Some cool one-offs Jerry built over the years
...and a 3x40-Channel Source Selector to go with its buddy below
This is the biggest board I've ever done, at about 17x10". 10 stacked DB25s, 82 relays, close to 2000 plated through holes and vias
40-Channel Volume Controller
This is likely the world's highest channel count analog volume controller. It acts like a 40-gang potentiometer, but with +/-0.05dB of channel gain matching, remote control, and stellar audio performance. I was initially tasked with buying something like this for an immersive audio research lab with dozens of active speakers. I looked hard, but nobody makes one. Great! One-offs are my specialty.
Fun fact: I gave a presentation about it in front of a roomful of researchers, Masters' and PhD students. The presenter just before me was none other than the president of Merging Technologies, who was visiting from Switzerland and had just presented his company's brand new Anubis monitor controller. No pressure there :)
Here are the slides. They're pretty sparse without my commentary, but you'll get the general idea.
The hardest thing I've ever made. A state-of-the-art, 2-channel, 24bit/384kHz USB audio interface with several calibrated input and output gain ranges. I designed it to use with software for audio tests and measurements.
It came in second place in a big Audio Precision measurements-based shootout between high-end audio interfaces at McGill University. And I think it got cheated out of first prize ;) Other worthy contenders: Merging Horus, RME Fireface UFX, Focusrite Scarlett 18i20, and others I forget.
Don't believe me? Just ask George.
Mobile Front End for Audio Testing. The precursor to Squiggly Lines above. It's not a standalone computer interface, but a calibrated, level translating front end designed to work with a laptop's built-in audio. It enables the laptop to input or output balanced or unbalanced, pro level audio (up to +30dBu balanced/+24dBu unbal, in 3 calibrated ranges, 20dB apart), on XLR and BNC connectors. It also has built-in +48V phantom power for testing microphones directly.
MFAT is USB-powered by the laptop it works with, internally generates the higher voltages it needs (+-20V rails, +48V), and manages to stay within the standard 2.5W power budget of a USB2 port.
Custom 16-in/16-out audio PC in a suitcase. Made with full size dektop PC components and the audio guts from a Mackie Onyx Firewire mixer.
Gig-Worthy Rackmount Audio PC
Long before Solution J, I built this rackmount PC for myself. A quad core MicroATX PC crammed into a tight 2RU case. It had two 8-channel M-Audio Delta 1010LT PCI sound cards inside, fronted by 16 mic preamps that I designed and built. I added a headphone amp on the front panel, a 2x15W digital power amp with speaker outputs in the back, MIDI I/O... the works.
The main design requirement was reliability (no audio glitches or crashes), at a time when external USB and Firewire audio interfaces were generally not stable enough to trust for live sound gigs. I played a few live shows with my cover band using this PC as the 16-channel house mixer and multitrack recorder simultaneously. No crashes!
A little 8-channel mic pre, about as small as can be while using standard XLR connectors for both ins and outs. Built-in power supply, too - no wall warts or line lumps.
See the PC above? When I decommissioned it, I couldn't bring myself to discard the 16 mic preamps that I built into it. Thus, two standalone 8-channel mic pres were born. This is one of them...
...and this is the other one, built inside a recycled Lexicon I-ONIX enclosure.
8-Channel Unbalanced to Balanced Audio Interface
I made several of these to balance the RCA outputs of some DVD-Audio/SACD and BluRay players and bring the level up to the pro standard.
Two of many I've made. I've lost count.
One of them is battery-powered, the other runs on AC (built-in power supply).
The Grey Box
This is really old, circa 2004. I believe it's my first 8-channel balanced/unbalanced interface. Built-in power supply (seemingly a recurring theme in my designs). Still works great to this day.