Grendel Grenadier RA-9 User manual

Rare Waves LLC Grendel RA-9 Grenadier
User Guide 1.3
© 2015
r a r e w a v e s . n e t
A N A L O G M U S I C S Y N T H E S I Z E R

Rare Waves LLC Grendel RA-9 Grenadier
User Guide 1.3
© 2015
r a r e w a v e s . n e t 2
The Grendel RA-9 Grenadier is a monophonic true analog
synthesizer with CV-Gate control and a built-in keypad for manual
play.
It was designed to seek a balance between simple controls and
maximum flexibility while adhering to a strict knob-per-function layout.
Fourteen patch points multiply the creative possibilities for sound
manipulation via interconnection with other analog equipment.
The Grenadier offers a unique filterbank with three voltage controlled
filters in parallel. It can produce a wider range of midrange and low
frequency timbres than one filter alone. Vowel effects are possible.
A built-in sequencer can be activated for minimal melodic and
rhythmic lines. Connecting a MIDI-CV converter (not included) allows
you to sequence the Grenadier from a computer music workstation.
The housing is built from tough steel and has a built-in roll cage to
protect the control surface.
C r e d i t s
Eric Archer - hardware and graphics
Nathan Wooster - firmware
M a n u f a c t u r e d b y
Rare Waves LLC
P.O. Box 729
Llano, TX 78643
United States
An AC adapter is required to use the Grendel RA-9 Grenadier. There is no internal battery.
The unit is on whenever power is applied. There is no power switch. The Grenadier uses very little power (less than the
AC adapter itself). To save electricity, it is wise to unplug the AC adapter when the unit is not in use.
A regulated 9VDC tip-positive AC adapter is supplied with the unit.
The Grenadier is flexible with regard to its DC power source. Nearly any adapter can be used that is rated for 7.5 volts to
12 volts output and has a 2.1mm center pin connector.
ŸIt is OK to use tip positive or tip negative power source.
ŸIt is OK to use a daisy-chain cable to power the Grenadier from a 9V adapter that is shared with other FX.
ŸDon’t connect an unregulated adapter that is rated for more than 500 mA. (If its large and heavy, avoid it)
ŸDon’t connect an adapter that is rated for more than 12 volts output.

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r a r e w a v e s . n e t 3
ŸManual play - Key gate
ŸManual play - Fading notes
ŸSteady drone with LFO modulation
ŸBasic analog sequenced VCO with filter envelope
ŸProgrammed rhythm with fading notes
ŸFour-note melodic sequence with programmed rhythm
SEQ
SEQ
SEQ
SEQ
SEQ
SEQ
DRONE
DRONE
DRONE
DRONE
DRONE
DRONE
FADE
FADE
FADE
FADE
FADE
FADE
REPEAT
REPEAT
REPEAT
REPEAT
REPEAT
REPEAT
PROG
PROG
PROG
PROG
PROG
PROG
The keypad responds like an electronic organ, sustaining a note for as long as the key is pressed down. The envelope
generator is triggered by playing the keypad, and its output can modulate the filterbank via the ENVELOPE DEPTH
knob.
The keypad triggers a note with exponential loudness decay. The envelope generator is applied to both VCA and
filterbank.
The synthesizer plays a steady tone. Play the keypad to change notes. Apply slow LFO modulation for drone effects.
The sequencer walks from step I-II-III-IV in an endless cycle, producing a melodic sequence with envelope filter effects.
Fading notes are triggered in a rhythmic pattern. Press PROG-+ to add events, and use PROG-X to erase events. Play
the keypad to make pitch transitions. Activate PITCH ENV for bass drops and sound effects.
Fading notes are played in rhythm, changing pitch as the sequencer steps I-II-III-IV in an endless cycle.
