[sdiy] TR808 accent question

[Seb Francis]

Yes.

But no reason from an analog point of view not to have individual 
accents.  If I remember the circuit correctly you have a couple of 
transistor on the trigger input of each sound and they kind of AND 
together the individual trigger signal and the accent/timing signal.  So 
the actual timing, pulse width and accent amount is set by the 
accent/timing signal (common for all voices) and the individual trigger 
signal comes on for an imprecise period around when the drum needs to 
trigger.

If you are triggering each drum voice from MIDI you need to send a pulse 
of the right length (1ms) with voltage between 4V and 14V.  Feed this 
signal instead of the accent/timing signal and leave the individual 
trigger signal always on.  You can probably even dispense with 1 or 2 of 
the transistors on the trigger input of each voice.

Seb



Dino Leone wrote:
> Hi all,
>
> I'm building a TR808 clone (without the seq) and  I have a question 
> regarding the accent signal:
>
> In the original, is there just one single accent signal, controlled by 
> a pot on the front panel ?  I'm using a midibox core to control the 
> the voice cards and I was thinking if I should try to implement 
> individual accent voltages for at least some of the voices (using a 
> AOUT module)?   Obviously, I've never touched a real TR808 (I'm too 
> poor a student ).
>
> Best Regards,
> Dino
>
>
>
>
>  
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