TR-808 Velocity Control

Design Concepts
1

Here is a velocity control for each voice module of a TR-808. The concept is simple..

What i did is i took the accent circuit from the original schematics and i place a digipot that will control the velocity for every single voice separately.

 

A Digipot chain will be connected at J19 of the STM32F4 Core. Each Digipot is controlling the Velocity Value on each instrument. So let’s see.

 

A Pin from Dout module sends a Trigger of +5 Volts. One Branch goes at the Trigger in of the Voice module.

The other branch is going into my circuit.

The digipot controls the velocity level from +5 volts to +15v. ( Even with 0 Velocity a 5v minimum trigger must go in voice module so we have sound.)

The result is a Trigger voltage  from +5v to +15v that goes into the Accent in of the voice module.

 

What we have here is a velocity control for every single note. :rolleyes:

 

I Need help on how to programm Digipots to do this job.

 

Here is the schematic [Accent 5-15v.PDF](< base_url >/applications/core/interface/file/attachment.php?id=11892)

 

Regards Tilemachos

2

that’s a good one, i really like something similar to cv the decay of the voices.

3

Hi i have used the seb Drumbox for have velocity control for each instrument of my  tr8060.

 

http://burnit.co.uk/sdiy/index.php?page=drumbox

 

I have connected the accent and trigger input on the same output pulse.

 

Trigger input work fine with a pulse between 5v and 15 v so you don’t need to send a spécific +5 Volts.