Joe Hart's Wacky Wah Adventure

Joe Hart · January 04, 2011, 03:49:59 PM

Quote from: SISKO on January 02, 2011, 11:03:20 AM
http://geofex.com/Article_Folders/wahpedl/wahped.htm#twowahs

I had seen that, but it doesn't seem to work too well with an inductor wah. Maybe I'll look into just building a two-wah circuit from scratch and give it a try. Thanks.
-Joe Hart

Joe Hart · January 05, 2011, 08:11:59 AM

Okay, so I picked up a Vox V845 yesterday because it was cheap, I had a gift certificate from Christmas, and I was starting to wonder if I was trying to make the Cry Baby something it's not. My first impression is that it sounds better (to me) stock than any Cry Baby I've tried. It's thicker sounding, and I like that. The heel down position is incredibly soft. I mean, volume-wise there is a very noticeable drop. I'm going to try the "mid mod" and the "bass/gain mod" to see if those help. And maybe I'll try moving the pinion gear to move the sweep up, then change the sweep cap to move it back down a little and see if that helps by shifting the pot rotation a little -- if that makes sense. Like maybe the heel down position of the pot is too abrupt going to "zero" on the pot?

And it SUCKS TONE more than any pedal I've ever had! But that's an easy fix.

I will report more later.
-Joe Hart

joegagan · January 05, 2011, 08:49:55 AM

if you think that sucks tone, you should see what a 72 boomerang maestro does in the 'volume pedal 'mode. ridiculous!

sounds like you got a nice project going. i really like the way the voxes look with the chrome and stuff.

Joe Hart · January 05, 2011, 10:39:18 AM

Quote from: joegagan on January 05, 2011, 08:49:55 AM
i really like the way the voxes look with the chrome and stuff.

The V845 is all matte black. I have a V847 that has the chrome top on it. It sounds great (modded, of course) and looks cool.
-Joe Hart

joegagan · January 05, 2011, 11:49:13 AM

oops egg on my face. at least now i can eat breakfast.

i like the all black ones too, sorta like a batman goth wah

Joe Hart · January 07, 2011, 11:27:39 AM

I've had a few days to play with my new wah and here's my "DIY Stompbox Forum Guy" take on the Vox V845. It's much lighter than my Cry Babies or my Vox V847 -- and that's nice when you have a pedal board with 8-10 pedals on it! The rack and pinion has very little grease on it. Not a huge deal, but something that some others have noticed, so I figured I would corroborate that issue.

I also like how the on/off switch works. There are slightly bigger rubber feet on the toe down end of the treadle, so it's near impossible to turn the pedal off with vigorous wahing, but it's still pretty easy to click it on or off when you actually want to. A small feature, but I like it a lot. The down side is that there's even less physical sweep to the pedal. I know that I can grind down the heel of the treadle to extend the range, or even replace the rubber feet or remove them altogether and then adjust the DPDT to extend the range, but I don't find it to be an issue (yet, at least).

The PCB is separate from the in and out jacks, so that makes it a little easier if/when a jack needs replacing and/or I decide to replace the entire board. And also the board is through hole plated, so that's nice for mods. There are a few components on the "top" side (the side facing up when you flip the pedal over and remove the bottom. Then there are a bunch of SMD components on the "back" of the PCB. There's also a small daughter board attached to the pot with a few SMD components on it.

Supposedly, there is no input buffer, so that would account for the tone sucking. But the actual wah still sounds good right out of the box.

So, with the input buffer removed, there should be something like 19 components (minus the pot) in the circuit (if memory serves). Here's what I find interesting: this pedal has 38 components! Huh? Even with the input buffer, the component count shouldn't be this high.

For through-hole components, it has:

1 inductor
2 transistors
2 .01uF caps
2 .22uF caps
2 electrolytic caps (4.7uF and 220uF)
2 diodes
1 one resistor (unfortunately, it's 1K, so that's nothing worth playing with).

If my counting is correct, the "back" of the board contains:

18 resistors
3 capacitors
2 items labeled "L" which I believe stands for inductor

And the daughter board contains:

1 resistor
1 cap
1 additional "L"

So this circuit contains (minus the pot):

2 transistors
8 capacitors
2 electrolytic capacitors
20 resistors
2 diodes
4 "L" inductors(!!!!)

