Two very simple buffers prototype : one based on a 2N5457 J-FET transistor, the other with a Burr Brown OPA 134. No really differences between the two pedal, maybe the one with IC is lightly brighter … hard to say.
- switch on the right is simply Buffer On / Buffer Off (to test with or without ;-))
- switch on the left insert a 6.8k resistor to “emulate” a guitar pick-up. Not a very accurate simulation, but it helps when buffer is in front of a fuzz face, for instance !