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The original PS Audio Sprout, which I reviewed in the May 2015 issue, showed newcomers an easier, smaller way to amplify music recordings in the home. At $599, the Sprout100 costs $100 more. It fixes a few of the old Sprout's weirdnesses: no power-on indicator light, no remote control, five-way binding posts that weren't really five-way. It also doubles the Sprout's class-D power output into 4 ohms, from 50 to 100Wpc (or 50Wpc into 8 ohms), and adds a few sonic and mechanical enhancements. The main sonic improvement is a newer DAC chip: An ESS Sabre 9016 replaces the Sprout's Wolfson 8524.…
Sidebar: Specifications
Description: Integrated amplifier. Inputs: phono (moving-magnet), analog, USB (24-bit/192kHz), digital coax (any sample rate and bit depth to 24/192), Bluetooth (built in). Maximum output power: 50Wpc into 8 ohms (17dBW), 100Wpc into 4 ohms (17dBW).
Dimensions: 6" (155mm) W by 1.75" (45mm) H by 8" (205mm) D. Weight: 2.9 lbs (6.4kg).
Serial number of unit reviewed: Not noted.
Price: $599. Approximate number of dealers: 65.
Manufacturer: PS Audio, 4865 Sterling Drive, Boulder, CO 80301. Tel: (800) PSAUDIO. Web: www.psaudio.com.
Doshi Audio first crossed my radar at the 2010 Rocky Mountain Audio Fest, where I wrote that the sound of the company's tubed monoblocks and preamp, connected to Wilson Audio Sasha loudspeakers via Transparent XL cables, "excelled in midrange strength as the system threw an exciting soundstage." After auditions of Doshi-Wilson pairings at many subsequent shows had convinced me that Doshi's products could truly sing, I contacted company owner and product designer Nishith "Nick" Doshi to inquire about reviewing one of his amps. Given that, in his home system, Doshi pairs his Monoblock V3.0…
I soon discovered how much the bias changed, depending on the time of day. Between 5 and 10:15pm, tubes biased for 190mV would drop to as low as 183mV. Conversely, tubes rebiased to 190mV at dinnertime would later rise to 196 or 197mV. Because each tube seemed to respond differently to voltage fluctuations, vigilance was essential to determine the correspondence of bias to sound. Ultimately, I contacted our locally owned utility company, which is considering installing a more powerful transformer that will provide more stable voltage during times of peak demand.
I wanted to discover a…
Sidebar 1: Specifications
Description: Tubed class-AB monoblock power amplifier. Tube complement: one 12SJ7 (input), two 12SN7 (driver), four KT150 (output). Inputs: 1 pair single-ended (RCA), 1 pair balanced (XLR). Outputs: 1 pair binding posts. Output power: min. 160W into 4 ohms (19dBW) (other output options available by special order). Frequency response (1W): 10Hz–75kHz, ±1dB. Input impedance: 47k ohms (balanced, single-ended). Output impedance: 0.5 ohm. Damping factor: 10. Hum & noise: >90dB below 0dBW (1W) output (A weighting). Sensitivity: 1.4V (full output).
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Sidebar 2: Associated Equipment
Digital Sources: dCS Paganini SACD/CD transport & Scarlatti clock & Vivaldi DAC & Network Bridge; Apple MacBook Pro computer with Intel i7, SSD, 8GB RAM; Intel NUC7i7BNH with 8GB RAM, 128GB SSD, running Roon; Linksys router with two TP-Link Gigabit Ethernet media converters, multimode duplex fiber-optic cable; external hard drives, USB sticks, iPad Pro.
Power Amplifiers: Dan D'Agostino Master Audio Systems Progression, Pass Laboratories XA200.8 (all monoblocks).
Loudspeakers: Wilson Audio Specialties Alexia 2.
Cables: Digital:…
Sidebar 3: Measurements
Our review samples of Doshi Audio's Monoblock V3.0 amplifier were well traveled, having been shown at the Rocky Mountain Audio Fest in Denver in 2017, and at AXPONA and Munich High End in 2018, before making their way to Washington and Jason Victor Serinus. Unfortunately, they then didn't survive their transcontinental trip from Jason's place to mine at the hands of UPS. Although the boxes seemed undamaged, they must have been dropped at some point: neither amp worked. Fortunately, Nick Doshi was able to drive up from Virginia to Brooklyn at short notice to repair…
"Any color, so long as it's black." That was the choice famously offered by Henry Ford to buyers of his Model T. Some makers of loudspeakers, notably GoldenEar Technology, follow the same dictum.
Not Focal. The Kanta No.2 ($9999/pair) is available with a cabinet finished in High Black Lacquer or Walnut veneer, with baffles finished in a variety of colors, including High Glass Carrara White and Gauloise Blue. The review samples had black cabinets and white baffles, which made me think of the two-tone cars that were the rage in the 1950s and '60s—and which may be coming back (footnote 1…
Focal's packaging includes a bright yellow sticker that warns: "The technologies in our loudspeakers require a running-in period." By "technologies," I think they mainly mean that beryllium tweeter. The word on the street about beryllium tweeters is that they require more break-in than the norm, and my experience supports that. I've been told that Audio Plus Services, Focal's US importer, normally breaks in Focal speakers by playing them at high volumes in a soundproof "bunker." However, due to a delay in the shipping of the speakers from France, and a misunderstanding about my need to have…
Sidebar 1: Specifications
Description: Three-way, floorstanding loudspeaker. Drive-units: 1.1" (27mm) pure-beryllium, inverted-dome tweeter; 6.5" (165mm) flax-sandwich-cone midrange unit; two 6.5" (165mm) flax-sandwich-cone woofers. Crossover frequencies: 260Hz, 2700Hz. Frequency response: 35Hz–40kHz, ±3dB. Low-frequency point: 29Hz, –6dB. Sensitivity: 91dB. Impedance: 8 ohms nominal, 3.1 ohms minimum. Recommended amplification: 40–300W.
Dimensions: 44" (1118mm) H by 18.8" (477mm) W by 12.6" (321mm) D. Weight: 77.2 lb (35kg).
Finishes: High Gloss Black Lacquer (cabinet); High…