Yamaha RX-A8A 11.2-CH AV Receiver Review

In 2021, Yamaha finally introduced the all-new RX-A8A 11.2-CH AV Receiver, not only upgrading hardware, audiovisual capabilities, and technological achievements over the past three years but also being another A.V. amplifier with 11.2 channels, following in the footsteps of the Z11. It’s undoubtedly a star product in Yamaha’s lineup and the entire AV industry

Features of Yamaha RX-A8A 11.2-CH AV Receiver

• Supports 11.2 channel output, including 7.2.4 channels.
• SURROUND: A.I. with 64-bit processing.
• HDMI 2.1 interface supporting 8K/60p and eARC.
• Supports 64-bit High-precision E.Q. spatial response processing.
• Utilizes the advanced 32-bit D.A.C. ES9026Pro by E.S.S. for digital conversion.
• YPAO 3D surround sound acoustic calibration.
• Hi-Res support for DSD 11.2MHz and PCM 384kHz/32-bit specifications.

Design

The Yamaha RX-A8A 11.2-CH AV Receiver, in terms of design and materials, is benchmarked against the previous flagship preamp/amp combo: the CX-A5200 and MX-A5200. Compared to the A6A we reviewed earlier, this flagship A8A boasts 11 amplifier modules, two more than the A6A, providing support for a 7.2.4 channel home theater setup.

The A8A, A6A, and A4A models all feature a double-layer top panel, with the upper layer of composite material and the lower layer of metal. This combination of materials offers excellent damping properties. The double-layer top panel is fastened to the chassis with screws around its edges and locked into place in the center by an overhead beam, further reducing vibrations.

At the bottom of the unit, Yamaha’s high-end AV amplifier not only features large vibration-damping feet but also includes an ART(Anti-Resonance Technology) Wedge for mechanical grounding and damping of vibrations in the center of the chassis.

The A8A’s preamp circuit board is a 4-layer PCB, with the top and bottom layers of copper foil serving as signal connections for audio circuits between electronic components. The second layer in the middle acts as a ground, also helping shield against noise.

The third layer of copper foil connects the power for the preamp circuit. Using a 4-layer PCB for the preamp reduces noise and crosstalk, shortening the path for the audio signal to pass through, resulting in more direct and pure sound. Each amplifier channel employs a crystal-clear, structurally simple, large-current Darlington power amplifier circuit with uniform output capabilities across all channels.

Each channel utilizes a pair of high-current Sanken STD05P/STD05N push-pull output transistors with built-in temperature compensation, delivering a rated power of 150W per channel, with a maximum output of 220W.

The digital circuitry in the RX-A8A uses a switched-mode power supply board located in the left rear corner of the unit. In contrast, the analog circuitry’s power source is a Yamaha-customized large transformer positioned in the front center of the unit (including the preamp and power amplifier circuits).

The voltage amplification circuit in the front and the power amplification circuit in the middle are powered by separate power circuits with different secondary coils, bridge rectifiers, and filtering circuits. This separation ensures stability in the voltage amplification circuit, even during high-power output conditions. The output stage utilizes two low-ESR, 22,000μF high-quality filter capacitors.

The most significant change in this new AVENTAGE model is the upgrade of SURROUND: AI from 32-bit to 64-bit processing, with a Qualcomm QCS407 SoC chip at its core. This SoC (System-on-Chip) combines four processor cores with a built-in AI Engine, ideal for Yamaha’s Surround AI’s audio and machine learning applications.

Importantly, its processing power is seven times that of the previous TI DSP chips, enabling 64-bit digital audio processing in SURROUND: AI.

Let’s also look at the design of the HDMI module in the Yamaha RX-A8A 11.2-CH AV Receiver, which features a configuration of 7 inputs and three outputs and supports the new HDMI 2.1 standard. This allows for a 48 Gbps audiovisual transmission rate, significantly improving over the previous HDMI 2.0’s 18 Gbps.

Due to the increased heat generated by the higher data rate, heat sinks are required. While most surround amplifiers that support 8K video have only one input and one output for HDMI 2.1, the RX-A8A supports 8K for all inputs, necessitating a larger number of heat sinks.

