The Mutant Rimshot
triple oscillator rimshot and clave generator with a state variable filter
Thank you for your interest in/purchase of the Mutant Rimshot eurorack module. We would like to thank you for
considering a place for the Rimshot in your modular synthesizer! We think you will enjoy its unique character and
find it highly useful in your musical endeavours. The Mutant Rimshot is a eurorack modular format product, and
requires a +/-12V eurorack standard power supply and enclosure to operate. The Black version of the Mutant
Rimshot is redesigned by Erica Synths in collaboration with Hexinverter Electronique.
SOUNDS FROM THE EDGE
A mainstay of electronic drums, the rimshot has a woody, staccato character that helps it cut through your
drum mix. The clave, which recreates the sound a pair of wooden claves make when struck together, has a
higher and brighter tonal quality.
The Mutant Rimshot is a fully analog rimshot and clave generator inspired by the rimshot found in the
legendary 909 drum machine; a triple bridged-T oscillator coupled with a state variable filter. The clave
sound (not a feature of the original 909 rimshot) is achieved by using just one of the oscillators.
As with the other Mutant Drums, the Rimshot has been designed from the ground up to be fully integrated
into your eurorack modular system, with a wealth of controls and CV inputs. Voltage control of pitch allows
adjustment of the fundamental oscillator over about two octaves. Other parameters such as voltage
controlled filter cutoff and resonance are present, allowing for distinctive and extreme percussive sounds.
CV inputs for most of these parameters mean it is possible to create rimshot or clave sequences with great
The Mutant Philosophy
expression and dynamism.
There are already some pretty awesome clones of vintage gear out there in the modular world. The
Mutant Drums were not made to replace these. Although each Mutant began as a favourable classic drum
topology, we wanted to create something modern and different, while maintaining an analog nature.
Features like CV inputs and signal routing not found on classic analog drum machines were incorporated
to make these circuits powerful creative tools in your modular synthesizer.
10.feb.2017
Mutant Rimshot user manual v1.01
Hexinverter Électronique, 2017
PG1
FEATURES
Three oscillator modes
Rimshot HI mode brings classic rimshot sounds
Rimshot LO gives a lower pitch range; try playing with the filter on this setting to get low tom and kickdrum sounds.
CLV (Clave) mode uses just one of the oscillators to give you a brighter, higher percussive sound.
A switch on the back lets you select between original and extended pitch modes. Original mode can give you
rimshots exactly modelling that of classic machines (in Hi mode), whereas extended mode gives a wider range of
pitch, at the expense of classic accuracy.
Three filter modes
Use the lowpass or highpass filter modes for classic sounding rimshots
Hipass and bandpass can give a wider range of clave and rimshot sounds, as well as completely different percussive
elements (especially when turning the resonance up!)
VCF IN lets you blend the clave or rimshot with other sounds. Try adding some filtered noise for a more acoustic
sounding rimshot, or for pseudo-snare type sounds.
Novel decay and filter mod controls
The MOD DECAY envelope controls the decay of the VCA envelope
The VCF MOD attenuverter allows you to modulate the filter cutoff with the MOD DECAY envelope
Alternatively, a switch on the back lets you modulate the filter cutoff with the pitch-controlled internal VCO, for filter
FM style percussive hits.
TECHNICAL SPECIFICATIONS
Width: 8HP | Depth: 30mm
Current draw: +45mA, -50mA @ 12V
10.feb.2017
Mutant Rimshot user manual v1.01
Hexinverter Électronique, 2017
PG2
INTERFACE
CUTOFF + RESONANCE
Modulate the filter cutoff with your fingers or the CUTOFF CV input. The filter self-resonates at
extreme settings.
PITCH
The pitch knob and CV input adjust the pitch of one of the three internal VCOs with a range of
around two octaves. Voltage control applied at the PITCH jack and adjusted by the
attenuverter at the PITCH CV control can modulate the pitch of the Rimshot. It is not v/oct, but
has an approximate exponential response.
MOD DECAY + VCF MOD
The MOD DECAY envelope controls a VCA allowing you to adjust the length of the sound.
Because the VCA is situated after the filter, you can control the decay of the ringing when the
filter is self-oscillating. The VCF MOD attenuverter lets you modulate the filter cutoff with the
same MOD DECAY envelope or alternatively, using the jumper on the back, with the internal
VCO.
DRIVE
This adjusts the overall volume of the rimshot/clave before the filter. At high settings, it will
overdrive for a different, more aggressive tone. It has no effect on external sounds going
through the filter, so when using VCF IN you can use the drive control to find a pleasing
balance between the internal and external sounds.
TRIG
This input jack is used to trigger the Rimshot. This analog circuit is specifically designed for modular use and will
trigger from virtually any positive-going signal source that lasts 2ms or longer, reaches a peak voltage of about 1V,
and falls back down to 0 (or below 0) before occurring again. Many piezoelectric drum trigger pads from electronic
drum kits should also be capable of triggering the Mutant Rimshot. The LED below the TRIG jack indicates when a
usable trigger is received.
ACC
The ACCent input jack allows you to modulate the intensity and volume of the Rimshot with CV input. A jumper on the
back of the module allows you to select whether the default state (with no CV plugged in) is pulled UP (highest) or
DOWN (lowest) to lowest accent level. 5V of CV will fully modulate the Rimshot to full accent level.
VCF IN
An audio signal input here adds an external sound to the rimshot/clave before both are fed into the filter. To adjust the
relative levels of the external input and the internal sounds, use the DRIVE control, which only affects the internal
rimshot/clave sound.
OUT jack
The OUTput jack is capable of putting out full modular level signals, up to 20 volts peak to peak.
10.feb.2017
Mutant Rimshot user manual v1.01
Hexinverter Électronique, 2017
PG3
SOME PATCH IDEAS
While you can use the internal VCO to modulate the filter cutoff at audio rate (using the Mod switch
on the back to select Osc), you can also use any CV signal input to the CUTOFF jack. Try using a fast
LFO or VCO, with its own frequency being slowly modulated, for ever-changing hits.
Try mixing different types of sounds with the rimshot and clave sounds for endless variants of
percussion. The filter effects both the internal and external sounds. Some filtered noise mixed in
gives a more acoustic style rimshot – with the sound of a snare as well as rim being impacted.
Trigger the Rimshot with a very fast (audio rate) clock signal and you can use it as a strange kind of
VCO in your system. Put a VCA after it in the signal chain and modulate the pitch and cutoff. You can
also adjust the pitch by modulating the clock rate. Don’t expect to be able to play Yankee Doodle like
this!
10.feb.2017
Mutant Rimshot user manual v1.01
Hexinverter Électronique, 2017
PG4
QUICK REFERENCE CARD
If you’ve lost the packaging, you might find it handy to print out this reference card and have it near
your modular for reference.
10.feb.2017
Mutant Rimshot user manual v1.01
Hexinverter Électronique, 2017
PG5
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