Hi Alfonso,
the piezos in my SDS9 pads have a diameter of 28mm an a capacitance of 13.8nF (13800pF).
You should replace the piezo with one of the original size. A bigger one will give you a "hotter" / more sensitive output - something you probably don't want (or you use a voltage divider / pot to adjust the level, should work too).
I use the SDS9 pads with an Alesis Trigger I/O (a trigger to midi interface) and even so you can adjust the sensitivity level, the 28mm piezos are probably just a bit to "hot" for the Alesis.
A lot of DIYers buy they piezos at Conrad Elektronik. They might not be the cheapest source but they have a nice selection of piezos.
regards
Jan
--- In Simmons_Drums@yahoogroups.com, "alfpaches" <alfpaches@...> wrote:
>
> Hi, list!
> I'm thinking of replacing some of the piezo triggers of my SDS9 pads. I'm not sure if any piezo trigger can serve this purpose. So, any advice is welcome.
> Thanks in advance
>