How to split Big Muff style tone control (DS-1 Example)

[Chistopher]

I modded my testbed DS-1 to have passive bass and treble controls instead of the stock control, which forces you to always be cutting at least a small amount of bass or treble. This is why Big Muff and DS-1s have a mid cut.


I think it looks good from the top, but the knob is a bit tall. It's a pretty simple mod if you're not afraid of using PCBs in a way they weren't originally intended. Adds a few more usable tones to a DS-1 without losing any of the stock sounds.

 

[Chistopher]

Also worth noting, I had to use a 50k pot instead of the 20k pot that the DS-1 uses. It doesn't make any difference at all in sound.

 

[GuitarStv]

That's a cool idea to make a DS-1 much more versatile. Do you know what frequency the cutoffs are at?

 

[Chistopher]

Stock the low pass is at a 234Hz corner frequency and the high pass is 1063Hz. At noon the bass and treble are flat with a mid scoop at around 500hz.

Splitting this into two knobs doesn't the corner frequencies, but it does allow you to in effect bypass the tone control if you have both knobs at 10, which will give you more mids and a slight increase in level over the stock unit.

Right now I'm experimenting with different resistor and capacitor values for both filters. Stock the tone control is designed so that if you want more treble you won't also cut too much bass and visa versa, meaning that when split they are more subtle in effect.

Right now the bass knob doesn't do nearly enough in the left half of rotation, which should be no problem to fix. I'll just make it cut bass fasted.

The other problem is the left half of the treble pot, which I think will be easier to explain once I improve it's range of travel. I'll probably have to look slightly else where, seeing as the tone control is passive so I can't add more treble to right half of the pots rotation.

As is though, I definitely like it better than stock, but I am constantly tweaking this pedal, so I definitely know I can improve the range of tones I can get from it.

 

[Chistopher]

Revisiting this, I added this mod to a friends "unmoddable" SMT DS-1, and he enjoys being able to make his DS-1 darker without making it boomy.

 

[Chistopher]

Also If you raise the value of R17 and R16 it makes the tone control more prominent, which would be a useful adjustment to make considering that your bass and treble rolloff are no longer governed by the same knob