Technical details aside, this Slovakian 12AX7 tube falls sonically at a midpoint between the Chinese 12AX7B and the Russian Sovtek 12AX7LPS. The listening panel found the main weakness of the JJ ECC83S to be a slightly lackluster level of resolution; it simply failed to capture many of the subtle nuances and micro details of our reference LPs. On the classic Ornette Coleman LP “This Is Our Music” the listener can occasionally hear the musicians take a particularly deep breath off-mike before a long run of notes. This and other subtle shadings were less well reproduced by the JJ than with either the Shuguang 12AX7B, or the Sovtek 12AX7LPS for that matter.
Listeners who primarily listen to rock and roll music will find the JJ more suitable; it has a sense of cohesion and balance that delivers much of the raw punch and metallic edge of AC/DC lead guitarist Angus Young’s opening salvos on their classic “Let There Be Rock” album. However, with any source material the JJ ECC 83 S maintained a consistent, “tube-like” sound characterized by a natural resolution of complex harmonic structure, good sonic balance from the lowest bass octaves to the surprisingly natural, extended treble response. Like the Shuguang 12AX7B, the JJ ECC 83 S produces a sonic image that is slightly less detailed and high-resolution than the ideal, but unlike the Sovtek LPS or the Tung Sol Russian 12AX7s, the JJ ECC83S never let the listening panel forget that they were hearing the magic of vacuum tube, analog audio.
Strengths—Natural sonic balance and presentation.
Weaknesses: Less than excellent detail retrieval and only medium resolution.
Note: This review is actually from a multi-listener session of new production vacuum tubes. Notes were summarized by my good friend Chris James.