on off

[teamastra]

i've built a feedback looper and i used a led and 9v battery. i'm now going to build an A - B Switcher and want to use an LED on each channel. I want to build the pedal  so that the led's only work if leads are plugged into the box.

does anybody know how to do this?, i reckon i need to use a stereo socket so that when a mono jack goes it the circuit is complete but do i then need to use a supressor to avoid mains hum?

[expanoncolin]

i've built a feedback looper and i used a led and 9v battery. i'm now going to build an A - B Switcher and want to use an LED on each channel. I want to build the pedal  so that the led's only work if leads are plugged into the box.

does anybody know how to do this?, i reckon i need to use a stereo socket so that when a mono jack goes it the circuit is complete but do i then need to use a supressor to avoid mains hum?

Get a stereo jack - wire the "ring" conductor (that is, the one that isn't on the mono jack) to battery - .  Then, when you plug in, the battery minus will connect to ground, completing the circuit and allowing the LEDs to light.

-Colin

[salocin]

If I'm not mistaken, you need to make sure you connect it to the 'ring' (not on the mono jack) or else the led will still light. Think I made that mistake on a recent build.

[expanoncolin]

If I'm not mistaken, you need to make sure you connect it to the 'ring' (not on the mono jack) or else the led will still light. Think I made that mistake on a recent build.

I'm pretty sure we're just misunderstanding each other - that's just what I meant.

-Colin

[crochambeau]

Perhaps I'm over thinking this?

Having just the battery switched will allow both A & B LED to light even if a lead isn't plugged into one channel. You could wire the LED ground for each channel through the stereo plug on the output side for the corresponding channels (in the way described above) and the battery power to the stereo plug of the input side. That way channel B LED will not light if nothing is plugged into channel B, etc, and the device will be unpowered if nothing is going into it.

[expanoncolin]

Perhaps I'm over thinking this?

Having just the battery switched will allow both A & B LED to light even if a lead isn't plugged into one channel. You could wire the LED ground for each channel through the stereo plug on the output side for the corresponding channels (in the way described above) and the battery power to the stereo plug of the input side. That way channel B LED will not light if nothing is plugged into channel B, etc, and the device will be unpowered if nothing is going into it.

Sounds like a good idea to me.

-Colin