Looking out that desk window, I notice also the spring-warmed radiance of the sun, the racing shadows of ravenous sparrows, and daffodils. Each one of those things, in its way, affects…
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Today is March 22, 2020. Outside my door, the plague is gaining intensity. People are wearing masks and rubber gloves. But outside the window by my desk, there is a Callery pear tree, and every day its blossoms are becoming more intensely white. Each day its brightness (measured in units of luminous flux) increases noticeably. The optical radiance of its zillion-petal whiteness illuminates the whole garden.
The HEDDphone's rectangular AMT drivers are installed into a conventional-looking but very solidly built (718gm!), circumaural, open-back headset with thick, tight-fitting ear cups that cupped my ears with greater bulk and pressure than I have previously experienced with headphones.
But that is okay. Form must follow function.
At 42 ohms and 87dB/mW, the HEDDphone is easier to drive than the 83.5dB/mW HiFiMan HE6se and about the same difficulty as the 47 ohm, 88dB/mW Abyss AB-1266 TCs, which means it still requires extra gain and current to sound its best.
I…
Spectral is a bit of an enigma in the high-end audio world. Although nearly 20 years old and one of the founders of the American high-end audio industry, Spectral isn't a name that comes quickly to mind when considering the best of the best in high-end.
Spectral's low profile is of their own choosing. They advertise very little, their products are demonstrated in a small number of stores, they almost never send products to magazines for review, and they are very quiet about their accomplishments. Rather than push their products on customers, they seem to let a small segment of the market…
The analog filter is a passive, fourth-order type designed for high out-of-band attenuation, low phase shift, and good transient response.
The analog output stage is based on the circuits Keith Johnson has been refining for more than 20 years. The SDR-2000 Pro's output stage is very similar to the electronics used throughout the signal path in Keith's recording electronics, which are used to make all the Reference Recordings releases. The circuit features a differential JFET input stage and a MOSFET cascode, followed by a differential cascode voltage-gain stage. High-current power…
Thomas J. Norton wrote about the Spectreal in November 1995 (Vol.18 No.11):
RH salivated over the Spectral SDR-2000 Professional HDCD D/A processor in Vol.18 No.5, and this was my first chance to hear it in my system. He did not exaggerate. It is clearly a Class A processor; it may even be the best processor in Class A, though I haven't had the opportunity to compare it directly with the Mark Levinson No.30.5, which isn't exactly chopped liver (footnote 1).
At first I found the differences between the SDR-2000 and the Mark Levinson No.36 D/A converter to be subtle—less notable…
Sidebar 1: Specifications
Description: Digital Processor with HDCD decoding. Inputs: three coaxial on RCA jacks, two AES/EBU on XLRs, TosLink optical, Spectralink. Controls: digital input select, polarity inversion, mute, display dim, operate/standby. Sampling rates supported: 44.1kHz, 48kHz. D/A conversion: four custom 20-bit DACs in balanced configuration. Digital filter: Pacific Microsonics PMD100 8x-oversampling. Analog filter: passive, linear phase to 22kHz. Frequency response: DC–22kHz ±3dB (limited by encoding). DAC step resolution: 5µV or less. Digital noise output: 100µV p-p or…
Sidebar 2: Robert Harley's System
I listened to the SDR-2000 Pro at the front of my usual reference system, and with an all-Spectral playback system with MIT loudspeaker cables and interconnects. The people at Spectral believe that their electronics and MIT cables are needed to fully hear the SDR-2000 Pro's musical performance. Although I agreed to replace my usual amplification and cables for part of this review, auditioning the SDR-2000 Pro in my familiar reference system was mandatory.
My system consisted of a Mark Levinson No.31 CD transport feeding the SDR-2000 Pro via…
Sidebar 3: Measurements
The SDR-2000 Pro's maximum output level was lower than that of most processors, measuring just 2.06V from the balanced outputs and 1.03V from the single-ended outputs. These low levels are a result of the 6dB attenuation in the SDR-2000 Pro's analog stage to conform to the HDCD requirement. When playing HDCD-encoded discs, the maximum levels will be 6dB higher: 4.12V from the balanced outputs, 2.06V from the single-ended outputs.
The output impedance measured 200 ohms from the unbalanced jacks, 400 ohms from the balanced outputs at any audio frequency. DC…
Capital Audiofest (CAF) has canceled its 2020 show, previously scheduled for October 30 through November 1, and announced dates for 2021.
We apologize for our silence but are happy to announce that the Capital Audiofest (CAF) has finalized an agreement with the Hilton Hotel that allows us to move the show from 2020 to 2021 without any issues. We feel it is better to wait a year in order to provide everyone with the same CAF qualities inclusive of…
Early Sunday, CAF issued this statement, signed by show founder and organizer Gary Gill:
To all friends of The Capital Audiofest:We apologize for our silence but are happy to announce that the Capital Audiofest (CAF) has finalized an agreement with the Hilton Hotel that allows us to move the show from 2020 to 2021 without any issues. We feel it is better to wait a year in order to provide everyone with the same CAF qualities inclusive of…
Most audiophiles are aware of the modification and add-on aftermarket. A few have learned the hard way that modifier competence varies from primitive magic and sales hype to real engineering skill. Some modifiers are serious audiophiles who are also good technicians; others are scam artists whose only goal is to make a quick buck on the latest fad. If you have only a rudimentary understanding of electronics, you may not be able to make a distinction. Even the most jaded and battle-hardened among us can still be hooked and reeled in by a slick sales presentation.
Can you tell a product…