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WiiM Amp streaming D/A integrated amplifier Measurements Page 1

Sidebar 3: Measurements

I performed a complete set of measurements on the WiiM Amp with my Audio Precision SYS2722 system. Before I did so, I installed the WiiM Home app on my iPad mini and connected the amplifier to my network with a CAT-5 Ethernet cable. The app (version 2.9.5.24041612) recognized the Amp, and I performed a factory reset.

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…

WiiM Amp streaming D/A integrated amplifier Measurements Page 2

Fig.13 WiiM Amp, optical input, impulse response (one sample at 0dBFS, 44.1kHz sampling, 4ms time window).

I examined the behavior of the WiiM's D/A conversion circuitry with Ethernet data sourced from Roon and with the optical input. The latter locked to S/PDIF data with sample rates up to 192kHz. The Amp's digital inputs preserved absolute polarity and with the volume control set to the maximum, a 1kHz digital signal at –20dBFS resulted in an output level of 2.283V from loudspeaker outputs, which is exactly 20dB below the amplifier's clipping voltage into 8 ohms. It is rare to find…

Re-Tales #43: Mark Mawhinney's Three Audio Retail Businesses

It's a truism in business—or if it isn't strictly true, it's at least a cliché—that you can't please everyone. But Mark Mawhinney sees everyone as a potential customer. He does his best to cover all customer bases, from old-school audiophiles to newcomers, from Boomers to Gen Z. "As long as they have two legs and two ears, they can be our customers," he told Stereophile in a recent phone interview.

Mawhinney owns and runs three businesses: Spin-Clean, the longstanding, inexpensive record-cleaning system; Northern Audio, a high-end audio dealership; and Music To My Ear, a record store…

Revinylization #55: An <I>American Beauty</I> Unblemished

Of all the albums in the Grateful Dead catalog, American Beauty is the one with the widest appeal. Its proto-Americana tunes are neither antique nor modern; instead, they are timeless. The album's sound is clean and lean, up to modern snuff even more than a half-century after its original release in November 1970.

The tunes seem to roll like a Sunday drive on a country road, in and out of dark hollows and up and down hills (footnote 1). Three of its 10 songs have become folk-rock standards: "Friend of the Devil," "Sugar Magnolia," and "Truckin'."

As you'd expect, the album has…

Triode Lab 2A3 EVO integrated amplifier

For 16 years, I bled jazz. Countless hours alone in my practice shed, honing technique, recording myself for brutal self-analysis, dissecting and transcribing master drummers' solos note for note. My dream was to transcend technique, to exist in a state of pure reaction among musicians in perfect communion, where improvisation flows as effortlessly as thought.

The years melted away—George Lawrence Stone's sticking variations, Benjamin Podemski's concert drum solos, dog-eared "Real Book" charts, college big band concerts, smoky jam sessions, a basement practice routine that nearly deafened…

Triode Lab 2A3 EVO integrated amplifier Page 2

Setup
The 2A3 EVO found a comfortable home on the lowest shelf of my Salamander rack. To optimize performance, I arranged three of Norman Varney's A/V RoomService large Equipment Vibration Protectors (EVPs) under the amp. I have found that the EVPs reduce noise and improve clarity without sacrificing dynamics or character; in this respect, they're better than various cork and rubber isolation options I've tried. Then I simply connected it to the rest of the system—see Associated Equipment for details—turned the system on, and started listening.

Listening
I began…

Triode Lab 2A3 EVO integrated amplifier Specifications

Sidebar 1: Specifications

Description: Tube-rectified single-ended triode integrated amplifier capable of outputting 3.5Wpc into 8 ohms (5.4dBW). Tube complement: Input/preamp, one pair each: Sophia Electric 12AX7, Northern Electric 6SN7; rectifier: Sophia Electric Aqua 274; power, one pair each Electro-Harmonix 2A3 EH or KR Audio 2A3. Maximum gain: 21.7dB. Input sensitivity: 350mV for max power. Total harmonic distortion: 1% at rated power. Bandwidth at rated power: 20Hz–20kHz. Frequency range (at 1W): 20Hz–2kHz. Input impedance: 220k ohms. Output impedance: Not specified.
Dimensions…

Triode Lab 2A3 EVO integrated amplifier Associated Equipment

Sidebar 2: Associated Equipment

Analog sources: VPI Avenger Direct turntable with 12" VPI FatBoy tonearm, Hana Umami Blue MC cartridge; Thorens TD 124 turntable with 9.5" The Wand Plus tonearm, Luxman LMC-5 MC cartridge.
Digital sources: HoloAudio May DAC, Sonore opticalRendu, Roon Nucleus+, Small Green Computer power supply, TRENDnet switch, Apple iPad mini.
Preamplifiers: PrimaLuna EVO 100 phono, Aurorasound Viva II phono.
Integrated amplifiers: PrimaLuna EVO 400.
Loudspeakers: Heretic AD614, Volti Audio Razz, Voxativ Ampeggio 2024.
Cables: Interconnects: Agent Pur,…

Triode Lab 2A3 EVO integrated amplifier Measurements

Sidebar 3: Measurements

After carefully installing the Triode Lab 2A3 EVO's tubes, I performed a complete set of tests of the amplifier with my Audio Precision SYS2722 system using the Electro-Harmonix 2A3 Gold output tubes, then repeated the testing with the KR 2A3 tubes that KM told me he preferred. As usual, I waited for an hour after powering up the amplifier before starting the testing.

The 2A3 EVO inverted polarity from both the 4 ohm and 8 ohm output transformer taps. The input impedance was a usefully high 61k ohms at 20Hz and 1kHz, 41k ohms at 20kHz. The source impedance…

Still More from Munich: Tedeska Cartridges

Unfortunately, there are always manufacturers at shows from which I fail to gather enough information to file a thorough report, so then I have to to follow up later. I finally caught up with Berlin-based cartridge manufacturer Tedeska Vinyl Groove Pick-Up Technology and their kind representative Francesa Lee, who explained their new wares, which were on static display at High End Munich.

Tedeska cartridges are all moving coils. They make mono and stereo cartridges. And this is where ordinary ends. Each Tedeska cartridge is a unique combination of tone wood, cantilever, and tk.…