There is a sound that steel guitars make on old country records from the ’40′s and ’50′s that you rarely hear anymore, sometimes referred to by steel guitarists as “boo-wah”. At its simplest, boo-wah is achieved by playing a major 6th chord and playing with the steel guitar’s tone control so that you are moving between a bassy sound and a more clear, trebly sound. Listen to Jerry Byrd’s playing on Hank Williams’s 1949 “I’m So Lonesome I Could Cry” to hear what I’m talking about:
We began by considering how we wanted to achieve the boo-wah effect. Some steel guitarists used the tone knob on the guitar. Others used a volume pedal with a side-to-side tone control, made by Fender or Bigsby. Still others suggest that the best way to get the rapid-fire effect you hear on Speedy West and Jimmy Bryant records requires a tone circuit attached to a momentary push-button switch. We decided to try the first two methods in our prototype, and also add in a “stutter” switch: a normally closed momentary kill switch.
With an idea of how we wanted to achieve our boo-wah, we headed off to Quinn Labs (Ryan’s basement) to draw up a simple circuit to build into an aluminum chassis. The signal comes in through a 1/4″ jack, and goes to a push/pull switch on a 250k potentiometer. When knob on the pot is down, it acts as a tone knob. When the knob on the pot is pulled up, treble is cut is controlled by a push button switch. After the tone controls, the signal passes through a second momentary switch for the “stutter” effect and then to the 1/4″ out jack.
Since this is just a prototype to work out capacitor/resistor values and prove to ourselves that it would be a worthwhile addition to Andy’s sound, the final result is pretty ugly. Here’s Andy using the effects a couple minutes after we hooked them up: