Monoprice Monolith Headphone Amps with THX AAA Technology Unveiled


Last week, Monoprice announced a partnership with THX to incorporate THX AAA amplifier technology into a new line of headphone DAC/amps called Monolith. The new units will be available in desktop and portable versions.

The ultra-quiet AAA amp was first implemented a couple of years ago by Benchmark in the AHB2. Now, the second generation of this technology is specifically designed for headphone amps. There are several AAA modules, all of which exhibit exceedingly low total harmonic distortion (THD) and high signal-to-noise ratio (SNR).

The THX AAA amplifier modules exhibit much lower THD than competing amp modules. The AAA-788 used in the Monoprice Monolith Desktop DAC amp exhibits a THD of less than -140 dB. The AAA-78 used in the Monolith Portable is not shown here, but it consumes much less power, thus extending battery life. (Source: THX)

The THX AAA amplifier design uses a bipolar class-AB output stage with feed-forward error correction to cancel zero-crossing errors. According to THX, this allows the amp to exceed the performance of class-A designs without their low efficiency, poor damping, and high power consumption. It also allows long battery life by reducing bias currents by a factor of 10 to 100 without increasing distortion.

The Monolith Desktop (seen in the photo above) uses the THX AAA-788 module that provides two channels, each with 1590 mW of amplification into 16 ohms. The portable version uses the THX AAA-78 module with 2×400 mW of amplification into 16 ohms and low power consumption.

The Monoprice Monolith Portable offers exceedingly low noise and long battery life.

Both models feature the new AKM AK4493 768 kHz/32-bit stereo DAC (digital-to-analog converter) that achieves -113 dB THD+N and 123 dB SNR. This DAC also supports DSD (Direct Stream Digital, the format of SACDs) up to 22.4 MHz.

Another feature common to both models is a custom implementation of Dirac Sensaround. This virtualization algorithm is designed to take the sound “outside” your head, creating a natural soundstage more like listening to speakers. Monoprice created a new version of Sensaround with some Dirac VR algorithms, which is why it is called Sensaround II in the Monolith headphone amps. If you don’t like the way it sounds, you can disable it.

The Monolith Desktop provides USB, optical, coax, and AES/EBU digital-audio inputs as well as two channels of balanced and unbalanced analog-audio inputs. Outputs include unbalanced line level as well as balanced and unbalanced headphone outputs. The Monolith Portable provides a micro USB input for streaming and a 3.5mm analog/optical audio input as well as a separate micro USB port for charging.

According to Jason Fiber, Director, Product, THX Ltd., “We are excited to partner with Monoprice to debut our THX AAA technology to deliver extremely high-quality audio to headphone users. Monoprice shares our passion for innovation and will be able to provide an unparalleled listening experience to consumers at an affordable price.”

Bernard Luthi, CEO of Monoprice, is equally enthusiastic about the partnership. “At Monoprice, we believe all consumers should have access to high-quality yet affordable electronics, and we have built our reputation on product excellence and customer service over the years. By partnering with THX to integrate their AAA amplifier technology into our offering, we continue to deliver on this mission and provide our customers the best-in-class audio experience when listening to their music library.”

The Monoprice Monolith Desktop and Portable headphone DAC/amps are scheduled to be available in February. Exact pricing has not yet been announced, but I’m told that both will be under $400.