The trick, for any IEM, is to be a good acoustic impedance matching coupler. An IEM is a completely enclosed system with no normally propagated sound. An IEM is bascally a sonic waveguide from driver to eardrum. As sound moves from the driver through the various spaces to the ear drum, the acoustic impedance in each area can stimulate reflections and resonances if not carefully designed.
Two major competing goals in the IEM design process are linearity and frequency…
Sound Quality with Standard Cable
I take Doc C.'s statement, "(still better than in most IEMs)," with a couple of grains of salt, but he's got a point. There are lot's of IEMs out there with blown up bass and/or uneven treble. Move up to the $600 level and things get better, but I still find many IEMs having too much fun with a "V"-shaped response. In that regard, the iSine 20 may indeed be a better listen by having a somewhat more neutral response...but it's not without flaw.
To my ears the most noticeable deviation from neutral is a fairly large chunk of the low treble…
Raw frequency response plots with the standard cable show ruler flat response form 10Hz to about 400Hz. To my ear bass below 150Hz needs some boost in order to have proper weight. A rising response is desirable above 500Hz, but in this case it rises too fast and peaks too early at 1.7kHz. The lack of a 3kHz peak and the trough between 2kHz and 8kHz is substantially below target and gives the earphones a veiled sound, lacking presence and vocal overtones.…
I still have it, but a decade ago, the battery stopped taking a charge. I put it aside, planning to replace the battery someday.
One late October afternoon, I looked over at the device and decided it was time to resurrect it. I opened it up and inside found an odd-looking soldered-in battery. I emailed Len Gregory, aka the Cartridge Man, and asked how he…
The DS-E1 CR cartridge weighs 8.1gm and features an aluminum cantilever to which is attached an elliptical stylus. It tracks between 1.6gm and 1.8gm—1.7gm is recommended—and offers 24dB or more of channel separation.
The DS-E1 EQ equalizer fits in an approximately 8" × 2 ¾" × 6" aluminum chassis and outputs about 500mV. Aside from the front-mounted On/Off switch, the only…
Unboxing
While removing the Benchmark HPA4 headphone amp from its simple-but-effective packaging, I noticed three things. First, I noticed that the amp had shipped from Syracuse, NY, where it was made. Second, one whole side of the box said "Benchmark. . . the measure of…
And then ...
I stumbled on a simple, easy-to-…
Description: Solid state line-level preamplifier and headphone amplifier with fully balanced relay-controlled gain stage/volume control providing up to 15dB gain or 127.5dB of attenuation. Its THX 888 headphone amplifier board is specified to deliver up to 11.9V RMS into 300 ohms and 6W into 16 ohms. Inputs: Two single-ended (RCA), two balanced (XLR). Headphone outputs: one via a 4-pin XLR jack, one via a ¼" (3.5mm) headphone jack. Line outputs: one unbalanced (RCA), one balanced (XLR), plus one balanced mono sum output (XLR).
Dimensions: 3.9" (99mm) H × 8.…
Analog sources: Dr. Feickert Analogue Blackbird turntable; Thomas Schick 10.5" tonearm; Koetsu Rosewood Signature Platinum moving-coil cartridge.
Digital sources: MacBook Air laptop, Mac mini running Audirvana Plus, HoloAudio May (Level 3) DAC, Integra DPS-7.2 used as CD transport.
Preamplification: Sunvalley SV-EQ1616D phono preamplifier; EMIA step-up transformer; Rogue Audio RP-7, Pass Labs HPA-1, line preamplifiers.
Power amplifier: Parasound A21+.
Integrated amplifier: Linear Tube Audio Z10e.
Headphone amplifiers: Pass Labs HPA-1,…
I measured the Benchmark HPA4's performance with my Audio Precision SYS2722 system (see the January 2008 "As We See It"), repeating some tests with the magazine's sample of Audio Precision's current top-line APx555. As a line preamplifier, the HPA4 performed almost identically to Benchmark's superb-measuring LA4, which Kal Rubinson reviewed in January 2020, so I will refer you to that review. This report therefore focuses on the HPA4's behavior as a headphone amplifier.
To examine the performance of the conventional ¼" single-ended stereo output, I used a…