Simon Paja
Overdrive/distortion
A lot of things to do, e.g. 8 pots and 5 switches.
Ok. All soldered.
There is also a booster add-on which is based on Klon Centaur. Located in the lower right corner in the picture above. Overdrive section from the Klon. No tone control. Just the Germanium diode hard clipping section of the circuit. Internal trimmer allows you to set the maximum distortion.
Another boost option is a Linear Power Booster. Simple transistor boost.
Huge amount of sounds available from this pedal. First of all there is the boost circuit which can be selected to be in front of the distortion or after it. There is a voltage selector switch to select the operating voltage of the distortion circuit, either 9V or 18V. The circuit includes both hard clipper and soft clipper. For the hard clipper you can select either silicon or germanium diodes, for the soft clipper you can select silicon diodes or LEDs. Tone stack has Treble, Mid and Bass pots. You can change the mid frequence value with a pot and you can also select how wide is the range for the Mid pot (Q value), normal, narrow or wide. There is also Precense and Drive adjustments.
With these different options it should be possible to make it sound like:
- Klon Centaur, hard clipper, Ge
- Tube Screamer TS-808, soft clipper, Si
- Boss HM-2, soft and hard clippers, Si
- Boss DS-1, hard clipper, Si
- Fulltone OCD, hard clipper, Ge
- Zendrive, soft clipper, schottky / LED
- Blues Breaker, soft clipper
- Timmy, soft clipper, Si
- Proco RAT, hard clipper, Si
With these different options it should be possible to make it sound like:
- Klon Centaur, hard clipper, Ge
- Tube Screamer TS-808, soft clipper, Si
- Boss HM-2, soft and hard clippers, Si
- Boss DS-1, hard clipper, Si
- Fulltone OCD, hard clipper, Ge
- Zendrive, soft clipper, schottky / LED
- Blues Breaker, soft clipper
- Timmy, soft clipper, Si
- Proco RAT, hard clipper, Si
Some examples, schematics following below should be doable with this distortion/overdrive pedal. All of the mentioned exaples have their own specific tone and gain circuits and feedback loops to be able to shape the sound they produce.
This is the circuit from Klon Centaur. Klon is using Ge-diodes. Boss DS-1 is same kind of hard clipper but with Si-diodes. Also Proco RAT is a hard clipper.
Tube Screamer is typical soft clipper. Made with two diodes.
Blues Breaker is also a soft clipper but it has four diodes.
Boss HM-2 has Si-diodes in hard clipper and in soft clipper and it has also a pair of Ge-diodes in series between the clippers. Soft clipper is asymmetric.
Fulltone OCD is a hard clipper but it has two FETs and a diode. It is also asymmetric.
Timmy is a soft clipper with 6 diodes from which 2 you can switch on or off. Asymmetric options.
Zendrive is a soft clipper using diodes and FETs. Also asymmetric.
