Adding an EQ to a crybaby?

[Myampgoesto12]

Couldn't find anything on here about it so I thought I'd ask.

Ultimate goal here is so tame the sharp distortion clipping on high notes played hard on the higher end of the sweep and achieve a more balanced perceived volume from heel to toe positions.

Through my Distortion 3 this is hardly noticeable due to its higher gain. But through my Custom Bada$$ Modified OD(M77) its extremely present. I know the M77 is much more like a TS than the D3, much more mid rangy. Upping the tone and the 100hz control and backing off the level to simulate a scooped mid tone doesn't help, but in fact makes it worse hah.

I've done several mods to my crybaby(gcb95) so far.

- True bypass with Circuit In grounded in bypass mode, input buffer left in the wah circuit(just lifted the input side of the cap to isolate it from the input jack, and ran a wire from the lifted side of the cap to the bypass switch).
- 68k input resistor replaced with 100k trimpot
- 390R "gain/bass" resistor replaced with 500R trimpot
- .0022uf cap currently switchable in parallel with the stock .01 sweep cap
- 10k pot for toe down frequency control
- 100k Q pot( will be adding series resistor to utilize full rotation without going to 0
- Currently have a .001uf installed on the bypass switch from Circuit In to ground as a recent attempt to taming the clipping

So far The doe down control helps a bit, but at the cost of sharpening the heel to toe transition.

My thoughts are to lower the input volume and gain to achieve a cleaner wah, and at the circuit out -before the bypass switch- adding a small cheapie EQ maybe like the Dano Fish n Chips, it has three small PCBs that should easily be added to the space in my crybaby.

Anyone ever do anything like this? Or have another workaround for the sharp clipping?

Thanks a lot!

[Fancy Lime]

Hi Chuck,

to be perfectly honest, you seem to be at the point in modding, where it becomes easier to just design and build something from scratch. I have recently commited to a similar endeavor, namely an envelope controlled filter. The filter section is much the same as in a foot wah. There are about as many possible ways of building such a filter as there are stars in the sky and I'm sure there is one that does what you want. Cannot tell you much about inductor wahs but what I can tell you is that State Variable Filters are extremely versatile and allow you to define if the peak gets louder with increasing frequency, or less loud, or stays the same, or has a loudest point in the middle of the sweep, or if that peak shall be distorted or not. You could even make it so that the Q gets smaller when you play louder, thus avoiding clipping. You could control Q with an oscillator, an ambient light sensor or even the room temperature, if you wanted to. The possibilities of controlling filters are basically unlimited if you don't insist on keeping the specific crybaby type of filter. So then "all" you need to know is what you want and people here will sure help you et there, as they do everyday for me and many others.

Keep on rocking,
Andy

[Myampgoesto12]

Thanks for the input, I may start to dig into that type of filter then, though my experience in building is quite limited. The most successful active circuit build of mine was an lpb1 clone, super simple, that I didn't bias properly hah.

I guess in a way I'm trying to cheat and make this crybaby act like an inductorless wah such as a weaping demon or something of that nature hah. I loved that wah, just not the bypass or the slight tonal variation from crybabies-though all wahs have that characteristic. I can avoid the clipping with my tone knob but it sacrifices tone  and a bit of sensitivity. That's what inspired the cap on the switch idea.

Through my time tinkering with the guts of pedals I've found that there are a lot of possibilities with minor passive additions or mods, and a crybaby is so simple that these changes are easy to emplament and to hear the differences.

Any builds or kits even that you may suggest for a wah type of effect?  Its hard to find time but I can see how that would be worth the effort.

[Redvers]

I did about 5-6 mods to my crybaby and just gave up and bought a vox.

[Myampgoesto12]

I'd like one of those too hah.

I believe that in the long run I'll probably "upgrade" my rig with a better wah type of effect. For now though I'll be working (or modding) with what I have. Never hurts to use the tone knob anyway. I should probably start gathering materials for a filter build. Looked up a few schems and though they are a little advanced and may require some troubleshooting, I think I can pull it off. Still up for suggestions.

Will post progress with the crybaby later on.

Thanks

[Transmogrifox]

I think you can get the Crybaby where you want it.  It's a simple circuit, but pretty versatile.

If the tone knob works, then you may consider adding a tone control before and after the wah.  You roll off or notch out the range where the clipping is the most irritating and then re-balance it after the effect.

Another thing would be simply a volume control before the wah to get the levels below clipping, and a booster after the wah to restore to a level you need.

At the same time, if your wah is clipping, then it's just too hot.  How far do you have to roll off the volume knob on your guitar to clean it up?

[BetterOffShred]

Doesn't the 535Q do what you are suggesting, just through selections on a 5T switch?  I have one, I just never use it anymore.  Plus it has a gain trimmer on the bottom so you can cut or boost signal if memory serves.  I know its not the model you have, but you might be able to find the schematic and see what's going on there. 

