Edgar Winter was the most unlikely rock star of 1973. For five years we had been led to believe that it was his brother Johnny who was going to make it big — but a gold single, "Frankenstein," and the platinum album from which it was culled, They Only Come Out at Night, have changed all of that.

The junior Winter brother has seemed an increasingly viable pop star musician since he formed his first serious rock band, White Trash — one of the great white horn bands. But it mainly served to prove to him that the rock and soul he had played for cash in Texas was just as artistically worthy as the more esoteric stuff he had played after hours for friends.

The new Edgar Winter Group (modified only slightly by the addition of Rick Derringer as guitarist as well as producer) consolidates the fruits of that realization. While they lack a singer as talented as White Trash's Jerry La Croix, or an instrumental voicing as distinctive as the old band's extraordinary brass section, the group has three talented songwriters in Winter, Derringer and bassist/vocalist Dan Hartman—as well as a flair for making compelling hard rock music.

The Edgar Winter Group is best, not at innovation, but at distilling the Anglo-American heavy rock tradition. Their power comes from an ability to bring discipline and control to a genre that often seems predicated on the absence of those prerequisites of pop. This is due in large measure to Derringer's ever steady production hand (they are much more lax onstage) but also speaks of an increasing maturity on the part of the musicians.

In fact, if the album has a major flaw, it is that the teenage idiom in which it is written often seems forced. These are not kids, even if they are playing primarily for a young audience. Song titles like "Some Kinda Animal" and "Rock & Roll Woman" are indicative of an occasional strained attempt to become more commercial which leads them into a certain silliness.

At their best the Edgar Winter Group sounds like an American Led Zeppelin. On Hartman's "Queen of My Dreams," they copy them perfectly, producing one of those multiple-guitar, vocal extravaganzas at which Zeppelin excel. Hartman's "Sundown" also reveals the melodic influence of Zeppelin's Jimmy Page and Robert Plant.

Edgar Winter's songwriting is more soul inflected. He is one of the very few white musicians who has had the good taste to pick up on the directions pointed by Stevie Wonder and Sly Stone. On "Do Like Me" Winter's synthesizer sounds especially like Wonder, and his guttural vocal is out of the Sly handbook. However, Edgar adds his own distinctive touch — one of those strange scat vocals, set against guitar, whose origin is known only to himself.

Rick Derringer is apparently, and I think unfortunately, reserving his songwriting for his solo albums. Since his playing and production are so dominant in the group, this may seem only a minor misfortune. But the problem is accentuated because his lyrics are just the kind of facile, unpretentious stuff Hartman's and Winter's never are: He doesn't overreach for poetry, he just tries to write a song.

Shock Treatment is fun to listen to, even if it doesn't produce anything substantial to ponder after it's over. Hopefully, increasing maturity will allow an otherwise excellent, if derivative, rock group to replace the teen veneer with something more substantial. (RS 165)

DAVE MARSH