Yamaha DTXpress/DTXplorer/DTXtreme

--- In DTXpress@yahoogroups.com, "Keith" <keith@...> wrote:
>
> Remember to adjust the KP65 pot as well.
> 
> Keith.
>
I'm attempting this mod myself and am running into similar issues.  
KP65 just doesn't feel responsive enough or misses hits when using 
it.  It's pretty good with your circuit but not perfect.  I've tried 
a few different variation with no luck including increasing the 
resistance across R2 and removing R1.  I've also swapped the polarity 
on the KP65 side but didn't seem to do much.  I'm very confident my 
circuit is implemented as designed in the .pdf

What I know is the Rock Band controller (drums) outputs 2.14v on the 
center post and registers a hit when connected to the collar (at 
anything under ~10kohms resistance).  What I don't know is how long 
the connection/short needs to be for the controller to recognize a 
hit.  The foot pedal for RB using a magnetic reed switch which 
grounds once the magnet in the pedal gets close to it and stays 
grounded until it is let up.  So even if you have the fastest foot in 
the world there will be a several millisecond window where the 
circuit is closed.

I only have an auto-ranging digital multimeter so it is hard to tell 
what the circuit is doing when hooked up.  Perhaps the connection 
from the transistor is so fast RB has a hard time detecting the 
circuit is being closed.  Any suggestions on how to keep the 
transistor in the closed state longer?  I would guess a cap or even 
the use a Darlington pair might work but I'm a novice at circuit 
design.

Thank, Jeff