Designing a New Piece of Recording Gear Pt. 1: The Concept August 07, 2012 14:22 60 Comments

For a while, I had been on the lookout for a collaborator to work with to bring something utterly new to the DIY community. Someone with professional design chops who understood the DIY community and was open to the idea of making their designs open source. I was lucky enough to find Link Simpson by stumbling accross his Steller Studios DIY projects page. Expecting to find the usual gallery of completed kits and and guitar pedals, I found instead totally new designs for a preamp, compressor, personal headphone mixer, and more, all made from the ground up by Link himself. This was some next-level stuff! So I arranged a call and we began immediately throwing around project ideas.

What should we make?

I went into the brainstorming session with three main criteria for our new piece of audio gear:
  1. Must be inexpensive, safe, and easy to build. Only modern, off-the-shelf components. No tubes or high voltages, avoiding AC power completely if possible. I wanted this project to be as newbie-friendly as possible.
  2. Not another clone, preamp, or compressor. I have only admiration and respect for the people who have brought great vintage clones to the DIY community, but that's not the direction I wanted to go with this project. Similarly, I don't think there will ever be a day when we have too many preamps or compressors (will there ever be too many craft beers? ice cream flavors?), but I wanted to do something more off-the-beaten-path.
  3. Something sexy. I'd had a lot of fun developing a passive summing kit and reamp box, but they weren't the kind of projects people were likely to drool over. I wanted our project to be something that would really capture peoples' imaginations and inspire them in the studio.
For a couple of weeks we tossed a ton of ideas back and forth, until Link astutely pointed out that most of my ideas included "the ability to push it hard for harmonic saturation." Why not--Link proposed--just focus on the harmonic saturation? Bingo.
"Harmonic distortion is sonic varnish." -Allen Farmelo

The Vision

500-series distortion front panel
We immediately began outlining a project that we're currently calling "Codename: Colour", a line-level harmonics generator with a variety of distortion stages that can be mixed in with the dry signal via independent wet/dry controls. Our vision is for a device that provides a range of subtle, yet distinctive "sonic varnishes" for your tracking and mixing palette. Because subtle harmonic saturation is often most effective when layered over multiple channels, our goal will be to make the Codename: Colour inexpensive enough that people can build numerous channels.

Refining the Design

Now that we had our core idea, we faced another round of big decisions. "Which types of distortion?" "How should it be racked and powered?" "How should we balanced the output?" Etc... For today, I'll cover our current thinking in regards to the distortion types and powering/racking the unit.

Distortion Types

Link proposed a few different distortion stages:
  • JFET, tube-like distortion
  • Rectified, octaver-type
  • Enhancer-type effect with treble-focused distortion
  • Opamp/diode tape-like distortion
All of these would be achieved with sold-state, currently available parts, similar to the distortion stages in gear like the Empirical Labs Distressor or the Crane Song HEDD. One thing we agreed upon early on is that our goal with this unit would not be to emulate some "classic" sounds, such as "tape" or "triode," but to create sounds that we found beautiful or exciting. This is in line with our shared belief that words like 'tape' and 'tube' have been abused into meaninglessness by marketing departments.

Powering and Racking

As we weighed power supply options and priced out a run of metalwork, it became clear that developing an API 500-series module would allow us to focus more deeply on the audio circuit itself and make the unit affordable enough to mass produce. Indeed, the more experience I have with designing and dissecting audio gear, the more I come to the conclusion that modular formats such as the API 500-series and the 51x Alliance provide the best solution for most rack-mount gear. This is especially true for small manufacturers (DIYers being the smallest) who don't move enough volume to get bulk discounts on specialized components such as the power supply tranformer and metalwork. This is something that the DIY synth world has been onto for years and that, thankfully, is finally gaining ground in the recording community. I am, however, very reluctant to alienate those builders who don't have a 500-series rack, and I know how frustrating it is to see great gear released in a format you're not ready to commit to. So the final version of the PCB will certainly have a built-in option for racking the unit in a 1RU case.

What's Next?

In the next post, we'll delve deeper into the technical details of the circuit and pose some more specific questions about how the unit will operate. For now, we'd love to get your feedback on the core idea and features. Can you see yourself using something like this? Are there any important features you think we've overlooked? What do you think of the idea of ditching words like 'tape' and 'triode'?