Modding A Dunlop Crybaby (True Bypass & Tone)

Here is a collection of mods that I do to Crybabys. They are all based on and taken from the ‘traditional mods’ that have been around for years but there is actually room for very easy personal tweakabillity as you will see later on.

So first up here is the stock (un-modded) Crybaby. Note that I did these mods on a revision H model, I’m not certain if they will work with all models before that. the picture comes courtesy of ‘Roadhouse Guitars’ as I can’t find the picture I originally took.

So here is the picture of the regular Crybaby guts. There is quite a lot that can be done to modify this classic circuit and I’m going to go through all of the mods that I personally offer.

The ‘Vocal’ Sweep Mod

The resistor inbetween the inductor and input jack is wired in parallel with the inductor and it controls the ‘Quality’ (often abbreviated as Q) of the sweep. This resistor should usually be 33k. In order to tighten / narrow the Q (and make the ‘wah’ a little more watery or ‘woh’ sounding) this resistor value needs to be raised. This is where you are free to experiment. Try a variety of resistors. I settled at around the 60k mark if I remember rightly. You obviously don’t want to overdo this and go too high but definitely enjoy experimenting. This is the simplest and most rewarding mod you can do to the Crybaby in my opinion.

The Mid Range Mod

Another one component change mod that drastically alters the sound. This mod basically smooths out the transition from heel to toe, giving a lot more midrange, just an overall smoother sound. The picture on the right shows which resistor to change. It should be a 1.5k resistor. You can up this to about 2.0k. I usually go with a 1.8k resistor.

True Bypassing The Crybaby

This mods are considerably less fun and more time consuming, but the stock Crybaby does have some tone suck and the input buffer was designed to help prevent this, since we are true bypassing we don’t need it.

Firstly you need to remove the input buffer.

Here is the picture of the stock Crybaby again (on the right) but with the components that need removing circled red. The buffer is on the left in the picture, 3 resistors, 2 capacitors and a transistor. Remove them carefully, take your time in de-soldering the components. I recommend using a ‘solder sucker’ as I found this to be much easier to use than the typical solder wick stuff. But whatever, use what is most comfortable for you.

With that done you need to take some wire to make a new input for the circuit from the switch (which we will install later).

On the left is a picture of a Crybaby modded by me, showing where to install the new wires. Basically install them on either side of where R14 was.

The yellow wire is the effect input.

The orange wire goes to ground.

That’s it, the buffer is now removed and we have installed replacement links between the switch (which is next  to come) and the circuit. Congratulate yourself on a job well done!

True Bypass With A 2PDT

For those not interested in adding an LED all you need is a 2PDT switch. I recommend and use Alpha 2PDT switches (which can be bought in the DirtBox store).

De-solder the connections to the old switch if your the patient type. If your not (like me!) then just cut the wires, but make sure you do it close to the switch as you do not get a lot of spare wire in the Crybabys and there really is little room for error. If your doing this for the first time I actually recommend you de-solder, just to give yourself that extra few mm of leeway.

Install the new switch. Depending on which switch you buy you may have to drill the hole slightly larger in the enclosure. This is pretty easy to do with a quality stepped drill bit but you should be able to hack it away with pretty much anything. Bare in mind that the more thread through the hole (towards the treadle) there is the easier the wah will be to turn on and off. Experiment until your happy.

The wires in the Crybaby are colour coded, just match then up with the picture on the right and everything should be good. (excuse the hacked together picture, I’m evidently no master of Paint!)

That’s it! All there is now is to close it all up again and test it.

Maybe in the future I will make a post of how to true bypass the Crybaby with a 3PDT and an LED.

Did something go wrong? Not working? Sing up to the forum and discuss it and ask for help.