Yamaha DTXpress/DTXplorer/DTXtreme

I'll try all combinations, but right now, the breadboard's over at my father's, so I'll have to wait for the weekend to get to it.  Bear in mind, I don't really know which way the polarity of my pads are...  They're old Roland PD-31s, but I assume they always to ceramic-to-the-tip so the first peak is positive-leading.  He has an oscilliscope, so we can hook it up and figure out the polarity.  But like I said, only removing D2 seemed to do the trick, and both pads had the same sensitivity to a "control" pad hooked straight in.



--- In DTXpress@yahoogroups.com, "Keith" <keith@k...> wrote:

> 
> I have managed to get my hands on a Roland tom pad for a quick test. 
> While the polarity is negative, there is plenty of positive going
> signal as well.  However, if the Roland module only takes notice of
> the negative going signal, a diode as I have drawn it would be a bad idea.
> 
> Could you try something?  Fit both D1 and D2, but the opposite way
> round to my diagram!  This should give the isolation between the two
> piezos, still drive the transistor for the rim switch and allow the
> negative pulses through for the Roland module.
> 
> Keith.