Description: Class-D stereo power amplifier. Analog inputs: Balanced (XLR/TRS Neutrik Combo jack), single-ended (RCA). Outputs: 1 pair binding posts. Input impedance: 47k ohms balanced, 47k ohms unbalanced. Rated output power: 150W into 8 ohms (21.76dBW), 250W into 4 ohms (21dBW). Frequency response: Not provided. THD: 0.0025% (1kHz, 8 ohms, 50W). Compatible speaker impedance: 2–8 ohms. Damping factor: >300. Voltage gain: 28dB set at factory; DIP switches allow for 22–36dB gain.
Dimensions: 4" (101.6mm) H × 14" (355.6mm) W × 11" (279.4mm) D (including…
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Sidebar 2: Specifications
Sidebar 3: Associated Equipment
Analog sources: Technics SL-1200MK7 turntable, Shure V15 Type III phono cartridge with Hyper-elliptical stylus.
Digital sources: Oppo DV-981HD universal disc player, coaxial S/PDIF output; dCS Bartók DAC/streamer, music streamed from Qobuz and in-house NAS via MinimServer using the dCS Mosaic app.
Preamplifiers: Pro-Ject Phono Box RS2; Benchmark LA4.
Power amplifiers: Benchmark AHB2, Aragon 8004.
Loudspeakers: B&W 808.—Tom Fine
Sidebar 4: Measurements
I performed the measurements of the LSA Discovery Warp 1 with my Audio Precision SYS2722 system. The Warp 1 runs cool—after 3 hours of testing, the chassis was still at room temperature. Because the amplifier has a class-D output stage, I inserted an Audio Precision AUX-0025 passive low-pass filter between the test load and the analyzer. This filter mitigates noise above 80kHz and eliminates noise above 200kHz that would otherwise drive the SYS2722's input circuitry into slew-rate limiting. Without the filter, 378mV of ultrasonic noise with a center frequency of…
A phenomenon formerly unique to Japan, which in recent years has been emulated in cities around the world, is the jazz café (known as jazz kissa in Japan; footnote 1), where salarymen can find respite from their hectic lives, loosen their ties, and enjoy hi-fi jazz over coffee or a drink. Jazz kissaten are typically charming, smaller shops, traditionally furnished and paneled in beautiful wood, which serve superb artisan coffee in artful ceramic cups.
Such respect for artistry, craftsmanship, and attention to detail—the Japanese word is shokunin—is reflected in many aspects of Japanese…
I began my evaluation by listening to what some may consider an odd choice for a tube-preamplifier comparison: the Mytek Brooklyn DAC/preamplifier (used as a preamp) with the Mytek Brooklyn AMP+ class-D power amplifier (250Wpc into 8 ohms, 300Wpc into 4 ohms). The amp is a few years old and the Brooklyn DAC is discontinued, but this combo remains reliable, powerful, full bodied, and creamy sounding. It proved perfectly suited for this comparison. In this setup, the phono stage was the Pathos In the Groove, in for review at AnalogPlanet.com.
And then there was light
An…
Sidebar 1: Tube Amplification Moves West
In the mid-1960s, as solid state amplifiers and acoustic-suspension speakers gained popularity in the US, low-power tube amplifiers and horn-loaded loudspeakers were abandoned. The recovery started almost immediately. Tube amps reappeared in the early 1970s, from Conrad-Johnson and Audio Research, followed by Cary Audio and others in the '80s. One of Julius Futterman's OTL (output transformerless) tube-amp designs from the mid-'50s (footnote 1) was reproduced by Harvey "Gizmo" Rosenberg (footnote 2) of New York Audio Laboratories in the form of the…
Sidebar 2: Specifications
Description: Two-channel, stereo, tubed preamplifier with MM phono stage. NOS vacuum tube complement: two E80F or EF86, two 6BX7, two 12AU7, two 6SN7. Inputs: Phono A, Phono B, Tuner, CD, Aux-1, Aux-2 (all RCA). Output: two pair single-ended (RCA). Input impedance: Phono A: 47k ohms; Phono B: 620, 15k, 30k, 47k, 68k, 100k ohms. Output impedance: 1.9k ohms (plate follower). Frequency range: 5Hz–70kHz (–2dB). Channel separation: 48dB. S/N ratio: 70dB. MM phono stage gain: 38dB; line stage gain: 47dB. Maximum input sensitivity: Phono 1.8mV (at 1V); Aux 21.3mV (at 1V…
Sidebar 3: Associated Equipment
Analog sources: Thorens TD 124 turntable/Jelco 350 S tonearm/Kuzma CAR-30 MC cartridge; VPI Avenger Direct turntable/VPI Fatboy Gimbal tonearm/VPI Shyla MC cartridge.
Digital sources: HoloAudio May DAC; Sonore opticalRendu; Roon Nucleus+; Small Green Computer power supply; TRENDnet switch; Apple iPad mini.
Preamplifiers: Shindo Labs Allegro (2), Sugden LA-4 line; Tavish Audio Design Adagio, Manley Chinook, and Pathos In The Groove phono preamplifiers, Mytek Brooklyn DAC (as preamp), Auditorium 23 step-up transformer.
Power amplifiers: Shindo…
Sidebar 4: Measurements
I measured the performance of the Miyajima Wo-1 with my Audio Precision SYS2722 system. When I connected the preamplifier's output to the analyzer and switched it on, the Audio Precision's gain-ranging kept changing. Ken Micallef had told me that he had heard "pops" when he turned the preamplifier on, likely the result of a DC voltage somewhere in the audio circuit. An obvious place to look would be on the wiper of a conventional volume control potentiometer; however, I would not have thought the Wo-1's unusual "shunt" switched-resistor volume control would suffer…
Marantz, the iconic company started by audio pioneer Saul Marantz in 1953, is inviting the public to visit a 7000-square-foot immersive, interactive exhibit in New York City to celebrate its 70th anniversary.
The House of Marantz at Spring Studios, in the city’s trendy TriBeCa section, will open its doors to the public on Wednesday, July 12, between 11am and 7pm. Admission is free. The exhibit will include:
A museum featuring rare audio gear and highlighting the history of hi-fi to commemorate the brand’s 70-year legacy A headphone listening station showcasing Marantz…