Envelope
Generator Filterbank
LFO
Patch Points
Keypad & Sequencer
FX Loop
Tone & Volume
I
I
I
I
FADE
FILT E RALPH A
ENVE L O P E
DEPT H
ENVE L O P E
TIME
LFO
RATE S Y M M E T R Y
LFO
DEPT H B E T A D R I VE VOL U M E
CV GATE CLK ALPHA BETA LFO CV
IN
OUT
ENV LFO TRIG
A N A L O G S E Q U E N C E R
DRONE
SEQ
REPEAT PROG
TRIG WAVE
WAVE XMOD
I I I I I I I V
LFO
RESO
OSC
OUT EXT.
IN
PROG
PITCH
ENV
PAD
-20 dB
Left-hand side: Pitch and rhythm controls Right-hand side: Tone and modulation controls

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User Guide 1.3
© 2015
r a r e w a v e s . n e t 4
SEQ
OFF ON
DRONE
FADE
REPEAT
PROG
TRIG
LFO WAVE
WAVE
XMOD
RESO
Keypad behaves like a keyboard.
Manual (real-time) performance
Analog sequencer steps once per trigger
event, endless cycle I-II-III-IV
Gate controls VCO output VCO always on
VCA always on (no fade-out) Envelope controls VCA (fade-out)
Keypad / Gate In triggers envelope Sequencer triggers envelope
One trigger event per two clocks
(steady 1/8 notes) Programmable trigger loop engaged
LFO runs freely LFO restarts at the beginning of each note
LFO generates triangle wave
(variable symmetry)
LFO generates square/pulse wave
(variable pulse width)
VCO generates triangle wave VCO generates square wave
Normal tone Filterbank modulated by VCO
Normal tone Filterbank high resonance and self-
oscillation when DRIVE knob = 10
PITCH ENV
Normal tone VCO pitch bend by envelope
PAD -20dB
Normal external audio level.
Best for portable music players
High level external audio input
Best for modular systems and pro audio.
Table 1. Reference information for switchable functions

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The VCO offers triangle and square waveforms. It covers a frequency range of approximately 20-500
Hz, or 4.5 octaves.
Activate the WAVE switch to select the square wave. The square wave output is pre-filtered internally to
emphasize low and upper-mid frequencies.
The VCO’s pitch is normally controlled by the tuning knobs I-II-III-IV on the keypad.
Connecting a patch cable to CV IN overrides the keypad’s control of the VCO. However, keypad activity
will still be available at CV OUT and can be patched to control other functions.
The VCO responds directly to GATE. When GATE is off, the VCO is disabled (silent).
The VCO is synced (reset to reference phase) by the GATE signal. This gives better low-frequency
output with staccato sequences.
Activate the DRONE switch to hold GATE on for continuous sound. When DRONE is on, the VCO
continues to produce tone regardless of the GATE IN and keypad buttons. Also turn off FADE for
endless drones.
The VCO follows the 1 v/oct standard. It responds to CV input in the range of 0..+5 volts. Voltages
outside this range are ignored. The scale response can be trimmed with the VCO trimmer. Insert a
small flat or Phillips screwdriver through the opening. It is a single-turn type trimmer.
Fine-tuning the VCO is possible with the TUNE trimmer. Insert a small flat or Phillips screwdriver to
adjust TUNE. It is a single-turn type trimmer. The fine tuning range is slightly greater than one octave.
Adjusting this control is recommended when using a MIDI-CV converter. This will allow you to put the
Grenadier in tune with other synthesizers in your system.
WAVE
:
:
DRONE
:
:
VCO ALWAYS ON
GATED VCO
:
:
1V/OCT ADJUST
FINE TUNE
CV
GATE
IN
IN
:
:
0..+5 VOLTS (1v/oct)
5 VOLTS = VCO ON (SYNC)
0 VOLTS = VCO OFF
A N A L O G S E Q U E N C E R
I I I I I I I V
0
1
23
4
5V 0
1
23
4
50
1
23
4
50
1
23
4
5
The keypad is active when the SEQ switch is off. The Grenadier’s keypad can be played in real time like
the keys on a keyboard. This makes it easy to experiment with phrases and jam along with a beat.
The keys are numbered I-II-III-IV. Above each key is a knob that sets its pitch. You can adjust these
knobs to tune the keys to notes from a scale that fits your composition.