Yamaha’s YPAO 3D testing of speaker angles and heights is designed to ensure soundstage accuracy and imaging. After automatically determining the positions of each channel’s speakers, the AV amplifier adjusts the ideal sound distribution for each channel based on the actual speaker setup.

If the speaker placement doesn’t completely meet specifications, Yamaha AVENTAGE high-end models can still deliver excellent soundstage performance and precise imaging.

The two-channel playback quality of the Yamaha RX-A8A 11.2-CH AV Receiver is exceptionally high. In addition to its meticulous design and support for Bi-Amping and various distortion reduction techniques, it also supports Hi-Res audio playback, including DSD 11.2MHz and PCM 384kHz/32-bit music files. Whether in Pure Direct mode or other music modes, you can experience the true essence of music with a clear and transparent soundstage; even delicate nuances are rendered with finesse.

This fully embodies Yamaha’s “True Sound” slogan, allowing you to experience unadulterated sound and understand the artist’s true emotions. The A8A includes 11 music DSP modes, including six related to classical music and five to jazz and pop music. So, no matter what type of audiovisual content you’re playing, there’s an appropriate DSP mode to enhance the experience.

If you don’t want to use these DSP modes, choose “Straight” to let the machine automatically adapt to different movie soundtracks. With the SURROUND: AI feature, which uses built-in artificial intelligence technology, the processor can instantly determine how to enhance the movie soundtrack.

In simple terms, when you enable this feature while watching any movie, the processor switches between the following four modes: when the movie focuses on dialogue, SURROUND: AI highlights dialogue in “Dialogue” mode; if you need to enhance front soundstage width and front-to-rear soundstage coherence, it switches to “Ambient Sound” mode.

“Sound Effect” mode enhances the soundstage depth and subtle sound effects in calm scenes; “Highly Intense” mode boosts the energy and surround feel of the entire spatial sound. You can also enable mode prompts to see the mode changes during different scenes in the movie.

It can intelligently enhance the audio effects based on different movie scenes, further elevating the movie-watching experience. In earlier AVENTAGE models, the processor responsible for this had 32-bit performance, while the A8A has evolved to 64-bit, offering improved processing power and precision, truly showcasing its flagship capabilities.

Sound Performance

Let’s start with a trial viewing of the high-definition TV program “Adele One Night Only 2021” Although it has a 5.1-channel audio signal, the addition of SURROUND: AI noticeably enhances the liveliness of the entire concert. After a long period of refinement, Adele’s voice has significantly improved in texture, and her live singing skills are remarkable.

You can hear her powerful yet sweet and melodious voice effortlessly, and the 5.1-channel audio positioning from the live recording is exceptionally clear. Playing the song “Easy On Me” the piano notes have a warm and gentle granular quality, and the sound of fingertips gliding on the piano keys is delicate.

Upon closer inspection, you realize it’s Yamaha’s very own piano. During the performance, Adele showcases her charming and captivating vocal allure, with each note and breath transition coming vividly to life on the screen.

Now, let’s give the war-themed movie “13 Hours” a try. During the machine gun firefights against the enemy, you can distinctly feel the weight and density of the low frequencies, with effortless control of the sub-bass.

In the final explosive sequence, even the vibrations in the seat and the slight tremors in the sofa become palpable to the viewer. SURROUND: AI always delivers a thrilling impact during key moments in the movie’s plot, enhancing the output across all channels and providing an exhilarating experience for the viewer.

The relentless low-frequency effects throughout this segment and the enjoyable low-frequency background music make the 5-minute trial feel like a brief but highly enjoyable experience.

Conclusion

Over more than a decade, from the Z11 to the current Surround: AI, Yamaha continues to present us with various audiovisual innovations and high-quality audiovisual experiences.

Whether watching movies or listening to music, the Yamaha RX-A8A 11.2-CH AV Receiver’s power output is robust and versatile. It is suitable for most speaker setups, especially bookshelf speakers or custom installation models, where it excels effortlessly.

In terms of sound, it offers a warm tonal quality with a slightly solid texture, making music listening a delightful experience and movie-watching fatigue-free. Moreover, it supports networking wireless transmission, features an integrated DAC for Hi-Res audio, and has a phono input for playing vinyl records. Its capabilities are comprehensive, living up to its status as the flagship of the AVENTAGE series.