L.E.D fader

[Zanius]

I wanted to have a momentary button that would maximize my tremolo speed. I tried just putting the switch across lug 3 (speed) and lugs 1&2 (ground) but the fast sweep felt un-natural, I wanted something smoother. So I found a little circuit making your led fade in and out when powered, used it with an Ldr and voila! Perfect, totally controllable sweep. Tried it, been very happy, shared!



Also thought I should try this for on-box leds, it is cool to have your indicator fading :)

[Travis]

That could potentially be pretty interesting on a delay :0

Thanks for sharing

[BuGG]

As an added bonus, gradually increasing/decreasing indicator LED brightness eliminates LED pop in the signal path.

[Frank_NH]

Interesting.  I was just looking at at similar circuit today from The Analog Alchemy collection:

http://www.diystompboxes.com/analogalchemy/sch/ledtrick.html

Using a transistor to turn a LED on and off gradually would indeed help eliminate the pop.

Also related - I was repairing a BOSS-style tube screamer pedal and had the opportunity to review the flip-flop circuit used to activate the pedal using a momentary switch (see below).  JFETs are added to key points in the audio path to activate or bypass the effect.  Note the zener diode used in the LED circuit (pop protection?).  Seemed like an easy circuit to experiment with, and may do so on the breadboard.  It's more parts than a relay-based momentary true bypass, but hey it's only transistors!