Wiring rate LED as Bypass LED

[Locrian99]

Hey guys,

I built this. 






On my test bench since power goes to the circuit whether its bypassed or not the rate LED is always going.   I want to keep the rate thing going with the LFO rate as it does but use it as my regular LED.   I use a little PCB for my 3pdt wiring, if I connect the ground from the Rate LED to the ground pad for the led on the 3pdt PCB should it still keep the LFO going but not be on when the pedal is bypassed?  I suppose I could just try it but want to figure it out if its going to work before I do all the drilling etc and the 3pdt wiring is usually the last thing I do. 

Thanks   

Thanks

[GibsonGM]

Yes, it should work if you use the switched terminal of the 3PDT.  You should be able to confirm it without soldering it by just jumpering a wire to that terminal after it's all built except for the rate LED gnd...

[ElectricDruid]

+1 agree with Gibson.

If you've got a "switched ground" on the 3PDT, then you can use that for the Rate LED instead of a bypass LED hanging off the 9V rail.

[duck_arse]

what's driving the led? your circuit dia shows pnp transistors and a negative supply, your layout dia doesn't mention transistor type [and suggests, at best, positive supply].

[Locrian99]

what's driving the led? your circuit dia shows pnp transistors and a negative supply, your layout dia doesn't mention transistor type [and suggests, at best, positive supply].

The circuit was altered from the original schematic to use npn transistors.  I'm not 100% positive but I believe the output voltage from the base of q3 is driving the led.   But I could be wrong. 

[duck_arse]

draw the circuit. be sure. get it right, be happy.

[Ripthorn]

I just recently did a project where I used a common cathode RGB LED where one color is solid on for bypass and the other color is for rate so that the LED is off when bypassed and blinks from red to purple in time with the LFO.

[Locrian99]

I just recently did a project where I used a common cathode RGB LED where one color is solid on for bypass and the other color is for rate so that the LED is off when bypassed and blinks from red to purple in time with the LFO.

I think I have some of those, that sounds pretty cool.