Indicator LED fades off REALLY slow...

[Phorhas]

Hi,

I rewired an old DIY effect of mine and I've noticed that when puuling out the plug from the stereo jack the LED doesn't shut off at once but fade slowly away... about 10 seconds until it's totally dead. the board is not yed wired to the box - just LED, switch and battery

What's going on?

[gez]

Most likely a large capacitor across the rails?

[Phorhas]

well, that's what I figured but I never saw a LED fading for 10 seconds or more...

[Mark Hammer]

If the LED doesn't need much current to glow brightly and the power supply smoothing cap is big enough to store a fair amount of current, and the circuit doesn't eat up much current either, that cap can easily power an LED for a while.  I've seen 5sec+ fade-out times on lots of appliances at home.

[petemoore]

  I built a DIST+, using both sides of a dual OA for the gain stage [piggybacking was easy, just parallel all the inputs and outputs...thanks to Pharoahamps for that method of Dual IC usage] !!...
 Anyway I used a BFC to filter the power supply, a 330uf/100v, and a 47uf 25v for the Vref.
 I thought I'd made a mistake, but watched the voltage slowly rising on the In/Out pins of the opamp upon second power up [after debugging / nothing]...it takes the circuit about 25 seconds to 'warm up' [fill the big caps] to where signal passes, longer for ungated sound and close to 1/2v readings on the mentioned OA pins.
 ///Sounds great and has an NPN Ge Driving it....
 Instead of rehousing my RM and DIST+...because they sound great for me these days w/ [setup], [I didn't want to disturb them...they work great, I just didn't like the look, two boxes, and the switches] I just built this thing, very similar, but in nicer box with EZ Stompswitch/switch/controls