Nurse Quacky

[Lonehdrider]

Ok, I've read all the search hits on Nurse Quacky and I know its finicky... But man... The nurse is going to need a nurse is she doesn't straighten up pretty soon. The details. Dim glow out of the one LED by the chip as is supposed to happen. Other light follows the signal, and after dicking with it tonight I've getting relatively good signal out of it. So far great. NO QUACK... I'm used the values that are supposed to be used, the chip I'm using is a 778A (I think thats the right number, I did look it up) its an equivelent to a 1458 in the NTE line (Which I know aren't the greatest, but I've had no problems with them before working and its easy to find at Frys). What specific part of the circuit should I look at that controls the quack? I've been over the wiring time and time again, and I must say its the cleanest prettiest perf job I've done, but this effect is really beginning to quack me off.
Any idea's and things to check are appreciated. Thanks guys.

Regards,


Lone

[B Tremblay]

Are you absolutely sure that the transistor type and orientation are correct?  Re-check the wiring of the Attack and Range pots.  An error with either could prevent the envelope signal from reaching the transistor.  Since you're hearing signal with no wah, I'd look around those areas.

[Mark Hammer]

Disconnect the transistor from the junction of the two caps in the filter section and replace it (temporarily) with a 100k pot, wired as a variable resistor.  Sweep the pot and see if you get a wah of appropriate volume.  If you do, then the "problem" lies somewhere between the output of the envelope follower and the transistor, and is most typically going to be a misoriented transistor.  Next down from that is probably a mis-tweaked or bad trimpot.

Geez I wish I knew this stuff 15 years ago!

[Lonehdrider]

Thanks guys, appreciate the help, I'll give it a look see and try the suggestions. Thanks again.

Regards,

Lone

[Lonehdrider]

Update: Well I tried the suggestions, I disconnected the transistor, hooked up a pot and got wah while working the pot. So I double checked the transistor orientation. It still was'nt working. I was putting together a "Uglyface" to get my mind off it and I got to thinking, hey if nothing else, I got a pretty LED that IS following the signal and hey push comes to shove I'll put a LDR type setup off of it and controll the variation that way instead of using the transistor. Well about this time I had snagged a pot off the N.Q. to use on the Uglyface, the range pot to be exact. So this morning I hook up the pot again and I'm about ready to test my LDR theory on it and I'll be darned, it quacked like a big duck!!!! I was jazzed, after trying to build this effect for the third time I was discouraged, but in the end it must have been I had the wires crossed on the range pot. So now I've got a hammond box all ready to box it up, I'll get a switch or two from Aron and box this puppy up. I have an idea for the graphic, white box, a big red cross where the push button will go and a female cartoony duck with a nurses hat on... Should be cool if it comes together, if it does I'll show a picture. Thanks again to those that helped me, it restored my confidence that I can actually build something outside of a distortion or booster with 6 parts in it. I may just have to tackle a easyvibe or something next. My other guitarist came over today and I showed it to him, Dan's pretty cool, anything he likes he calls "Frightening", he says, Thats 'Frightening' I like it. Anyway, thanks guys, appreciate the help.

Kindest Regards,

Lone

[Transmogrifox]

Great to hear it worked for you! I'll have a good beer on your behalf this afternoon.

It was actually pretty exciting for me the first time I got something other than a distortion working.  I'm looking forward to seeing your pix of the finished product.  It sounds like you have some good ideas.

[Mark Hammer]

It's always dumb stuff, isn't it?

On the one hand, it makes you think "I'll NEVER get anything to work if I make mistakes this boneheaded".   On the other hand, boneheaded mistakes are easily reparable, and you can easily learn to keep an eye out for them, or know to look for them when troubleshooting.

Living with the embarrassment - even if YOU'RE the only one who knows about it - well, that's the hard part. :lol:

Congrats.

[smoguzbenjamin]

Everyone makes a boo-boo now and again It's human. I gotta make myself a Dr Q! :mrgreen: