What’s up DAC?

The GO bar’s digital audio circuitry is based around a 32-bit Cirrus Logic DAC chipset with advanced multi-bit modulation. This is coupled with a customized digital filter to minimize pre-echoes and ringing artifacts, and iFi’s GMT (Global Master Timing) precision clock system to ensure ultra-low jitter, thus reducing errors and distortion in the digital audio signal. The DAC is fed by a powerful 16-core XMOS microcontroller, which processes the audio data received at the USB input. iFi’s in-house digital development team has programmed the XMOS firmware to optimize sound quality and ensure a perfect partnership with the Cirrus Logic DAC. Hi-res PCM is supported to 32-bit/384kHz, alongside DSD64, 128 and 256, and single- and double-speed DXD. The DAC’s architecture maintains DSD data in true native form, unlike other DACs that convert DSD to PCM.

The GO bar also delivers full decoding of MQA, the hi-res streaming technology. This means that the complete ‘three unfold’ decoding process is performed internally, as opposed to just the final unfold in the manner of an MQA ‘renderer’, which makes the GO bar an excellent choice for subscribers to Tidal’s ‘HiFi Plus’ tier where Tidal Masters (MQA) content can be found.

Balance of Power

Remarkably given its diminutive size, the GO bar’s analog circuitry features a balanced design with a symmetrical twin-channel output stage. This topology, usually reserved for larger and more expensive amplifiers owing to its cost and complexity, reduces noise and crosstalk in the signal path by fully separating the left and right channels. Rather than resort to space- and cost-saving integrated circuit solutions which compromise sonic quality, the GO bar’s circuitry packs in high-quality discrete components such as TDK C0G ceramic Left The GO bar’s robust yet lightweight alloy enclosure sports a range of useful LED indicators, controls and even a balanced output 3 capacitors, Panasonic OS-CON aluminum polymer capacitors, and high-density tantalum capacitors, plus Taiyo Yuden and Murata inductors, all with excellent characteristics for high-quality audio applications. Special attention has also been paid to power supply filtering, dramatically reducing signal noise introduced through the USB input. The amp’s design combines sonic purity with exceptional power. In fact, with an output of 550mW (into 64 ohms) and 7.5V (into 600 ohms), no headphone amp of such diminutive size can match its impressive ability to drive even tricky headphone loads – that’s enough current drive for 16-ohm headphones and sufficient voltage drive for 600-ohm headphones. Combining serious muscle with beguiling finesse, the GO bar sounds wonderful with a wider range of headphone and earphone types than any other ultraportable USB DAC/amplifier. Adding to this versatility, the GO bar incorporates two power-tuning technologies, enabling adjustment of its output to suit specific requirements. IEMatch attenuates power to suit high-sensitivity headphones and in-ear monitors, removing potential background noise and increasing the usable volume range. Conversely, Turbo mode ramps up the gain by 6dB to satisfy more power-hungry headphone types.

Suits You

Further user-adjustable sonic tuning is provided in both digital and analog domains. Four bespoke digital filter options – Standard, Bit-Perfect (non-oversampling), Minimum Phase, and GTO (Gibbs Transient Optimised) – can be selected according to preference, while iFi’s familiar analog processing modes, XBass+ and XSpace, can also be switched in or out of the signal path according to taste. X Bass+ is a sophisticated form of ‘bass boost’ that enhances low frequencies without muddying the midrange, useful with earphones and open-back headphones that may lack deep bass. XSpace is designed to compensate for the ‘in-head localization’ effect that can occur when using headphones to listen to music that was mixed using a pair of speakers, effectively widening the headphone soundstage to deliver a more spacious and speaker-like experience. With such a variety of digital streaming platforms, file types, headphones, and earphones to choose from, not to mention music styles and recording qualities, this suite of sonic tuning options is valuable to ensure optimal sound – and unique in a DAC/headphone amp of this type and size. Left Both sides of the GO bar’s diminutive circuit board are packed with high-quality components to deliver remarkable sonic performance for such a small device

External Affairs

Most ultraportable USB DAC/headphone amps offer little or no control via the device itself, with volume adjustable only via software running on the connected source device. The GO bar is different, its smart alloy case sports physical buttons for precise volume adjustment – which can be synchronized with the volume controls on the source device – together with controls to select between the various sonic tuning options. A column of colored LEDs provides a handy guide to the format and sample rate of the digital audio currently playing, and whether XBass+ and/or XSpace are engaged. At one end of the GO bar is an asynchronous USB-C input, at the other resides a pair of headphone outputs. One of these is a fully balanced 4.4mm output, enabling headphones equipped with a balanced cable/connector to make the most of the GO bar’s balanced audio circuitry. The other is a 3.5mm output utilizing iFi’s ‘S-Balanced’ technology – this cuts noise and crosstalk by 50 percent with regular single-ended headphone connectors. Both outputs are gold plated to maintain contact quality over time.