Grendel Drone Commander CLASSIC PEDAL User manual

Rare Waves LLC USA
Grendel Drone Commander CLASSIC PEDAL
rarewaves.net
Analog Music Synthesizer
Grendel Drone Commander Classic Pedal

Grendel Drone Commander Classic Pedal is a
unique synthesizer that delivers thick drone tones
with the convenience of an FX pedal stompbox.
Grendel Drone Commander Classic Pedal brings
back the same true analog oscillators and filter from
the sought-after original ammo can model that was
made from 2008-2014.
The LFO section delivers rhythmic sweeping
modulations that animate the filter.
The stomp switch brings the sound in and out,
allowing hands-free convenience when adding
analog drone tones to specific parts of your
performance.
Get new sound effects by processing external audio
signals through Grendel Drone Commander’s filter
and LFO, via its 3.5mm monophonic line input jack.
This analog synthesizer fits conveniently into a
pedalboard and can be powered with a daisy-chain
cable from a standard 9VDC FX pedal power supply.
Contents
P O W E R ............. . . . . . . . . .
C O N N E CTIONS . . . . . . . . . . . . .
O S C I L L AT O R S . . . . . . . . . . . . . .
L F O . . . . . . . . . . . . . . . . . . . . . . . . . . .
F I LT E R . . . . . . . . . . . . . . . . . . . . . . .
G ATE / E N V E LO P E . . . . . . . . . .
AU D I O I N P U T . . . . . . . . . . . . . .
R E V I S I ONS . . . . . . . . . . . . . . . . . .
PAT C H E X A M P L E S . . . . . .
3
4
5
6
7
8
9
1 0
1 1 +
What is it?
Size (L x W x H) ................. 16 x 10.5 x 5.5 cm
Mass (not incl. battery) ........................ kg
Battery type .................................. 9V (PP3)
Power consumption ................ 15 mA @ 9V
AC adapter ...9VDC tip negative (BOSS-type)
Outputs ............... Audio Line Out, Clock Out
Inputs ............. Gate In, Filter CV In, Audio In
Clock Out format ......... analog square wave
MIDI IN/OUT,,........................ not supported
DIN SYNC ............................. not supported
1V/oct VCO CV....... ............... not supported
USB ..................................... not supported
Specifications
So, its just like an effects pedal?
No, because it creates its own sounds, and its not
intended to be patched in the middle of a chain of
FX pedals. It can process audio like an effect, but
please read further on how to do that best.
The stomp switch isn’t a wet/dry bypass switch.
Instead, its used to mute/un-mute the output and
trigger fade-ins and fade-outs.
Grendel Drone Commander Classic Pedal

P O W E R S U P P LY
3
Power switch in jack
This unit has a replaceable battery.
To access the battery compartment, turn the unit over and
rest it on a soft surface.
Remove the screw that secures the battery door and lift
the door off. The battery rests inside a bracket within the
opening.
It is OK to use an alkaline, cabon-zinc, lithium, or
rechargeable battery.
After servicing the battery, immediately replace the
battery door to avoid misplaced parts.
** To prevent damage from corroded / leaking batteries, always remove the battery before putting the unit in storage.
Battery installation and replacement
The power is on whenever a cable is plugged in to the 1/4” audio output jack.
To save battery life, unplug the audio output cable when the unit is not in use. (This is not necessary while an AC adapter is connected)
Using an AC adapter
This unit requires a BOSS-type AC adapter with 9 volts DC
output and tip negative polarity.
Its current requirement is only 15mA, and it is OK to share
power with other FX pedals using a daisy-chain cable.
It is protected against reverse polarity and overvoltage.
If the LEDs don’t ash after connecting an AC adapter:
Be sure a mono-type cable is plugged in to Audio Out
Verify the AC adapter has tip-negative polarity
Check for damage to the AC adapter cable
Using a daisy-chain power cable (not included)
Q: Does it need time to warm up?
A: No, its ready to use as soon as power is applied.
Grendel Drone Commander Classic Pedal