The keypad remembers the last key that was pressed and the VCO will continue to sound that pitch if the
DRONE switch is on, or if GATE IN is active.
The CV OUT patch point sends analog voltage corresponding to the active key. The range of output is
0..+5 volts. The GATE OUT patch point is active whenever a key is pressed. You can use the
Grenadier’s keypad to control another CV-Gate synthesizer by patching CV OUT and GATE OUT to it.
SEQ
:
KEYPAD ACTIVE
PROG
:
:
PROGRAMMABLE LOOP
8TH NOTES
SEQUENCER STEP PATTERN
I I I I I I I V
CV GATE
OUT 0..+5 VOLTS
:
When the SEQ switch is on, the analog sequencer is active. The LEDs above the keys I-II-III-IV will cycle
automatically in a loop from left to right.
The Grenadier’s LFO supplies clock to the analog sequencer. You can supply an external clock to the
sequencer by connecting it to the CLK IN point. Typically, a 16th-note square wave clock is
recommended. The external clock should be a 5 volt square wave (0..+5 volts). The sequencer steps
on the rising edge.
The rhythm pattern of the analog sequencer is controlled by the PROG switch.
ŸWhen PROG is off, the sequencer will step once for every two clock transitions (half time or 8th
notes).
ŸWhen PROG is on, the sequencer will step once for each trigger event in the programmable loop.
The next page explains how to use the programmable trigger loop for interesting rhythmic sequences.
SEQ
:
SEQUENCER ACTIVE

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PROG
I
I
I
I
The Grenadier’s programmable sequencer generates trigger pulses in a 32 step (2 bar) endless loop.
To step the analog sequencer with the trigger loop, SEQ and PROG switches.
To trigger the envelope generator with the trigger loop, activate the REPEAT and PROG switches.
The sequencer is controlled by the PROG+ and PROG-X buttons. The LED between the buttons
flashes to visually indicate the programmed pattern.
Set the LFO (or external clock) for a 16th-note tempo. If the LFO is very slow, or if there is no valid clock
signal patched to CLK IN, the sequencer will appear inoperable.
Erase the old sequence by pressing and holding PROG-X while tapping PROG-+
Add trigger events to the loop by tapping rhythmically on the PROG-+ button. After 2 bars (or 32 clock
cycles), the LED will begin flashing the recorded pattern. It is quantized to match the clock. In other
words, you can’t program notes faster than the clock rate. It is not possible to change the loop length.
Erase unwanted trigger events by pushing PROG-X over the event as it comes around. You can erase a
longer portion of the sequence by holding down the PROG-X button like an eraser.
Press and hold PROG-+ while tapping PROG-X to make the sequencer play a steady 16ths note roll
(one event per clock cycle). Tap the buttons again to get out of roll mode. Use this function if you want
to trigger the Grenadier from an external rhythm machine.
Once you have created an interesting rhythm pattern, try alternating the PROG switch (near
ENVELOPE) to switch back and forth between metronomic 8th notes and your programmed pattern.
The sequencer can trigger external modules from the TRIG OUT patch point.
When SEQ is on, the analog sequencer always steps in order I-II-III-IV, repeating from step I... it is not
possible to program the sequencer to play in a different order. Use CV-Gate control instead for complex
patterns.
PROG
:
ENVELOPE GENERATOR
TRIGGERED BY LOOP
OUT
TRIG
:+5 v
0 v
REPEAT
ADD
EVENT ERASE EVENT
16th ROLL
PROG
:
ANALOG SEQUENCER
STEPPED BY TRIGGER LOOP
SEQ
10 ms
F I L T E R
0 10
A L P H A
B E T A D R I V E
0 10
0
+5
0
+5
The Grenadier’s filterbank contains three voltage controlled bandpass filters working in parallel.
The filterbank processes the VCO’s output. It is also capable of being a signal source of its own - it can
be set to generate low frequency self-oscillations. This can be useful for percussion effects.
Use the ALPHA, BETA, FILTER, and DRIVE knobs to modify the frequencies that the filterbank
emphasizes and sculpt interesting tones.
