till.com  Articles

A collection of my articles on various topics. Some readers may find them interesting.

Business and Economics

32 Startup Ideas
Want to do something different? I'm now keeping a collection of my startup ideas. Updated!

Startup Proposal: Intelligent Traffic Signals
A proposal for a startup company to disrupt the century old traffic signal industry, while lowering fuel consumption and exhaust emissions.

A New Business Model for the Music Industry
How record companies can actually win big in the next couple decades.

Guitar Electronics

Pickups Part 1: Response Effects of Guitar Pickup Position and Width
Analysis, equations and plots of pickup response curves.

Pickups Part 2: Response Effects of Guitar Pickup Mixing
Analysis, equations and response plots of mixes of pickups.

Parts 1 and 2 were heavily referenced in Paiva, Pakarinen, Välimäki, "Acoustics and Modeling of Pickups", Journal of the Audio Engineering Society, October 2012.

Pickups Part 3: Pickup Response Demonstrator
Try it out!  Move pickups around, draw pretty curves. This is the new HTML5 version that runs anywhere.

A Discrete FET Guitar Preamp
A popular example circuit for a guitar preamp based on a single FET stage.

An FET Preamp Cable
A phantom-powered preamp built into a 1/4-inch phone plug.

Original Synthesizer Circuits

Root Locus Demo of Real Poles with Feedback
An interactive Javascript demo shows how feedback liberates the poles of a passive circuit from the tyranny of the real axis. New!

A Palette of Static Audio Waveforms
Bored with audio oscillator waveforms? Me too. Here is a musically powerful palette of waveforms, including two that didn't have names before.

The Quadrature Trapezoid Voltage Controlled Oscillator
An original oscillator topology features quadrature waveform outputs and graceful thru-zero FM.

Voltage Controlled Duty Cycle Sawtooth Circuit
Some quick notes on a circuit I came up that can morph from a sawtooth to a triangle to a reverse sawtooth with a control voltage.

An Interpolating Scanner Circuit
An alternate approach to Juërgen Haible's interpolating scanner.

Keyboards and Synthesizers

Javascript Muse New!
A software implemenation of the Triadex Muse that runs on a web page.

Square Wave Variations
Square Waves may appear uninteresting at first...

Moog Synthesizers: Moog Patents
A project to dig up, research, and review all of the patents by Robert Moog and related to Moog synthesizers.

ARP Synthesizers: ARP Patents
A project to dig up, research, and review all of the patents related to ARP Synthesizers.

ARP/Rhodes Chroma: Upgrading the Power Supply ("Nuclear Powered Chroma")
Replace a Rhodes Chroma power supply with a modern switching unit.

Don's Mellotron Page
Mellotron resources, notes, projects, the Mellotronists mailing list and the tale of a restored M400 with Mike Pinder's autograph.

Mellotron/Chamberlin Patent Reviews
Reviews of the Harry Chamberlin Mellotron Patents, as well as the Birotron patents.

[Outdated] Analog Synthesizer Resources
My favorite synthesizer design links.  General, historical, manufacturers, design, schematics, research.

[Outdated] ARP Synthesizers: ARP Resources
A collection of resources for ARP Synthesizers, including the ARP/Rhodes Chroma.

[Outdated] Moog Synthesizers: Moog Resources
A collection of Moog resources.

[Outdated] Hohner Clavinet Resources
A collection of resources for the Hohner Clavinet.