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Audiophiles who need something to do during RMAF should check out Soundings Fine Audio and Video. Situated just two blocks from the Marriott DTC at 8101 E. Belleview Ave X-1, Denver, CO 80236, the Denver retailer is having a party at 6pm Friday, October 2, and all showgoers are invited. They will be serving hors d'oeuvres, drinks, and adult beverages. Boulder Amplifiers has graciously given them the opportunity to have their new 2120 D/A converter in the store for the event.
Perhaps because I grew up in post-WWII England, with austerity and food rationing the norm, I learned at an early age the value of frugality. It was a financial stretch for me to buy, in the late 1960s, my first real audio system: Garrard SP25 turntable with Audio-Technica cartridge, Kenwood integrated amplifier, Wharfedale Super Linton speakers. Even when I could afford to upgrade the system, other than replacing the Garrard with a Thorens TD 150 and the Audio-Technica with a Shure, I went the DIY route. Back then, in the early '70s, I assumed that the advent of op-amp chips like the…
The DX's two USB output ports offer the choice of including the usual 5V DC supply or just the data connections. USB-connected DACs often derive their receiver's power from the bus, to isolate the analog circuitry from the digital, in which case the 5V port should be used. But if the USB receiver is powered by the supply of the DAC in which it is housed, the DX's data-only port should be used. The PS Audio DirectStream needed the bus power for the receiver, whereas Michael Lavorgna reports that the Auralic Vega does not (footnote 1). In light of my enthusiasm for AudioQuest's JitterBug, I…
Class-A amplifiers have a well-deserved reputation for being power guzzlers that run hot enough to burn fingers. They're inherently inefficient because their output devices conduct full current at all times, and much of that current is dissipated as heat—requiring, in the case of class-A solid-state amplifiers, massive heatsinks. This is why class-A amps tend to produce relatively low power, and tend to be heavy and expensive to buy and run. And these days, energy inefficiency is out of fashion.
These disadvantages are the results of class-A's advantages: When output devices are biased…
Also immediately obvious was less air on top than with the darTZeels, and a narrower soundstage that concentrated more of the orchestra between the speakers instead of spreading it out past their outer side panels. I'm not sure how this is possible with monoblocks; perhaps it had something to do with the Krells' somewhat less generous top-end extension.
The overall sound was definitely drier than the darTZeels, but this was still at the very beginning of my listening. I decided to stop analyzing and instead just listen for pleasure—the way I used to before this became a job—to find out…
Sidebar 1: Specifications
Description: Media Server running Linux (Fedora release 20), VortexBox v.2.3, Squeezebox Server 7.8.0. Formats supported: WAV, AIFF, FLAC, ALAC, AAC, M4A, MP3, Ogg, DSF, DFF. Resolution and sample rates supported: PCM up to 32-bit/384kHz, DSD64 and DSD128. Inputs: USB 2.0 Audio 5V On, USB Audio 2.0 5V Off, Ethernet. Output: USB for backup, stereo analog audio/S/PDIF TosLink on single 3.5mm jack.
Dimensions: 16.75" (430mm) W by 3.3" (85mm) H by 10.65" (273mm) D. Shipping weight: 15.4 lbs (7kg).
Serial number of unit reviewed: 701173.
Price: $7500 with…
Sidebar 1: Specifications
Description: Solid-state class-A monoblock power amplifier. Inputs: 1 unbalanced (RCA), 1 balanced (XLR), 1 CAST. Outputs: 1 pair binding posts. Output power: 575W into 8 ohms (27.6dBW), 900W into 4 ohms (26.5dBW). Frequency response: 20Hz–20kHz, +0/–0.15dB; <0.5Hz–100kHz, +0/–3dB. Gain: 27dB. Output voltage: 192V peak–peak. Output current: 22A peak. Slew rate: 40V/µs. THD at 575W into 8 ohms: <0.03% at 1kHz, <0.19% at 20kHz. Input impedances: 100k ohms (single-ended), 200k ohms (balanced). Input sensitivity: 3.03V RMS (single-ended or balanced). Signal…
Sidebar 2: Associated Equipment
Digital Sources: Apple 2.7GHz i7 Mac mini running OS 10.10.3, with iTunes 12, Pure Music 2.0, Audirvana Plus 1.5.10; iPad mini running iPeng 8; PS Audio PerfectWave DirectStream D/A processor; AudioQuest JitterBug USB noise filter.
Preamplification: Bel Canto Design Black ASC1.
Power Amplifiers: Bel Canto Design Black MPS1, MBL Corona C15 (both monoblocks).
Loudspeakers: GamuT RS7, KEF LS50.
Cables: Digital: AudioQuest Coffee (USB) & Vodka (Ethernet). Interconnect (balanced): AudioQuest Wild Blue. Speaker: Kubala-Sosna Elation! AC:…
Sidebar 2: Associated Equipment
Analog Sources: Continuum Audio Labs Caliburn, Cobra, Castellon turntable, tonearm, stand; Kuzma 4Point, Swedish Analog Technologies tonearms; TechDAS Air Force Two turntable with Graham Engineering Elite tonearm; Air Tight PC-1 Magnum Opus, Fuuga, Lyra Atlas & Etna, Miyajima Labs Zero (mono) & Madake, Ortofon Anna cartridges.
Digital Sources: Simaudio Moon Evolution 650D transport-DAC; Lynx Hilo A/D–D/A converter; Meridian Sooloos Digital Media System; Pure Vinyl, VinylStudio LP-ripping software.
Preamplification: Ypsilon Electronics MC-…
Sidebar 3: Measurements
I performed a full set of measurements on the Krell Solo 575 (serial no. 30315060125) using my Audio Precision SYS2722 system (see www.ap.com and the January 2008 "As We See It"). Before measuring it, I preconditioned the amplifier by running it at one-third the specified power, 190W, into 8 ohms for 30 minutes. (I usually run an amplifier for an hour, but my test load was getting uncomfortably hot after half that time.) The amplifier's cooling fans turned on immediately at this power level and were noisier than I was anticipating. At the end of 30 minutes, the…