For a while I didn't know where to post this exactly, but I've chosen Effects. Anyway, here goes.
A couple of weeks ago my singer/guitarist who likes DIY stuff, decided to put an EHX Double Muff Nano under a Jazz-type bass' pickguard.
We dug almost all the area in front of the control plate, as you can see in the pics. Wired from the tone straight to the input of the pedal and from the output of the pedal to the output jack of the bass.
We connected the battery straight to the power supply in, because if we put it normally, we would need a jack inside the pedal's input.
Drilled holes in the pickguard and we even cut the horn, so it can be unscrewed to change the battery.
After we finished it, we thought of what we could have done better. One would be to use a stereo jack, like active basses, instead of using a toggle-switch to cut the power.
A second one would be to find a way to change the 9-pin footswitch with a similar toggle-switch, but we're not good with electronics so didn't know how to do that.
The pedal sounds great. Didn't know that the Double Muff retains all the low-end.
Here are the photos just to know that I'm not lying.