[Myampgoesto12]

-Transmogrifox
I use my tone usually to back off the highs and some high mids to the pedal. Usually about half way off cus after that its pretty steep to off. Its a linear 500k with two parallel caps .047uf and a .022 hah, nuts right? The bridge pickup which this happens most with is a Duncan Custom with a double thick ceramic. That was all I could do to balance its output with the phat cat I put in the neck.

-Betteroffshred
I haven't found the schem for the 535q but I think the 5t switch is a sweep cap selector. No idea what the gain actually controls. If its the same as the "gain/bass" mod for the gcb95 it may not help me. I keep my input trimmers pretty close to stock because there's this odd octive overtone with the gain set just a little over stock.. So with a booster/eq post wah circuit I could passively cut before the wah and actively boost after.

[Myampgoesto12]

Got to messing with my rig for the past couple of hours and I have an interesting conclusion about my wah and the way I'm approaching the whole two gain type pedals with it thing. I'm happy with my wah tone other than the heel position presence-more on that further down.

I really like my Distortion 3 after modding it, its deffinately got a more modern sound.. I sorta want to compare it to the Carvin V3.. The tone control totally changes that but it still has that kinda sound. And its super responsive to pick attack, which I love about natural amp drive, my M77 not so much-gets sorta harsh with the higher gain settings.

Digging around I found the demo video for the M77 AND M78, where he stacks them. Juicy awesome tones. So I thought I'd try it. I set my M77 to lower gain and darker tone and BAM, i dig the result. And I dig the slight drive tone the M77 produces alone on those settings.

I'll loose the "middle ground" of drive levels running it like this (with my guitar dimed at least), and ill loose some sustain using the M77 alone. But heres the best part, the wah works fine for both pedals this way hah.

I still plan on looking into other filter types for my own education on them and possibly a build as it would be awesome to have a treadle type enclosure with so many USABLE controls on it. but I'm totally still adding the EQ to the Crybaby first for i can control the level of several (lower)frequencies. Must..keep..tinkering...

Thanks again for all the input and dealing with this super long post.. Btw M77 before D3, the other way is sorta sputtery no matter the settings.

[Danich_ivanov]

A few months ago i completely rebuilt my chinese vox wah to Clyde Mccoy spec leaving only a stock inductor, spend a whole week testing, triyng different things and mods, and can say that the only thing that helped me with taming highs, which wasn't afecting range and overall tone was 1uf cap instead of stock 0,01uf on the input, and pretty much every other component, if changed in order to have less treble, ruined something at the core of it's sound. As for mods i recommend having a pot for Q and Gain (which is a very first resistor), everything else didn't seem mega important. Also, first transistor is super important, and i was lucky to have C828 (which as far as i know fulltone uses this days), and when it wasn't the right one, it just didn't wah the way it should. As for noise that pretty much all wahs suffer from, 4700uf cap from + to - helps a lot, but i may even put 10000uf in the future. Hope that helps, cheers!

Oh, and here are the guts, just because i'm very proud of the way it turned out)



And the last thing, if you will rebuilt the whole wah, i recommend to not apply any buffers to it first, simply because they can ruin things, and in my case, be it before or after, they just didn't work with other pedals, and i tried various buffers.

[thermionix]

I'll admit I skimmed, but I don't think anyone mentioned this, try a lower gain transistor for Q1.  Look for an hFE around 300, maybe even a little less if you use hot pickups.  2N3904 or something like that.

I'm pretty sure you said you bypassed the input buffer, and I'm pretty sure that darlington is called Q0 in the Crybaby, but if I'm wrong about that, I mean Q1 as the first transistor of the classic two transistor circuit, not the input buffer.  In my experimenting, I've found that higher Q1 gain adds distortion and snarl, higher Q2 gain adds volume.

I don't know if upping the Q1 emitter resistor achieves the same thing, I haven't messed with that too much.

[Myampgoesto12]

I left the input buffer intact and in the signal path of the wah, I just true bypassed the entire circuit before the buffer by isolating the .01uf cap at the buffer from the input jack. I did it this way as to not permanently damage a perfectly good PCB, and because I've heard the true bypass mod with and without the input buffer and preferred the buffered sound. It seems to help maintain some lows to my ears.

-Danich
Is the .01uf cap you swapped out the one that's after the 68k input resistor? And if so will it help me to swap that one sine I've left my buffer installed?

