Last month, we attended the Audio Engineering Society show in New York City looking for interesting things to feature here on iLounge. We stopped by Shure’s booth — it’s a company we’ve long known for their microphones and reference IEMs like the SE530. What we were not expecting was a chrome-bodied, MFi-certified portable headphone amplifier with an OLED display. Shure sent us a review sample of this amp — the SHA900 — and though we’re very impressed with its performance and features, we’re not sure its price is fully justified.
At first glance, the SHA900 sets expectations — this is a luxury product. It’s made entirely of chome-plated aluminum, with exposed fasteners and a grippy surface sandwiched between chrome at the top and bottom. A large, shiny knurled multi-function rotary knob sits flush on the top-left corner of the SHA900; it’s a little loose, but its movements are well-defined and satisfying. The SHA900 is about the size of an iPhone SE, but over twice as thick. Despite its size, the SHA900 is surprisingly light; we would have no problem carrying it with us if its thickness didn’t make it nearly impossible to fit in a pocket while attached to a cell phone. On top is a charging/status LED and two 3.5mm analog jacks for line in and headphone output. On the bottom panel is a single micro USB input and, one plastic (why plastic?) Line In / USB input switch. The SHA900’s visually striking design is complemented by its one-inch OLED display.
In normal operation, the display features left and right level meters, battery level, input and EQ selection, and a circular volume indicator. Simply put, the SHA900’s build and looks are awesome.
Like its peers, the SHA900 comes with a kit of accessories that make it usable in a wide variety of scenarios. In the box is a wall charger, USB-A to micro USB cable (for PC/Mac connection and charging), a micro USB OTG cable (Android), a micro USB to Lightning cable (iOS), and two silicone bands for attaching the SHA900 to a cell phone. The SHA900 also comes with a variety of analog cables, including long and short 3.5mm cables, a 3.5mm adapter with inline volume control (cheap plastic, but we doubt this will see much use), airline adapter, and a 3.5mm to 6.3mm adapter. We suspect that the center portions of the 3.5mm jacks can be unscrewed to allow quarter-inch inputs, but we elected not to risk breaking an expensive device that we have to return immediately after this review. The SHA900, with its included accessories, feels like a mostly complete package, though at this price we’re surprised that a storage case or sleeve wasn’t in the box.
Using the SHA900 is easy, if not initially intuitive. Pressing and holding the power button toggles the unit on and off, and a hold switch can lock the controls from accidental input. In our testing the SHA900 worked perfectly as a USB DAC/amp with Mac, PC, iOS, and Android without drivers. To navigate the SHA900’s menus, one must first double-press the control knob, scroll up and down by rotating the control knob, then select options by pressing the control knob again. In these cases, the power button acts as a “back” or “cancel” button.
Through these menus, users can access basic functions like high/low gain and a volume limiter, as well as some less-common features like the ability to adjust screen and knob direction, disable USB charging to preserve laptop battery life, and selection of the analog sample rate. Notably missing on the SHA900, however, are useful functions like power bank mode, line out, and a secondary optical or coaxial input. In addition, we would have much preferred a standard USB-A input — microUSB to Lightning cables are much harder to find, and Shure doesn’t sell a direct replacement for the cable included with the SHA900.
Perhaps the biggest differentiating feature for the SHA900 is its graphic equalizer function. There are five preset equalizer modes, like Flat, Low Boost, and Vocal Boost, but more interesting are its four user-definable presets. In each of the user presets, we could essentially draw an EQ curve: starting with four pre-defined spots (80hz, 500hz, 2000hz, and 5000hz), rotating the control knob can micro-adjust the frequency being altered, the width of the band affected by the adjustment, and the size of the adjustment in decibels. It’s a little fiddly to manage all these features through a tiny screen and a control knob, but incredible that Shure has packed so much functionality into the SHA900. We’re not huge fans of EQing our headphones, but we can verify that the SHA900’s sophisticated EQ functions work as advertised. When analog line in is used, the SHA900 can be used in “Bypass Mode,” which passes the analog signal without any digital processing.
The SHA900’s specs are good, but not mind-blowing for a device at this price point. Inside is a 24bit/96kHz DAC and analog-to-digital converter; we could not find any official specification for the brand or model of DAC used. Frequency response is 10 HZ to 50 kHz, with total harmonic distortion plus noise of 0.05% at 1kHz. The SHA900 outputs 135 mW per channel into 16 ohm, or 95 mW per channel into 42 ohm, and its output impedance is an IEM-friendly 0.35 ohm.
