How Tube Amps Work: Premier Guitar

Premier Guitar August 2013 cover xsm


Happy to have written, illustrated and photographed the cover story of this month’s (August 2013) issue of Premier Guitar magazine. The article gives a part-by-part description of tube amp technology using my favorite amp, a 1960’s Vox AC4. It traces the guitar signal through every component, from pickup to speaker. And it gets into a not-overly-technical description of electrons, current flow and the basic operation of vacuum tubes.

In addition to print, an online version is here:

How Tube Amps Work

Also, if following along here is the original Vox AC4 schematic mentioned in the article.

Special thanks to Mitch Colby ( and Tim Schroeder ( for their technical assistance with the article.

Include 2013, Hong Kong

Include Asia 2013 logo sm


I was in Hong Kong earlier this month giving a talk and workshop at the Include Asia 2013 conference. Usually held in London, the conference focuses on design for all – it was a first for Hong Kong. My keynote talk covered a range of topics, but with the underlying idea that “questioning everything” is a pretty good first step in innovation.

The workshop was titled Body & Mind. I ran it with Steve Wilcox, head of Design Science in Philadelphia. Steve’s Ph.D. is in cognitive psychology, mine is in biomechanics. There is, unfortunately, not enough of either being taught in design schools. For the 40 participants in the workshop this was apparently an introductory exposure to either topic. Of course, if you are going to design for all, basic (or extended) knowledge in these areas will help immensely.

Thanks to everyone who attended the conference and the workshop. In addition to the conference presentations, it was great seeing (and having a chance to hang out with) the RCA crowd again.