Vox Wah Problem

[kyle31]

Ok, I've been modding this wah. I have converted to true bypass, installed whipple inductor, changed r3 (Q) to 68k, and r1 (volume) to 47k. I changed the two .22 caps to better metal film caps just because I had a couple laying around. I have a resistor and trimpot on r2 (mids) and r8 (gain and bass).

I previously also had resistors and trimpots on r3 and r1.

The pedal worked fine yesterday before I replaced the film caps and put resistors in r3 and r1.

Today I plug it in and much to my suprise; I have no wah. It has kind of a volume swell effect. With the toe down, volume is a around unity. With the heel down volume is cut quite a bit.

I've reflowed joints measured resistances, and checked for soldier bridges. I would really appreciate any help on figuring this thing out. If voltages would help just let me know.

[mistercoffee1]

Check the 4.7uF Electrolytic capacitor.  Reflow those solder joints if you haven't already (I wasn't sure if you did all of them, or just those ones where you did mods).  When this goes out or gets disconnected, the wah acts like a volume pedal.  It may need replacing if all the connections are good but it still acts like a volume pedal.

[kyle31]

Well, I took it out and measured it. It still reads 4.7. I put it back in and made sure it was connected well, and it still acts like a volume pedal.

I have a 10uf I'll try, but I can't get another 4.7 until tomorrow.

Here goes with the 10uf...

Update: Changing to the known good 10uf cap didn't change anything. Still sounds like a crappy volume swell.

Any other ideas?

[mistercoffee1]

By the way, did you happen to change the 0.01uF caps (sweep range)?  Are you sure you changed the 0.22uF, instead of the 0.01uF caps?

[kyle31]

Ok, I fixed it. When changing the caps I had broken one of the hot pins on my inductor. I just soldiered a little piece of lead on it, and now it works fine.

Thanks for your help!!!

[mistercoffee1]

Well, I took it out and measured it. It still reads 4.7. I put it back in and made sure it was connected well, and it still acts like a volume pedal.

I have a 10uf I'll try, but I can't get another 4.7 until tomorrow.

Here goes with the 10uf...

Update: Changing to the known good 10uf cap didn't change anything. Still sounds like a crappy volume swell.

Any other ideas?

Congrats on fixing the problem.
Now that it's fixed, consider trying the 10uF in place of the 4.7uF.  This something that Teese does.

[kyle31]

Ok, I'll try it tomorrow and tell you how it goes.

[kyle31]

I decided on the 10uf. It makes the wah seem a little more present, and allows it to cut through a little more.

[mistercoffee1]

Nice!  Glad you liked it.