Anyone have any idea on any of this??
-Joe Hart

Joe Hart · January 09, 2011, 09:31:08 AM

No one's going to bite? Am I going to have to try to trace this whole pedal out just to figure out why there are so many components? :-)
-Joe Hart

Gus · January 09, 2011, 09:38:42 AM

Post some pictures. Extra Ls could be ferrite beads for RF rejection. Extra board at the wha pot could be for taper resistor(s) or caps.

Joe Hart · January 09, 2011, 09:36:22 PM

Quote from: Gus on January 09, 2011, 09:38:42 AM
Post some pictures.

Okay. They're big, but I wanted to show as much detail as I could. The through-hole component side is a little blurry because the camera kept trying to focus on different things! But I think most of the traces are on the flip side anyway. Any ideas? Thank you!
-Joe Hart
http://www.rabbathrecordings.com/VoxV845Board01.jpg
http://www.rabbathrecordings.com/VoxV845Board02.jpg

Joe Hart · January 11, 2011, 11:13:26 AM

I've been playing around with the V845 and I'm actually fairly happy with it as is. It doesn't have the "grit" that my Cry Babies have, so I was wondering about swapping out caps. Does anyone know what kind of caps are on the V845 board? Two .01uF caps are "clearish" yellow with what looks like silver foil inside them and have "103J" printed on them, and two .22uF are green with "224J 100V" in two lines printed on them. I've heard that the cap type has a noticeable effect on the tone of the pedal and I don't want to swap out caps for ones of the same type! Thanks!
-Joe Hart

zombiwoof · January 11, 2011, 04:13:50 PM

Quote from: Joe Hart on January 11, 2011, 11:13:26 AM
I've been playing around with the V845 and I'm actually fairly happy with it as is. It doesn't have the "grit" that my Cry Babies have, so I was wondering about swapping out caps. Does anyone know what kind of caps are on the V845 board? Two .01uF caps are "clearish" yellow with what looks like silver foil inside them and have "103J" printed on them, and two .22uF are green with "224J 100V" in two lines printed on them. I've heard that the cap type has a noticeable effect on the tone of the pedal and I don't want to swap out caps for ones of the same type! Thanks!
-Joe Hart

The vintage type for the .01's was polystyrene, but I doubt that they are using that on the modern Voxes. The .22's are most likely poly film, I wouldn't doubt that the .01's are also, even though they seem to be a different manufacturer.

Al

Joe Hart · January 11, 2011, 08:16:44 PM

I figured the green ones were mylar (I think some people call them "greenies"). I have some polystyrene caps, so I'll check to see if I have .01's and see how the change sounds. Thank you!
-Joe Hart

Joe Hart · January 12, 2011, 12:24:02 PM

Whoops. A day later... I meant .22uF.
-Joe Hart

Joe Hart · January 21, 2011, 03:13:10 PM

In doing some research, it seems that the higher the inductance of the inductor, the fatter the sound of the wah pedal. It also seems that inductors vary widely. I have a bunch of random inductors that came out of old radios and whatnot. Could I add these in series to the stock inductor to get a fatter wah? I have no way of measuring an inductor, so I would just be messing around and LOTS of trial and error, but before I start cutting traces and all that, has anyone tried it and does it work at all?
-Joe Hart

Joe Hart · November 04, 2011, 04:10:04 PM

Quote from: Joe Hart on January 09, 2011, 09:36:22 PM
Quote from: Gus on January 09, 2011, 09:38:42 AM
Post some pictures.

Okay. They're big, but I wanted to show as much detail as I could. The through-hole component side is a little blurry because the camera kept trying to focus on different things! But I think most of the traces are on the flip side anyway. Any ideas? Thank you!
-Joe Hart
http://www.rabbathrecordings.com/VoxV845Board01.jpg
http://www.rabbathrecordings.com/VoxV845Board02.jpg

The new addresses for the pictures:
http://www.joehartband.com/VoxV845Board01.jpg
http://www.joehartband.com/VoxV845Board02.jpg

Joe Hart · November 04, 2011, 04:17:30 PM

Ressurecting an older thread.

I replaced C5 of the Vox V845 (which was a .01uf capacitor -- I think polystyrene??) with a .022uf metal film capacitor and the wah is thick and rich and growly! It's AMAZING! I'll post a sound clip soon. I'm blown away!! I believe this is the sweep cap (so there's no new information here), but for anyone trying to mod the V845, it seems that C5 is the sweep cap. Anyway, I'm happy!
-Joe Hart

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Joe Hart's Wacky Wah Adventure