Another very interesting option of doing the processor-/pitch mod is installing it on the Roland Sp404-SX.
Changing the processor speed here does not lead to the usually known bitcrushing or aliasing, known from machines that use lower bitrates. Only on the lowest settings some hiss appears.
This mod gives you a very unique way of pitching samples on the fly. The range reaches from ulra low, almost stopping the playback, to higher pitches. Its independent of all other controls and also doesn’t effect the speed of the internal sequencer. But it does change the sound of the internal effects in interesting ways.
The circuit i designed, switches the processor-mod on after the boot process is finished. That ensures that the machine doesn’t crash. Also a switch to turn off the mod circuit lets you alway return to usual, uneffected operation. This mod is very non-invasive. It can be built without changing any internal components. Neverthless you have to be a skilled and experienced builder. Using a precise and quality soldering iron is a must!
Besides that i added three CV-Inputs. As soon as there are cables plugged into the minijacks, external CV sources(0-5V) control the respective parameters of Ctrl1/Ctrl2/Ctrl3. With these possibilities the Sp-404SX reaches a completely new level of effect manipulation and integrates it to the modular synth world.