Headphone Amp Power Upgrade
Apr 1, 2009 12:00 PM, By John Landry, CSRE
Landry’s modification to the Sanyo LA4440 amplifier chip.
Click to enlarge
A friend recently had to produce a remote and was short a headphone amplifier (there also was no money to buy anything, so whatever we could find would have to do). Digging through the equipment pile resulted in several pairs of headsets and cables, and a Realistic SA-150 amplifier. When we set up the remote (a talk show at a small diner) it was obvious we would need more volume in the headphones.
I took the SA-150 home and found a simple solution: Turn it into a bridging amplifier. The SA-150 uses a Sanyo LA4440 amplifier chip. After downloading the spec sheet from www.datasheetarchive.com I found out the chip could deliver 19W in bridging mode instead of the as-designed 6W. And because the Radio Shack designer used Sanyo’s circuit straight from the datasheet, this would be an easy mod. The end result was good enough.
Landry is an audio maintenance engineer at CBS Radio/Westwood One, New York.
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