This is how to add velocity sensitive midi to the Roland TR-77 drum machine using Tubbutec Unipulse.
Installation is very straight forward, you just need to solder some wires and drill holes for the Midi socket and learn button. To get a sound over midi, the machine needs to be started and no pattern selected.
Config file here: TR-77 config file
This manual is just a brief description of how to install the uniPulse, for further information please check out the uniPulse page.
Trigger points
Trigger points are shown for all 13 instruments including Maracas:
trigger inputs 1-7
trigger inputs 8-12
Maracas CV input (Resistor is 56K)
This is where to get the supply voltage for the uniPulse:
Unipulse supply connections
CLOCK SYNC
It is possible to sync the TR-77 to midi clock, you will however need to press the start button of the TR-77 once after turning it on.
- Start the machine using the ‘button’.
- Start the midi clock
In order to add midi sync you need to lift one leg of resistors R5 and R6 on the TR77 pcb and solder the lifted legs together, see picture, and run a wire from the joined resistor legs to switch pin C3. Run a wire from solder point T2 on the pcb to switch pin C2. Add a 4K7 resistor to switch pin A1. Connect the D1 wire of Unipulse (white) to the resistor soldered to A1. Run a wire from pin A2 to the leg of R4, see picture.
To add Start/Stop you need to solder the collector of the provided NPN transistor to pin B1 of the switch. Connect the Emitter to Gnd (you can use the orange Gnd wire of Unipulse). Solder a 220R resistor to the Collector of the transistor, and finally run a wire from the pen end of the transistor to switch pin B1. Run a wire from pin B2 to the tip contact of the Start jack, see picture.
The transistor and resistors are included in the kit. Just order the TR-77 kit.
Installed board
