Setup and Use
The VPS comes configured with its jumpers set for the signal to pass through the internal transformers with "no additional loading." To make use of the supplied loading cards, turn the unit off and wait at least 10 minutes, to avoid a…
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Finally, should the VPS tube stage's 300mV output prove insufficient to drive your preamplifier—which, based on my experience of many preamps, it likely will—a solid-state gain stage, based on Nagra-designed circuits for microphone preamps and offering 16dB of gain, can be selected with a rear-panel switch, to give a total gain of 60dB.
This 1958 audio spectacular of imaging and soundstaging also seemed a good choice for testing the efficacy of Nagra's optional VFS platform. After enduring an entire side of Schory's percussive silliness, I removed the VFS, then listened to the side again. Even though the VPS was now resting on Finite Elemente's excellent Pagode Master Reference stand, and even though Nagra's main circuit board floats within the chassis, removing the VFS platform produced a profound change: images became somewhat bloated and indistinct, bass got boomier and less well controlled, and the overall sound lost…
Sidebar 1: Specifications
Description: Single-ended, hybrid moving-magnet/moving-coil phono preamplifier with separate power supply. Inputs: 1 MC; second MM or MC input optional. Outputs: RCA, XLR (unbalanced). Tube complement: one 12AX7, one 12AT7. Input impedance: variable (with supplied load cards). Voltage gain: transformer input, 11dB; tube stage, 34dB; solid-state stage, 15dB. Frequency response: 20Hz–30kHz, +1/0dB. THD: <0.15%. Crosstalk: typically 60dB. Signal/noise (MC): >77dB (A-weighted. Output levels: 300mV (low mode, direct from tubes), 2V (high mode, via solid-state…
Sidebar 2: Associated Equipment
Analog Sources: Continuum Audio Labs Caliburn turntable & Cobra tonearm & Castellon stand; Graham Phantom tonearm; Lyra Titan i, Einstein TU-3 cartridges.
Digital Sources: Musical Fidelity kW DM 25 CD transport & DAC, dCS 904 A/D converter, BPT-modified Alesis Masterlink hard-disk recorder.
Preamplification: Manley Steelhead, Einstein Turntable's Choice phono preamplifiers; DarTZeel NHB-18NS, Luxman C-800f preamplifiers.
Power Amplifiers: Musical Fidelity kW monoblocks, Luxman M-800A.
Loudspeakers: Wilson Audio Specialties MAXX 2.…
Sidebar 3: Measurements
I measured the Nagra VPS using, for most tests, Audio Precision's top-model SYS2722 system, with some use made of the older AP System One. I used the internal jumpers to set the preamplifier to moving-magnet (MM) or moving-coil (MC) operation, and also looked at the effect of the solid-state output buffer by operating the rear-panel switch.
As used by Michael Fremer, the preamp was set to MC with the internal step-up transformers engaged and the input loading set to 1000 ohms. The input impedance measured 1024 ohms at 1kHz, dropping slightly at the…
Spending $10,000 for a machine that spins CDs and SACDs may seem extravagant in an age when the latter format is pretty much dried up and the former seems headed there. But hold on—there are reasons for the Krell Evolution 505's five-figure price, and a payoff, too.
The Evolution 505 is massive for a CD player: 29 lbs, a half-foot high, nearly a foot-and-a-half wide and deep. The aircraft-grade aluminum chassis, which comes in silver or black, has rounded edges and slitted sides that give its bulk a streamlined grace. Like the power and preamplifiers in the Evolution series, the…
The function buttons on the Evolution 505's front panel are not an ergonomic delight; they're small, the labeling is smaller still; and the way they're arrayed doesn't strike me as very logical. The remote control, however, is just fine in its arrangement of controls.
The other minor problem—in fact, now it's vanished—is that the disc transport in some early units had problems. In my sample, a small number of discs skipped in places. I'm told that, in some other cases, and again on only a few discs, the first few seconds of a track or two were snipped off. The problem, I'm told, has been…
Sidebar 1: Specifications
Description: SACD/CD player with wireless IR remote control. Plays SACD, CD,CD-R, 44.1kHz WAV, AAC, DVD-R/RW/+R. Outputs: digital S/PDIF via RCA, TosLink; 1 pair CAST via 4-pin bayonet connectors; 1 pair balanced (XLR); 6 single-ended (RCA). Control inputs: RS-232 port via 9-pin D-subminiature connector, 12VDC trigger input, Krell CAN Link. Frequency response: 20Hz–20kHz, +0/–0.5dB. Signal/noise ratio (A-weighted): 105dB. THD: 20Hz–20kHz, –82dB. Power consumption: 61W.
Dimensions: 17.3" (438mm) W by 6" (153mm) H by 17.3" (438mm) D. Weight: 29 lbs (13.2kg)…
Sidebar 2: Associated Equipment
Analog Source: VPI HW-19 Mk.4 turntable & JMW Memorial tonearm, Clearaudio Victory H cartridge.
Preamplification: Audible Illusions Modulus 3a (used only as phono stage).
Integrated Amplifier: Krell FBI.
Loudspeakers: Verity Audio Parsifal Ovation.
Cables: Nirvana interconnects and speaker cables; Krell and Nordost CAST interconnects.
Accessories: Bybee Technologies Signature Model Power Purifier, Black Diamond Mk.IV Racing Cones, Mapleshade pucks, VPI HW-19 record-cleaning machine.—Fred Kaplan
Sidebar 3: Measurements
I examined the Krell Evolution 505's measured behavior using Audio Precision's top-model SYS2722 system (see www.ap.com and "As We See It" in the January 2008 issue), as well as, for some tests, our Audio Precision System One and the Miller Audio Research Jitter Analyzer. The sample measured was S/N 18007010184, the second of the two samples Fred auditioned. As with other Krell components using the company's proprietary CAST current-mode outputs, I could assess the Evolution 505's performance only from the conventional single-ended and balanced jacks. This doesn't…