C O N N E C T I O N S
Clock Out
Filter CV In
AC Adapter
Audio Out
Audio In
Gate In
Controls filter frequency from an external
voltage source. Connect to external LFO,
Envelope Generator, MIDI-CV converter, etc.
(not 1 volt / octave)
Synchronizes other gear with this pedal’s
LFO. The clock frequency is equal to the
PULSE rate. Connect to CLOCK IN or SYNC IN
on an external analog sequencer. (8 volts
square wave output)
Turns the sound on/off from an external
voltage source. Has the same effect as the
stomp switch. Connect to GATE OUT from an
analog keyboard, sequencer, or MIDI-CV
converter. Also try connecting to an external
LFO.
Allows processing external audio signals
through the pedal’s filter, LFO, and gate.
Inserting a patch cable mutes the internal
oscillators.
For best results with guitar, bass, and
microphones, use an external preamp first.
1/4” Line level audio output (-10dBu). Connect to an
amplifier, FX pedal, mixer line input, recording
device, DI box, audio interface, etc.
Powers the pedal from an AC Adapter.
Use a Boss-type FX pedal adapter with
9 volts DC output and center negative
polarity (2.1mm).
Its OK to use a daisy-chain cable with
multiple pedals.
The internal battery is disconnected
when this plug is used.
The pedal has internal protection
against damage from reverse polarity
and over-voltage.
Clock Out, Filter CV In, Gate In, and
Audio In require 3.5mm mono cables
Use standard Eurorack synthesizer
patch cables.
Also OK to use 3.5mm “AUX Cable”
Use a 3.5mm-to-1/4” adapter when
connecting to audio sources with
1/4” line output.
** To avoid accidental damage, don’t
connect heavy-weight cables directly
to the 3.5mm ports.
4
Mono
Stereo (TRS)
Grendel Drone Commander Classic Pedal

O S C I L L AT O R S
Practicing this simple procedure will create a
harmonic tuning with Oscillator 1 as the low
note and Oscillator 2 as the high note.
Set the MIX knob to only hear Oscillator 1.
Turn the Filter knob clockwise, to cancel
self-oscillations that can interfere with
clearly hearing the pitch.
Using another instrument in your
composition as a reference, play the root
note of your composition or song, or ask
your band mate to play the root note in a
low octave.
Adjust OSC 1 so it is in tune (in unison)
with the root note.
Now, set the MIX knob straight up, so you
hear an equal blend of OSC 1 and 2.
Adjust OSC 2 to a higher pitch than OSC 1.
Listen carefully while fine tuning OSC 2 to
create a pleasant harmonic interval.
Now the synthesizer is set up for a drone tone
that matches the key of the composition or
song you’re performing.
OSC 1 and OSC 2 knobs Tuning Tip: Harmonic Intervals
Manual tuning adjustment for the oscillators
MIX control
Blends the oscillators together
OSC 1 and OSC 2 switches
The toggle switches choose the waveform
for each oscillator
5
20 Hz 360 Hz
OSC 1 50% Mix OSC 2
Square Triangle
The highest pitch, 360 Hz, is near
the F above middle C
The oscillators do not have CV input
When Audio In is patched, the oscillators are
muted and the MIX control is deactivated.
190 Hz
Grendel Drone Commander Classic Pedal

L F O M O D U L AT I O N
LFO knob
Sets the rate of the LFO cycle
This is also the master clock for the PULSE
modulations.
SHAPE knob
Adjusts the waveform for modulating the
filter with the LFO cycle
2-4-8-16 knob
Choose the number of PULSE modulations
per LFO cycle. This also sets the Clock Out
frequency.
LFO switch
Enables filter modulation by the SHAPE knob
SHAPE switch
Controls the direction of the filter sweep from
the SHAPE knob
PULSE knob
Controls the depth of filter modulation from
the 2-4-8-16 knob. The waveform is a
square wave. The indicator LED ashes with
the timing of the PULSE waveform.
The Pulse LFO waveform is created by a
phase-locked loop (PLL). The PLL tracks the
LFO and multiplies its frequency by 2, 4, 8, or
16 times.
When you adjust the LFO rate, the PLL does
not track the changes instantly, but takes time
to lock on. The slower the LFO is, the longer it
takes the Pulse to lock on the new tempo.
LFO Tips : Phase Locked Loop
6
Rising FallingPos. Neg.
Click Click + Ramp Ramp
Filter Mod. ON Filter Mod. OFF
(SHAPE cancel)
Ramp RampClick Click
To synchronize the LFO with other analog
equipment, patch Clock Out from this unit to
the Clock In or Sync In on an external
sequencer.
This method only applies to external
sequencers with analog square wave Clock In
** This unit does not take Clock In from an
external sequencer.
To approximately match the tempo of this pedal to an
external rhythm, by ear:
Turn PULSE knob full counter-clockwise
Turn SHAPE knob full counter-clockwise
Turn LFO switch ON
Beat-match the click from the LFO with the external
rhythm, listening carefully while turning the LFO
knob in small increments.
When you have got it close enough, wait for the
Pulse LED to stabilize, then turn up the PULSE knob.
LFO Tips : Synchronization
Grendel Drone Commander Classic Pedal

