I was looking to build this snare/tom module, unless someone can recommend a better one? On the layout it calls for 3 “CBE.” Can someone tell me what that is? My other question is should the volume pots be “A” instead of linear “B?” Finally, my last question…what do the white squares outlined in red mean?
Thanks!
the white squares with red mean a cut/break, CBE is the Collector, Base and emitter legs of a Transitor, The pots probably would be better as log (A) type but having not built this i wouldn’t like to be definitive on this point 
Speaking of Log pots, in one of the early iterations of the Function Generator I just made I found out I was using them the hard way! I’d forgotten or not looked at what I’d ordered ages ago, and then was only getting any change in the timing at the very bottom of the swing. Of course I went to my programming first, but it pays to keep track of which kind you have and are using.
we’ve all been there! 
So is all this schematic is saying is that the 3904 transistors will be placed in the position the CBE icon is facing and that 1 of the 3 legs will go on each rail?
The term CBE implies an order. Install the transistors so that their three legs are in the order specified.
Most transistors are constructed in a way that makes the identity of the three legs (CBE, Collector, Base and Emitter) obvious but do ask here if you need help identifying them.
Correct.
The reason they spell out the pins might be that the 2N3904 is commonly replaced with BC547 (which is easier to source in some parts of the world), and that has the pins the other way around.
EDIT: “is easier” should be “used to be”. It’s 2020, after all 
I ordered some sliders. They were sold as “10K Linear Potentiometers”
Could not get my circuit to work reliably…
Guess what, they may have been linear in motion but not in resistance!
I had that ordering "2 way faders " and got singles that the seller explained ‘move 2 ways’.
You have to laugh. (Well I do or I break things)
Hmmmmm am I missing something here? It looks to me like the TL072 would be referenced from ground up, meaning that the output will be offset to sit above 0V.
Am I right? Gosh it’s a tight squeeze little stripboard layout!