Although its packaging appears as sturdy as I have experienced, the Aesthetix Rhea arrived with the metal mesh panels that ventilate the top cover detached and one of the 6922 tubes loose inside the chassis, suggesting that the box had been dropped. Nevertheless, once I'd reinserted the tube in its socket, the unit appeared to be working, with both channels basically identical in their measured behavior. And having to plug the tube back in gave me a chance to look inside the chassis, whistling through my teeth as I caught my first glimpse of the Rhea's…
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Michael Fremer wrote about the Rhea in June 2005 (Vol.28 No.6):
The Aesthetix Rhea tubed phono stage ($4000, reviewed by Paul Bolin in the September 2003 Stereophile), which I have in-house in association with a forthcoming review of the companion Aesthetix Calypso preamp, offers three independent inputs, remote-controlled loading and gain on the fly, and automatic MC demagnetization. The Musical Fidelity kW phono preamp ($3500) can't begin to compete with the Rhea's versatility and ease of use, nor does its midrange offer the Rhea's lushness and soft finish. The Rhea can't begin to match…
Kinergetics Research was a name to be reckoned with in the early days of CD, when they produced some of the earliest well-received, audiophile-grade CD players. They've branched out since then, producing amplifiers, preamps, subwoofers, and surround-sound processors. In fact, they're so busy with such products that they no longer build CD players! The last Stereophile review of a Kinergetics CD player appeared way back in 1993.
Before that, in 1990, Dick Olsher reviewed one of Kinergetics' early power amplifiers, the KBA-75. The KBA-280 is a modern update of that design, still specified…
The KBA-280 is also THX-certified, which means that it must meet a certain set of standards—voltage gain, output power, distortion, input impedance, etc.—specified by the THX division of Lucasfilm.
Performance
There are as many definitions of what constitutes a neutral-sounding amplifier as there are audiophiles (or at least those of us who admit that amplifiers don't all sound alike). Ask a solid-state fan and you'll be regaled with descriptions of tight, powerful bass, an open top end that seems to go on forever, and an overall neutrality that renders the warm, fuzzy sound of tube…
Comparisons
While the Aragon 8008ST is less expensive than the Kinergetics, the two amplifiers are naturals to square off against each other, not least because the Aragon remains my long-term reference for a relatively affordable high-end amplifier. Directly compared, it sounded more laid-back through the midrange and lower treble than the Kinergetics. Its midbass was less rich than the KBA-280's, and it sounded less liquid overall. These qualities gave the Kinergetics a greater presence, and more rounded dimensionality on vocals.
While the Aragon 8008ST is less expensive than the Kinergetics, the two amplifiers are naturals to square off against each other, not least because the Aragon remains my long-term reference for a relatively affordable high-end amplifier. Directly compared, it sounded more laid-back through the midrange and lower treble than the Kinergetics. Its midbass was less rich than the KBA-280's, and it sounded less liquid overall. These qualities gave the Kinergetics a greater presence, and more rounded dimensionality on vocals.
On the other hand, the Aragon was more open on top,…
Sidebar 1: Specifications
Description: Two-channel, THX certified power amplifier with a class-A output stage. Power output: 140Wpc into 8 ohms (21.5dBW), 280Wpc into 4 ohms (21.5dBW), 437Wpc into 2 ohms (20.4dBW). Rated full-power bandwidth: 1Hz-300kHz. THD: 0.02%. Input impedance: 100k ohms unbalanced, 1k ohm balanced.
Dimensions: 17.25" W by 6.75" H by 16.75" D. Weight: 55 lbs net.
Serial number of unit reviewed: KIA280G1100271.
Price: No longer available; $2795 (1998). Approximate number of dealers: 70.
Manufacturer: Kinergetics Research, 4260 Charter St., Vernon, CA…
Sidebar 2: System
The Kinergetics KBA-280 was auditioned in a system consisting of the Mark Levinson No.37 transport and No.36S D/A converter, Jeff Rowland Design Group Consummate preamplifier, and Energy Veritas v2.8 loudspeakers. The interconnects were TARA Labs RSC Reference from D/A to preamp, and Cardas Hexlink from preamp to power amp. The digital link between transport and D/A converter was Kimber AGDL. Loudspeaker cables were a bi-wire hookup of Monster M1.5s (top end) and Monster M2.2s (bass).
All listening was conducted in my listening room, approximately 18' W by 26' L…
Sidebar 3: Measurements
Following its 1/3-power, one-hour preconditioning test, the KBA-280's chassis was surprisingly cool, except for the fan-driven heat coming from its rear vent.
The input impedance of the KBA-280 measured 10.7k ohms unbalanced, 1062 ohms balanced. Its output impedance was a maximum of 0.027 ohms at 20Hz and 1kHz, and 0.034 ohms at 20kHz. Its voltage gain into 8 ohms measured 29dB unbalanced and 26.5dB balanced. DC offset was 2.8mV in the left channel, 5.8mV in the right. Signal-to-noise (at 1W into 8 ohms) measured 91dB from 22Hz to 22kHz, 88.4dB, 10Hz-…
Fig.6 shows the KBA-280's spectral response to a 50Hz input at 187.6W output into 4 ohms. This is a superb result; all of the artifacts are well below -80dB (0.01%). Fig.7 shows the output spectrum with a combined 19+20kHz signal—the intermodulation products resulting from an input signal consisting of an equal combination of these two frequencies—at 164W into 4 ohms. The only artifact here above -80dB is at 1kHz (-68.3dB, or about 0.04%), though there is a lot of power-supply-related noise floor "grass," implying that the amp is working hard with this high current output. The result into 8…
BEETHOVEN & MENDELSSOHN: Violin Concertos
Joshua Bell, violin; Roger Norrington, Camerata Salzburg
Sony Classical SK 89505 (CD). 2002. Andrew Keener, prod.; Arne Akselberg, eng. DDD. TT: 69:58
Performance *****
Sonics *****
Joshua Bell, violin; Roger Norrington, Camerata Salzburg
Sony Classical SK 89505 (CD). 2002. Andrew Keener, prod.; Arne Akselberg, eng. DDD. TT: 69:58
Performance *****
Sonics *****
So it's still possible for Joshua Bell to make a serious recording. How quickly we forget that Bell was once a strictly classical recording artist who, with Roger Norrington, premiered and recorded the great and massive Violin Concerto of Nicholas Maw. Since then, each of Bell's crossover recordings have him photographed in a different designer…