Build Your Own Clone Message Board

The first time I built my BYOC wah I adjusted the trimpots according to ear but wasn't satisfied with the tone I was getting out of it. Last night, I decided to take the trimpots out and adjust them with a multi-meter, mark them, and then put them back in. I wouldn't recommend doing this because it is a total pain in the ass to take em in and out after they've been soldered already. Best bet is to adjust them before you install them the first time.

To make a long story short, I can't seem to dial in a tone that I like. I was wondering if people can take a glance at my board and tell me if there is anything that I'm missing.

Here's a summary of my tone:

Clean: Very vocal and fat wah but low volume with heel down.
Fuzz/OD/Distortion: Very thin sounding, kind of tinny, lack of vocal tone but it is still there.

I am aware that Fuzz/OD/Distortion have a different impedance than a wah pedal so there should be some tone differences when placing these effects after the wah.

Range Switch:
.033 - Fat vocal wah that is really bassy but volume drops off with heel down.
.022
.01
.0082 - Much more thin sound with less vocal wah and more tinny.

I usually keep the Q pot cranked all the way up or half way when I'm using the .01 or .0082 caps on the range swith.

Here is my guess as to what is occurring:

1) I need to add some different range caps to get more of a diverse tone.
2) I damaged my trimpots with too much adjusting and taking them in and out.
3) I don't have my buffer switch set properly.
4) I'm totally crazy, have an obsession with tone, and need to take some Fluoxetine and undergo cognitive behavioural therapy in order to treat my tone disorder.

Question:
I am thinking of swapping the gain, mids, and bass trimpots out for tone pots. That way, I can adjust the tone when using different forms of fuzz/OD/distortion. The only problem with this is that it puts you in a position where you have too many options, which can sometimes be overwhelming. Anyone have experience with this?

Here is my pedal chain: guitar = BYOC wah = BYOC OD2 = BYOC Shredder = Delay (rarely used) = RC-2 Loop Station = Fender Deluxe (40 watt)

It's been a while since I built this pedal and I'm being lazy by not checking the instructions but there is a jumper missing from the board no? (the resistor space that has a "0" on it)

I'm not a huge wah guy but my experiences have told me that, like a Fuzz Face, wah is a temperamental little effect. Maybe put the trims that you tweak most on the outside for quick adjustments but I'd recommend using small pots because you wouldn't want them to move when you don't want them to.

I simply cannot comprehend why anyone would ever want to place their distortion pedals AFTER the Wah Wah. I've tried it with all sorts of pedals and it sounds like wimpy crap. Maybe someone can explain to me what is good about this arrangement.

I hugely prefer the sound of distortion pedals placed in front of the Wah wah pedal. The only reason I can think of for people placing Fuzz after Wah is 'cos it is what Jimi did'. It is well know that the classic Wah Wah and Fuzz Face do not work very well with the Fuzz Face after the Wah. You lose the ability of the Fuzz Face to interact with the guitar controls, the low impedance of the Fuzz Face reduces the Wah sweep and may result in oscillations.

The circuit of the original Cry Baby Wah Wah is very simple and it is my impression from experiment that the engineers at Vox did a good job of optimising all the values. A new Wah Wah built to the original specs, but with modern high precision parts should be close to perfect. Having all those pre-sets may be more of a disadvantage than anything else, the range of adjustment is quite large while only small fine adjustments are probably what are needed. And all those trimmers will interact to a degree.

Knight of Cups is of course right about the 0 link. You don't need to use a '0' resistor, just a piece of wire would do to make the link. Unfortunately there is no picture of the back of the PCB in the instructions so I can't say what the effect of the link being missing would be.

If the Wah sweeps too high it will sound tinny and if too low then output volume will fall. Both of these extremes are exaggerated when the resonance (Q) is set high. With higher resonance the Wah will sound more vocal, but it can get too selective and nasal. Don't forget the exact rotation of the pot mounting and its relationship to the rack and pinion is critical.

The old ICAR S law pots have quite large neutral zones at either end of their rotation (ICAR S laws are linear over the centre 200 degrees of rotation, with 50 degree neutral areas at either end). Moving the pinion gear by one tooth on the rack rotates the pot shaft by about 24 degrees so you have only two teeth of safety travel on either end of the pot rotation. On the other hand Dunlop Hot Potz (a modified log law) seem to have all the neutral zone (only 30 degrees) at the anti-clockwise end of the rotation.

The Q trimmer is the one next to the battery connections and it is a 250K. Production values varied, apparently the very earliest pedals had no Q damper and values as high as 100K have been used, but it eventually settled down at between 33K and 47K (quite low compared to the maximum of the 250K trimmer). The gain of the first transistor stage sets the maximum amount by which the tuning capacitor is multiplied to reach the low frequencies when the pot is at its maximum travel (toe up). So the 1K preset, the next along from the Q preset, is the one that has the most effect on the actual gain of the first transistor stage.

Normal guitar Wah Wah range is 300Hz to 2,000Hz with a 0.01uF cap. For guitar I cannot see the point of changing this cap value, it will just move the range up or down out of its optimum position for guitar. Using a 0.033uF is just way too much, the bass end as you say, will be too low and there won't be much output. It does make sense to fit a 0.02uF (or 0.22uF for a standard value) moving the range down an octave to use the Wah with a bass.

