He played with laryngitis and wore a portable amplifier during regular season games with San Francisco.

A product called the JamPod can turn an iPod into a portable private amplifier.

People now drive to the sanctuary, mainly by truck - and the journey is accompanied by the sound of religious chants played by portable amplifiers.

A multi-purpose battery-powered portable amplifier featuring 5 Watt stereo power and two 4" speakers.

A portable amplifier with four 4" speakers.

It is a small, lightweight, portable amplifier, for use as a portable practice amp or when larger or more expensive amplifiers may not be practical.

A portable amplifier, for example, may be used to increase the volume of speech and thus its intelligibility.

He plays a Fender stratocaster guitar with a strap and a portable amplifier.

He was speaking over a portable amplifier as he stood in the tonneau of the command car.