LEPLOOP was designed to be a minimalist electronic music live-performance groove-box, which can be used to create a variety of electronic musical styles. Small in nature but aggressive in sound, the user will be able to create a variety of analog timbres and beats.

The LEPLOOP can be synched via MIDI to another LEPLOOP for tempo-synched operation or to another MIDI device or sequencer to receive sequence stop & start instructions.

Leploop Tecnical info

  • 1 oscillator (VCO1) triangular/square wave
  • 1 oscillator (VCO2) sawtooth wave with ring modulator and FM modulation
  • White noise generator
  • 24 dB/OCT Low pass filter
  • Kick drum with distorsion and trigger mixer
  • 2 VCA’s
  • 2 AR Envelope generators
  • 1 LFO
  • 16 Capacitors analo sequencer PWM programmable
  • 4 Track digital rhythm sequencer 64 step each track
  • 4 Channel audio mixer
  • Midi input(clock and notes)
  • 5 CV out: SH, SEQ, LFO, ENV1, ENV2
  • 3 gate out: SH, SEQ, CASSA
  • 3 CV in: VCO1, VCO2, VCF cutoff
  • 1 audio in (VCF)
  • 4 audio out: MIXER, CASSA, VCO2, VCO mix
  • 1 clock output: clock 24, MIDI startstop
  • EEPROM memory 16 banks 10 pattern each


The 4 audio signals CASSA, VCA2, VCA2, VCF are mixed and sent to MIX output. The Bass Drum (CASSA) has it’s own dedicated output,
when connected the CASSA volume knobs remain active for the MIX output.

Rhythm Sequence

There are four rhythm instruments and one capacitor analog sequencer.
4 small red LEDs for track playing or analog sequencer mode.
16 Led’s bar shows rhythm sequencer and other informations.
The maximum length for the analog sequencer is 16 notes.

This is a true analog sequencer becausennotes are stored into 16 capacitors switchednby analog multiplexer.

The Analog Sequencer

This is a true analog sequencer becausennotes are stored into 16 capacitors switchednby analog multiplexer.

As the capacitors are subject to discharge, the note pitches will slowly decrease. It’s not possible to store the note value in memory.

Thusly, the LEPLOOP has a 16-step analog recorder, much like an analog delay.

Over time, as the analog sequencer cycles through its pattern, the signal will degrade and the sound will change. This is because the capacitor can only store the signal for a limited amount of time.
The analog sequencer is digitally controlled tempo-wise, and will work in conjunction with the digital track sequencer.

Midi Implementation

When you turn on the LEPLOOP, default is midi channel 16 for percussive instruments and channel 1 for midi notes, LEPLOOP use two midi channels: the first accepts notes for percussive instruments (4 coloured LEDs), the second is used to play PWM notes.

Leploop reviews

An unexpected review written by Chris Carter, ( Throbbing Gristle, Chris & Cosey ), he performed, recorded and upload on soundcloud short sound example.

I’ve used a lot of synths over the years but this one is something different… it’s a strange instrument. It’s small, much smaller than it appears in photos: it is part synth, part drum machine, part multi-track sequencer. I’m still figuring it all out but initial impressions are that it’s very unpredictable and slightly unstable… but in a good way.

Chris Carter – CCCL

This by Benjamin Weiss, author for instrument and music Blog

Some small-scale manufacturers of analogue hardware intitally go for a public-beta-test and leave the manuals out of the box when they send their devices to the distributers in order to see what they make of it. In this case, the distributor found the box quite promising, but decided to leave the acid test to me: “Give it a go and then tell us how it works.

Benjamin WeissDE:BUG


The Arpopone AKA HARP’O’PHONE is a melody/bass line generator with a chord  and  rhythmic section, available in desktop and euro rack format. It is based on analog ramp divider, similar to those used for the Multicassa which are inspired to Oskar Sala’s Mixtur Trautonium, an early electronic musical instrument.

Each divider generates a voltage ramp starting from a master clock (internal or external) a potentiometer is used to set the number of steps and thus the division ratio with a minimum of 1.

There are ten of such divider in the different sections of the instrument:

  • 2 for the rhythmic section (trigger pulses 1 and 2)
  • 2 for the scale generator, these have a ramp output that forms the melody line
  • 6 for the audio dividers, the 2 prescalers are chained with 4 note dividers, one for bass    and 3 for chords

A further divider comes into play if external clock is selected, in this case the BPM control acts as a clock divider making possible the synchronization with other instruments (at maximum speed divider=1)

Technical Info


BPM : Set the speed of master clock or the external clock divider (RED led)

EXT-INT: select internal clock (set by BPM) or external clock (via the EXT CLOCK IN) the EXT CLOCK OUT pulses are synchronous with the RED led flashes.

