Nevada wah

[bossa]

Hi All
Got myself a Nevada wah , solid build really heavy ...but the wah sound is practically no existent  .Any distortion in the chain and it might as well not be on. I thought it might be crap but it cost me £20 and figured I could use the case at least. Should I just gut it and bung in a board from GGG or is there something I can do? Will try and get a gut shot.

[John Lyons]

Most Wahs are based on a very common schematic.
Download a schematic for the Vox Clyde McCoy from Fuzz central and compare it to your wahs circuit board.
Also take a look at the Technology of the wah article at GEOFEX above.
These will get your started. There is no reason the board you have can not be made to sound good.

john

[bossa]

Hi John
Thanks for your reply. Being a total noob schematics make me scared. So in theory I could do something with my board then ? I will have a look at those links. I was going to go for the the BYOC or GGG boards , I guess thought it would be easier for me. I even saw a complete original drop in board by Dunlop for $24 http://www.jmimusic.com/products.php?pg=8  ...but I think that would be a total cop out.  This was an attractive option as the mods/instructions to make the original board better are online.

[Johan]

that board looks identical to the Carvin wha I got a while back, and the wha probably suffers from the same basic problem.
check the SIZE of the gear on the pot!!!!..on mine, the gear was much larger than usual, meaning a much smaller portion of the pot-rotation is used...meaning less wha effect..change the pot and you'll have a basic VOX wha with an input buffer built up by two 2sc1815 connected as a darlington pair...
with the original pot it sucked, but changing to a pot with a proper gear, it's quite nice...

j

[CodeMonk]

I may be incorrect here (someone please tell me if I am cause I have the same sort of problem)...
But I think what is needed is to add an output buffer to the wah pedal.

[earthtonesaudio]

I may be incorrect here (someone please tell me if I am cause I have the same sort of problem)...
But I think what is needed is to add an output buffer to the wah pedal.

Well, that would be one of the easiest things to check at least (easier than changing a battery!)... just stick a buffered-bypass pedal after the wah and see if it makes it better.  Or plug the output of the wah into a high impedance input (like a tube amp).

[Johan]

I may be incorrect here (someone please tell me if I am cause I have the same sort of problem)...
But I think what is needed is to add an output buffer to the wah pedal.

..no...it's simply a case of the same old China copy story..geting close but not being carefull with the details and missing the mark..

the one on the left is an old crybaby pot, the one on the right is the China-pot...do you see it...it's like starting on a slope in fifth gear...the circuit is a buffered VOX..change the pot and you have a good wha..
j

[CodeMonk]

I was more referring to the lack of wah sound when there is distortion in the chain.

[bossa]

I get a wah sound but its pretty slight when clean and with a Big Muff its hardly noticeable .
@ Johan  I just measured the gear and it 15mm across how does that compare ?

[R.G.]

Given that the circuit is similar to the stock wah, you can make it do almost anything, including sit up and beg.

If you can , take good, high res photos of the top and bottom of the PCB for reverse engineering, and some of us will be able to tell you what to do in the form of 'Take out that resistor there, and put in a new one of this value.'

[Johan]

I get a wah sound but its pretty slight when clean and with a Big Muff its hardly noticeable .
@ Johan  I just measured the gear and it 15mm across how does that compare ?

yeah, the China gear is about 15mm..the hotpot gear is about 12.5...if you want to confirm what I say, pull the pot out without disconecting it. then turn it by hand to its end position with the wha engaged...it's the gear ratio, not the circuit, that is the problem...
j

[bossa]

I get a wah sound but its pretty slight when clean and with a Big Muff its hardly noticeable .
@ Johan  I just measured the gear and it 15mm across how does that compare ?

yeah, the China gear is about 15mm..the hotpot gear is about 12.5...if you want to confirm what I say, pull the pot out without disconecting it. then turn it by hand to its end position with the wha engaged...it's the gear ratio, not the circuit, that is the problem...
j

Johan
Yeah I just tried it and it makes a big difference it actually wahs ( picks up the radio when I touch it too  )...which pot would you recommend ?

[Solidhex]

Yo

  Looking at the board it seems it already has a buffer. The usual wah has 2 transistors, you've got 4. Everyone is right about changing the board out. Its not necessary. Put some nice caps in there. Change some resistors to your liking. Wah pot is probably pretty crappy.

--Brad

[bossa]

Hi Guys
Just an update. I just changed the pot on this wah to a Blacktop pro wah pot. The gear is definately smaller to the original. Unfortunately the improvement in wah is minimal  . Clean there is a definite improvement also with a screamer, but with the Big Muff it barely wahs . The wah is last in the chain (first into the guitar).My set up is a 76' Strat into a Traynor 100 watt YGL- 3A MkIII  and 2x12 speaker cab .
Any advice on which caps /resistors I should change ..is there a need to change the inductor maybe ?

[Pedro Freitas]

Have you tried it after the BigMuff? Like in,  Guitar -> BigMuff -> Wah -> Amp

Pedro

[bossa]

Have you tried it after the BigMuff? Like in,  Guitar -> BigMuff -> Wah -> Amp

Pedro

Hi Pedro

Yeah I tried that , as the wah sound goes its louder but the actual wah kind of dies , as the treadle moves down two thirds of its travel you expect it to wah but there is really nothing . Also there is a lot of extra distortion at the beginning of the sweep (not from the Big Muff ).Unfortunately I don't have mic other then a crappy computer one ...maybe I can do a clip. Sorry its hard to describe

[Jered]

  If you do decide to change the inductor, I strongly recommend a Whipple. They sound every bit as good as the guy claims they do. He sells them on ebay $25

[Paul Perry (Frostwave)]

Bossa, you say it wahs when you tweak the pot over the full range by hand, is the wah sound OK when you do this?
Because if it is, then the problem is that when the unit is assembled, the pot is moving through the 'wrong' part of the range. It is critical to have the rack and pinion together and the pot oriented 'just right'.

Another thing, sometimes the centre frequency of the pot/cap combination is a bit off (after all, they might be using 20% caps!) and it could be, if you try out various caps, you might get the unit to operate over a range more appropriate to your playing. (the pot in parallel with the inductor is the one I mean.)

Replacing the inductor isn't the FIRST thing I would try, sure you can possibly get a better TONE doing that, but if it isn't already wahing, then it isn't going to suddenly come alive, even with a $25 inductor.

A non-wailing wah is depressing, but I am sure it will eventually go, and in the mean time we will all be learning..