Schematic Questions

[Mackguitar92]

Hey guys, quick question on this schematic.

http://www.smallbearelec.com/Projects/ReverbPedalSchematic.pdf

What does the "SW" and "REF" mean that are coming of some of the connections/components?

Thanks

Mack

[CynicalMan]

REF is the reference voltage for biasing the op amps. It's made by the 1M/1M voltage divider on the bottom left and buffered by an op amp.
SW connects the bypass switch to the CMOS LED driver stage on the bottom right.

Just wire all of the pins marked REF together, and wire all the pins marked SW together.

[Mackguitar92]

Thanks Alex.  This really clears things up.

[charmonder]

In that diagram, is the CMOS part just there to turn the led on and off? Is this a type of millennium bypass?

[slacker]

Yeah it's a variation of the mil bypass.

[CynicalMan]

It's close to the Millenium C, but not identical:
http://www.smallbearelec.com/Projects/ReverbPedalSchematic.pdf

When the effect is on, the leakage of the 1N914 diode pulls up the voltage on the inverter input, making a low output. Because the LED is connected to 5V on the other side, this makes it light up. When the effect is bypassed, the switch connects the input of the inverter to the 100k resistor. This makes the input low, so the inverter has a high output, making the voltage over the LED close to zero.