Perhaps the century-long presence of the Philips research center in the Netherlands led to the country being a hotbed of science-based audio engineering. Kees Schouhamer Immink, who was responsible for the optical-disc reading…
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In 1979, I visited Philips Electronics' renowned Research Center in Eindhoven, Holland, to examine a prototype of what would eventually be called a compact disc player. In 1989, I returned to the Eindhoven lab to witness the birth of the first sigma-delta DACs, which eliminated the problem of large linearity errors at low recorded levels in resistor-ladder DACs.
Learning how to use the wheel didn't take long, and the inconvenience of having to walk over to the MU1 wasn't a problem given that almost all the operations it enables are "set'n'forget."
Since I purchased the review sample, along with a lifetime subscription to Roon, the Roon Labs Nucleus+ music server ($2559) has been my primary source for digital music. I have been using it with network-connected D/A processors that can act as a Roon endpoint, like the PS Audio DirectStream and MBL N31. I am currently without a NAS drive, so Roon accesses my music library via an internal drive I…
Sidebar 1: Specifications
Description: Music streamer/Roon endpoint with Intel i3 processor and 4GB RAM running Linux and Roon Core, 3.5", 480×320 pixel, color TFT display, and optional internal SSD for music data storage. Digital audio outputs: two AES/ EBU (multichannel capable, with switchable volume control) and one Grimm LS1. Digital audio inputs: one each AES/EBU, coaxial S/PDIF, TosLink S/PDIF. Other inputs/outputs: FM cable input; Ethernet network port; 2 USB ports; 3.5mm socket for external IR remote sensor. All sample rates and formats supported. Tidal, Qobuz, and Spotify…
Sidebar 2: Associated Equipment
Digital sources: Roon Nucleus+ music server; Astell&Kern AK100 portable player; MBL N31 CD player/DAC; PS Audio DirectStream D/A processor; Ayre Acoustics QA-9 A/D converter.
Preamplifiers: MBL Noble Line N11, Pass Labs XP-32.
Power amplifiers: Parasound Halo JC 1+ monoblocks.
Loudspeakers: KEF LS50, Sonus Faber Lumina III.
Cables: Digital: AudioQuest Vodka (Ethernet, TosLink), Canare 110 ohm (AES/EBU, 15', auditioning, and 45', measuring). Interconnect: AudioQuest Wild Blue (balanced). Speaker: AudioQuest K2. AC: AudioQuest Dragon…
Sidebar 3: Measurements
I examined the amount of timing uncertainty—jitter—in the Grimm Audio MU1's AES/EBU output using my Audio Precision SYS2722 system's digital oscilloscope function. I overlaid successive snapshots of the MU1's AES/EBU output, taken over a 60-second time window, to show what's called an "eye pattern." To make things as difficult as possible for the MU1, the AES/EBU link was a 45' length of Canare 110 ohm balanced interconnect and the data represented the 24-bit Miller-Dunn J-Test signal sampled at 44.1kHz. With an ideal transmission system, all the pulse transitions…
I am not a fan of that amp designer who promoted his products by pointing a condescending finger while scolding audiophiles, like errant children, for preferring their records to sound "pleasant" rather than "accurate."
He reminds me of my least favorite teacher, Professor Grausamkeit, who was just like that and said similar things. Every time I smarted back, "Accurate to what?" he'd whack me with a wooden yardstick.
Grausamkeit would twist my ear painfully while scolding me but would never explain what "accurate" sounded like or why it didn't sound pleasant. Best I could figure…
Be aware: When choosing speakers for use with low-power tube amps, the sensitivity spec is less important than finding a speaker with a flat, high, nonreactive impedance characteristic.
The Soul Supremes satisfy this requirement by using a crossover with only a voltage divider (two resistors), and a single capacitor to attenuate the 113dB/W/m–sensitive Radian ribbon tweeter at 12kHz. The Zu's doped-paper cone mid/woofer handles the other octaves wide open, with no crossover or response modeling. The tradeoff is, running full-range, the Zu's 10.3" cone makes a bit of jitter-like breakup…
On top of a desk, an audio system must be able to deliver satisfying sound in a nonoptimal environment: a flat, reflective plane (the desktop) cluttered with keyboard (or maybe a laptop computer); a mouse; assorted papers, books, and trash; and, perpendicular to that, another flat, reflective plane (the computer display), which, if it's not a tiny laptop screen, will block some of the soundwaves emanating from the speakers. Such sonically inhospitable spaces can consign 3D stereo imaging (and other desirable sonic traits) to the realm of the imagination.
My workspace is especially…
The four digital inputs (USB, Walkman, optical, and stereo mini) are on the "A" speaker's left side. A's rear panel offers pairs of unbalanced (RCA) and balanced (XLR) analog inputs and a left/right switch, which determines whether speaker A or speaker B receives the right (or left) signal. Here, also, are the aforementioned digital sync cable and the power inlet.
Speaker B's front panel holds four acoustic adjustment knobs. Addressed from left to right, the D.A. ASSIST (D.A. Hybrid amplifier analog assist) allows you to choose whether to use the analog amplifier only for error-…
Sidebar 1: Specifications
Description: Nearfield active speaker system for desktop listening. Drive-units: ¾" (19mm) titanium-sputtered soft-dome tweeter, two 9/16" (14mm) titanium-sputtered soft-dome tweeters; two 4" (100mm) anodized-aluminum–cone woofers. Crossover frequencies: 5kHz, below 200Hz (adjustable, for assist woofer integration). Inputs, digital: USB-B, Walkman/Xperia, TosLink. Inputs, analog: XLR, RCA, Stereo Mini. Total amplifier power: 106W. THD: 0.03% (1kHz, 10W). Frequency range: 10Hz–200kHz. S/N ratio (A-weighted): 100dB. Power consumption, active: Speaker A, 60W,…