A Brief History of Tremolo: Premier Guitar

premierguitar201311 tremolo cover 200W

What do Bo Diddley, Muddy Waters, Big Bill Broonzy, The Staple Singers, Nancy Sinatra, the 1939 World’s Fair and a 16th century organ in Italy have in common? They are all discussed in my second article for Premier Guitar magazine, A Brief History of Tremolo, appearing in the November 2013 issue. Tremolo, an oscillation in volume, is a “natural” effect for many instruments. Move a bow on a violin back and fourth while holding a note and you’ll hear it. But what about guitar? Not possible by any normal means – only when you electrify things. Who was first?

The online version (click above) also contains links to some YouTube videos.

Medical Packaging Innovation blog


Over the last few months I’ve been writing a series of blogs for Medical Packaging Innovation. My posts are here: MPI: Dan Formosa. The site is new, just started up earlier this year. Some lively discussions are going on. For my topics, the definition of “technology” elicited quite a bit of discussion (is it “technology” if no one can use it?) Or whether your product is male or female (the product itself, not the people using it – that thought seemed to cause confusion for a few people.)

If you get a chance check out all the posts on the site – some great people are blogging there. Comments are closed here on my site (been getting too much spam, need to fix that), but when you get to the MPI site, leave comments!

May 21 2104 Update: Medical Packaging Innovation has been rechristened, becoming Medical Packaging Community. My posts are scattered throughout the pages. To find them faster you can try searching Google with:
“dan formosa site:http://www.pmpnews.com/news”


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 (colbyamps.com) and Tim Schroeder (schroederaudioinc.com) 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.

Arthritis, hearing and vision trouble in the US

The Center for Disease Control in the US periodically publishes updates on health statistics. Here is a chart showing age distribution of three common problems – arthritis, hearing trouble and vision trouble (even after corrective eyewear).

The CDC reports this data in age brackets. For this chart, I interpolated that data – because a line chart makes the age distribution easier to understand. I also placed a dividing line at age 55, to split the adult population into two groups. (Choosing 55 was an arbitrary decision, I did it just to make the information easier to discuss.)