If you’ve never heard of the Spin Semiconductors FP-1 digital signal processor chip, don’t worry– that just means you haven’t been deep into guitar petals and audio effects hardware lately. [adamjvr], a.k.a. [avr] has, and he’s gone to the point of creating a PC-based emulator of this sound chip to simplify development.

If you don’t see the utility, stop and think about the development cycle without a simulation like this: you program, you flash to a board, and you test there. Not only does the ‘flash to the board’ step add time and friction, you do also have a limited number of flashes on the board’s memory. With an emulator on your PC, the workflow tightens to ‘code, test’ and you don’t flash the board until the simulated DSP is doing the sounds you want it to.

As for the FV-1 itself, it’s an interesting little chip in that it’s quite a full-featured DSP– rather, it’s small instruction set is focused entirely on audio effects. If you’re into that world– be it guitar pedals or otherwise– you may find this project very useful. There are releases for Linux, MacOS and Windows, and it’s all open-source on GitHub, under the Mozilla Public License. It’s not the most common choice, but we’re hardly going to complain about licenses to anyone willing to share their hard work.

If you like the idea of testing your work before you go to the bench, we’ve seen software that offer the same functionality for Arduino projects, as well as other AVR and PIC micros. It’s been a while since we featured a programmable guitar pedal, so we hope this tool enables others to rock out.

It’s likely that even those of us who have never picked up a guitar in our lives will recognize the sound of an electric guitar with a fuzz box effects pedal. The raspy distorted sound has been at the heart of so many very well known recordings. Behind it is a distortion circuit, or as [Bill Jehle’s Mad Scientist Guitar Lab] is here to tell us, eight different circuit topologies.

The result is a fascinating trip through the evolution of rock music through the 1960s, as he examines circuits from simple diode clippers through to frequency doublers and phase shifters. He’s provided a playlist as an accompaniment so you can even have an immediate listen to each sound. It’ll mess up our YouTube recommendations, but worth it for the informative journey.

It’s also a window into a lost period in electronics where all they practically had was the transistor, so each device had to put in the maximum work for a living. Designing circuits like these called for intimate knowledge of the device characteristics, and just how they could be safely exceeded. The video is below the break, and well worth a watch.

If clever transistor music circuits interest you, you’ll love the flawed devices that gave the Roland 808 its sound.