The FILTER knob affects the overall frequency range of the filterbank. It adjusts all three VCFs in
parallel.
The ALPHA and BETA knobs primarily affect the positions of the midrange resonators and affect the
color of modulations from the LFO and Envelope Generator. ALPHA and BETA are bipolar controls. The
normal position for ALPHA and BETA is zero, located at 12 o’clock.
Patching a CV source to ALPHA IN or BETA IN will modulate the filterbank.
The full range of control is 0..+5 volts. External LFOs with bipolar (+/-) output may not behave as
expected.
The DRIVE knob mainly affects the low-frequency qualities of the signal. If the RESO switch is on, self-
oscillation will occur when DRIVE is set to maximum position. The self-oscillation is accompanied by
overdrive distortion in the filterbank. The volume level can increase significantly when self-oscillation
sets in.
The filterbank can process external audio via the EXT IN patch point. For this purpose, cancel the
internal VCO by plugging a dummy cable into OSC OUT. Use the PAD -20dB switch if the external signal
overdrives the filterbank, such as from a modular VCO or +4dBu mixing desk line output.
Note that the filterbank is not designed for full cutoff (hi-pass or low-pass). Instead, it is designed to
emphasize low and mid frequencies in a way similar to a vowel formant filter. Therefore, setting the
FILTER knob to its extremes will still allow some sound through.
RESO
:
:
MORE BASS, SELF-OSC
LESS BASS, LIGHTER TONE
EXT.
IN
ALPHA BETA
IN FILTERBANK CV 0..+5V
:
:
EXTERNAL AUDIO INPUT

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L F O
R A T E
0 10
S Y M M E T R Y
L F O
D E P T H
TRIG WAVE
20 80 %
50 0
+5
LFO
The LFO modulates the filterbank and also serves as the clock source for the Grenadier’s sequencer.
The LFO offers triangle and square wave output. Activate the LFO WAVE switch to select square wave.
An LED flashes in time with the LFO. The LFO frequency range is approximately 0.05 Hz to 60 Hz.
The TRIG switch can make it appear that the LFO cycles are synchronized with the tempo of the music.
ŸWhen the TRIG switch is off, the LFO runs freely.
ŸWhen the TRIG switch is on, the LFO is reset when the keypad is pressed, or when the GATE IN
patch is active.
The SYMMETRY knob affects the LFO’s triangle wave by varying its ratio of rise time to fall time. It also
affects the duty cycle of the square wave in the range of 20% to 80%. The normal position of the
SYMMETRY knob is 12 o’clock. This control also has a slight effect on the LFO frequency.
The LFO DEPTH knob is used to modulate the filterbank. It is a bipolar control. To cancel LFO
modulations, the LFO DEPTH knob should be set near 12 o’clock. Listen carefully - the exact position
for zero modulation can be tricky to find, and may not correspond perfectly with the indicator at 12
o’clock.
LFO DEPTH works in conjunction with the BETA knob, affecting the filterbank the same as if you were
manually turning the BETA knob.
The LFO’s waveform is available at the LFO OUT patch point. Its voltage range is approximately +1..+4
volts. The LFO OUT patch point is post-LFO DEPTH.
CLK OUT sends raw square wave LFO output.
The LFO rate can be modulated over a wide range by patching a control voltage to the LFO CV IN patch
point. It has exponential frequency control, but not 1v/oct.
TRIG
:
:
GATE SYNC LFO
FREE LFO
:
:
WAVE
LFO
OUT
LFO
CLK
OUT
:
:
+5 v
0 v
+2.5 v
IN
CV
:
LFO
0..+5 VOLTS
E N V E L O P E
D E P T H
0
PROG
+5
E N V E L O P E
T I M E
0 10
REPEAT
ON
PITCH EN V
The Grenadier’s envelope generator is of the exponential decay type. The ENVELOPE TIME knob
adjusts the length of the decay. Very long decay times (>1 min) are possible when this knob is set to 10.
When the REPEAT switch is off, the envelope is triggered by playing the keypad (or GATE IN).