-Thermionix
Adding resistance to ground on Q1 is my "gain/bass" mod. It does cut the signal clipping but at the cost of over all volume and "balls" or "presence" which is what I was hoping an EQ could fix after the fact. It seems the design of this circuit since it which a balance between Q1and Q2 that one mod does in fact come with a price hah. Perhaps a lower gain transistor AND an EQ could make for a better over all tone and control.. Similar to a high gain amp being fed a weak guitar signal sometimes there's unwanted peaks in output that clip.. I have a 2n3904 somewhere around here.. May try it

[Danich_ivanov]

Yes, that one, although in some schematics it appears after resister, in others before, but generally this is the one. And yes try swapping, or you can simply put 1uf cap in parallel with 0.01uf cap. But i would also recommend to try it without a buffer, since after applying cap you might not want buffer anymore, or it may not play well with a buffer.

[Myampgoesto12]

Thanks, I didn't know how swapping that cap would turn out since from what I've read most ppl do that after removing the buffer, or if they don't have a buffer to begin with, to let more lows through. I've thought about removing my buffer lately because input impedance isn't the only thing it does. Maybe its pushing too much into the Q1 section.

Another question regarding lower gain transistor for Q1, the current transistor is indeed quite high gain. Lowering the resistance to ground does add bass and some over all volume (heel and toe) but makes the signal clip AND the heel position has that higher octave overtone on many notes, even when using headphones so its not proximity to the amp.

If using a lower gain transistor and swapping caps doesn't solve my perceived volume difference between heel and toe positions well enough, will Q1 suffer similar octave overtones if its biased a bit hotter to compensate?

I'm not afraid to try it, but I figured I'd ask just to see if anyone knew.

After my tinkering around yesterday with my M77s settings I came to realize just how transparent that thing really is no matter the gain. This is why I now believe the wah acts the way it does with it. The M77 is just very true to what comes before it tonewise, hah. Kind of odd though, I can still easily hear the difference between guitars through my D3.. But the wah seems compressed( I love this about the two pedals interaction) but not scooped out of perception.

I'm gunna give the new OD approach thing a try for a bit, see if it settles with me when playing different styles of music.

Keep the suggestions coming though, there's a lot on here to learn so I intend on doing so and helping anyone I can as well!

Thanks!

[Danich_ivanov]

There's also something to keep in mind regarding lower hfe, that while it does reduce highs, it also reduces the range, so that it might not wah as much as it should, so i wouldn't bet on a lower gain transistor too much, it can help, but it also can ruin things.

[pinkjimiphoton]

try my "stupid simple tone control " trick
use it on the output q between c and b

10p cap to pin 1 of a b250k pot, 2.2n-3.9n cap to pin 3. tie the two ends of the caps together. connect that side to collector, the wiper of the pot to base.

this will fake a variable cap, and let you sweep from very little treble reduction to quite a bit of treble reduction without killing your mids or affecting the tone very much adversely.

may help ya dial out the shriek.

or maybe just adjust the pot on the wah to have a little less treble?

[thermionix]

There's also something to keep in mind regarding lower hfe, that while it does reduce highs, it also reduces the range, so that it might not wah as much as it should, so i wouldn't bet on a lower gain transistor too much, it can help, but it also can ruin things.

That's true, but IMO the input buffer reduces range too, so maybe bypassing that would balance out somewhat with a lower hFE Q1.  To the best of my knowledge, the vintage wahs with no input buffer generally had lower gain transistors in them than modern MPSA18s.  But yeah, too low would be a bad, it's a balancing act.  I'm still not totally settled on everything in my wah, but I built it on eyelet board with experimenting in mind.

[pinkjimiphoton]

in my experience ya need at least a gain around 400 or better. i tried some npn ge's with lower gains in my old thomas wah last nite for shits n giggles and the filter didn't work anymore.. tried 80, 100, 120hfe areas. soon as i put the bc109 (i think) back in it fired right up.. i did test when it was out, 400hfe

i find lower hfe's work better for distortion than filters, but maybe its just me. i built a BM pi with a couple ge and a couple si stages with really low hfe's... 40-60 for the ge and 100-200 for the si and it totally kicks ass in a different way than a standard muff.
less distortion, but that same silky sustain. kinda cool.

[Myampgoesto12]

I have tried adjusting the pot and it just didn't feel right, sorry I forgot to state that before..

I may devise an internal switch to truly bypass the buffer, why not? Could even add a switch for for Q1 swapping hahah. The idea of a fully customizable circuit without needing to pull the pcb is intriguing.

That would take at least one daughter board, on top of an EQ, that's a lot of stuff cram into this enclosure hah. I'll have to take the time to see if I like the non buffered tone on either, both, or neither of my dirt pedals to see if that would be worth it.

[Myampgoesto12]

Transmogrifox mentioned a passive tone control prior to the circuit, that's a lot easier to emplament, I thought about that initially but I'm slightly concerned about the load on the signal, maybe its no big deal since it currently has the buffer anyway.. May try both hah.