Joys of Low-Voltage Audio: Avoiding input stage crossover

high-voltage lines

In this installment of the Joys of Low Voltage Audio series, I want to present some considerations and techniques to help you work with one of the biggest quirks found in RRIO opamps.

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Joys of Low-Voltage Audio: R2R terms and techniques

high-voltage lines

In the third installment of this series, I want to talk about one of the device types you’re almost guaranteed to encounter in low-voltage audio: the rail-to-rail opamp. More specifically, I want to talk about the terminology around rail-to-rail opamps and the techniques used by IC designers to achieve rail-to-rail behavior. So let’s start by answering a fundamental question.

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Design bind: Can you make the logo bigger?

The scenario: You’ve been hired to do some design work, you’ve submitted the deliverables, and they were accepted. You maybe even got paid. The client later comes back and asks you to change something in a way that you think breaks the design in an unacceptable way. What do you do?

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More module talk

Schematic of module interface

A few years ago, I developed an audio gain cell that was exceptionally fast for a fully discrete circuit and quite clean. That design ended up being adopted commercially, including by Audio by Van Alstine, who are using it in their DAC MK 5 and Vision preamplifier. I like to think that this gain cell is a key factor behind why the owner of a well-regarded manufacturer of luxury loudspeakers called the AVA DAC MK 5 one of the best sounding DACs he’d ever heard and a model for other manufacturer’s to live up to.

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Designed to fail: An absence of commitment

Ugh! photo by Nathan Dumlao on Unsplash

I had a discussion recently with someone about a not entirely uncommon situation consultants can find themselves in. You get hired to solve a problem, but the reason they have hired the work out rather than do it internally is because they aren’t really committed to making the project a success. What do you need to know to best deal with this situation?

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Joys of Low-Voltage Audio: Power strategies

high-voltage lines

In an earlier post, I talked about how I entered the world of low-voltage audio and my commitment to delivering the best possible performance subject to that constraint. In this post I’d like to consider some strategies for generating power in your LV application.

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Doug Self’s “The Design of Active Crossovers”

I just discovered that I got a mention in Doug Self’s book The Design of Active Crossovers for the work I did a while back on loudspeaker crossovers. If you don’t know who he is, he’s one of the big names in British audio engineering. He’s done work for Cambridge Audio, TAG-McLaren Audio, and other respected brands. Feeling warm and fuzzy.

Joys of Low-Voltage Audio: A journey begins

high-voltage lines

It turns out the world of low-voltage audio is a lot of fun, and I’d like to start sharing some of my journey through it.

I suspect everyone has a different reason for entering this world, lending each story a different color and set of priorities. Mine goes something like this.

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FreeCAD for Industrial Design

The open source community has produced a number of serviceable tools for two-dimensional design. These include GIMP for bitmap graphics and photo editing, Inkscape for vector art, and Scribus for page layout. On the 3D side, Blender, Wings 3D, Art of Illusion, and a few others have served the needs of those doing surface and subdivision modeling. And while lots of good work has been done using those tools, I haven’t found surface and subdivision modelers very useful for industrial design work, except for occasional rapid ideation or visualization. FreeCAD is different in that it’s a parametric modeling tool, which has a history of effective use in ID.

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Timestamps for KiCad footprints

I’m bulk editing a bunch of KiCad footprints (a.k.a. modules) in a text editor. Said footprints have a tedit field, which turns out is a hex-coded timestamp. This means to properly edit a KiCad footprint in a text editor, you should update that field when you save it.

A one-liner for producing a hex-coded timestamp in Linux bash is:

printf "%X\n" $(date +%s)