Yamaha DTXpress/DTXplorer/DTXtreme

Yeah, I dropped R1 to 1.5k..  What makes you think that's low?  I kept
trying lower and lower values until I was satisfied that the switch
occured for all reasonable hits.  It still does occasionally fail to
switch for VERY light hits-- so light you can't hear the sound
produced, so I'm not complaining.  When I go to build the circuit for
use, I'm definately going to put a potentiometer on instead so I can
adjust the switch sensitivity of each pair.

I did as you said, Keith, and tried reversing the polarity of the
diodes..  No combination seems to work much better than just removing
the main pad's diode-- although I didn't have much time to play around
with it 'cause my parents wisked me away to Olive Garden before I had
a chance to execute proper experimental method (i.e. write stuff
down).  My dad does suggest using germanium diodes, as they've got a
much lower voltage drop than that of regular silicon diodes, but
again, I didn't get a change to test that out, and now I'm out-of-town
on a business trip.

Sorry if the cross post offends anyone.

--- In DTXpress@yahoogroups.com, "Keith" <keith@k...> wrote:
> --- In DTXpress@yahoogroups.com, "plancheeproductions" <DJ-Fille@p...>
> wrote:
> > Hi guys,
> > 
> > today i've built the piezo peizo/ rim switchcircuit from Keith (many 
> > thanks for this, Keith!) and have to say that it is working very good!
> > i just want it to have a little more gain, is there anybody who knows 
> > what to do? I used the design on the edrum for free website
> > http://edrum.for.free.fr/modules.php?name=Content&pa=showpage&pid=48
> > the one with the two piezo's so there is no D1 and D2.
> > On the edrumming website they say to use this type of 
> > transistor:2N3904, i might try this out tommorow.
> 
> Someone has dropped R1 to quite a low value - around 1.5k - improve
> gain. That is a little low, but certainly try lower values.
> 
> Almost any NPN transistor will work, but ones with a higher gain (hFE)
> may give a little more sensitivity.
> 
> Keith.
> 
> (copy of reply also posted to DIYedrums)