© 2019 Christian Ekren Design

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PROJECT

Wireless guitar amp
Associated Show: RENT, West Fargo Summer Arts Intensive
Time: June - August 2015

For this production of RENT, the director and I collaborated to find a solution to the ubiquitous guitar amp that Roger is supposed to play onstage during the first scene of the show. Unfortunately, power was inaccessible -and our actor was unable to play the instrument anyway! After a few brainstorming sessions, an answer was proposed: a portable, wireless guitar amplifier that would give the appearance of our Roger playing, while actually outputting our guitarist playing from the pit, located onstage. Fortunately, stage volume was a non-issue for all instruments but the drum kit, as every musician was using in-ear monitors and direct-inputs, so there was no pit guitar amp-noise to conceal!

The final rig contained the following gear:

  • x1 "vintage" Peavey Backstage guitar amp, circa early-1990's

  • x1 modified Shure PGX receiver and transmitter

  • x1 small car audio amplifier

  • x2 AGM 12v RC project batteries

  • x1 RC controller w/ voltage regulator

  • x1 power LED

  • x1 power relay

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Most of the amp's original components were completely bypassed, except for the speaker itself. The RC project batteries fit perfectly inside the cabinet, giving power to a Shure PGX receiver (with modified power cable to accept 12v DC directly) who's output fed into the car audio amplifier. This amplifier powered the original Peavey driver inside the cab. The PGX transmitter was fed from an aux output on the pit console, with a cue changing the routing of the guitar between the main bus and guitar amp aux. 

 

A small remote-controlled toy was salvaged to create a remote on/off relay switch that could be controlled from the booth. This switch controlled 

both a small red LED "power light" on the front of the unit, as well as triggering a relay controlling every other piece of gear. The sudden power-loss caused the cheap car amplifier to send a loud "pop" through its output to the speaker, which in this case was desirable to accent the sudden loss of power that helps start off the titular song, RENT

The RC controller in the booth was modified to accept a constant power source from a wall-wart power adapter, to have one less item to worry about charging each night. The original "drive forward" joystick was converted from a momentary to toggle switch so the operator would not have to constantly engage it to keep the amplifier on. The RC receiver, originally a small toy tank, was completely disassembled and modified to be powered from the 12v project batteries via an LM317 voltage regulator. The power leads originally used to control the drive motor were routed instead to a power relay, allowing the 3v output to toggle the much higher power 12v circuit being used by the PGX receiver, car amp, and power LED.

Photo: RENT, 2015

West Fargo Summer Arts Intensive