The Apopone accepts any type of clock pulse or square wave of 3/12 volts amplitude, with any polarity including the Midi clock (with custom cable) as long as in the midi bit line is present only midi clock message and no other messages like, notes, control changes, sysex, etc.
When in external clock, tempo pot. works as clock divider for the incoming clock in pulse, this is useful for divide fast clock like midi or synch 24 for slow clock like Korg volca series keep the divider to 1, tempo pot to max.


TRIG1 TRIG2 : set how many clock pulses are needed to flash the GREEN and YELLOW led

DIVIDERS : the two trigger output are the rhythmic section of the instrument and are used for playing notes and advance notes of the scale generators the division ratio is 1 to around 40

TRIG MIX : selects a single trigger (1 or 2) or both (1+2) to advance the scales the output of TRIG MIX is also fed to the TRIGGER OUT

SCALE #STEP : Sets the number of steps for the two scale generators that, added together by the SCALE MIXER will play the melody on the VCO.


The pulses selected with TRIG MIX are sent to two scale generators, each scale generator outputs a voltage that increases in steps.
The brightness of the two led’s (WHITE and BLUE) are proportional to the output voltage giving an indication of the current position in the scale.
The  number of steps is set by the two #STEP controls from a minimum of 1 to around 40.


In the mixer section the two scale are summed together to obtain a more complex pattern, the amount of each scale can be set by two controls and can be positive (ascending scale) or negative (descending scale).

In center position the amount is 0 (steady note) an OFFSET control set the minimum voltage and hence the lowest note that can be played.

Be aware that these are NOT tempered scales, all micro intervals are possible fine tuning of the melody being played is done with these three scale mixer controls.


The notes are played by the vco, the VCO PITCH transposes the melody maintaining the same interval between notes, as set through the SCALE MIXER.


The note generated by the VCO is fed to a chain of dividers to obtain 4 sub harmonics of the original note, one of these is the bass section with its own filter and envelope, the other three form the chord section with their envelope.

Arpopone module

Each divider is similar to the trigger dividers with the difference that it acts on notes and not on rhythms generating a subharmonic sequence: for example if the note produced by the VCO is C4 the output will be:
(rotating from left to right) C4,C3,F2,C2,Ab1,F1,D1(not really),C1,Bb0…

Two prescalers are used, each of them is chained with two dividers that further divide the note, the same way many types of chords can be generated by setting the proper dividers each single divider can be played separately by means of  the four buttons in the MANUAL PLAY section one for the bass the other three for each note that form the chord (CH1,CH2,CH3)


The two envelope section are identical, both have a selector for different trigger sources :
– TRIG1 & TRIG2 the envelope starts at the flash of the GREEN LED (bass) or YELLOW LED (chord)
-SB1 & SB2 the envelope starts at the first step of  SCALE1 (bass) or SCALE2 (chord)
-White & Blue  the envelope follows the intensity of the WHITE LED (bass) or the BLUE LED (chord) except for this setting the envelope length is set by the two controls BASS ENV and CHORD ENV an EXT CV input allows to provide an external envelope to drive the VCA.


The bass channel is passed through a resonant low pass filter with CUTOFF and RESONANCE control.


Finally the two channels BASS and CHORD are mixed together, the output level is set by the BASS LEV and CHORD LEV controls.
Two outputs jacks are present: the mono OUT jack on the back panel and the STEREO jack on the front panel useful for listening with phones and for separate channel out.


Power also non-stabilized 12 volts with + central tip There are two power inputs, one can be used for power link another device with custom cable.

Aropopone Reviews


The Multicassa is an electronic instrument composed of three cassa generators controlled by an analog trautonium like rhythm generator.

The term trautonico is inspired by a vintage instrument, the Mixturtrautonium, invented by Oskar Sala, a student of Hindemit. His research elborated on since the 1930s was based on another, more simple instrument, the Heimtrautonium, manufactured by Telefunken in the 20s. The Heimtrautonium being one of the first electronic instruments for the living room.

Early versions of Mixturtrautonium use as frequency dividers the Thyratron (a type of gas valve that could be used to build oscillators and frequency dividers), these dividers acting on the notes producing subharmonic that could be mixed (hence MIXTUR) for produce complex sounds.

Same principle is used here with two differences:

– The valves are replaced by solid-state trigger circuits.
– Dividers act not to the notes but on the rhythms, by dividing a basic rhythm (clock) for a variable number (with the command Clock Divider) rhythms are then mixed 2 by 2 (Trig Mix) generating a complex poly rhythms.
– An output mixer allows you to adjust the volume of each speaker.

