3E Audio A7

Premium Performance in a Compact Package - The Next Level of Class D Amplification

The Class D amplifier market has evolved dramatically in recent years, with companies like Aiyima and Fosi Audio pushing the boundaries of the budget end of the market and companies like Purify and Hypex pushing the technical capabilities of the technology at the high-end. But 3E Audio quietly entered the scene with what I believe was the first PFFB implementation, and now with their A7 amplifier (and its sibling A5 and A7se models), they are offering Class D performance to rival brands like Purify and Hypex with exceptional power handling, heat management, and pristine sound quality, all for a similar price to a pair of V3 Mono’s.

Why upgrade?

So for me, since the implementation of PFFB on some excellent affordable amplifiers like the Aiyima (A70 and A80 models) and the Fosi Audio V3 Mono’s, I had been less interested in upgrading and reviewing amplifiers. These are excellent amplifiers for small and mid-sized rooms with a flat neutral yet sound, with no worries about load impedenace issues.

But a few months ago I spotted a few reviews over on ASR of both the AE Audio A5 and A7 amplifier, and it got my interest going again. While ASR’s SINAD ‘charts’ tell you very little about the sound, it is IMO a good indication of the quality of the engineering and how to squeeze every last bit of performance out of an amplifier.

As you can see above, both the A5 and the A7 are well-placed and highly competitive, and having setup and listened to the A7 for a few weeks now I think I can share my initial thoughts.

But before we get into the sound, let’s see what you get out of the box.

Unboxing and First Impressions

The 3E Audio A7 arrives in a sturdy, well-designed box that protects the amplifier during shipping.

Opening the box reveals the amplifier nestled securely in custom foam inserts, along with the power supply and documentation.

Removing the manual reveals the A7:

The amplifier itself has a clean, minimalist design with a solid aluminum chassis that feels well-built.

In the box, you will just find:

• 3E Audio A7 amplifier
• User manual

Obviously, if you go for the bundled power adapter, you will get a bigger box.

So, here it is with the Fosi Audio 48V 10A power supply:

Build Quality and Design

The build quality is good but not premium looking. But the robust aluminum chassis that also serves an important functional purpose in heat dissipation.

The front panel is elegantly minimalist, featuring just a volume control knob that also serves as the power and input selector and a few lights, including crucially clipping lights.

The clean design would fit well in any audio setup, whether in a dedicated listening room or a living space.

On the rear panel, you’ll find a comprehensive set of connections:

• 1x Single-ended RCA input
• 1x Balanced XLR/jack 6.35mm combo input
• 1x Speaker terminal output (accepting banana plugs or bare wire)

The speaker terminals are high-quality and well-spaced, making connections easy and secure. The inclusion of both RCA and balanced XLR/TRS inputs provides flexibility for integration with various source components. I swapped between using the RCA (with and without the gain switch) and the XLR inputs depending on where in my house, I was using the A7. As I have a few rooms setup with different speakers (my wife is very patient).

Audio architecture

Note: The sibling amplifiers from 3E Audio the A5, the A5se, the A7se and the A7 Mono have slightly different layouts but share the majority of these components.

Internal Components and Features

I believe what allows the 3E Audio A7 to outperform the recent Fosi Audio and Aiyima amplifiers are the quality of its internal components and thoughtful design choices.

The overall internal architecture of the A7 shows careful attention to signal path optimization and power management:

Let’s explore some of the key features that contribute to it getting that last bit of performance:

ELNA Silmic II Capacitors

The A7 utilizes ELNA Silmic II HiFi grade capacitors for audio. These are Elna’s highest grade audio capacitors that exhibit superior acoustic characteristics.

Dual TPA3255 in PBTL Configuration

The A7 amplifier is implemented using two TPA3255 chips configured in PBTL (Parallel Bridge-Tied Load) mode, the A5 comes with dual TPA3215 chips instead. This configuration reduces the internal inherent resistance of full bridge MOSFETs, maintaining the highest continuous output power while reducing total power loss and minimizing thermal dissipation. Furthermore, it can support down to 2Ω load conditions, making it compatible with even the most demanding speakers, in Amir review he tested with 2Ω as well as 4Ω ans 8Ω which another aspect of the A7 which brings it to that next level. I believe some of the overheating issues with V3 Mono were from driving speakers with low impedance for extended periods. With my V3 Monos, while they never overheated, they did get uncomfortably warm, while in the past month with the A7, it never got even near that level.

