Sound 2 Light circuit built into fuzz

[StanleyDuke]

Hey guys, so I'm in the process of hooking up a signal reactive LED to a fuzz circuit I just built (buzzumble from Five Cats Pedals). I've bought the LED pictured from eBay, because I want it spiralling inside a glass tube to imitate an old filament bulb. I'm going by the Sound 2 Light circuit by Deadastronaut. My question is simply what resistors am I going to need for these LEDs running through a 9v battery? The circuit will be coming from the output of the fuzz circuit, will that have much effect on voltage?

Thanks!

[antonis]

It strongly depends on LED current..

CLR = (V_CC -V_LED) / I_LED

Supposing +9V for V_CC and 3V for V_LED, you conclude in CLR = 6 / I_LED

[MrStab]

What's the output impedance of your fuzz? Input resistance of LM386 is rated at a mere 50K-ohm.

[StanleyDuke]

It's based on the Third Man Bumble Buzz which is Input impedance: Zin @ 1KHz 30K / Output impedance: Zout @ 1KHz: 33K. I'll check on my one tomorrow to make sure.

[StanleyDuke]

Ok so I have 2 of the LEDs hooked up to the S2L circuit and looking beautiful, but my problem now is they're just constantly on whether or not the fuzz circuit is on (I'm building this all into my guitar btw). Now I'm wondering if my 9v power cable is going to the right place. I've wired the fuzz circuit into my guitar just as if the signal chain is Guitar>fuzz>output. I suppose I'm asking where I need to place the S2L for it to turn on/off with the 3PDT switch and not be constantly powered. Ignore the fact that I'm hacking into a Les Paul, I'm going to clean up all the routing work soon 😂