Tube Power Amp Reviews

The Horn Monos also excelled in providing dynamics. Constantine Orbelian and the Philharmonia of Russia's Vodka & Caviar (Delos DS-3288), a recent recording of Russian orchestral showpieces and one of my "Records To Die For" this year, is full of material to give any system a dynamic workout, and selections like Khachaturian's "Saber Dance" simply crackled with energy. Compared to the Wavelength Gemini and the CAD-2A3, whose power output is in the 3-5W range, the Horn Monos were, as one might expect, able to drive the Avantgardes to a higher undistorted level.

One aspect of performance where, I believe, SETs like the Wavelength and the Cary are still superior is in providing a kind of see-through quality—what Sam Tellig refers to as music being "lit from within." The view through the Horn Monos was by no means veiled or obscured, but when the speakers were driven by SETs, voices and instruments seemed to have a more rounded, three-dimensional quality. I would also put the sound of the SETs ahead (though not by much) in communicating the most subtle aspects of musical expression—what some call microdynamics. Again, it's not as though the Horn Monos were obviously deficient or lacking in this area, but that the best SET designs offer even more. Of course, the Wavelength Gemini and Cary CAD-2A3 amplifiers cost more than three times the price of the Horn Monos; they're not nearly as quiet, and won't play as loud.

A real-world paradigm
The Horn Mono appears to be a niche product designed specifically for high-sensitivity speakers, and I was initially content to use it only with my Avantgarde Unos. However, I did wonder what the amplifier would sound like driving a speaker with average sensitivity, and, given the low gain, whether the preamp would have sufficient output for this type of setup. As it happened, as an adjunct to a review I was working on for Stereophile Guide to Home Theater, I had on hand a pair of Paradigm Reference Studio/20s, and I thought that using these speakers would provide a good test of the Horn Mono's performance in a more conventional system.

The results were astonishingly good. First of all, the Studio/20 (the ones I had were the v.2 series, updated since the version reviewed by Bob Reina in February 1998, Vol.21 No.2) is a terrific little speaker. It's superior in some ways—more coherent, with better imaging—to the Studio/100 v.2, which I reviewed for Stereophile in June 2000 (Vol.23 No.6). The Studio/20 has a rated sensitivity of 89dB, about 10dB lower than recommended by Quicksilver Audio, but the Horn Monos were able to drive the speakers to surprisingly high levels. The CAT SL-1 Ultimate preamp had to be turned up a few clicks beyond the usual setting for the Avantgardes, but there was no indication of any sort of electronic mismatch, and the preamp was still a few clicks short of full gain when the amplifier-speaker combo reached its maximum comfortable level (footnote 2). The sound was really quite excellent, and hard to credit to a combination of amp and speaker costing less than $2500.

Conclusion
The Quicksilver Horn Mono is very much my kind of amplifier: a solid, no-nonsense product singularly lacking in quirkiness, with design principles that involve no extravagant or controversial claims. Intended primarily for use with high-sensitivity loudspeakers—a purpose for which it is eminently suited—the Horn Mono can also work well with speakers of just slightly higher than normal sensitivity.

Although the Horn Mono doesn't offer the ultimate in every parameter of sonic performance, its presentation is always convincing in musical terms. I recommend it especially for audiophiles who can just stretch their budget to go for a pair of Avantgardes or other expensive horns, but have little left over for suitable amplification. The Horn Mono is good enough not to be outclassed in this sort of system.

Quicksilver Audio does little or no advertising, which may help explain how the Horn Mono can be offered for $1595/pair. Given its sound, as well as its quality of parts and construction, this is an obvious bargain.

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Footnote 2: The CAT SL-1 Ultimate preamplifier has higher-than-average output capability, so the match with other preamplifiers may not be as good. Check and see.—Robert Deutsch