Up to 6000uF Buck Capacitors

The A7 employs large capacitors with lower ESR (Equivalent Series Resistance) in conjunction with each full-bridge. Multiple capacitors placed in parallel achieve better reduction of switching noise and bus pumping under heavy load, thus obtaining better THD in high power output conditions.

Flat Wire Inductor

High current flat wire inductors with exceptionally low DC resistance provide greater efficiency. These magnetically shielded inductors achieve higher current ratings, bringing the best performance in various load conditions.

Swappable Op-amp

The A7 supports a super simple method of swapping of op-amp. An easier way to swap op-amps without opening the chassis is implemented in the design, saving the user from the risk of disassembly. While I did experiment in the past with different op-amps and I will in the future, I didn’t feel like it was necessary with the A7 as its performance was excellent with the provided op-amps

TDK Film Capacitors

High pulse strength and reliable components for the LC filter are critical to meet the desired audio performance, efficiency, and EMI requirements. Multiple film capacitors are used to achieve the best demodulated signal, restoring the true music sound.

Technical Specifications and Measurements

The 3E Audio A7 boasts impressive specifications that reflect its high-performance capabilities:

Product Specifications

• Product type: Class D amplifier
• Channels: Stereo
• Amplification chip: 2x TI TPA3255
• OPA: Dual OPA OPA1612A
• Structure: PFFB
• Inputs: 1x Single-ended RCA input, 1x Balanced XLR/jack 6.35mm combo input
• Output: 1x Speaker terminal output
• Volume attenuation: -50dB

Audio Specifications (RCA IN)

• THD+N (5W): 0.0007% @ 4Ω, 0.0006% @ 8Ω
• SNR (1% THD+N, 1KHz, A-wt): 123dB
• Dynamic range (1% THD+N, 1KHz, A-wt): 123dB
• Frequency response (±0.5dB): 20Hz-35KHz
• Noise (A-wt): < 20uVrms
• Crosstalk: -100dB
• Gain: 26dB / 29dB
• Input sensitivity: 1.75Vrms
• Output power (1% THD+N): 2x 250W @ 4Ω, 2x 140W @ 8Ω
• Output power (10% THD+N): 2x 300W @ 4Ω, 2x 180W @ 8Ω
• Output impedance: 2Ω-16Ω

Audio Specifications (XLR IN)

• THD+N (5W): 0.0006% @ 4Ω, 0.0005% @ 8Ω
• SNR (1% THD+N, 1kHz, A-wt): 126dB
• Dynamic range (1% THD+N, 1KHz, A-wt): 126dB
• Frequency response (±0.5dB): 20Hz-35KHz
• Noise (A-wt): < 15uVrms
• Crosstalk: -110dB
• Gain: 20dB
• Input sensitivity: 3.5Vrms
• Output power (1% THD+N): 2x 250W @ 4Ω, 2x 140W @ 8Ω
• Output power (10% THD+N): 2x 300W @ 4Ω, 2x 180W @ 8Ω
• Output impedance: 2Ω-16Ω

General Specifications

• Power supply: 38V-48V DC 5A/10A (The power supply operates on 110V and 230V)
• Power consumption: OFF: < 0.4W, ON (no audio): 9W
• Dimensions: 170 x 168 x 46mm
• Weight: 1000g

Measurements

For those interested in objective performance metrics using indepdedent Audio Precision measurements as I mentioned earlier, the 3E Audio A7 (and its A5 subling) were thoroughly measured by Amir at AudioScienceReview. I encourage readers to check out the full review at AudioScienceReview.

But for completeness, and before I get into my subjective (and some of my more ‘pragmatic’ measurements), I thought I would share some key measurements from that review that highlight the A7’s exceptional performance:

Balanced Input Measurements

SINAD of 102 is exceptional (though slightly less than the A5) it is above the already exceptional Sinad that the Fosi Audio V3 mono’s and other PFFB implementations. While I don’t believe anyone will ‘hear the difference’ for me it is more about peace of mind to get the best possible technical performance for the price. Obviously, there are amplifiers with even better SINAD values but they are typical 2 or 3 times the price of the A7.

RCA Input Measurements

The RCA measurements are slightly worse but still 20dB or more beyond the level of being a concern:

Power Output into 4 Ohms

These types of diagrams are very useful, as it shows a range of performance over the different power levels up until clipping and ultimately the Amplifier shutting down.

