Yamaha DTXpress/DTXplorer/DTXtreme

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.
anyway here is the link: http://www.edrumming.com/forum/viewtopic.php?
t=2107 
so, if there are people over here with other solutions, keep em 
comming folks!

many thanks in advance.
Cheers.

www.plancheeproductions.tk

--- 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)

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)

--- In DTXpress@yahoogroups.com, "Chris Todesco" <desco@m...> wrote:
> Yeah, I dropped R1 to 1.5k..  What makes you think that's low? 

the fact that if the pad puts out 30V you may blow up the transistor!

> My dad does suggest using germanium diodes, as they've got a
> much lower voltage drop than that of regular silicon diodes

try schottky diodes - lower voltage than germanium and you don't have
to find an old valve radio to steal them from ;-)  Just make sure you
buy something with a decent reverse voltage (30V+) becuase some are
quite low voltage.

Keith.

Mmmm... Well I put my pads (old Roland PD-31s) on an oscilloscope and even for the hardest of hits, never saw more than 6 or 7 volts. Is there a better way to

--- In DTXpress@yahoogroups.com, Christopher Todesco <desco@m...> wrote:
> Mmmm... Well I put my pads (old Roland PD-31s) on an oscilloscope
and even 
> for the hardest of hits, never saw more than 6 or 7 volts. Is there
a better 
> way to increase the sensitivity of the switch other than reducing R1? 

If that is all you see, I wouldn't worry.  It is just that I saw some
30V signals off one of my Yamaha's and also off a Roland tom pad. 

Keith.

Yow! Do they have any kind of signal boosting circuitry? Speaking of, I had asked if anyone (on DIYedrums) had a link to the gain boost circuit that was

--- In DTXpress@yahoogroups.com, Christopher Todesco <desco@m...> wrote:
> Yow! Do they have any kind of signal boosting circuitry?

No - maybe I hit too hard?

> 
> Speaking of, I had asked if anyone (on DIYedrums) had a link to the
gain 
> boost circuit that was floating around and I never got a response...
I know 
> I could boost it with a powered op-amp circuit, but I coulda sworn
there was 
> also a passive booster. Know of any?

You cannot boost without gain and gain needs power.  You could
possibly resonate with a tuned circuit, but I cannot see that being a
good idea.  If you want an opamp circuit I can post one, although I
would have thought you would be able to tweek the module to get some
more gain.  What module are you using?

Keith.