When the REPEAT switch is on, the envelope is triggered automatically. The trigger pattern will depend
on the position of the PROG switch and the programmed loop in the sequencer.
ŸWhen PROG is off, the trigger pattern is regular metronomic pulses at 1/2 the rate of the LFO.
ŸWhen PROG is on, the programmed loop triggers the envelope.
Use the ENVELOPE DEPTH knob to apply the envelope to the filterbank. This is a bipolar control. To
cancel filterbank modulation, ENVELOPE DEPTH should be set near its 12 o’clock position.
ENVELOPE DEPTH works in conjunction with the ALPHA knob to control the filterbank timbre.
Activate the FADE switch to apply the envelope to the VCA. This makes the tone fade away to silence.
For full fade-out, the DRONE switch should also be on.
Turn on the FADE, DRONE, SEQ, REPEAT, and PROG switches for a sequenced melody effect.
The rear-panel slide switch PITCH ENV ON applies the envelope to modulate the VCO pitch. Adjusting
ENVELOPE DEPTH will vary the pitch envelope from rising to falling. This can make pitched bass
drops, as well as other sound effects.
Use the ENV OUT patch point to control other functions or CV inputs on external equipment. The range
of voltages is approximately +1 .. +4 volts. The ENV OUT is post-ENVELOPE DEPTH knob.
FADE
:
:
ENVELOPE TO VCA
VCA ALWAYS ON
OUT
ENV
:+2.5 v

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V O L U M E
0 10
The controls on the right-hand side of the Grenadier affect tone and volume.
The WAVE switch chooses between triangle and square wave from the VCO.
The XMOD switch applies the VCO waveform to modulate the filterbank cutoff frequency.
The RESO switch converts one of the filterbank’s three VCFs to lowpass mode and increases its Q-
factor. When RESO is active, the low frequency output will increase, and self-oscillation begins when
the DRIVE knob is rotated to near its maximum position.
VOLUME is an attenuator for the Grenadier’s main output.
The main output is a 1/4” mono phone jack. Use a guitar cable or any shielded instrument cable.
Connect MAIN OUT to an instrument amplifier, FX pedal, FX processor, mixing desk line input, -10dB
tape input, computer sound card input, microphone preamplifier, or Hi-Z DI box for stage use when FOH
is far away.
WAVE
:
:
XMOD
:
:
RESO
:
:
VCO MODULATES VCF
NORMAL TONE
MORE BASS RESONANCE
NORMAL TONE
Activating RESO and turning DRIVE to 10 will increase the output volume with
heavy low-frequency distortion.

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CV GATE CLK ALPHA BETA
LFO
CV
IN
OUT
ENV LFO TRIG
OSC
OUT EXT.
IN
ON
PAD -20 dB
The Grenadier has 14 patch points for connecting analog signals between its own modules, another
Grenadier, MIDI-CV converter, or some Eurorack modules.**
The patch points are designed for 3.5mm (1/8”) mono phone plugs, such as Eurorack patch cords.
Shielded cable is not essential but may improve sound quality when patching audio to EXT IN.
All of the jacks on the top row are inputs. All of the jacks on the bottom row are outputs.
Connect a MIDI-CV converter to CV IN and GATE IN. If there are auxiliary CV outputs, such as mod
wheel or expression, try patching these to ALPHA IN, BETA IN, or LFO CV IN.
A MIDI-CV converter’s analog clock output can be patched to CLK IN. This is normally a square wave
signal at 16th note intervals. (DIN SYNC is not supported unless you use a DIN SYNC-to-clock
converter.)
The OSC OUT and EXT IN patch points can be used as an effects insert point, or to mix in external audio
for processing through the Grenadier’s filter. Inserting a patch cord into OSC OUT cancels the
connection of the VCO to filterbank.
The signal levels of OSC OUT and EXT IN are compatible with FX pedals, portable audio players, and -
10dBu consumer equipment. In some cases you will need to add gain to the signal with external
equipment.
The PAD -20dB switch is an attenuator for the EXT IN jack. Activate the pad if unwanted distortion is
heard when processing external audio. Using an external preamp or buffer pedal is suggested when
connecting guitar or bass guitar to EXT IN.
