Looking over the music tech DIY landscape, one of the things I need that’s most blatantly missing is a sampler. My synth and sequencer needs are well-catered for, and analogue mixer schematics are readily available.
To the best of my knowledge, there are currently four documented DIY sampler projects on the net:
The first is the 8-bit Where’s The Party At?. It grew out of a project made for a circuit bending festival, and like most things from that end of the world is focused on glitchy nonsense (I say that with nothing but affection). It’s based around an Atmega CPU and an SRAM chip from Cypress; the firmware is written in C. The WTPA site mentions an upcoming version 2, but the last blog post about it is years old. Since it was originally aimed at circuit benders, a lot of whom don’t know much about electronics, it seems to be quite well-documented.
The second is the DeMIDulator, which is a four-voice digital synth that also samples. It’s open hardware, based on a Microchip PIC microcontroller. The firmware’s written in assembly.
The MicroGranny is a granular sampler based on the Arduino Waveshield and associated library (C++). It plays samples (one at a time) from an SD card and does granular madness to them. It doesn’t sample.
The last project is the Sample Player app for the MIDIBox platform. The hardware is basically just an I2S DAC hooked up to the MIDIBox Core module. It’s different to the others in that A) it doesn’t actually sample by itself, it only plays back samples from SD card, and B) it doesn’t allow much manipulation of the samples as it is. It is, however, much higher quality than the others, using CD quaity samples and 24 bit DACs. There are designs for two different DAC circuits on the MIDIBox site, but one is very old, and the other has recently been dropped from TI’s product line. Also, at least from looking at DigiKey, there no longer seems to exist such a thing as a through-hole DAC IC, it’s all surface mount.
None of these project fit what I’m looking for exactly. What I’m currently using my sampler for, mostly, is recording drum sounds and other one-shot noises from my synths. I need multiple outputs for this, and obviously some polyphony. Pitch envelopes are a must, and filters also. Once I’m done with my sequencers, I hope to start on this project more seriously. It’s definitely the hardest nut to crack, though, so I might do something easier first.