LH Labs Geek Out V2 USB DAC and Headphone Amplifier

More Power in a State-of-the-Art Case

Equipment report
Digital-to-analog converters
Light Harmonic Geek Out V2
LH Labs Geek Out V2 USB DAC and Headphone Amplifier

Computer audio advances rapidly. Shortly after I reviewed LH Labs’ Geek Out 450 amplifier/DAC (Issue 251), an improved version appeared. Named the Geek Out V2, the new model offers some interesting improvements on the original Geek Outs. If you’re wondering what a Geek Out is, well, it’s a combination DAC and headphone amplifier built into a very small (1.48" x 0.51" x 3.07"), light (1.2 oz.) package. As was the case with the original, power for the V2 comes from a USB port on a computer, which is also the only signal input for the V2. There are several different models of the Geek Out V2; this review deals with the basic one, which sells for $299. There’s also a larger V2+ model that includes a battery and uses a smartphone as a source instead of a computer.

The Geek Out V2 is functionally similar to the Geek Out 1000; both amplifiers can produce 1000 milliwatts (that’s a whole watt) into 16 ohms. A 1000mW power output will comfortably drive most headphones on the market today. The V2 also has a setting that resembles the Geek Out IEM 100 USB DAC and headphone amplifier that produces 100mW into 16 ohms. “Why,” you might wonder, “would I want an amplifier that produces so little power if it also produces ten times as much?” The answer is that a lot of in-ear monitors, a.k.a. earbuds, require very little power, but need a very quiet source, which is what the 100mW setting of the V2 offers. A button on the side of the V2 switches between power settings. It’s audibly obvious which setting has been selected, but there’s also an LED to let you know.

The original series of Geek Out DAC/headphone amplifiers was housed in an aluminum chassis that got surprisingly hot, thanks to the use of a Class A headphone amp and the fact that the case was not ventilated. Class A amplifiers produce top-notch sound, but run very warm. The Geek Out 450 wouldn’t burn you, but it would surprise you when you grasped it. One of the V2’s major upgrades is that it’s housed in a case manufactured on a 3-D printer and has lots of heatsinks and vents to dissipate the heat from its toasty Class A amplifier. In another improvement, the amplifier parts are better distributed on the tiny printed circuit board inside the case, which also promotes heat dissipation. The case is made of high-temperature resin.

It’s just my opinion, but to me, the V2’s case, decorated with interesting scrollwork, looks much more elegant than that of the original Geek Out. This was the first item I’d seen that was created by a 3-D printer, and I was surprised to see how intricate the design and execution were. I expected the case to be larger than that of the original Geek Out, but it was approximately the same size. The V2 did not come with a USB dongle extension cable, and the original did. That dongle was very handy for a couple of reasons: 1) it didn’t put as much strain on the computer’s USB connector as plugging the V2 directly in did; and 2) if you plugged the USB connector directly into the computer (without the dongle), it would block adjacent USB ports. LH Labs offers USB dongles at extra cost, or you can use any cable with a male Type A USB plug on the origin end and a female Type A plug on the destination end.

The V2’s DAC chip is an ESS SABRE9018AQ2M DAC (an upgrade over the 9018K2M in the previous version), and it’s pretty impressive: It plays PCM files up to 384kHz/32-bit and DSD files via DSD-over-PCM (DoP) up to DSD128. Although a few DSD256 albums are beginning to be released, their number is limited so far, so the V2’s inability to play them isn’t a serious problem—yet. The V2 offers two filter settings, explained in the manual as follows: “TCM (Time Coherence Mode) uses LH Labs minimum-phase digital filter and time-optimization algorithm, which removes all pre-ringing from the converted signal and realigns the impulse response, [presenting] the listener with a more well-defined and natural soundstage; FRM (Frequency Response Mode) uses a slow roll-off digital filter and frequency-domain-optimization algorithm to provide a smoother and clearer sound with even lower THD+N in the high frequencies.”

The button on the side of the V2 furthest from the USB connector switches between the two settings, with a colored LED indicating which is selected. This button, plus the one for the power setting, are the only physical controls on the V2. The manual says a green LED indicates the FRM filter, while a red LED indicates the TCM filter. However, the two LEDs on the review sample were green and blue. Volume is a 64-bit digital arrangement controlled by the computer. I had some problems with the original Geek Out 450’s volume control, which I later discovered were peculiar to the computer I was using, but the V2’s volume control operated just as advertised.

LEDs on the side of the V2 show the sampling rate of the files being played. You have to look carefully to see the labels printed on the V2, because the LED colors don’t tell you the precise sampling rate. The LEDs indicate the following: 88.2/96kHz (white), 176.4/192kHz (white), 352.8/384kHz (white), DSD64 (blue), and DSD128 (blue and white). If music is playing but none of the sampling-rate LEDs is lit, that means you’re playing a 44.1 or 48kHz file.

The V2’s circuitry is fully balanced. A second headphone jack, which comes with a plug inserted, makes it possible to connect balanced headphones or connect the V2 in balanced mode to your amplifier using TRS-to-XLR adaptor cables. Output impedance is 0.47 ohms, which should be sufficiently low enough to drive any headphones or earphones you might want to use, no matter their impedance.

The V2 plays PCM files up to DXD level (384kHz/32-bit) and DSD128. LH Labs believes it will be able to upgrade the firmware to play Meridian’s Master Quality Authenticated (MQA) files in the future, which is something you should look into before buying any DAC. As of late July 2015, I haven’t personally heard any MQA-encoded recordings, but every report I’ve seen about MQA gives a glowing account of its sonics.