The reference system used to audition the four loudspeakers reviewed here includes the VTL 225W Deluxe monoblock and Krell KSA 200 amplifiers, driven by a Theta DSPro Basic digital processor through the passive Electronic Visionary Systems Stepped Attenuator. The analog front end was a Well-Tempered Turntable and tonearm fitted with a Sumiko Boron vdH cartridge. Phono preamplification was provided by the Precision Audio outboard phono module, connected to the passive attenuator. The phono preamp has enough gain for the moving-coil Sumiko and is able to drive…
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Sidebar 4: 1990 Measurements
Playing the LEDR recording from the Chesky jazz sampler and test CD, I thought the 3.5ti did moderately well in the "Up" test. The image moved slightly above the loudspeaker and stopped without achieving the height sometimes heard. The "Over" was a little better, with the image leaving the left loudspeaker and traveling toward the right. The "Lateral" test, the easiest for a loudspeaker to reproduce, was good, the test signal producing a continuous image between the loudspeakers. I next drove the 3.5ti with a sinewave oscillator while feeling and listening to…
Sidebar 5: Specifications
Description: two-way, reflex-loaded loudspeaker. Drive-units: 1" plastic-dome tweeter (Camber 3.5A) or 1" metal-dome tweeter (3.5ti), 8" polypropylene-cone woofer. Crossover frequency: 3kHz. Frequency response: 48Hz–20kHz ±2dB (3.5A); 45Hz–23kHz ±3dB, 80Hz–2kHz ±1dB (3.5ti). Sensitivity: 90dB/W/m. Nominal impedance: 8 ohms. Amplifier requirements: 15–175W.
Dimensions: 23.5" H by 12.5" W by 10.25" D (3.5A); 24" H by 10.5" W by 11.5" D (3.5ti). Weight: 35 lbs each.
Finish: black ash.
Price: $669/pair (3.5A); $699/pair (3.5ti); no longer available (2010).…
Compared to the Krell KSA-300S power amplifier that I also review this month, the KRC preamp's design is, at first glance, almost conventional. But its thoroughly high-end internal design has been equally well thought-out and executed. Its main, four-layer, glass-epoxy circuit board is for the audio signal, DC power, and ground—two layers for the latter are said to minimize noise. The gain stages are pure class-A and complementary. As in the amplifier, the circuit is direct-coupled, with servo circuits controlling the DC offset. The fully regulated power supply is housed in an external…
The slight softness I noted in my earlier evaluation of the KSA-300S power amplifier was, apparently, not inherent in the amplifier itself. It largely disappeared when the 300S was paired with the KRC, replaced not by any degree of hardness or brightness, but simply by a more alive, open quality. To be fair to the Consummate (it remains a superb preamp, and I intend to continue using it in situations in which precise, repeatable control of listening level is required), it was not able to benefit here from the undeniable synergy which exists between the new Krell KSA-300S and the KRC.
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Sidebar 1: Specifications
Description: Solid-state remote-controlled preamplifier. Frequency response: 20Hz–20kHz ±0.02dB; 0.2Hz–400kHz +0.0, –3dB. Distortion: <0.01% THD at and 20kHz. S/N ratio: >95dB, unweighted. Input impedance: 47k ohms. Output impedance: 5 ohms. Maximum output voltage: 14V rms.
Dimensions: 19" W by 2.75" H by 14.5" D. Weight: 29 lbs (shipping).
Serial numbers of samples tested: 23-85487 & 23-85435.
Price: $6300 (line only; phono stage optional at $500 additional). Approximate number of dealers: 55. Warranty: 5 years, limited, transferable.
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Sidebar 2: Reference System
My reference system was initially based on the Wilson WATTs/Puppies, the Rowland Consummate and Krell KSA-300S and KSA-250 power amplifiers, the C.E.C. TL 1 transport, and the Levinson No.35 D/A processor. I later used Apogee Stage loudspeakers, a Krell Reference 64 D/A processor and DT-10 transport.
In addition, Kimber AGDL digital cable linked transport and processor, TARA Labs Master RSC (unbalanced) linked processor and preamp, Cardas Hexlink (balanced) connected preamp and power amp, and TARA Labs RSC loudspeaker cable ran between amp and speakers…
Sidebar 3: Measurements
The KRC's balanced output impedance at its line outputs measured just over 3 ohms (just over 2 ohms unbalanced). Its (line) input impedance measured just over 104k ohms (L) and just under 100k ohms (R), balanced, and just under 47k ohms unbalanced. The output impedance at the tape output was just under 45 ohms, regardless of the source impedance, indicating a buffered tape output.
The DC offset at the KRC's outputs measured under 0.3mV either channel, balanced or unbalanced. The preamp is noninverting from its inputs to its main outputs, and in the…
Remember the early days of CD, when some players were touted as having the revolutionary new "2x-oversampling" digital filters?
Those early oversampling players were the first to replace the analog output filter with one that operated in the digital domain, thereby avoiding the problems of steep analog filters. In fact, those analog filters were a significant source of unmusical sound in first-generation CD players, introducing severe phase shift, ringing, passband ripple, and often upper-treble attenuation. They were necessary, however, to remove the spurious images that appeared at…
Five digital inputs are provided: two on RCA jacks, one TosLink, one AES/EBU, and one ST-type optical. A digital in/out tape loop on RCA jacks (with an additional tape input on an ST-type jack) is included for driving a digital recorder. A sixth input on an ST-type jack, marked "Time Sync," allows the Reference 64 to lock to an external clock from Krell's transports. When the Time Sync connection is made between the Reference 64 and a Krell transport, the clock is sent separately instead of being recovered from the S/PDIF or AES/EBU datastream.
This technique can theoretically eliminate…