Rhythm Ace FR-1 uniPulse install

This manual shows how to connect uniPulse to the Ace Tone Rhythm Ace FR-1. It is possible to control all 10 drum voices via midi and they are velocity sensitive.
It is even possible to control the Brush sound in a velocity sensitive way.


Here you can see the voice board with the connections of uniPulse triggers P1-P10. The brush control needs a general purpose PNP transistor such as BC557 and a 56k resistor. Connect them them just the way it shown in the picture.
B, C, and E are the Base, Collector and Emitter of the transistor.
Connect the base to point B, the emitter to point E and the collector to uniPulse CV-out via a 56k resistor. The 56k resistor is not connected to the 470k resistor on the board, it only looks like that in the picture.

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Maestro Rhythm King uniPulse install

Trigger the voices

Here you can see the trigger points for the Maestro Rhythm King.
In the upper right corner you can also see the +12V power supply for uniPulse.

Here is a picture of the voice board.A kind person from 9bit.se sent us this annotated version:

Interfacing the clock

The following created by our customer James Lo who did an awesome job interfacing the Maestro Rhythm Kings unusual clock circuit.

These instructions show a way to inject uniPulse sync clock and sync gate signals into a Maestro Rhythm King MRK-2. This is the MRK-2:

The MRK-2 has the unusual feature that it changes internal clock speed dependent on whether triplet or 16th note beats are selected. The circuit also encapsulates one of the more convenient clock injection points inside an RC network SIP, so we have to resort to unusual means. My solution parallels the transistors that comprise the “clock multivibrator” and selects the correct sync pulse based on the current beat. Here is a schematic-view of the points we will be attaching to:

Next is a component-view of those same points. The board containing the clock circuit is underneath the voice board, which can be easily removed to gain access.

To interface the uniPulse to the MRK-2, the uniPulse triplet and 16th note sync pulses are first level-shifted to the MRK-2’s v+ (~19V), and then one is selected by the triplet switch position (which is itself set by the current beat). The chosen pulse is used to drive a pair of BJTs that take over from the MRK-2’s clock multivibrator transistors. The MRK-2’s transistors are disabled by shorting their bases to ground via diodes, and the BJTs are enabled by shorting their sources to ground via diodes. Finally, the sync gate is used to switch v+ to the MRK-2’s start signal bus, mirroring the function of the start footswitch.

Here’s the uniPulse configuration:


The MRK-2’s clock multivibrator produces 15ms positive and negative pulses at all frequencies, so its duty cycle is frequency dependent. The uniPulse sync clock however is a square wave, but it doesn’t seem to matter. It’s possible to switch between duple and triplet beats while the machine is running, but you risk losing sync alignment. Note that the selection of active components isn’t particularly sensitive; you could, for instance, substitute a CD4011 for the CD4093. I just used garden variety small signal transistors I had left over from previous projects.

One known issue is that the clock rate is not quite right for the waltz and swing waltz beats.

Rhythm Ace FR2 uniPulse install

This manual describes how to install uniPulse in the Rhythm Ace FR2L

This is based on the schematics and has not been tested yet. Please let us know if you have installed it. Bonus points if you send us a video of the drum machine in action 🙂
Download the uniPulse Configurator file for Rhythm Ace FR2L

uniPulse power

In order to power the uniPulse, you need to install a few additonal components. Due to the high voltage after the transformer, an additional 15V regulator must be used (7815). The capacitors should have a voltage rating of at least 35V, more is ok. Connect the uniPulse V+ and V- wires as shown in the picture.


Trigger are very straight forward. Most triggers are soldered to the legs of diodes on the voice boards. Cymbal and Maracas triggers are simply connected to the solder points on the voice boards. It is also possible to control the Brush (B), but without testing it is hard to tell exactly how. This will be updated as soon as this information is available.

Clock sync

As always syncing the drum machine to the midi clock is optional and requires additional circuitry.
A level shifter is needed for the start/stop signal. Two pole switch (included in the kit) is used to switch between internal clock and midi clock. In order to access points A and B, desolder one leg of R12. A is connected to the resistor, B is connected to the board where the resistor was connected originally.
Point C can be directly connected to the Start/Stop switch.

ELKA Drummer One uniPulse installation

This manual shows how to install uniPulse in the ELKA Drummer One and thus allows to trigger voices via midi and to sync the Drummer One to midi Clock.

Thank you very much to Thomas Kayser of SynthMedic for figuring this out and providing pictures.

After installation use the Config Tool to upload the Config file for ELKA Drummer One (right click, save as).

Connecting trigger points

Below you can see the installed uniPulse. Trigger points are on the right the picture below shows the trigger points in a bit more detail. Two of the triggers needed additional 1Meg resistors to ground which can also be seen in the picture. UniPulse channels 1-9 are used.

Midi Clock Sync

If you like, you can also sync the Drummer One to midi clock. This requires a bit of additional circuitry. A two-pole switch is used to switch between internal and midi clock. This switch is provided with the uniPulse kit since uniPulse MK2. You will also need two general purpose NPN Transistors and 2x10k and 2×2.7k resistors. The circuit can be seen below. Its purpose is to level shift the clock and gate voltages.

The GATE signal is connected to uniPulse pin D1, the CLOCK signal to uniPulse pin D2.
The picture below shows the location of the C point and the circuit on a prefboard. To access points A and B, one leg of a capacitor needs to be desoldered. This is also shown in the picture below and in more detail in the next picture.

Installing the uniPulse board

You can mount the uniPulse board in the case using distancers as shown here:

The Drummer One needs to be in start mode with all Rhythms deselected in order to be synced to midi.

Roland TR-66 unipulse Installation

A customer sent us the uniPulse trigger points for the Roland TR-66. Thank you very much! Installing is very simple, just connect the unipulse to the trigger points as shown and upload the config file via the tool.

As you can see there are 9 instruments you can trigger:

BD = Bassdrum
SD = Snare Drum
HH = Hihat
CY = Cymbal
HC = High Conga
LB = Low Bongo
HB = High Bongo
C = Conga
RS = Rim Shot

Just connect uniPulse outputs P1 .. P9 to these points, configure these outputs using the configurator as ’15V, negative, Open Rect’ and you are good to go.

The CB (Cowbell) sound can be achieved by connecting the CB shunt point to GND. You could install an additional switch to achieve this. Alternatively you might use an NPN transistor to pull that point low, controlled by an uniPulse digital output. We have no way of testing, so this is some experimentation left to you.

uniPulse needs some Power and you can get it by connecting uniPulse GND to G1 or G2, and connect uniPulse V+ to B0 of the voice board as shown in the next picture.

Have fun!

Boss DR110 uniPulse install

This manual describes how to install uniPulse in a Boss DR-110. If gives you velocity sensitive trigger of the instruments, accent trigger and midi clock sync.

There are two additional sounds that can be triggered via midi: Part of the clap (electric snare) and part of the cymbal.

For the DR-110 you need to get the custom DR-110 uniPulse version.

Installing the kit does not require to cut any traces and is generally a simple soldering job. You do however need to drill a hole for the MIDI socket. We use a 3.5mm jack socket and include an adapter. If you require, you can also install a DIN-socket, but it only barely fits. You also need to install 2 additional switches: One switch to select the clock source (MIDI or internal). The other to switch the bassdrum trigger from MIDI to internal.

MIDI is received on channel 10 with the following notes:




Bass Drum






Electric Snare (extra sound)


Closed Hihat


Open Hihat




Extra Cymbal


Accent on/off

Installation manual as PDF