Flatline LED problem (pics inside!)

[ianlogan123]

Hi there, been lurking for a while and posted a couple of times. So far I've been tinkering with my Boss pedals (DS-1, GE-7 and SD-1[came up with my own mod!]) and my Crybaby, but recently I've built a Flatline compressor. I used the stripbaord layout found here - http://aronnelson.com/gallery/bcreekmur/flatline_compressor?full=1 - and it works pretty well, although I'd like to have a little more squish at the extreme end of the effect. However, I have a problem with the status LED, in that it seems to be on all the time. The offboard wiring came from a couple of different sources, so it is possible that I got a couple of things mixed up.

I've drawn out a few schematics of what the wiring looks like, and would be grateful if someone could have a look at them to see what I've done wrong. I've included a couple of pictures of the boxed pedal for interest's sake.

In addition, would anyone be able to tell me what the current draw on this pedal is? How long will a 9V battery last for, or should I think about wiring in a DC jack?

Many thanks for any help offered,

Ian.

Here's the almost complete stripboard - all it needs is the IC and wiring up...



All the wiring, ready to go into it's case...



In the case...



And how I stopped the circuit from shorting itself on the case...



First schematic for my wiring. A little bit spaghetti junction...



Then I did it again with straight lines...



And finally I took out most of the wires, as half of them were running to the pots, and were doing so correctly...

[psiico]

You mean the LED in the upper right corner?  The way it's wired it will be on all the time as long as the pedal is getting power.  To make it go on and off either use a 3PDT switch or use the DPDT switch you have with either a millenium bypass or the led trick with an NPN.  That pedal has a 100k pot on the output so the led trick would work.

Here's the led trick:

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

It works with more then just a 2N3904, I just built one with a 2N4410.   I know a 2N5088 or 2N5089 will also work.  Different transistors will likely need a different resistor value.

The millenium bypass is a similar trick but it uses a JFET:

http://www.geofex.com/Article_Folders/Millenium/millen.htm

http://www.geofex.com/FX_images/milltbbx.gif

http://www.generalguitargadgets.com/pdf/ggg_millenium1.pdf

[twabelljr]

One option is to cut a trace and use a 3PDT like this:

Since you already have a DPDT wired up it would definately be easier to try the LED trick first.

[bcreekmur]

Hi Ian.

I used a 3PDT switch for my Flatline to (break/make) the connection from the wire coming off the board labeled LED- to the actual negative side of the LED. Similar to what twabelljr posted in his pic but I use the LED- wire to make or break the connection.

Brian 

[Ge_Whiz]

In almost any pedal that includes LEDs (and this one has two with the status LED), the current draw of the LEDs will be many times higher than the rest of the circuit. In such circumstances, I'd always recommend using a DC jack rather than just battery alone (especially if the battery is just a PP3).

[Mark Hammer]

It bears repeating that using superbright status LEDs can provide the needed brightness levels with much lower current requirements, and accompanying battery savings.

Get yourself a status indicator LED that is rated at a brightness of at least 2500mcd and you will likely be able to get away with a current-limiting resistor of at least 10k and maybe more (I've been able to go up as high as 18k).

The principal is that if it takes 5ma to make one kind of LED provide suitable illumination as a status indicator, and you can find one that provides 10 times the brightness at that same current, you can likely get the same brightness at 1/10 the current with the extra bright one.

[ianlogan123]

Many thanks for all the replies. All taken on board! I'll go and have a think about what to do next and will post some pics once it's all painted and boxed up.

Ian.