Control Panel

Having your name appear as a logo makes anyone proud.

The Layout

Designing a control panel requires two disciplines: ergonomics and aesthetics. Not only should it look nice, it should perform nicely as well. The controls should be laid out with enough room between them so that adjustments can easily be made with human hands.

While working on my control layout mock-ups, I kept going back to a "V" theme. At first I had all 5 knobs aligned in a "V" configuration, and then I found some knobs at Mouser Electronics that came in various sizes. I thought using three different sizes, with the largest one in the center, might look really unique. Most amps have identical knobs all the way across the front panel, and I used this opportunity to give my design some flair. 

Normally, "volume" or "gain" is the first knob you might see on an amp, left to right. However, with the various sizes of knobs, there is a center emphasis, meaning the centermost (and coincidentally, the largest) knob should hold higher importance. Some guitarists might disagree, but in my mind the volume control is the most important, so I put it in the center. That left two "banks" of controls, one pair to the left of the volume and one pair to the right. I chose to make the bank to the left the "tone" controls (treble and bass) while the bank to the right holds the controls for tremolo (Fender calls them speed and intensity -- I chose to call them rate and depth).

Even though I changed the order of some control potentiometers in this layout, it didn't seem like it was going to cause wiring issues. The order of Fender's Vibro Champ read, left to right, Volume, Treble, Bass, Speed, & Intensity. In my layout, by putting volume in the center, I wanted to make sure I kept things relatively neighboring each other to prevent unnecessarily long wire runs and additional resistance or hum. Logic tells me that bass should come before treble anyway (as it does on most equalizers I've ever used), so essentially I just flipped the controls as Fender had them: Bass, Treble, Volume, then left Rate and Depth as they were. 

I now had a control panel layout that looked nice, made logical sense to me, and would hopefully make sense to anyone else who used the amp.

Control Panel Construction

Being a prototype built in my kitchen, I'm trying to control costs wherever I can. Certainly, I could have a piece of steel bent, chromed, and silkscreened just like Fender does, but that would be prohibitively expensive for only one panel. I also considered skipping the chroming step and just silkscreening my design on metal. Still pretty expensive. I thought of making a vinyl label and adhering it to the chassis, but die-cut vinyl might peel up, and printed vinyl might fade or rub off with prolonged use. The durability might increase if a thin piece of plexiglass or Lexan was placed over it. 

I work at a newspaper, and we use aluminum plates to transfer the ink to the newsprint on the presses. The images from our computers get on the plates through film negatives and emulsion exposure, much like that of combining the photographic and lithographic processes together. Once a plate has been exposed and washed, the images appear on the aluminum plate in dark blue. I asked a few of the press operators how durable this blue emulsion was, and they all told me it would last pretty much forever. I had found a solution, at least for my prototype!

I had been doing my mock-ups of control panel layouts in Adobe Illustrator at full size, so ultimately all I had to do was print that layout to our film negative imager and expose a plate. The result, once placed under plexiglass for further scratch protection, looks quite professional (see photos above). 

After drilling both the plate and plexiglass, it looks like my alignment was off by about 1/16" but not very noticeable unless pointed out. The result is that the labels beneath each knob nearly touch the knob itself. The only spot that is quite noticeable is at the On/Off switch, since the toggle switch is supposed to be centered between the words "on" and "off."  Overall, I decided I could live with those imperfections. Afterall, this project should retain some "hand-made charm."