F I LT E R
FILTER knob
Adjusts the center frequency of the filter
(Full cutoff is not possible)
FILTER switch
Sets the frequency range of the filter and
enables filter self-oscillation
The Grendel Drone Commander filter can self-
oscillate, adding complexity to the tone.
Self-oscillation of the filter happens when the
FILTER switch is down, and the FILTER knob is
set anywhere from fully counter-clockwise to
mid-way.
The self-oscillation gets stronger as the filter
is tuned to lower frequencies. It gives an
overdriven quality to the sound.
The self-oscillation can alter the sound of OSC
1 and OSC 2, by emphasizing their harmonics.
As the LFO sweeps the filter, the self-
oscillations can stair-step through a cascade
of overtones and subharmonics from OSC 1
and OSC 2.
To use the pure sound of the filter’s self-
oscillation, “dead-patch” the Audio IN jack.
This mutes OSC 1 and OSC 2.
Filter Tips: Self-oscillation
Filter Drive Trim**
Adjusts the amount of filter overdrive
**Normally there is no reason to adjust this
setting, but if you like tweaking things, you
can try it. To adjust this control, insert a 2mm
at blade screwdriver through the port. The
factory setting is 50%.
7
High Range Low Range
(self-oscillation)
Low Middle High
(self-oscillation)
The Filter CV input lets you modulate the filter from an external LFO, analog
sequencer, or envelope generator. The maximum input voltage range is -10
to +10 volts. The response is not 1 volt/octave. The depth of modulation
may be light to moderate, depending on the output voltage range of the
device that is patched to Filter CV.
Grendel Drone Commander Classic Pedal

G AT E & E N V E LO P E
Mute effect Fade effect
(slow envelope)(fast envelope)
VOLUME knob
Master volume control for the synthesizer’s
Audio Out
ENV switch
Controls the behavior of the stomp switch
and Gate In jack
The envelope generator is an attack-release
type (AR) with equal attack and release
time.
Stomp switch
Mutes the audio output, or gives a fade-in /
fade-out effect, depending on the ENV switch
setting.
When the Gate In jack is used, the stomp
switch is still active, and toggles Gate on/off,
overriding the Gate In status.
** Use a moderate touch on the stomp
switch. (Don’t use your ying leap attack)
The Gate In jack allows you to switch the
sound of the pedal on and off from an
external analog controller. It has the same
function as the stomp switch.
Connect Gate In to the Gate Out of an analog
keyboard, or analog sequencer. You can also
patch it to an external LFO or envelope
generator.
Try self-patching the Clock Out jack to the
Gate In jack. This makes the sound cycle on
and off automatically, and can be used for
rhythmic effects and tremolo effects. It works
best when ENV switch is in the UP position.
Gate In jack signal specification:
< 2.5 volts : Gate OFF
> 2.5 volts : Gate ON
Gate Tips: Patching
8Grendel Drone Commander Classic Pedal