Note: There is a clipping indicator on the front, but with my own usage I never got near clipping.

Frequency Response with PFFB

And as I mentioned in the intro, I believe 3E audio where the first of these lower cost TPA3255 amplifier implementations to utilise PFFB and again the A7 shows a flat FR across the audio range with different loads:

Measurement summary

These measurements confirm the A7’s excellent performance, with very low distortion, high signal-to-noise ratio, and flat frequency response regardless of load. As the measurements show, this amplifier moves the bar for Class D amplifiers closer to the premium Purify/Hypex territory and outperforms the best offerings from Fosi Audio and Aiyima.

Sound Quality

The 3E Audio A7 delivers exceptional sound quality across the entire frequency spectrum. Its implementation of PFFB ( Post Filter Feedback) ensures a flat frequency response regardless of speaker impedance, resulting in accurate and consistent performance with any speaker, so these subjective opinions below should come as no surprise.

Bass

The bass response is tight, controlled, and extends deep with authority. There’s no bloat or muddiness, just clean, articulate low frequencies that provide a solid foundation for the music. Even with demanding bass-heavy tracks, the A7 maintains its composure, delivering impact without distortion.

Midrange

The midrange is where the A7 truly shines. Vocals and instruments are rendered with exceptional clarity and natural timbre. There’s a sense of transparency that allows you to hear into the recording, revealing subtle details and nuances that lesser amplifiers might obscure.

Treble

The high frequencies are extended and airy without ever becoming harsh or fatiguing. The A7’s implementation of PFFB ensures that the treble remains consistent regardless of speaker impedance variations, resulting in a smooth and natural presentation.

Soundstage and Imaging

The A7 creates a wide and deep soundstage with precise imaging (as the left / right channels are perfectly matched). Instruments and vocals are placed with pinpoint accuracy within the soundstage, creating a three-dimensional presentation that enhances the listening experience.

‘Pragmatic Comparisons’ with Aiyima A70 and Fosi Audio V3 Mono

To put the 3E Audio A7 in context, I conducted extensive comparisons with two of its closest competitors: the Aiyima A70 and the Fosi Audio V3 Mono.

Test Setup

For my subjective testing, I used KEF LS50 Meta speakers in a medium-sized room and utilised Fosi Audio LC30 amplifier A/B testing (after using a digital SPL level meter to match output SPL on both Amplifiers during the test):

As I mentioned earlier, I used a 48V10A Fosi Audio power supply for all amplifiers in this test:

Subjectively, I honestly could not near any differences during this A/B test setup, but I did notice the heat dissipation of the A7 was better than both the Aiyima and Fosi Audio amplifiers.

Frequency Response Comparison

As I do have some room correction measurement microphones (UMUK-1) I also decided to do some ‘raw’ measurements (without any Room Correction DSP) of these amplifiers in this setup and I have graphed these measurements below:

As you can see, all three amplifiers show remarkably similar frequency response curves, which is expected given that they all implement PFFB technology. This confirms that all three amplifiers are delivering a linear frequency response regardless of speaker impedance that the Audio Precision measurement showed.

Note: I also tested the A7’s frequency response with RCA gain switch and you can see I am getting roughly 4Db extra gain:

Rating

While it shares some characteristics with similar priced competitors like the Aiyima A70 and Fosi Audio V3 Mono, the A7 distinguishes itself through superior build quality, better heat management, and better measurements. These advantages may seem subtle at first, but I do think over time this is the better amplifier,
especially if you use it every day at reasonable loud volumes with harder to drive speakers.

So, I am giving the A7 a very pragmatic 5-star rating as I can’t really fault it, and based on the other Measurements I have seen on ASR, its siblings should be equally high-performing class D amplifiers.

For those seeking a high-performance amplifier that will provide years of reliable service and exceptional sound quality, the 3E Audio A7 represents an excellent value. It’s not the least expensive option in its category, but its premium performance justifies the slightly higher price.

Conclusion

The 3E Audio A7 represents a significant step forward in affordable high-performance audio amplification. By combining premium components, thoughtful design, and advanced technologies like PFFB, 3E Audio has created an amplifier that challenges much more expensive offerings.

Whether you’re building a new system or upgrading from an entry-level amplifier, the 3E Audio A7 deserves serious consideration. It offers a level of performance that was previously available only in much more expensive amplifiers, making it a pragmatic choice for discerning listeners who want the best possible sound without breaking the bank.