MUSIC REVIEW : Soviets Please and Disappoint : The U.S.S.R. Symphony was impressive in its 1988 tour, but in Orange County the 110-member orchestra played with only middling thrills.

In the 27 months since its last local appearances, the U.S.S.R. Symphony seems to have lost ground.

Mightily impressive in its accomplishments and musical powers when it played here in November, 1988, the 110-member orchestra from Moscow, opening the Southern California portion of its seventh U.S. tour Saturday night in Segerstrom Hall at the Orange County Performing Arts Center, played with only middling thrills, and with considerably less achievement than remembered.

The lack was certainly not in the first of its tour programs, a really satisfying agenda mostly in the key of D: Prokofiev’s “Classical” Symphony and First Violin Concerto, and Tchaikovsky’s Third Symphony. The problem seemed to be a low energy level and occasionally sloppy execution.

Another problem was the uncharismatic, often disinterested conducting of Yevgeny Svetlanov, the orchestra’s longtime, 62-year-old music director, who seemed to be walking through these performances.

By the end of the program, Svetlanov and the orchestra found a higher plateau of concentration in the closing movements of the Third Symphony. But even there, lagging focus and mechanical imperfections surfaced. Still, the many charms of the work were indicated, and often delivered.

The disappointments in Prokofiev’s Symphony in D had to do with the familiarity of the work, which in this country is usually heard in pristine and transparent readings by chamber-size ensembles.

Here, the playing was mostly respectable and mostly heavy-handed. Eschewing a light touch, Svetlanov let the orchestra lumber through the work at slow, uneager tempos. Some nice contrasts emerged periodically, but generally this was a weighty and charmless project.

At mid-program, the orchestra introduced, as it had at its last visit, a spectacularly accomplished, magnificently gifted young violinist--from the provinces, as it were. Vadim Repin, a 19-year-old fiddler from West Siberia, sailed handsomely through and over the myriad musical and technical challenges of Prokofiev’s cherishable First Violin Concerto.

All the tenderness in its lyric passages, all the ethereal qualities to which it regularly returns--as someone remarked years ago, this is a Prokofiev concerto for people who hate Prokofiev concertos--were manifested without self-consciousness and with complete confidence.

The mechanical hurdles? Repin leaped them with aplomb, revealing in no moment even a hint of immaturity or inexperience. Masterful.

Except for occasional lagging behind, the orchestra contributed wholeheartedly to this performance.

The U.S.S.R. Symphony--for most of the past 30 years, it has toured under the name Moscow State Symphony--is scheduled to appear at the Dorothy Chandler Pavilion Tuesday and Wednesday nights.