Nurse Quacky - again LEDs problem

[matej_mlody]

Yesterday I finishing my nurse quacky effect and I have problem with LEDs. Effect working to clean, but not quacky. I found very much posts in forum but I don't found response to my problem.  What's type LED I must use? What size ? What power? maybe color... and... Must I use resistor ? What if I need it?..
Sorry my english is not really good I hope to I get really helpful response. Greetings from Poland

[matej_mlody]

Yesterday I finishing my nurse quacky effect and I have problem with LEDs. Effect working to clean, but not quacky. I found very much posts in forum but I don't found response to my problem.  What's type LED I must use? What size ? What power? maybe color... and... Must I use resistor ? What if I need it?..
Sorry my english is not really good I hope to I get really helpful response. Greetings from Poland

UP

[daverdave]

I built this a few years ago and it worked pretty well, what layout are you using?

Think I used 3mm standard red leds, they worked fine.

[deadastronaut]

hi .i built the nurse quacky a while ago too...standard 3mm 'red' leds did it for me.

i got it to wah (quack) but it didnt quack on the b and e strings.....it wasnt sensitive enough for my liking..

nice bit of fun though..i ended up boxing it up with a fuzz just so it didnt go to waste......

rob

[Mark Hammer]

Yes.  Use red.

[matej_mlody]

I used the layout from http://www.generalguitargadgets.com/pdf/ggg_nurse_quacky.pdf . I must use 3 mm red leds? I have 5 mm and leds lights but I dont have wah effect. Tommorow I will buy 3 mm and check it. Thanks for responese!

[Mark Hammer]

Yes, use red.  Different colors of LED have different forward voltage.  Red has the lowest.

[matej_mlody]

I change 5mm led to 3 mm red and not working. Sound is clean but not qaucky. I give several photo, maybe somebody look for mistake If you can check.. I will be really grateful.

[Mark Hammer]

1) Measure the AC voltage on the output of the rectifier op-amp before the second LED.  This will confirm that you have a proper audio signal.  It should be more than 1.5v when the Sensitivity is turned up and you strum hard.  Now measure on the other side of the LED.  You will have less voltage, but you should see an appropriate change in voltage when you strum.  If not, then you may have a problem with the LED.

2) To confirm the filter works, turn the sensitivity down all the way, and replace the 47k resistor to ground from the two .0047uf capacitors, with a 50k-100k variable resistor (pot).  Feed the Quacky with an audio signal, and change that resistance around.  It should produce a change in the filtering.  If it does, that means your filter path is okay.

If it seems that your filter path is okay, and the rectifier is producing a suitable voltage, then maybe you have the transistor oriented the wrong way.