Each Cassa has a pitch, resonance and distortion control, the tree Cassa generators have different pitch range:

1. Low

2. Medium

3. High
(rim shot\wood block)

The high channel can produce some scratch noise when you move the frequency pot, because the circuit design and the very high pitch, this is normal. The clock can be generated internally or applied externally through jack on the left side of the unit.

The Multicassa accepts any type of clock pulse or square wave of 3-12 volts amplitude, with any polarity including the Midi clock, as long as the midi line is present only midi clock and no other messages (notes, control changes, sysex, etc.) .

Technical Info

FREQUENCY: Adjusts the pitch of the sound of the case, also affects the resonance

RESONANCE: Adjusts the resonance, ie the damping time of the case.
Beyond a certain level the Cassa go into permanent oscillation.
The level at which the oscillation begins varies with frequency..

DISTORSION: Adjusts the level of signal distortion of Cassa.

TRIG MIX : The rhythm played by each Cassa is the sum of the rhythms generated by the two dividers that are located under the Cassa.
For example, the Cassa 1 plays the rhythms of DIVI1 if trig mix pot. is all to the left, of DIVI2 if all to the right or a mix in between.

CLK DIVIDER : These set the clock divisor, ie how many clock pulses (white LED)it takes to get a shot of cash (colored LEDs).
If the potentiometer all the way left, to each pulse of the white LED will have a shot (divisor 1), slowly moving forward we will have dividers more and more high (shots more and more slow).
The max divider is about 64 (potentiometer fully right).

OUT: Multicassa have an internal mixer, the mixed channel is sent to the mix out connector, there is also individual out of the tree channel, when use individual out keep the mix out volume pot to 0.A

TEMPO: In internal clock mode adjusts the speed of the basic clock, and then all of the rhythms.All on the left, minimum speed, maximum speed all right.When you are on the external clock the tempo pot. acts as a divider (clock prescaler) in the same way of the clock divider, in this case we will have the maximum speed with the tempo potentiometer all at the left dividing by 1, this is useful for divide fast clock like Midi or Synch 24 for slow clock like Korg volca series keep the divider to 1, tempo pot to 0

TRIG OUT: The trig mix 2 and 3 is sent to trig out connectors,
5 Volt positive trig out.

Power Input: Power also non-stabilized 12 Volts DC 200 Ma with + central tip, Tip diameter 2mm ( a standard\universal 12V 500 Ma will work anyway). There is a protection diode for reverse polarity on power in.
Multicassa use an internal 10V voltage regulator, this means power in can be 12V or more like 14v. 18v till 36v max.

The power supply is not included, before you buy a new one, try to recycle a power supply you have at home from an old hd or other device, it’s safe Multicassa did not burn, try to save the planet 😉


Percussion Modules

Line of percussion modules are an electronic euro rack modules for create percussion sound and special efx, created by LEP laboratories, percussion modules based around the LepLoop V2 cassa design.


Same as Leploop v2 cassa section.

Cassa CV

Add CV control over frequency and resonance with amount.


same as cassa with an octave higher pitch range for tom and bongo like sounds.

Bongo CV

Add  cv control over frequency and resonance with amount.


very high pitch cassa for rim shot, wood blocks, fingers snap like sounds.

Legno CV

add  cv control over frequency and resonance with amount.


Hi-hat module based around cassa design with white noise and tow release envelope.

Technical Info

All percussion module have tow trig input and a trig mix pot. aceepting different signal:

Trig: short trig less than 10ms will play one time, longher trig will play tow times.

Cv: you can use different cv signal like envelope, lfo for trig the modules.

Audio: since cassa deseng is based around a stepped resonant filter you can route audio signal to a trig input for filter and distorsion effect.

TRIG MIX : The rhythm played by the Cassa is the sum of the tow trig IN1 and IN2.The trig mix pot. adjust the mix between the tow trig input, great  for create poly rhythms. If only IN1 or IN2 are plug the trig mix pot. adjust the level of the trig in signal.

FREQUENCY: Adjusts the pitch of the sound of Cassa, also affects the resonance.
Frequency and resonance are related.

RESONANCE: Adjusts the resonance, ie the damping time of the Cassa. Beyond a certain level the Cassa go into permanent oscillation, the level at which the oscillation begins varies with frequency.

DISTORTION: Adjusts the level of Cassa signal distortion.

FREQUENCY & RESONANCE CV IN: This are cv input for control the frequency and resonance of the module with cv, a cv in amount is available.
The cv control is made with a vactrol connected in parallel with the frequency and resonance potentiometer, this way you can set the range of modulation.

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