Optoma NuForce DAC80 DAC and STA120 power amplifier

Solid-state power amplifiers,
Digital-to-analog converters
Optoma NuForce DAC80 DAC and STA120 power amplifier

A few short years ago, NuForce was the audio industry’s enfant terrible: a new brand, growing at an exponential rate, with some of the best products in every category it touched. It couldn’t last, and the company burned out almost as fast as it appeared on the scene. But the name never quite went away.

Today, NuForce is back. Many of the original people behind the brand are still there, but it’s now the audiophile arm of Optoma, a company better known for making high-performance projectors. Optoma NuForce is still pursuing the goals of the original NuForce brand, with a range of earphones, headphone amps/DACs, and Class D power amps, but home theatre multichannel preamps and power amps replace the previous high-end stereo audio range. Optoma NuForce’s new core strength in the home is high value desktop-meets-audio-enthusiast models, like the DAC80 and STA120.

The £500 DAC80 is a DAC with a volume control. It has an optical, two coaxial, and an asynchronous USB input, and a single set of stereo RCA analogue outputs. It can support digital files up to 24bit, 192kHz with the appropriate drivers for Windows or Mac (these are easy to download from the Optoma website). The volume knob doubles up as the DAC’s power button and the red ‘U’, ‘C’, ‘O’, and ‘C’ indicators on the ultraminimalist front panel indicate the four sources. There is also a sextet of lights to denote sampling rate, which light sequentially if the input signal is not a multiple of 44.1kHz or 48kHz. DSD is not supported. Curiously, given Optoma NuForce’s continued link with the in-ear world, there is also no sign of a headphone socket on board the DAC80. The product comes supplied with a tiny remote control that operates every function on the DAC80 (that sounds impressive, but really that means power, volume, source selection, and mute), and Optoma NuForce also supplied the DAC80 with the £70 BTR100 aptX and A2DP friendly Bluetooth hub receiver, which slots into the Toslink input of the DAC80.

Setting aside the bluff exterior and the basic controls, there’s a lot of good under the skin of the DAC80. It features an AKM AK4390 32-bit DAC coupled to an AK4118 digital receiver chip, while filtration and jitter reduction is all coded onto a FPGA chip. The output stage is op-amp based, and the whole DAC is fed from a small toroidal transformer. Those armed with keen eyes and a screwdriver might notice the circuit is very similar to that of its more expensive DAC100 predecessor, except that the DAC80 no longer has a headphone amplifier stage. In fairness, that task is now handed over to the HA200 dedicated headphone amplifier.

The DAC80’s matching power amplifier is the £500 STA120, a stereo Class D chassis delivering 80W per channel into an eight-ohm loudspeaker load. NuForce of old (NuAuldForce?) was built around getting a very good sound out of a Class D circuit and its V3 amplifier was something of a game-changer for the switching amplifier circuit, and it certainly sounds as if that technology was passed on to new NuForce (NuNuForce?). Like the DAC80, that technology is the use of a linear power supply and a large toroidal transformer to drive the Class D switching circuitry. As the foil to the minimalist DAC80, the STA120 is similarly light on features. There are just two RCA inputs and a pair of basic multi-way loudspeaker terminals. There isn’t even a power switch, save for the rear-mounted one next to the IEC socket. There are two red-orange LEDs on the front panel, just above the laser-cut NuForce name, but that’s about it.

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