Christian Tetzlaff's interpretations of Bach's Sonatas and Partitas for Solo Violin are more cerebral than romantic, yet Tetzlaff manages to play with such subtlety and grace that you never mistake him for a machine. His tempos are swift - sometimes swifter than I prefer. Perhaps for this reason its easy to overlook just how little vibrato he is using. His playing is characterized by a pure, clean tone, lively phrasing, subtlety, and spontaneity. He plays the fugues with such ease that they never fall into the "sword slashing" often heard in other recordings. The Adagio of the first sonata is an example of how he can develop incredible tension without resorting to ultra slow tempos. Another noteworthy movement is the second double of the first partita. I doubt you have ever heard it, much less imagined it played like this - blindingly fast but with subtle phrasing and intonation completely intact. Really you can find something interesting about how he plays practically every movement - there is so much artistry to savor here.
The differences between his two recordings, the first for Virgin in 1995 and the second for Haenssler Classics in 2007, are subtle save for one - the recording acoustic. Whereas the earlier recordings on Virgin are given a slight reverberant sheen the latter recordings on Haenssler are presented in an intimate but unforgiving up-close acoustic that accentuates the darker tones of his violin. Sound aside, one might argue that there is just slightly more dynamic and rhythmic subtlety in the second recording and tempos sometimes seem just slightly more relaxed. Sometimes I think I prefer the earlier recording - I find the acoustic to be more beautiful - but then I listen to the latter recording and find so much to enjoy in Tetzlaff's playing.
Those looking for romantic interpretations of the sonatas and partitas, in particular those who tend not to like fast tempos in these works, can safely avoid Tetzlaff's recordings (you might consider James Ehnes on Analekta). Also, I must say that his swift and spare way with this music is best appreciated when complimented by recordings from the opposite end of the spectrum (Milsten, Grumiaux, or Ehnes for example). With those caveats aside I can comfortably say that Tetzlaff's Bach recordings are among the most thoughtful, virtuosic and stimulating I have heard. They have an elusive quality that always beckons me back to listen.