width
from 0% to 100% and modulates it via the CV
input through an attenuverter. Note that at
audio rates, 0% or 100% pulse width results in
no audio, just a static DC level.
Symmetry and Sym Modulation
(Mod Oscillators)
Varies the duty cycle of the triangle wave
output from sawtooth to triangle back to
time reversed sawtooth, and also varies
the sawtooth output to have an upward or
downward kink in the middle. Sets the pulse
width when the pulse waveform is selected.
Symmetry can be modulated via the CV input
through an attenuverter.
Zing Level and Zing Modulation
(Mod Oscillators)
Sets the amount of a Mod Oscillator’s
Zing modulation of the Carrier Oscillator.
Modulates the Zing amount via the CV input
through an attenuverter.
Phase and Phase Modulation
(Mod 2 Oscillator only)
Varies the phase of the Mod 2 Oscillator
compared to the Carrier when Mod 2 Sync
is enabled. Modulates it via the CV input
through an attenuverter.
Sync Buttons (Mod Oscillators)
When engaged (with the LED lit), a Mod
Oscillator is hard synced to the Carrier
Oscillator’s frequency.
Track Buttons (Mod Oscillators)
When engaged (with the LED lit), causes the
Mod Oscillator to track precisely the Carrier
Oscillator’s frequency.
Carrier Oscillator Sync In
Hard syncs the Carrier Oscillator to the rising
edge of an external source or to either of the
Mod Oscillators (by patching their output to
this input).

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Outputs
The Carrier Oscillator provides simultaneous
triangle, sawtooth, and pulse outputs. The
Mod Oscillators each have a single output
with selectable waveforms.

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5. Make Some Noise!
If you’ve already followed along with the
Make Some Noise! section of the printed
Trident Quick Start Guide included with your
module, you can skip this chapter and go
directly to the next. However, if you haven’t,
spending a few minutes here will give you a
quick introduction to the function and eects
of the basic controls.
Given Trident’s plethora of knobs and mod
inputs, experimentation is the order of the
day. To get you started:
> Monitor the triangle output of the Carrier
Oscillator.
> Turn up the Zing level of Mod 1 and turn
down the Zing level of Mod 2. Ensure that
Mod 1’s Sync and Track are enabled.
> Vary Mod 1’s Frequency, Symmetry, Zing
settings, and waveform and listen to their
eect. Try modulating the parameters with
external signals (or with the output of Mod
2).
> For dual Zing Modulation, turn up the Zing
on Mod 2 and vary its parameters and
waveform.
> Try disengaging Sync and/or Tracking on
each Mod Oscillator and listen to their
eects.
> Zing!

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6. The Carrier Oscillator in Detail
Trident’s Carrier Oscillator is a precision
voltage controlled oscillator in the tradition
of the legendary oscillators Dave designed
for the original E-mu Modular System. It
can, of course, stand alone as a superb
VCO, but it truly comes alive as the target of
Zing Modulation by one or both of Trident’s
Modulation Oscillators.
Here’s what it oers:
COARSE and FINE FREQUENCY
Using the COARSE FREQUENCY and FINE
FREQUENCY controls, the Carrier Oscillator’s
initial frequency can be set between 20Hz
and 20kHz.
With the addition of the frequency
modulation CVs described below, the
available range is between 0.01Hz and 25kHz.
1V/OCT Input
The 1V/OCT CV Input is a
calibrated full level control voltage
input that is summed with the
values of the Coarse and Fine
Frequency controls and the Expo
FM input.
Trident’s 1V/Octave tracking is accurate over a
10 octave range.
EXPO FM
The EXPO FM Input is a
control voltage input that is
modified by its associated
attenuverter and then
summed with the value
of the Coarse and Fine
Frequency controls and the
1V/OCT input.
When the attenuverter knob
is set to its “0” position, no
control voltage is passed
to Trident. As the knob is turned clockwise
from 0, the amplitude of the control voltage
increases until, at maximum clockwise
rotation, the full amplitude of the signal at the
EXPO FM Input is passed through and results
in a nominal 1V/Oct response.
As the knob is turned counterclockwise from
0, the signal at the EXPO FM input is inverted
(e.g., a CV of +2.5V becomes -2.5V). The
farther counterclockwise the knob is turned,
the less the attenuation of the inverted signal,
until, at maximum counterclockwise rotation,
the full amplitude of the inverse of the signal
at the EXPO FM input is passed through, also
at a nominal 1V/Oct response.
A TIP: You can use the Carrier Oscillator
(or, in fact, any of the three oscillators) as
precision LFOs by setting the Coarse and
Fine Frequency controls to their minimum
(fully CCW) positions and patching 5V (or
more) into the Exponential FM input. Adjust the
input’s attenuverter in the negative range to set
the LFO’s frequency.