Overview

3e Audio A7 is a finished stereo power amplifier built around two Texas Instruments TPA3255 chips operated per-channel in PBTL, with post-filter feedback (PFFB) to minimize load-dependency. It provides balanced XLR/TRS combo and single-ended RCA inputs, a volume-bypass mode, and user-swappable DIP-8 op-amps (OPA1612A by default). The A7 series launched in 2024 and is commonly sold with a 48V/10A PSU included depending on SKU. [2][5][1]

Scientific Validity

\[\Large \text{0.9}\]

Manufacturer measurements (A7, Balanced input): THD+N 0.0006% @ 5W (4/8Ω), SNR 126 dB (A-wt, 1% THD+N, 1 kHz), dynamic range 126 dB, frequency response 20 Hz–35 kHz (±0.5 dB), noise <15 µVrms, crosstalk −110 dB, gain 20 dB, input sensitivity 3.5 Vrms. Single-ended RCA figures are similarly excellent (THD+N 0.0007% @ 5W, SNR 123 dB). [1]

Independent data (A7 family): Bench tests on the A7 Mono (same next-gen PFFB platform) show THD+N minima below −100 dB (~0.001%) around 1–5 W and “hi-fi” power over 200 W (<0.1% THD+N) into 4Ω, corroborating the platform’s transparency and power capability. Output impedance was measured just over 10 mΩ, implying damping factor ≈400 with 4Ω loads. [4][3]

Together, these figures comfortably meet the transparency thresholds for amplifiers across FR, THD+N, SNR, dynamic range, crosstalk, and damping factor.

Technology Level

\[\Large \text{0.7}\]

The A7 is an evolutionary but well-executed design: dual-TPA3255 PBTL channels with PFFB, low output impedance, and replaceable front-end op-amps. While the chipset is established, the implementation (board layout, feedback network, EMI control) and balanced I/O elevate measured performance beyond typical budget Class-D builds. [1][2][3]

Cost-Performance

\[\Large \text{1.0}\]

Denominator (this product): 300 USD.

We surveyed cheaper finished stereo amps to find equal-or-better function and measured performance:

• Fosi V3 (stereo): Cheaper, but RCA-only (no balanced input) → fails functional equivalence. [10]
• Fosi ZA3 (balanced): Has XLR/TRS, but independent tests show lower SINAD (~≤89 dB) / higher noise than A7 family → fails measured-performance equivalence. [6]
• TOPPING PA5 II/II+ (balanced): Excellent low-level THD+N, but maximum power ~100–125 W/4Ω @1% vs A7’s 250 W/4Ω @1% (well outside ±5%) → fails output-performance equivalence. [7][8][12]

As of this review, we could not identify any cheaper finished stereo product that matches or exceeds the A7’s balanced I/O + transparent metrics + ≥250 W/4Ω output. Therefore, by definition, CP = 1.0. [1][5]

Reliability & Support

\[\Large \text{0.8}\]

Solid-state Class-D topology, conservative PFFB implementation, and minimal moving parts suggest good inherent reliability. 3e’s recent firmware/behavior update lengthened auto power-off to 20 minutes, raised audio-sensing thresholds to RCA 200 µVrms / XLR 400 µVrms, and added a user toggle to disable/enable auto-sensing—addressing low-volume users’ reports. Typical retail packages include a 48V/10A PSU. Long-term field data is still limited given the product’s youth. [5][1]

Rationality of Design Philosophy

\[\Large \text{1.0}\]

The A7 channels spend strictly on measurable fidelity: PFFB to defeat load-dependence, robust power headroom, balanced input path for lower noise, and serviceable front-end op-amps—no cosmetic excess. The design choices map directly to improved FR linearity, THD+N, SNR, crosstalk, and damping. [1][3][4]

Advice

If you need a compact, balanced-input power amp that remains transparent at typical listening levels yet supplies ≥250 W/4Ω (1% THD+N) and supports 2–16Ω loads, the A7 is an evidence-based choice. If balanced input is unnecessary and budget is paramount, cheaper options exist (e.g., Fosi V3), but they do not meet the same functional or measured-performance bar used in this review. [1][5][6][10]

References

[1] 3e Audio, “A5/A7/A7 Mono User Manual (Nov 2024),” specs for A7 (balanced/single-ended), FR/THD+N/SNR/DR/crosstalk, auto-sensing description. https://www.3e-audio.com/wp-content/uploads/2024/11/A5_A7_A7-Mono-User-Manual_202411.pdf (accessed 2025-08-26).
[2] 3e Audio, “A5x A7x Series Next-Gen PFFB Amplifier,” product family page and manual link. https://www.3e-audio.com/finished-amp/a5x-a7x-series/ (accessed 2025-08-26).
[3] Archimago’s Musings, “Part I: 3e Audio A5 Stereo & A7 Mono – features & initial measurements,” discussion of PFFB platform & behavior. https://archimago.blogspot.com/2024/11/part-i-3e-audio-a5-stereo-and-a7-mono.html (2024-11-30).
[4] Archimago’s Musings, “Part II: 3e Audio A5 Stereo & A7 Mono – power & distortion,” THD+N minima (<−100 dB), “hi-fi power” >200 W @<0.1% THD+N, output impedance ~10 mΩ. https://archimago.blogspot.com/2024/12/part-ii-3e-audio-a5-stereo-and-a7-mono.html (2024-12-11).
[5] Audiophonics, “3E Audio A7 Class D Stereo Amplifier (2×TPA3255),” product page with product update (auto-off 20 min, sensing 200/400 µVrms, user toggle) and package including 48V/10A PSU. https://www.audiophonics.fr/en/integrated-amplifiers/3e-audio-a7-p-20372.html (accessed 2025-08-26).
[6] Erin’s Audio Corner, “Fosi Audio ZA3,” measured SINAD/SNR/noise of ZA3 (balanced). https://erinsaudiocorner.com/electronics/fosi_za3/ (2024-03-16).
[7] Apos Audio, “TOPPING PA5 II Plus — specs,” balanced inputs, THD+N @5W, power rating context. https://apos.audio/products/topping-pa5ii-plus-amplifier (accessed 2025-08-26).
[8] Archimago’s Musings, “Topping PA5 Mk II Plus – power,” measured ~102 W/4Ω @0.1% THD+N; ~125 W @1% (both channels). https://archimago.blogspot.com/2023/10/part-ii-topping-pa5-mk-ii-plus-pa5ii.html (2023-10-28).
[10] ASR, “Fosi Audio V3 amplifier review,” notes on features (RCA-only) and price context. https://www.audiosciencereview.com/forum/index.php?threads/fosi-audio-v3-amplifier-review.45757/ (2023-06-20).

(2025.8.25)