This project pushed “constraints as creative resource” to the limit. The client specified that the design language and elements from the product’s predecessor be maintained—down to the knobs, faceplate treatments, and typography.
The project brief revolved around electronic and industrial design work to bring the client’s preamplifer platform up to functional parity with current market offerings within a framework that fits with the client’s existing manufacturing capabilities. The result is a platform that is significantly more capable than what it replaces yet easier for the client to manufacture. It is also amenable to comprehensive appearance changes if and when the client deems the timing is right.
So while it might not seem there’s much innovation on the outside, there is a lot of innovation for the client on the inside.
I’ve just published Volume-AlpsRK16814MG, an open source hardware design that integrates a high-quality Alps motorized quad potentiometer with an H bridge. The design lets you control the motor’s direction using two logic-level signals: VOL_UP and VOL_DOWN. The fact that it’s a quad pot means you can use it to control regular stereo volume by ignoring one of the dual gangs or a differential stereo signal.
Here’s the schematic* to give you an idea what it’s doing. Gerbers and PCBs are available at OSH Park.
I’ve started a FLOSS remote control receiver project for DIY audio preamplifiers. I think it’s just about good enough to make public.
Remote control is one of the more challenging things for an audio DIY person to implement, so I thought having an open source hardware and software platform for doing this would be useful. It uses our good friend Arduino for brains and works with the Philips RC-5 protocol. I like RC-5 because its the closest thing I know of to a universal, well-documented, brand- and model-agnostic protocol.
The IR command decoding is done using Guy Carpenter’s excellent RC5 library. I also considered using Ken Shirriff’s multi-protocol IR library. Ken’s library works with a large number of protocols, but I thought its larger memory footprint might preclude porting this thing to tiny AVRs.
Details on the project are available in my RC5-Preamp GitHub or GitLab repository.[2021 update: This project is currently abandonware, so I have made the above repos private. If anyone wants access, contact me and we’ll figure something out.]