The Shuguang 12AX7B is a popular current-production vacuum tube from China that offers reasonably natural sound reproduction at a budget price. It is not perfect, but represents one the better currently available 12AX7 tubes. The Shuguang 12AX7B reproduced the bass, drums, and vocals of the classic Marvin Gaye LP “What’s Goin’ On”quite convincingly, laying down a strong bottom octave and lending vocals a warm, natural openness. The Shuguang 12AX7B’s warm, lively midrange also does well with Jazz and Classical music. Above the upper levels of its pleasant midrange, however, the 12AX7B from China begins to gradually roll off treble response. Brass instruments lose the leading edge of their fierce attack transients to a degree, and cymbals are reproduced mainly as the initial crash, with much less harmonic “shimmer” content resolved as compared to the Russian 12AX7s. The treble that IS there has a harmonic “rightness” to it, but much of it simply gets lost in the mix. And while the 12AX7B from China is not exactly ultra-high resolution it does produce an organic, natural-sounding soundscape. The Shuguang’s deficiencies are relatively easy to live with; this tube did not mangle or greatly alter any part of any recording we played using it, nor did it dry out or impart a “cold” presentation to well-recorded music.
Strengths: natural timbres which produce a harmonic rightness and midrange warmth, both of which make it the most natural sounding 12AX7 of the current production tubes.
Weaknesses: Does not have much upper treble extension, washes out some detail of great recordings.
Note: This review is actually from a multi-listener session of new production vacuum tubes. Notes were summarized by my good friend Chris James.