The Slovakian conductor Juraj Valcuha made his National Symphony Orchestra debut in 2010 with an ambitious program of Haydn, Szymanowski and Mahler; I liked his conducting, and his restraint. He returned in 2012 with Szymanowski, Mozart, Ravel and Debussy; I still liked his restraint. He came back this week and conducted, on Thursday night, an arguably somewhat less ambitious program of Stravinsky’s “Pulcinella” suite, the Bruch violin concerto and Tchaikovsky’s Fifth, which fits with the NSO’s Tchaikovsky focus of the past few weeks but which we have surely heard often enough in recent years. This time, I found his conducting really, really slow. He may be taking restraint a little too far.

This particular program didn’t open by playing to his strengths. The suite from “Pulcinella” is a delightful, faux-archaic romp, sweet and dusty and distant like the musical equivalent of a sepia snapshot in its evocation of the late Baroque/early Classical period in general and the music of Pergolesi in particular.

But Valcuha seems to be a conductor more naturally suited to big, generous Romantic sounds. “Pulcinella” is scored for a chamber orchestra, but he made it sound a lot bigger. Absent, in his reading, was the work’s light, spry, antic, quirky charm. In its place we got a sound that was often almost lugubrious, a lot of oddly murky textures, and heavy, heavy playing from the NSO’s soloists. It was a different “Pulcinella” than I’m used to. If Valcuha was making a point, I don’t know exactly what it was; it sounded like kind of a mess.

The second piece on the program brought out a ray of clarity in the person of Vilde Frang, a young Norwegian violinist who has made strongly favorable impressions on me first with her recording of the Tchaikovsky and Nielsen concertos and then with her appealing Washington debut, courtesy of Washington Performing Arts, two years ago. Appearing as if out of a painting by Dante Gabriel Rossetti, with a cloud of red-brown hair, she tucked into the Bruch concerto with an inward focus that drew the listener toward her, pulled into the vortex of compelling sound rather than trying to impress with a huge flourish. Her phrasing was exquisite, except when it was overwhelmed by the orchestra.

This piece was a much better fit for Valcuha: Right away, there was a sense that on a canvas of this scale, he could start to make himself at home. But this didn’t speed up the playing any. The whole thing was slow, and the second movement, though lovely, took so long I am almost surprised the concert ended at the normal time. This did Frang no favors; dragging out the pace sometimes led her to the brink of a kind of self-conscious lingering over sound that didn’t seem natural to her. There was a risk of dwelling on the It-ness of it all — something fortunately mitigated by the pace of the finale, shot through with similarities to the Brahms concerto. (A friend at intermission noted the easy-to-forget fact that the Bruch concerto was actually premiered more than 10 years before the Brahms one.)

I’ve liked Valcuha in the past for his authoritative, flexible, fluid sound, and the Tchaikovsky symphony bore this out. It also featured the slowest opening I have ever heard: The symphony’s signature Fate theme, which recurs like a leitmotif throughout the piece, took on the dream quality of moving through quicksand. In this piece, I got the point: The slow start gave the music a place to go, and Valcuha led the orchestra through a leisurely march and into a kind of balletic grace, which recurred again and again. There was time for the music to breathe — time to hear the articulation of the sections at the start of the second movement, the grace of the third movement, and the gleaming unsheathing of brass in the fourth. There was so, so much time to hear it. I liked a lot of what Valcuha did in this piece, but I have never spent quite so much time in a Tchaikovsky Fifth before. If you love Tchaikovsky, you might want to get to the second or third performance: seldom will you be able to wallow in his music with quite so much abandon.

The program repeats tonight and tomorrow at 8.