search

Boulder 1151 monoblock power amplifier Measurements

Sidebar 3: Measurements

I performed a complete set of measurements on one of the Boulder 1151 amplifiers (serial number 14142) with my Audio Precision SYS2722, then repeated some of the tests with the magazine's higher-resolution Audio Precision APx555. I preconditioned the 1151 by following the CEA's recommendation of running it at one-eighth the specified power into 8 ohms for 30 minutes. At the end of that time, the temperature of the top panel was just 89.8°F (32.1°C) and that of the side-mounted heatsinks 97.3°F (36.3°C).

Fig.1 Boulder 1151, frequency response at 2.…

Stromtank’s Path to Pure Power

"What is the most important element in a high-end audio set-up?" As much as the question is asked over and over again, as if it were a requisite baseline test for admission into the Holy Fraternity of the High End, most responses start with the end of the chain rather than with the fundamentals.

It's like asking which comes first, the cart or the horse, while ignoring what's in the cart. For audio, the cargo is music. Without music, there's just noise (as in test signals and chatrooms).

After music come the medium (cart) that contains it, e.g. the file, platter, or disc, and the…

Stenheim Alumine Two.Five loudspeaker

Stereophile has favorably reviewed three loudspeakers from Swiss manufacturer Stenheim. Art Dudley reviewed the Alumine standmount in April 2012 and the Alumine Five floorstander in March 2018. More recently, Herb Reichert reviewed Stenheim's three-and-a-half-way Alumine Three tower in October 2021. My assignment for this month's issue was to review the company's Alumine Two. Five floorstander, which, at $23,500/pair, fits neatly between the Alumine Two ($13,500/pair) and Three ($36,500/pair).

Stenheim was founded by four engineers who previously had worked at Goldmund. A couple of years…

Stenheim Alumine Two.Five loudspeaker Page 2

Listening to music
Straight out of their flight cases, the Alumine Two.Fives sounded bright. The manual recommends 200–300 hours of break-in, but the treble balance became more neutral after only a few days of casual listening. (The review samples had been previously used at a hi-fi show, so I figured that they already had plenty of hours on them.) Nevertheless, while the Stenheim's midrange was impressively uncolored, its low-treble balance was not an optimal match with the Ayre preamplifier, which itself sounds somewhat forward. So I performed all my critical auditioning with the MBL…

Stenheim Alumine Two.Five loudspeaker Specifications

Sidebar 1: Specifications

Description: Two-way, reflex-loaded, floorstanding loudspeaker with aluminum enclosure. Drive units: two 6.5" (170mm) coated cellulose-cone woofers, 1" (26mm) soft-dome tweeter. Frequency range: 35Hz–30kHz. Nominal impedance: 8 ohms. Sensitivity: 93dB (half-space). Maximum power handling: 125W, 250W peak. Minimum recommended power: 10W. Supplied accessories: precision mounting spikes, floor-saver discs, and a spanner.
Dimensions: 37.2" (945mm) H × 9" (230mm) W × 10.8" (275mm) D. Weight: 100lb (45kg) each.
Finish: Metallic Light Gray, Dark Gray, with black…

Stenheim Alumine Two.Five loudspeaker Associated Equipment

Sidebar 2: Associated Equipment

Digital sources: Roon Nucleus+ file server; Ayre Acoustics C-5xeMP universal player; MBL N31 CD player/DAC; Ayre Acoustics QA-9 A/D converter; NetGear Nighthawk router.
Preamplifier: Ayre Acoustics KX-8.
Power amplifiers: Ayre Acoustics VX-8, Parasound JCA100 Tribute monoblocks.
Loudspeakers: MoFi SourcePoint 888.
Cables: Digital: AudioQuest Vodka (Ethernet), AudioQuest Coffee (USB), DH Labs (1m, AES3). Interconnect: Ayre/Cardas (balanced). Speaker: AudioQuest Robin Hood. AC: AudioQuest Dragon Source & High Current; manufacturers' own.…

Thales, Stenheim, Master Fidelity, Boulder, Pink Faun, and the Turntable That Waited

Before the show, I’d heard rumblings about the new Swiss-made Thales Reference turntable. Art Dudley had previously reviewed the Thales TTT-Compact turntable and Simplicity II tonearm, writing: “In 34 years of writing about playback gear, I have seen no products better made than the Thales turntable and tonearm, and precious few that equal them.”

So I walked into room 4.2 F213 expecting to love the Reference model (approx. $28,500), paired with the Thales Simplicity II tonearm ($9900) and the new Thales Magnifier phono preamplifier ($42,000, all prices approximate, converted…

Vinnie Rossi Audio, Merason, and QLN: No Stylus, No Problem

At the Munich show, I ran into familiar faces: Mark Sossa of Well Pleased AV and Vinnie Rossi of Vinnie Rossi Audio, both far from their usual American stomping grounds. Seeing them overseas gave me a flicker of homesickness, but a journalist's job is to focus on the gear, not the friendships.

Sossa represents Merason DACs and QLN speakers; Rossi, his namesake electronics. Their Munich system included the new Merason Mountain DAC ($22,000), which had debuted at AXPONA; an Innuos Statement music server ($21,700); and an Innuos PhoenixNET network switch ($4250; all prices approximate,…

Phasemation and Wolf von Langa: From Jet Lag to Joy

Japan’s Phasemation has always occupied a special place in my audiophile fantasies. I’ve heard the company’s products in the rooms of American Sound’s Angie Lisi at AXPONA, but auditioning a complete Phasemation system? Never had the chance—until Munich.

A Yukiseimitsu Audio AP-01 Rec-Player and tonearm ($49,975) was fitted with a Phasemation PP-2000 MC cartridge ($7999), which uses custom-made 35µm 6N oxygen-free copper wire wound around an iron core. Either a Phasemation EA-550 Phono Amplifier ($9600) or Phasemation EA-1200 Tube Phono Amplifier ($19,800) fed the recently…

Muarah, Ilumnia, Circle Labs: Subtle Force, Measured Calm

I’d been in touch with Muarah Audio’s US distributor, Octopus Audio, ahead of the Munich show, as I’m currently reviewing the company’s entry-level MT3 turntable for AnalogPlanet. But having that deck in-house didn’t prepare me for the striking flagship MT1 EVO ($8700) or the new Ilumnia loudspeakers. And the room offered more surprises still.

The MT1 EVO, equipped with a $2250 Muarah MY-1/9 tonearm, was fitted with an Aidas Mammoth Gold LE MC cartridge ($11,300; all prices approximate, converted from Euros), and routed through the Polish-built Circle Labs V1000 phono…