As explained in this thread, one must add a 1Mohm resistor across C83 to fix the snare delay. However, when building the Extra 9, there is not enough space to add the resistor on the backside.
Because the space on the upper side is equally rare, I thought about soldering the 0.1uF cap together with the 1Mohm resistor to a piece of wire, which then goes to the C83 pads. But this seems very messy. I would have to stick the components down with some tape.
Are there any other solutions?
Extra 9 and Snare decay fix
You may be able to fit both on the component side.
I use a larger sized .1uf cap like a green myler from Tayda/eBay then solder a 1/8w 1Mohm resistor in parallel. I then form the leads of the cap to make it fit the foot print. Nice and neat and will not compromise space.