All of the Grenadier’s patch points are designed to operate within a voltage range of 0..+5 volts. Voltages
outside this range are limited by the internal protection circuitry. Negative voltages have the same effect
as 0 volts. Voltages more positive than +5 volts are limited to +5 volts. Never apply voltage above +15 or
below -15 volts. Never connect an external module’s output to a Grenadier output.
**
IN OUT
FX PEDAL
GATE OUT
MIDI-CV
CONVERTER
CV OUT
GRENADIER
COMPUTER
GATE IN
CV IN
CLK OUT CLK IN
Open arrows ( ) indicate a connection that is broken when a plug is inserted.
LFO TRIGGER
SEQUENCER
CLK IN
CLK OUT
ANALOG
SEQUENCER
& KEYPAD
CV IN
CV OUT
GATE IN
GATE OUT
GATED
VCO FILTER
BANK VCA
DECAY
ENVELOPE
GENERATOR
TRIG OUT ALPHA IN
BETA IN
ENV OUT
LFO OUT
MAIN OUT
LFO CV IN
ON
OFF
PITCH ENV
OSC OUT
EXT. IN
ON
OFF
PAD - 15dB
gate
post- ENVELOPE DEPTH
pre- ENVELOPE DEPTH
post- LFO DEPTH
Diagram 1. Grenadier internal signal flow including patch points.
MIDI CONTROLLER

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SEQ DRONE FADE REPEAT PROG
:
:
I I
:
I V
:
GATE OUT
MIDI-CV
CONVERTER
CV OUT
GRENADIER
GATE IN
CV IN
CV
OUT
VDC
VCO Tuning Method # 1 - Using a voltmeter and A440 reference
This is a fast and accurate way to tune the VCO. It requires a digital voltmeter and a pitch pipe or tuner
with A440 tone output.
Getting ready
ŸPower on the Grenadier for 30 minutes before beginning the procedure.
ŸLocate a small screwdriver suitable for adjusting the Grenadier’s TUNE and VCO trimmers.
ŸLocate a digital volt meter (DMM) with 3.5 digits precision or better. Connect the DMM to the
Grenadier’s CV OUT patch point. You can use a pair of alligator clips to make connection
between the DMM’s test probes and a patch cable. Connect the patch cable’s tip to the DMM’s
red probe, and the patch cable sleeve to the black probe.
ŸTurn DRONE on. All other switches should be off, including PITCH ENV. Set LFO DEPTH to
zero (12 o’clock). The Grenadier should be sounding a steady tone without modulation.
ŸGive the Grenadier’s TUNE and VCO trimmers some exercise for cleaning purposes. Do this by
rotating them from one end to the other two or three times. These are single turn trimmers.
Procedure
1. Sound A440 reference with the pitch piper or tuner.
2. Press the II key and set the knob above it so the DMM reads 2.270 volts DC.
4. Adjust the TUNE trimmer so the Grenadier’s pitch sounds exactly 2 octaves below the reference.
5. Press the IV key and set the knob above it so the DMM reads 4.270 volts DC.
6. Adjust the VCO trimmer so the Grenadier’s pitch matches the reference.
As further verification, you can set the I key to 1.270 volts and the III key to 3.270 volts. Now all
four keys I-II-III-IV should play a sequence of ascending octaves in tune with the reference.
Note that at 2.270 volts, the VCO’s pitch is independent of the VCO trimmer setting.
Final adjustment
7. Use a MIDI keyboard to control the Grenadier by patching your MIDI-CV converter to the
Grenadier’s CV and Gate inputs.
8. Play a pitch of “A” on the MIDI keyboard. Listen to the Grenadier’s audio and adjust its TUNE
trimmer so it sounds in tune with the reference pitch.
Now your Grenadier will play in tune with a synthesizer ensemble controlled by your MIDI
workstation and MIDI-CV converter.
You may need to octave transpose MIDI parts from your existing compositions so they will sound
correct on the Grenadier.
SET TO 440 HZ
SET TO 110 Hz