Hello Sam, seasons greetings.
The pad with the grey "O" inlay is the snare pad. It contains 2 piezos for rim and head. Use a stereo jack (like on headphones) cable to get the effect, a simple mono guitar type cable will not work.
In the SDS 8 pads are resistors (1k) soldered inside to the jack output sockets. You have to remove these. This is tricky: Remove the 6 staples you find under the rubber "rim" of the pad without breaking anything (kitchen knife is good for that), then the shell falls off. Locate the jack output and cut away the resistor. Re-assemble the pad. Then everything will be fine.
If you need to play an SDS8 / 800 later, you can apply the resistors in the jacks of the cables and you have all possibilities then.
Best
Michael
The SDS8 pads (or perhaps SDS200/400/800) are difficult to trigger, even with sensitivity turned all the way up. Is this because of defect, or are they electrically different than the SDS9 pads, and not very suitable for use with the SDS9? The resistor, I suppose.
If they are defective, I should like to restore them, however, if that is normal, I’d like to keep them stock, as plan on picking up a SDS8 or SDs800, as I think it will better suit my needs.
Thanks,
Sam