My wah is not wahinng!!

[crawler486]

I built a wah wah effects found in this site :
 http://www.generalguitargadgets.com/v2/diagrams/wah_original_lo.gif

I etched my pcb, bought the components and solder it into place.
BUT , its not working.  I cant get no wah out of it.

Here something to help u guys to help me me debug.

- MPSA18 transistor is not available so I bought MPSA13.
- I cant get a 500 mh inductor so I bought  an Audio Transformer
 but I dont know its value. (the store clerk have no idea).

Please help me guys. I'm getting frustrated. Ive spent so much effort
of this..


[/img]

[gez]

I cant get a 500 mh inductor so I bought  an Audio Transformer but I dont know its value. (the store clerk have no idea).

You've just answered your own question.  Maybe it isn't this, but you can't expect a circuit to work by slapping in any old part.

Do you have a scope?  If so, you can measure the transformer's inductance.

PS  It would help more if you linked to the schematic not the layout.

[Ansil]

I built a wah wah effects found in this site :
 http://www.generalguitargadgets.com/v2/diagrams/wah_original_lo.gif

I etched my pcb, bought the components and solder it into place.
BUT , its not working.  I cant get no wah out of it.

Here something to help u guys to help me me debug.

- MPSA18 transistor is not available so I bought MPSA13.
- I cant get a 500 mh inductor so I bought  an Audio Transformer
 but I dont know its value. (the store clerk have no idea).

Please help me guys. I'm getting frustrated. Ive spent so much effort
of this..


[/img]

i got two 500mh inductors in the mail  would you like to get one

[crawler486]

I built a wah wah effects found in this site :
 http://www.generalguitargadgets.com/v2/diagrams/wah_original_lo.gif

I etched my pcb, bought the components and solder it into place.
BUT , its not working.  I cant get no wah out of it.

Here something to help u guys to help me me debug.

- MPSA18 transistor is not available so I bought MPSA13.
- I cant get a 500 mh inductor so I bought  an Audio Transformer
 but I dont know its value. (the store clerk have no idea).

Please help me guys. I'm getting frustrated. Ive spent so much effort
of this..


[/img]

i got two 500mh inductors in the mail  would you like to get one

Does it have to be the an exact 500mh for it to wah?
Im here in the Philippines. I'm not sure how to get your inductor.

If all still fails. Do you know another type of simple Wah circuit that doesnt
use inductor ?

[Alpha579]

The idiot wah by tim (Escaped??? cant remember hos last name :oops: ). Its had a lot of praise. Its a simple dalington booster with a twin t wah in the feedback. http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html ull have to scroll down the page a bit  :wink: ...

[Joep]

Try other transistors, like 2N5088, 2N5089, 2N3904, BC54x, BC550. Maybe not optimal, but better that the MPSA13 which is a darlington.

Also the audio transformer might not work, or not work optimal. Make sure you use the right wires.

Also check this excellent article: http://www.geofex.com/Article_Folders/wahpedl/wahped.htm

Bye,

Joep

[crawler486]

thanks guys. cant wait to have a crack at it again after office.

[crawler486]

Try other transistors, like 2N5088, 2N5089, 2N3904, BC54x, BC550. Maybe not optimal, but better that the MPSA13 which is a darlington.

Also the audio transformer might not work, or not work optimal. Make sure you use the right wires.

Also check this excellent article: http://www.geofex.com/Article_Folders/wahpedl/wahped.htm

Bye,

Joep

Hi Joep,
   How do you determine  replacement capacitor?

[gez]

Crawler, do you know the serial number and make of the transformer you used?  It maybe that someone here knows whether it's suitable or not, in which case it can be ruled out/in as the cause of your lack of wah.

Twin-T won't sound the same, but it's a good compromise.  

I think Small Bear sell inductors.  I don't know what Steve sells them for (if he does) though they tend to be pricey just about everywhere.

[Joep]

How do you determine replacement capacitor?

What do you mean by this? A capacitor always must be the same value. Types like ceramic, mylar, polyprop etc are interchangable, but can have (subtile) differences in sound.

Joep

[crawler486]

How do you determine replacement capacitor?

What do you mean by this? A capacitor always must be the same value. Types like ceramic, mylar, polyprop etc are interchangable, but can have (subtile) differences in sound.

Joep

I mean replacement transistor. Like what transistors can replace MPSA18.
How do u determine if one transistor will work as a replacement if the required is not available

[zener]

I always consider wah as my toughest build.

[smoguzbenjamin]

SBE sells inductors for sure, at a reasonable price. The transistor, as Joep said, might also cause a problem.

[zener]

If all still fails. Do you know another type of simple Wah circuit that doesnt
use inductor ?

http://www.morleypedals.com/schem.htm

These op-amp based wah may not be as good as those inductor-based.

Check your PM

Zener

[smoguzbenjamin]

Check Tim Escobedo's idot wah by the way, that's a good example of a twin-T wah:

http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html#idiotwah

[Transmogrifox]

Well...whether you like the inductorless wahs more or less is all a matter of opinion.  I tend to think the crybaby/vox/classic inductor wah is a little limp, lacking in range.  They tend to pull a little more "wah-wah" out of your guitar signal, whereas a wah that goes higher and lower in range usually produces a little more "wow-wow".  So...it's worth trying everything to see what you like.

I recommend trying some more transformers and inductors.  Try things like connecting the transformer coils in parallel and series.  If you play through your wah pedal and it seems very treble-ey, or no effect at all, you probably have a "too small" inductance, then connect the transformer coils in series and see if anything changes.  If it is very bass-ey, or very low signal level output, you likely have too large of an inductor, then connect the coils in paralell---try uniform polarity once, then opposing polarity.  This will change things as transformers are mutually inductive.

To be sure it's the inductor, take the transformer/inductor completely out of the circuit and play through it, working the pedal or pot or whatever.  If you hear a bit of a volume swell effect happening, the circuit itself is fine, and its just the inductor, if nothing happens, or if strange things happen-- you have other problems to work out first.  Always check your traces .  As a rule of thumb, it is good to just run a pocketknife blade gently between all the traces, taking a little dust off the board, just to make sure there aren't any small metal bridges that you can't detect with your eyes.

I was chatting with a guy while he was fixing an old analog synth and he just couldn't figure out what was wrong. He handed the board to me and asked me to examine the traces to see if I could see anything not right.  All of it looked absolutely great, except for some small solder splatter between a couple traces--which you would think wouldn't do anything--but he decided to run a blade between there just in case, and sure enough, it worked.

[crawler486]

Thanks guys! I appreciate all your response!
ROCK ON!

[WyldeSnake]

Bump, because I have a question too

I'm a new guy here, but this place looks hemma tight for information.  Anyways, I'm an electronics geek and I've been real interested in buildin pedals/efx for a while.  I built a crybaby-clone for my brother a while back, but I ran into one major problem:

It sounds great.  By spinning the pot it wahs like a champ.  The problem is, you have to turn the pot with your hand.

Anyone know where I can get a good wah shell with all the mechanical parts?  I'm really pretty useless with mechanical stuff, but that's all I need to get this wah workin great.  I'd really like to finish it up properly so my bro can actually use it.

Thanks for the time