First off, I should note that I actually built my Klon off of a different supplier's PCB, before I knew about PedalPCB. But, I wanted to share it here to add to the mods section of this forum. I wrote all the component numbers with reference to PedalPCB's schematic for the Kliche Mini.
VOICE SW MOD
This mod changes the mid focus character of the clipping signal path. I find it allows for more clarity, and makes the treble knob easier to dial in.
In the clipping signal path, C8(390pF) and R11(422k) form a low pass filter cornered at around 1kHz. This fattens up the sound and focuses the mids. This contributes to the well-loved Klon sound.
However, I wanted some more clarity out of this pedal. Turning up the Tone knob doesn't exactly help since the Tone knob boosts both mids and highs. One option would be to voice the tone knob to only affect highs. I tried that, but didn't really like that either, as it sounded too thin as the knob was turned up.
So, I added a switch to toggle between different values for C8. 22pF was soldered in place of C8, and other values were soldered on a vero board which was wired to the switch. Instead of using a separate vero, the caps could be tacked onto the switch. In the 3 positions, the C values I chose are:
1. 122pF (100pF in parallel with 22pF)
2. 22pF (switch is off)
3. 392pF (220pF, 150pF, and 22pF in parallel) (similar to original)
My favorite is position 1, but I like having the other options available too. If you don't want to include a switch, I'd suggest socketing C8. C14 would also be a good spot to experiment, but I got the sound I was after by just adjusting C8.
BASS KNOB MOD
This is a pretty involved mod, since it requires soldering up an aditional vero board and tucking it away somewhere in your enclosure. However, it is small enough that it could fit next to the stomp switch (which is how I did mine).
This mod converts the tone circuit to a baxandall circuit with treble and bass controls. I noticed that the Klon tone control is already somewhat close to a baxandall circuit, needing just a few component swaps/additions. I believe the Bondi Sick As does something similar, although with different values. The values I chose were based on my personal preference. I did try to voice it so that the new treble control sounds/behaves similar to the old tone control. The bass control is unity at noon, and can cut or boost from there.
There is another way to add a bass control to a Klon, which involves adding a pot and larger cap in parallel with C7. In my opinion, this has 2 drawbacks.
1. It only affects the clipping path, not the clean path, so with the gain knob set low it has no effect. 2. It adds bass pre-clipping, which could make the sound muddier. The mod I did adds bass after the clipping and clean paths are mixed.
I've attached a page that shows my changes to the circuit and my vero layout. Hopefully this is helpful for someone who wants a little more bass out of their Klon build, or inspires someone to come up with other ideas.
VOICE SW MOD
This mod changes the mid focus character of the clipping signal path. I find it allows for more clarity, and makes the treble knob easier to dial in.
In the clipping signal path, C8(390pF) and R11(422k) form a low pass filter cornered at around 1kHz. This fattens up the sound and focuses the mids. This contributes to the well-loved Klon sound.
However, I wanted some more clarity out of this pedal. Turning up the Tone knob doesn't exactly help since the Tone knob boosts both mids and highs. One option would be to voice the tone knob to only affect highs. I tried that, but didn't really like that either, as it sounded too thin as the knob was turned up.
So, I added a switch to toggle between different values for C8. 22pF was soldered in place of C8, and other values were soldered on a vero board which was wired to the switch. Instead of using a separate vero, the caps could be tacked onto the switch. In the 3 positions, the C values I chose are:
1. 122pF (100pF in parallel with 22pF)
2. 22pF (switch is off)
3. 392pF (220pF, 150pF, and 22pF in parallel) (similar to original)
My favorite is position 1, but I like having the other options available too. If you don't want to include a switch, I'd suggest socketing C8. C14 would also be a good spot to experiment, but I got the sound I was after by just adjusting C8.
BASS KNOB MOD
This is a pretty involved mod, since it requires soldering up an aditional vero board and tucking it away somewhere in your enclosure. However, it is small enough that it could fit next to the stomp switch (which is how I did mine).
This mod converts the tone circuit to a baxandall circuit with treble and bass controls. I noticed that the Klon tone control is already somewhat close to a baxandall circuit, needing just a few component swaps/additions. I believe the Bondi Sick As does something similar, although with different values. The values I chose were based on my personal preference. I did try to voice it so that the new treble control sounds/behaves similar to the old tone control. The bass control is unity at noon, and can cut or boost from there.
There is another way to add a bass control to a Klon, which involves adding a pot and larger cap in parallel with C7. In my opinion, this has 2 drawbacks.
1. It only affects the clipping path, not the clean path, so with the gain knob set low it has no effect. 2. It adds bass pre-clipping, which could make the sound muddier. The mod I did adds bass after the clipping and clean paths are mixed.
I've attached a page that shows my changes to the circuit and my vero layout. Hopefully this is helpful for someone who wants a little more bass out of their Klon build, or inspires someone to come up with other ideas.
