Schematics of a footswitch with an indication LED.

[Toxer]

Hey guys!
What is the proper schematics for a latching forthwith with an LED indicator for AXE FX/AX8?

 

[Choral Mist]

What are you switching and what are you using to switch it?

 

[Toxer]

What are you switching and what are you using to switch it?

I have made an expression pedal out of a Cry Baby one. I threw away the wah guts and wired the pot and DPDT button everything according to the schematics attached. Now I want to attach an LED to the DPDT circuit. The LED should indicate whether the switch is engaged or not. It seems like tip-sleeve current is too low to activate the LED, but ring-sleeve seems to be ok. So, is there any proper way the LED should be wired to operate with no external power supply?

 

[Choral Mist]

First, you of course should run everything by FAS tech support before testing anything out on the unit.

Here's a simple circuit to get you started. I assume you're using the "pedal" jack on the AX8? The manual doesn't spec the signals, but I'm guessing ring = +5V (check this), tip = sense, sleeve = gnd. You will need to verify this with FAS and also obtain the max load the +5V can drive--if it can drive an LED at all. Size the resistor to stay below that max load and to limit the diode current to safe levels. Q1 is a PNP signal transistor-- 2N2907 or similar. Also if the tip signal floats internal to the AX, you may need a pullup resistor (between tip and ring).

 

[Toxer]

This scheme seems to be a bit excessive. Having a DTDP in the pedal it is possible to make an easier solution presented at the attached picture.

My main concern was about the ring to sleeve voltage source specifications, it seems they are unknown.
I bet FAS guys made a shortcut protection that limits the ring-to-sleeve and tip-to-sleeve currents, otherwise a TS cable inserted into a Pedal Jack or a simple latching footswitch would kill the device. Nevertheless, I placed two current limiting resistors R3 and R4 for extra security, or for the case of the pedal usage with any other equipment.

 

[Mr.X]

This is what I use for the Axe-FX II.
Very simple.