However, I recently installed Dirac Live 3, which effectively reduces the available system gain by almost 20dB! In my salad days, I would have designed and built a balanced driver with gain for…
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There has not been a conventional preamplifier in my main audio system for quite a while, because no multichannel preamp is available that's of high enough quality. Instead, I use the high-precision digital volume controls in my players and DACs and choose sources with a relay-based multichannel analog switch. Plus, I tell myself that no preamp can be more accurate and transparent than no preamp.
Moving to a larger ensemble—10 voices and players—L'Escadron Volant de la Reine (The Queen's Flying Squadron) offers a stylish program of music in the French style by Giovanni Girolamo Kapsberger (Il Tedesco, Harmonia Mundi HMM 902645, 16/44.1 PCM download). The opening a cappella of "Lunge da voi ben mio" is lovely and airy with realistically rounded voices spread across the front within a moderately deep acoustical space. The full ensemble soon joins; the instruments fill that space, front to back and side to side, even as all the voices and instruments remain distinct.
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Sidebar 1: Specifications
Description: Stereo line-level preamplifier with remote control and relay-selected resistor arrays for level control. Inputs: 1 pair RCA (unbalanced), 1 pair XLR (balanced). Input impedance: 2k ohms. Input sensitivity: 9.2V @ 0dB. Outputs: 1 pair RCA (unbalanced), 1 pair XLR (balanced). Output impedance: 20 ohms (RCA), 40 ohms (XLR). Gain: –99dB to +10dB (RCA output), –93dB to +16dB (XLR output). Maximum output level: 25V (RCA), 50V (XLR). DC offset at output: <1mV RMS. Frequency response: 20Hz–100kHz, ±0.1dB. Channel separation: >130dB (1kHz). THD+N (1kHz…
Sidebar 2: Associated Equipment
Digital sources: Oppo Digital UDP-105 universal disc player, custom , exaSound s88 streaming DAC and Okto DAC8 PRO D/A processors. QNAP TVS-873 NAS.
Preamplifiers: Coleman Audio 7.1SW for source switching, Pass Laboratories XP-32.
Power amplifiers: Benchmark AHB2, NAD C 298.
Loudspeakers: Revel Ultima2 Studio with IsoAcoustics Gaia I isolation feet. Revel Performa3 f206 for surrounds. Two SVS SB-3000 & one SB-2000Pro subwoofers.
Cables: Digital cables: AudioQuest Coffee (USB). Analog interconnects: Benchmark Studio&Stage XLR-XLR,…
Sidebar 3: Measurements
I measured the Topping Pre90's performance with my Audio Precision SYS2722 system (see the January 2008 As We See It), repeating some tests with the magazine's higher-performance APx555 system.
The Pre90's volume control operated in accurate 0.5dB steps. The maximum gain at the unbalanced outputs was the specified 10dB for both the balanced and unbalanced inputs; the maximum gain at the balanced outputs was the specified 16dB for both types of inputs. The preamplifier preserved absolute polarity (ie, was noninverting) with both balanced and unbalanced…
I'm deep into audio power amplifiers because they remind me of race car engines. Both power sources are wildly inefficient, converting only a small percentage of their stored energy into work while dissipating the rest as heat and vibration. Mainly though, I love how race car engines sound. How they shake the air. Just like amps and speakers.
Audio-frequency power amplifiers take a small input signal—usually less than 1V—apply it to an input impedance of (typically) no less than 10k ohms, and make this tiny eye-blink of power (0.0001W) into a waveform that's many times more powerful,…
According to Matuszak, output power into 32 ohms is about approximately 9.5Wpc balanced. It's around 8.3W into 50 ohms and 2W into 300 ohms, both balanced (footnote 2).
On the left of the OOR's front panel is a four-pin XLR headphone output; to its right is a ¼" (6.3mm) output jack followed by a flat knob switch for choosing the RCA or XLR input; that's followed by another knob switch for choosing –4dB, +6dB, or +16dB of balanced gain or, in single-ended mode, –10dB, 0dB, or 10dB of gain. With the Susvara and Abyss headphones, I used balanced at +16dB.
Listening to OOR
I…
In my April 2020 review of Fyne Audio's inexpensive F301 standmount loudspeakers, I wrote, "The Fyne F301s impressed with their exceptional rendering of soundstage width and depth, reasonably wide dynamic range, extended low end (for their size), and exuberant, I-can't-stop-spinning-records presentation. The Fynes presented a finely layered, spatially convincing soundstage with images that were solid, if small."
Upon receiving Editor Jim Austin's assignment to review the Fyne F301's big brother, the F500SP, an upgraded version of the company's F500 model, I wondered if listening would…
The F500SPs were texture kings. They captured the sound of a wire brush circling a plastic drumhead; of air rushing through a metal saxophone; of the resounding rasp of a vibraslap; of the bristling character that distinguishes a Fender Telecaster from a Stratocaster.
Parasound's Hint 6 Halo extracted clarity from the F500SP, but the combination produced glare that left my ears ringing. The Hungarian Heed Audio Elixir proved a warmer and more liquid match, fleshing out the speaker's low end and producing a more balanced tonal palette. The Schiit Audio Ragnarok 2 made the best match yet…
Sidebar 1: Specifications
Description: Two-way, bass-reflex loudspeaker with coaxial tweeter/midbass driver and down-firing port with diffuser. Drive-unit complement: 6" (150mm) "IsoFlare" point-source driver with multifiber bass/midrange cone with "FyneFlute" surround, 1" (25mm) magnesium-dome compression tweeter with neodymium magnet system. Crossover frequency: 1.7kHz. Crossover type: Biwired, passive, low-loss, 2nd-order low-pass, 1st-order high-pass. Frequency response (–6dB in a typical room): 42Hz–34kHz. Sensitivity: 90dB/2.83V/m. Nominal impedance: 8 ohms. Recommended amplifier…