First Listen: Oppo HA-1 desktop headphone amplifier/DAC/preamp

As Hi-Fi+ readers know, we have been closely following Oppo Digital’s ongoing expansion in the high-end headphone and personal audio electronics marketplace.

First came the firm’s flagship PM-1 planar magnetic headphones (reviewed in issue 1xx), then a set of critically important optional ear pads that make the PM-1s sound even better (reviewed in issue 115), and now we have the long-awaited HA-1 desktop headphone amplifier/DAC (£1,199), which effectively completes Oppo’s high-end headphone system.

To jump right into the thick of things, let me say from the outset that the HA-1 is a pretty remarkable piece of kit, and one that—in the finest Oppo tradition—is not only chockfull of innovative features, but offers a generous helping of performance for the money. To lend some substance to these assertions, let me provide a brief verbal ‘walking tour’ of the unit.

As you might expect, the HA-1 leverages the considerable body of digital audio know-how developed by Oppo in the course of creating its award-winning and exceptionally versatile BDP-105EU audiophile-grade universal Blu-ray disc player (reviewed in issue 96). But in certain key respects the HA-1 DAC section ups the performance ante vis-à-vis the capabilities of the BDP-105-series players.

Specifically, the HA-1 provides a broader set of digital inputs than the BDP-105-series players: one front-panel USB port geared for use with smartphones, one rear-panel asynchronous USB power, a pair of S/PDIF inputs (one optical and one coaxial), an AES/EBU input, and an aptX-enabled Bluetooth interface. Moreover, the HA-1 provides two sets of analogue inputs (one single-ended via RCA jacks and the other balanced via XLR jacks), so that it gives owners quite a lot of flexibility in term of the types of sources it can support.

In keeping with long-standing Oppo practice, the DAC section of the HA-1 is based on the ESS 9018 Sabre32 Reference DAC. The HA-1 shares not only this ESS DAC but also DAC-section output stage circuitry with the firm’s time-proven Oppo BDP-105D universal Blu-ray player. The HA-1’s DAC section is nothing if not versatile and can therefore support PCM formats up to 32-bit/384kHz and DSD files ranging from DSD64 on up to DSD256.

However, where the BDP-105D is, first and foremost, a disc player, the HA-1 is designed to fill a much different set of roles. Thus, the HA-1 can be used as a conventional DAC in traditional high-end audio systems, or it can be used as an analogue/digital stereo preamplifier (with home theatre bypass), or as a high-powered and full-featured headphone amplifier that supports both digital and analogue inputs. Our bet, though, is that most buyers will gravitate to the HA-1 for use as the heart of (and central power plant for) their high-performance headphone systems.

The analogue amplifier section of the HA-1 is a fully balanced design that is based on discrete, Class A circuitry. As you might imagine, this mean that at idle, the HA-1 tends to run a bit warm, though not unpleasantly so.  But in exchange for that extra bit of heat, listeners enjoy the precision and clarity for which Class A circuitry is known, plus all of the gain/low-noise benefits that fully balanced amplifier circuits confer. Oppo takes an unabashedly purist approach to its balanced circuit topology, emphasising that “For digital audio, the signal runs in balanced mode all the way from the DAC to the output jacks.” Further, Oppo stresses that the HA-1 “Balanced analogue input is kept intact, and (the) single-ended input is converted to balanced at the input buffer.” 

In turn, the HA-1 provides both a single-ended headphone output (via a 6.35mm headphone jack) and a balanced headphone output (via a 4-pin XLR connector). Oppo points out that, “the balanced headphone output provides twice the voltage and four times the power of the single-ended output, enabling the HA-1 to drive the most power hungry headphones.” What kind of power are we talking about? In balanced mode the amp offers maximum output of 2400 mW @ 600 Ohms or 3000 mW into 32 Ohms, while in single ended mode the amp delivers maximum output of 600mW @ 600 Ohms or 3500mW @ 32 Ohms. Frequency response is quoted at 10 Hz – 200 kHz (+0B/-1dB) or an even more ruler-flat 20 Hz – 20 kHz (+-/-0.04dB).

Apart from audio performance, I think four other aspects of the HA-1 will be real crowd pleasers. First, the unit offers arguably the most refined fit and finish of any Oppo electronics component to date. Units are offered either in black or silver, with both versions offering the type of upscale anodizing and surface finishes rarely seen in such affordable products. Second, the HA-1 comes with a lovely, sturdy, and very easy to use remote control whose metal enclosure gives it a just-right touch of weight and heft in the hand. Third, the HA-1 provides an absolutely beautiful, colour user interface screen that is highly reconfigurable to suit the owner’s tastes. Apart from screens that provide basic setup and control functions, for example, the unit offers three display options: a settings summary screen, a bar-graph type spectrum display, or a display depicting an old-school set of VU meters. It’s very cool looking indeed. Last but certainly not least, the HA-1 comes with a really first rate User Manual.

I admit it; I’m an inveterate reader of product manuals and one thing I’ve learned is that product documentation for many contemporary audio components is woefully inadequate if not downright misleading. Why should you care? Because multifunction components such as the HA-1 offer so much control over such a broad range of features and functions that it pays to take the time to learn how the component actually works. The excellence of the Oppo manual stands in stark contrast to the documentation for some personal audio products that I’ve tried recently, where—I kid you not—at least one competitor’s manual described product functions that quite literally did not exist (how’s that for maddening?).

Since Hi-Fi+ will be reviewing the HA-1 in an upcoming issue, I won’t say too much about its sound in this blog, except to note that the HA-1 offers a richly revealing, intensely multi-layered sonic presentation coupled with more than enough power to make Oppo’s PM-1 planar magnetic headphones sing.  The jury is still out on whether the HA-1 does or does not offer enough oomph to make today’s most power hungry headphones happy, but that is a question we will address in our full-length review. For now, though, I feel comfortable in saying that the combination of Oppo’s PM-1 planar magnetic headphones with the firm’s HA-1 headphone amp/DAC will give its owners instant entry into the upper tier of contemporary headphone performance.

Watch for our upcoming Hi-Fi+ review of the HA-1, and in the meantime, Happy Listening!