Why does Lou Donaldson attach an electric pickup to his alto saxophone? It's not to increase his volume. The Blues Alley, where he's appearing through Sunday, is cozy enough for every seat to hear the softest acoustic passages. So it's not for the special effects possible with electronics, for Donaldson avoids them totally.

It's certainly not to improve his sound, for the amplifier flattens out his highs and lows and gives every phrase the same buzzing, mild tone. One suspects the reason is convenience. An electric pickup on a saxophone can compensate for less than total concentration and effort and still produce acceptable if not exciting results.

Donaldson's approach to jazz Wednesday night was acceptable results for minimal effort. Once a noted musical heir of Charlie Parker, Donaldson coasted on his technical competence. There was little real improvisation, only the reshuffling of familiar bebop runs.

No one in Donaldson's quartet was disposed to challenge this approach. Donaldson seldom varied the tempo, volume or emotional flavor of any song. He did play the melodic embellishments on old standards like "Caravan" and "For All We Know" with fluid confidence. But when he did "Cherokee," the old jazz testing ground for how fast and hard you can play, Donaldson typically took it easy.