Remove all screws from the back cover and
disconnect the battery connection (indicated by the red arrow).
The back will then be totally removed form the unit. (click image
to enlarge)
The lines indicate where you will need to splice
into. You can use
Telecom Tap Conn-ub connectors. Or you can do what I did and remove
some insulation from the wires you need to splice into. Wrap and solder
the lead wires from 1/4" jacks.
(click image to enlarge)
The 8" wire length I used gave me just enough
room to install the 1/4" jacks in the bottom cover. You would have more
room to work with using longer wires.
I now have created a Yamaha DD-55 drum module. I connected one of my DIY
mesh head Drums to the Yamaha DD-55 for testing. I was very surprised at
how well it triggers since the unit seems to have only one
trigger adjustment for Pad sensitivity. You could probably find one on
EBay cheap.
Update: I connected the Yamaha to my drum kit to
see how well it would work and here are the results.
All the DIY drums worked great. I had to lower the volume setting for
the 12" tom to 3. The 10" toms and snare set to 9.
The pad sensitivity is set to the highest setting. There are only 3 to
pick from and that setting controls all pads at the same time.
I had to kick the Roland KD-8 a little harder than normal to get it to
trigger. It would be nice if there where individual sensitivity settings
for each pad. If I could turn up the sensitivity a couple of notches the
kick pad would be perfect.
Same goes for the Roland Cymbal Pads. If I use one of the mesh head
drums for a cymbal then it triggers fine.
The closed Hi-hat was a little quiet. Open hi-hat is normal. The click
when you push down the hi-hat pedal is loud. Maybe that's normal. I
could never hear it with my TD6 module.
The only pad setting the Yamaha have are the individual pad volume
setting and the overall pad sensitivity setting.