Snarkdoodle / Tube Sound Fuzz unused IC pin for LED

[Bored]

Sorry if this is not the right section for this question, but if we get an answer it should go here.

Anyway-
A few years ago I ran across a layout for the TSF/Red Llama that used one of the unused pins on the IC as an LED indicator control. I read reports that it worked well, but for the life of me I cant recall where I saw it. 

Does anyone know what I'm talking about?

[madbean]

Haven't seen it. The un-used input pins are grounded on the Snarkdoodle, though.

[Thomas_H]

Hi Bored,

just following up the discussions here and came across this thread.

As the 4049 is just an inverter surely it can drive a LED. See schematic.
Feeding the audio signal from Pin 4 of the 4049 IC via a 270k resistor will make some nice light effects.
(I couldnt help and actually tried this on my Snarkdoodle using the Inverter on Pin 14/15)
I also ordered a bicolor LED to have a common On/Amplitude indicator :-)

If you have socketed your IC you just need to pull the respective pin from the socket and solder directly to the pin - this is some very ancient technique used by us computer cracks when I was young :-)

hope this helps
Thomas

[Bored]

Cool, I'll give it a go... thanks!