Technology
Like the KSE1500s', the KS1200SYSes' drive-units feature a virtually massless diaphragm suspended between two back plates, with a 200V polarizing voltage…
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In November 2016, I reviewed Shure's KSE1500 electrostatic in-ear headphone system, which featured a D/A amplifier with both analog and USB inputs that drove in-ear headphones with unique electrostatic diaphragms. At $2999, the KSE1500 was and is pricey, and recently Shure introduced a less-expensive electrostatic headphone system, the KSE1200SYS ($1999), with the same amplifier and earpieces but just an analog input.
Sidebar: Specifications
Description: In-ear headphones with electrostatic drive-units and dedicated headphone amplifier and power supply. Drive-unit polarizing voltage: 200V DC. Maximum output voltage: ±200V. Output current: <1mA. Noise attenuation: #60;37dB. Frequency range: 10Hz–50kHz. Maximum SPL: 113dB (1kHz at 3% THD). Amplifier input: analog line-in (3.5mm). Amplifier output: Lemo connector. Signal/noise: <107dB, A-weighted. Adjustable gain range: –40 to +60dB. Amplifier functions: line input pad (–10dB). Amplifier power supply: rechargeable 3.6V Li-ion battery. Battery life…
Sidebar 2: Associated Equipment
Sources: Roon Nucleus+ server; PS Audio PerfectWave DirectStream DAC; PonoPlayer, iPhone 6S, iPad mini.
Headphone amplifier: Ayre Acoustics EX-8 integrated amplifier.
Headphones: Audeze LCD-X, Ultimate Ears 18 Pro.
Cables: Digital: AudioQuest Coffee, USB. Analog: AudioQuest Forest, manufacturers' own. AC & analog: manufacturers' own.
Accessories: AudioQuest Niagara 1000 Low-Z Power/Noise-Dissipation System.—John Atkinson
One of the recurring themes of this column has been my search for servers that will support the playback of high-resolution multichannel files with DSP for speaker/room equalization (EQ), as well as the format conversion and downsampling that are often part of those processes. Because most EQ software is PCM-based, format comversion is needed to convert DSD files to PCM. In addition, because most EQ products work within a limited range of sampling rates, PCM files sampled at high rates may have to be downsampled before being subjected to EQ. Those of us who use home-theater preamplifier-…
Sidebar 1: Associated Equipment
Analog source: Ortofon MC-3000 cartridge, Well Tempered Tonearm and Turntable, Ortofon X-3000 step-up transformer.
Digital sources: Pioneer CLD-99 multi player, Sony DTC-2000ES DAT recorder.
Surround processor: Lexicon DC-1.
Preamplifier: Threshold FET-10/pc, Threshold FET-10/hl.
Power amplifiers: Lexicon 225 and 312, Boulder 102 (x3).
Loudspeakers: Five Tannoy 10 DMT-IIs with PS115 subwoofer.
Cables: Canare Video Coax interconnects, Monster loudspeaker cables.
Accessories/room treatment: Owens-Corning fiberglass.—J. Gordon Holt…
Sidebar 2: Specifications
Description: Surround-sound decoder for music and films. Inputs: Left & Right. Outputs: L, C, R, Surround L and R, Subwoofer. All connections unbalanced. Input impedance: 42k ohms. Output impedance: ±100 ohms. Frequency response: 20Hz–20kHz, ±0.1dB. S/N ratio: 92dB (no ref. level specified). Distortion: 0.02%. Power consumption: 1.4A. Controls: Noise sequencer (On/Off), Modes (Video Surround, Music Surround, Stereo, Mono), Center channel (On/Off), Surround Bandwidth (20kHz, 7kHz), Surround Field (Wide, Normal), Output Level (unity gain to –17dB), Master…
Making digital audio sound good appears to be a much more difficult job than its developers first realized. When digital audio was in its infancy, there was a tendency to think that digital either worked perfectly, or didn't work at all. This belief led the engineering community to devise ill-considered and flawed standards that affect the musical quality of digitally reproduced music today.
The S/PDIF and AES/EBU interfaces used to connect a CD transport to a digital processor are a perfect example. When the digital interface was standardized, no one considered that its design could…
The current-to-voltage converter (I/V) is a discrete design first used in the Theorem, but with some modifications that reportedly result in better transient performance. This is followed by a fully discrete, class-A, direct-coupled analog output buffer that runs on ±35V rails (most output stages run on ±15V). The output low-pass filter is a newly designed third-order Bessel type. The I/V converter, low-pass filter, and output buffer are integrated into a single stage that uses very little feedback. Moreover, the output transistors are hefty TO-220 packages that can reportedly drive half an…
Sidebar 1: System
I treated the Axiom and Theorem primarily as a CD player in two boxes: the advantages of a separate clock suggest that these two products will work best together. I also evaluated the Axiom and Theorem separately, driving the Theorem with Mark Levinson No.31 Reference and Theta Data Basic transports. Similarly, the Axiom drove the Theorem II and Adcom GDA-600 digital processors. Digital interconnects included AudioQuest Diamond x3 (AES/EBU), Parasound DataBridge (coaxial), and a Prisma coaxial cable.
The processors under audition drove an Audio Research LS5…
Sidebar 2: Measurements
The Theorem II's maximum output level was 2.03V, conforming with the CD standard of 2V output. The output impedance was a low 70 ohms at 20Hz, decreasing to 50 ohms at 1kHz and above, making the Theorem II insensitive to preamplifier loading. DC levels were negligible, measuring just 0.2mV (left channel) and 0.1mV (right channel). The Theorem II's polarity button works: set to positive polarity, the Sumo doesn't invert absolute polarity from its RCA outputs. Because pin 2 of the XLR connector is the signal conductor and pin 3 is grounded, the Theorem II will be…