Boss CE-2B

And I may as well add this one as a separate layout so we know what versions the comments are based on.  This changes a cap value and adds an Effect Level pot to the CE-2.  If you want to add an Effect Level pot to the guitar CE-2, just use this layout and swap the 12n cap to the left of Q3 for a 33n.  Or if you want the option of using both, use a DPDT on/on toggle like this:

1---4
2---5
3---6

Solder a 12n between 1 and 4, solder a 33n between 3 and 6, and connect wires 2 and 5 to the holes that the 12n should have connected to on the board.

This obviously isn't yet verified but it's so close to the guitar version that it will be good to go.

The BOSS Bass Chorus CE-2B is designed specially for a bass guitar, giving you the best result when used with a bass guitar.

The Rate, Depth and the Effect Level knobs serve to create various chorus effects.