Four high-end tube and hybrid pre-amplifiers

Source: Revue du Son July/August 2005

RDS reviewed a dream team of pre-amps: Audio Research Reference 3, Conrad-Johnson ACT2, EAR/Yoshino 912 and Musical Fidelity kW. All are either tube based designs or hybrids employing tubes. There was undeniably something about these pre-amps that seduced even jaded audio reviewers like Jean Hiraga into using superlatives.

Audio Research Reference 3 was noted for its phenomenal transparency and resolution and one reviewer perceived that the addition of Reference 3 into RDS's usual listening system brought substantial gains in system transparency, dynamics and resolution.

Conrad-Johnson ACT2 has been discussed before in this blog. I also pointed out some questionable rise time of 14,5µs. In RDS measurements rise time was 9,8µs, still on the high side. Measurements aside, RDS reviewers wowed this masterpiece of mechanical engineering and industrial design: incredible charming, so seductive that one tends to listen the most favourite disks one after another. However, its price of €18.900 was considered punitive, resulting in 3/5 in quality/price ratio - whereas all other ones were 5/5. See also SoundStage's ACT2 review.

As for EAR/Yoshino 912 this was propably the first review ever. This is hybrid design, using five PCC 88 tubes and the only one which includes phonostage (and hence, strictly speaking the only pre-amp here, other ones are linestages). Both reviewers noted the sensational dynamic range of which the EAR/Yoshino 912 is capable to reproduce, easily the most dynamic of quattro tested. Considering the company quite a remark.

Musical Fidelity kW preamp was undeniable winner with respect to quality/price ratio - at €4.145 it's one quarter of the price of the ACT2! The RDS listening notes were pretty much idenytical what I reported earlier, i.e. exceptional pre-amp for the money. Only criticism is lack of balanced input and outputs, which limits its use with all symmetric components.

Viewpoint: A preamp in my book has to justify its inclusion by adding dynamics, body, tone and spatial dimensionality. For me, that means tubes. Based on this review one might conclude that as for pre-amps we're almost there - wherever "there" is.

I also point readers to the Absolute Sound issue April/May 2005 where in HP’s Workshop four other interesting line-stages are reviewed and positioned against Conrad-Johnson ART II (now discontinued): Tom Evans Audio Design Vibe, Burmester 808 Mk V, the Keith Herron VTSP-2 and the Lector Zoe. The Lector Zoe especially looks interesting at €2.000. Although somewhat dark sounding, HP mentioned exceptional dynamics - a test against EAR 912 might be interesting in this domain.

The one sure thing these reviews illustrate is that all linestages impose themselves on the music, and in a sense, limit and interpret its truth. As HP said in April/May 2005 TAS: "If cost alone were the determining factor, then one linestage would be the hands-down winner, and that linestage is, indeed, the very best buy in the business. But, otherwise, we have to juggle between the sonic aspects, like the handling of dynamics, the tonal character of a unit (e.g., whether dark or light, yin or yang), or its handling of the ambient and dimensional qualities of the reproduced soundfield. Taken together, these things will be at the root of your perception of the linestage’s musical worth."