Oh and by the way you appear to have ceramic capacitors on the 'range' switch. These are a bad choice for audio and in particular for Wah tuning caps because they tend to be microphonic and usually have a large tolerance range, the actual value could be 20% off. You would be better off using a close tolerance plastic film 0.01uF for the tuning cap.

That 0 resistor on the board is suppose to be left out, as I added a buffer switch.

I queried the reliability of ceramic caps before I installed them and was told that they wouldn't make a noticeable difference in the tone, not on an effects pedal anyway. Do you think it's worth it to swap them out for film caps?

the material isn't as much of an issue as the tolerance. You probably couldn't hear any difference between a ceramic cap and a film cap that had exactly the same measurement. But you'd sure as heck hear a difference of 20% tolerance as opposed to 5%. Just my 2pF.

So, I guess it's probably worth my while to replace the caps.

What kind of pots would I use to put external pots on the gain, mids, and bass?

None

I'd get it set right and leave it (fit the standard values). With all those variables you will either, just confuse yourself and spend forever endlessly twiddling knobs in search of a sound you will never get, or you will end up with a favourite setting and leave them there. Referring to the title of your post - Difficulty with dialling in a tone - with so many variables on trimmers, all of which adjust over a wide range, some of which is not useful since you would never want any of them adjusted down to zero or even much less than half, it is not surprising you cannot settle on settings you like.

In my opinion the only control it is worth having on an external control is Q and you already have that. Any good quality metal shaft pot should do. I would fit a 100K log in series with a 22K fixed resistor since you would never want the Q damper to go down to zero. Or possibly a 47K / 50 K log in series with a 33K resistor.

And yes it is the tolerance that is the real issue with those ceramics. Like I say, all you really need is a 0.01uF for guitar and maybe a 0.022uF for bass otherwise you end up with the pedal range extending too far into the bass or the treble. I know, I have tried all this. With a Wah Wah it is all about finer adjustments and less is more.

I hear ya on the too many options. I don't want to be in a position where I'm spending 60 minutes tweaking my wah pedal and 10 minutes playing my guitar.

Last night, I disconnected my Q pot from the board and turned it until it measured 35 k on my multimeter. I then made a mark on the pedal housing with a paint pen and put the pot's knob on so that the knob's marker lined up with that dot, which was straight up. I then reconnected the Q pot wire to the board. Basically, what I have is a marker on the pedal housing that tells me where 35 k is. That way, I can vary off and explore as many tones as I want but easily dial it back to stock settings whenever I want. I'm also going to mark on the pedal housing the full rotation of the tone pot. That way, if I ever take the knob off, I don't have to find 33 k with my multimeter again. I may actually mark the pedal housing with a small indentation using my dremel tool so that it is permanent.

I'm not sure what you mean by this, or how I would go about doing it:

I would fit a 100K log in series with a 22K fixed resistor since you would never want the Q damper to go down to zero. Or possibly a 47K / 50 K log in series with a 33K resistor.

Hey Tark,

I think I might understand what you mean by the 100k log with a 22k resistor in series. Basically, does that mean that I connect a 22k resistor to the existing 100k pot so that the pot does not dial down a resistance that is below 22k. Essentially, making the 100k more practical in it's range?

OK, well with all the trimmers on the PCB the flaw is that they all can be turned down to zero ohms - an option that you would never want. As far as I can see many of the 'mod' trimmers in BYOC kits are wired like this and I think it is less than optimal. In fact if you have to have adjustments of any kind on any pedal, you want those adjustments to be only over a useful range between a minimum and a maximum beyond which you would never want to go. At the moment the Q trimmer, or the external pot as you have it, rotates between zero and 250K. This means you have at least 20K at its low end and maybe 150K at its high end you won't use, leaving less than half its rotation to do anything useful.

Now historically we know that the Q resistor has never been higher than 100K and never lower than 33K. If we accept that those values represent the full range of sensible experimentation then we can connect one end of a 33K to one of the end pads of the trimmer position on the PCB, connect the other end of this resistor to the anti-clockwise end of a 100K log pot, connect the wiper of the pot to the clockwise end with a short wire link (the trimmer likely has this link present on the PCB) and connect the clockwise end to the other end pad of the trimmer position. This gives us an external Q control that goes from a 'normal' fairly low Q when fully anti-clockwise to the most nasal narrow Q when rotated fully clockwise (maximum will actually be 133K), with a useful range in between. If you like you can drop the fixed resistor to say 22K for a bit more low range.

I was just writing this when you made the above post - yup - you got it.

I think I'm gonna add a 22k resistor onto the existing B 100K pot for the Q vocal. It makes more sense, as I'll get less sensitivity with the tone pot. Essentially, I'll be able to dial in a 22k to 133k tone throughout the pots full turning capability, as opposed to a 0k to 133k range.

I think I'm also gonna replace the ceramic caps with film capacitors. While I'm at it, I'll install the following values. Might as well, given that I have the space on the range switch:

.033
.022
.01
.0082
1.2nf
10nf
1.8nf
3.9nf
6.8nf
15nf
27nf

I think I'll also install a momentary switch, as the current bypass switch gives off an annoying mechanical clicking sound when using the pedal, which I've been told you can't get rid of.

As for replacing the bass, mids, and gain pot. If I wanted to do so in the future, what size of pots would I use and what value of resistor?

Hey Tark,

I just tried placing my wah after my 'dirt' pedals. There is no way I am going back to having the wah in front of the 'dirt'. It is absolutely night and day Now, I have to find out what I'm going to do with my buffer on/off switch.

Yay!! another convert