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Esoteric DV-50 universal player Measurements

Sidebar 3: Measurements

The Esoteric DV-50 had a maximum balanced output level at 1kHz of 5.05V RMS for CD and DVD playback, 5.11V for SACD. The unbalanced output was a little less than half this at 2.34V, which is an audible 1.4dB greater than the standard CD output. The output impedance was moderately low across the audioband, at 448 ohms unbalanced and 664 ohms balanced. Error correction was good, the player coping with gaps in a CD's data spiral of up to 1mm in length without audible glitches.

The frequency response for SACD playback (fig.1) extended above 20kHz, but showed…

Esoteric DV-50 universal player Measurements part 2

The Esoteric's DACs offered excellent linearity, any error in CD playback remaining below 2dB to -110dBFS (fig.6). For SACD playback, there was less than 2dB error down to below -120dBFS, with just +6dB of error at -130dBFS. The player's low analog noise floor meant that its reproduction of an undithered 16-bit sinewave at -90.31dBFS was nigh-on perfect (fig.7).

Fig.6 Esoteric DV-50, left-channel departure from linearity, 16-bit CD data (2dB/vertical div.)

Fig.7 Esoteric DV-50, waveform of undithered 1kHz sinewave at -90.31dBFS, 16-bit LPCM data.

As is…

HeadRoom Total BitHead headphone amplifier

When, on his long-running TV variety show, Jackie Gleason used to order up some "traveling music" from music director Ray Bloch, he got a live orchestra's worth. But when Gleason, a composer and conductor in his own right (he wrote his show's unforgettable theme song, "Melancholy Serenade"), actually traveled, his listening options were severely limited compared to ours. By the time the comedian died in 1987, Sony had introduced the Walkman cassette player, but Apple's iPod was still more than a decade in the future.

No one will accuse HeadRoom's new Total BitHead headphone…

HeadRoom Total BitHead headphone amplifier Page 2

For best performance, HeadRoom suggests setting all computer volume controls to max. In the case of Mac OS X, there's a main volume control on the desktop, another in System Preferences (along with one for balance), and another in iTunes. iTunes also has a neat 10-band graphic equalizer with multiple presets and manual settings you can name and save to memory, and yet another level control, found under Window in the iTunes menu.

What difference does it make?
Some readers will complain that the Total BitHead has nothing to do with high-end audio. I disagree. For one thing, if it…

HeadRoom Total BitHead headphone amplifier Specifications

Sidebar 1: Specifications

Description: Battery-powered headphone amplifier. Includes rubber feet, Velcoin Velcro discs, USB-to-mini-USB cable, 1/8"-to-1/8" audio cable. Maximum voltage gain with 300 ohm load: 11.2dB. Maximum THD+N, 20Hz-20kHz, 300 ohm load: 0.15%. Input impedance at 1kHz: 20k ohms. Output impedance at 1kHz: 1.7 ohm.
Dimensions: 2.75" W by 4.5" D by 1" H. Weight: 2.5oz per website, 5.5oz per spec sheet (with batteries).
Serial number of unit reviewed: Not noted.
Price: Total BitHead, $269.
Manufacturer: HeadRoom, 2020 Gilkerson Drive, Bozeman, MT 59715. Tel…

HeadRoom Total BitHead headphone amplifier Measurements

Sidebar 2: Measurements

I loaded the Total BitHead with four fresh AAA batteries and looked first at its performance via its analog input. The maximum voltage gain into 100k ohms was 11.4dB, and the DC offset varied between 5 and 7mV. This offset will not be high enough to damage headphones, but its presence led to a scraping noise when I rotated the BitHead's volume control. The input impedance at 1kHz was a moderate 47.5k ohms, dropping slightly and inconsequentially to 36k ohms at 20kHz. The unit preserved absolute polarity; ie, it was non-inverting.

As befits a headphone amp…

Ken Nelson 1928–2004

On Friday morning, March 25, 2005, my friend Maura Rieland, Stereophile's show coordinator through the second half of the 1990s, e-mailed me to say that she had just learned of the passing of Ken Nelson.

For those of you who didn't know him, Ken was a legendary figure in the audiophile publishing world for many years. Publisher of one of the daily newspapers of the annual Consumer Electronics Show, he was hired by Larry Archibald at the beginning of 1984 to be Stereophile's first full-time advertising representative. He had his own rep business, Nelson and Associates. The associates were…

NHT SuperZero loudspeaker & SW2 subwoofer

What makes someone a good hi-fi reviewer? A fine critical sensibility? A good technical background? Ears? Eyes? Nose? Throat? So many different people are reviewing audio gear these days that it's downright impossible to characterize a good reviewer. But I do know that Beavis and Butt-head would make killer hi-fi reviewers!

I know this because I just spent a whole weekend watching the Beavis and Butt-head Marathon on MTV—two full days of the clearest, most incisive social commentary since Charles Kuralt stuffed himself into a souped-up Winnebago and hit the road searching for the naked…

NHT SuperZero loudspeaker & SW2 subwoofer Page 2

But that was then and this is now. Ken Kantor, NHT's designer/founder, has totally redesigned his smallest speaker—the cabinet is the only thing left from the older Zero—giving it high-performance drivers, a better crossover, and real speaker connectors. And while NHT never claimed that the original Zero was anything but a decent budget speaker, they're calling the SuperZero a true high-end component that just happens to cost very little.

I first heard the SuperZero when NHT introduced it at the 1993 Las Vegas WCES along with their new flagship 3.3 ($4000/pair). But while the 3.3 really…

NHT SuperZero loudspeaker & SW2 subwoofer Page 3

The MA-1 offers two ways to mate the SW2 subwoofer with a pair of speakers, and was designed to allow the use of other manufacturers' speakers as well as NHT's own models. Via the MA-1's speaker-level inputs and outputs, the signal from a system's main amplifier is taken to the MA-1 and crossed over passively at 100Hz to the main speakers. The MA-1 also sums the two channels and sends the signal to the active low-pass crossover, whose feed to the subwoofer is then adjustable in terms of level via the front-panel level knob and crossover frequency—50Hz, 80Hz, or 110Hz (footnote 3). (The MA-1'…