E X T E R N A L AU D I O I N P U T Grendel Drone Commander Classic Pedal
AUDIO INPUT
Audio Tips: Processing External Signals
Allows you process external audio through
the filter and LFO
Inserting a plug mutes OSC 1 and OSC 2.
** OSC 1, OSC 2, and MIX knobs are inactive
when this feature is used
Suggested connections for processing guitar, bass, and microphone signals:
The Audio Input feature works best with raw synthesizer waveforms that have a constant signal level, such as the output from a VCO module. When
experimenting with it, expect to hear a distorted band-pass filter effect. The Filter Drive Trim (pg. 7) controls the gain level of Audio In.
You’ll need a 1/4” - to - 3.5mm adapter when connecting the Audio In to effect pedals or instruments.
To get the best results when processing guitar, bass, or microphone signals, it is recommended to use a preamp or buffer pedal first. Most effect pedals that
don’t have true bypass switching are OK as a buffer for electric guitar or bass. (Without a buffer, the instrument may sound dull, lacking high end detail.)
The preamp’s gain settings will affect the amount of overdrive in the Drone Commander’s filter. Patching a compressor or sustain effect between your
preamp and the Drone Commander may also improve the results.
Audio In can be driven by any analog unbalanced line output. If a stereo plug is connected, only one channel will be used. The nominal input level is -10dBu,
and the input impedance is 10k ohms.
Avoid connecting heavy weight cables and adapters directly to this pedal’s Audio In jack, as it might be damaged by accidental force.
Preamp
or Buffer
1/4”-to-3.5mm
Headphone adapter
3.5mm audio cable
or AUX cable
Electric guitar,
Bass guitar,
Piezo pickup,
or Microphone
3.5mm mono
FX pedals,
Mixer line input,
Amplifier,
etc.
3.5mm
input
1/4”
output
Flexible, light weight cable preferred
9

R E V I S I O N N O T E S1 0
2008-2014
How does Grendel Drone Commander Classic Pedal differ from the original ammo can version?
The DC input jack is now tip negative. This lets you power it with FX pedal-style 9VDC adapters and daisy-
chain power with other stomp boxes.
Protection against over-voltage damage caused by connecting an incorrect AC adapter has been added. The
unit has a built-in self resetting fuse. (Trying random junk-box AC adapters is no longer a risky maneuver.)
The power switch is gone. If running on battery, unplug the audio output cable when the unit is not in use.
Power Supply
Filter section
The Filter CV In jack now sums its modulation with the internal LFO, so both modulations can be used simultaneously. (The original
ammo can disconnects the internal LFO from the filter whenever something is plugged in to Filter CV In.)
Front panel port to access to the filter drive trimmer has been added. Use a 2mm at blade screwdriver to adjust this control. The
factory setting is 50%.
The main LFO now can reach slower frequencies.
The PULSE LFO now can track the main LFO at higher frequencies, extending into the low audio frequency range.
The PULSE LFO has been stabilized so that adjusting the 2-4-8-16 knob does not disrupt its rhythm.
The Filter CV In jack now sums its modulation with the internal LFO, so both modulations can be used simultaneously. (The original
ammo can disconnects the internal LFO from the filter whenever something is plugged in to Filter CV In.)
An LED has been added that ashes once per LFO cycle.
The Shape knob can now be set to fully eliminate the sharp click from the LFO cycle, giving a smoother ramp modulation.
LFO section
Gate control, envelope generator, and VCA have been added, controlled by the stomp switch and Gate In jack.
The push-pull potentiometer switching has been replaced with toggle switches.
External Audio In has been added. Patching to Audio In disconnects the internal oscillators. To simply mute the internal oscillators,
as was done in the ammo can model by pulling up the MIX knob, dead-patch the Ext. Audio In jack.
Et cetera...
Grendel Drone Commander Classic Pedal

PATC H E X A M P L E S1 1
12
3 4
Drone accompaniment for guitar Pure filter self-oscillation
Auto-gate / Tremolo drone Processing guitar with Drone Commander
Dead-patch (not connected)
FILTER Switch = Down
FILTER Knob = 0% .. 40%
Note: Stomp Switch function is affected
ENV Switch = Up
1
Amplifier with 2 inputs
2
Patch an effect pedal between
the guitar and the Drone
Commander as a buffer
3.5mm
plug
Note: Stomp Switch is mute function (not bypass)
1/4” to 3.5mm
adapter
Grendel Drone Commander Classic Pedal

PATC H E X A M P L E S1 2
56
7 8
Interfacing with an external keyboard synth Sequencer connection 1
Sequencer connection 2 Filter modulation with external BPM control
VCO Out / Line Out
Gate Out
Analog synth keyboard
SYNC IN SYNC OUT GATE OUTCV OUT
Analog synth
keyboard
Analog sequencer
SYNC IN SYNC OUT GATE OUTCV OUT
Analog sequencer
A D S R
Envelope generator
GATE IN ENV. OUT
The sequencer’s tempo is controlled
by MIDI or another Sync source
LFO Switch = OFF
PULSE knob = 0%
SYNC IN SYNC OUT GATE OUTCV OUT
Analog sequencer
square wave clock
square wave clock
Grendel Drone Commander Classic Pedal