Overview

The Topping E2x2 is a USB audio interface released in 2024. Leveraging the company’s accumulated DAC and headphone amplifier technologies, it delivers recording equipment with superior measurement performance. The 2-input 2-output configuration includes 48V phantom power and supports up to 192kHz/24bit audio processing. It features the NFCA-LE headphone amplifier module with low impedance output and high power capability. Priced around 149 USD, it positions itself as a product with both technical superiority and high cost-performance in its class of audio interfaces.

Scientific Validity

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The E2x2’s measurement performance demonstrates excellent results that significantly exceed transparency levels. ADC THD+N <0.0003% and DAC THD+N <0.001% are well below the transparency threshold of 0.01%, while Input DNR 118dB and Output DNR 115dB surpass the transparency standard of 105dB. Particularly noteworthy is the headphone amplifier section, with 1Ω output impedance and 580mW output at 32Ω, capable of effortlessly driving high-impedance headphones up to 600Ω. The microphone preamp EIN of -130.5dBu also reaches transparency levels, achieving scientifically meaningful audio quality improvements across all major indicators. These measured values sufficiently contribute to ensuring transparency in the audible range.

Technology Level

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The E2x2 employs advanced proprietary technologies. The NFCA-LE (Nested Feedback Composite Amplifier - Low End) headphone amplifier is the company’s original design, achieving both low distortion and high output. The microphone preamp also features an in-house developed ultra-linear design, achieving an excellent EIN performance of -130.5dBu. The USB section uses an XMOS chip to ensure stable digital transmission. However, the DAC and ADC sections primarily utilize existing chips rather than a complete in-house design. Nevertheless, it demonstrates above-industry-standard technical capabilities in analog circuit design and headphone amplifier technology, possessing valuable technologies that other companies would desire.

Cost-Performance

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Against the E2x2’s price of 149 USD, competing products with equivalent or better functionality and measurement performance, such as the Focusrite Scarlett 2i2 (4th Gen) or the MOTU M2, are all priced from around 200 USD. The E2x2 offers superior headphone amplifier performance compared to these products while being significantly cheaper. While cheaper alternatives like the PreSonus AudioBox USB 95 (around 100 USD) exist, they clearly fall short in functionality and performance with 96kHz limitations, inferior measurement performance, and insufficient headphone amplifier capability, making them unsuitable for comparison. Therefore, the E2x2 is effectively the world’s cheapest option among products with comparable performance, earning a cost-performance score of 1.0.

Reliability & Support

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Topping faces significant challenges in reliability and support. While the 1-year warranty meets industry standards, multiple users report initial defects and short-term failures. Cases of volume issues, LCD display problems, and random errors are frequently observed. More seriously, customer support response includes numerous reports of “no email replies” and “6-month replacement times,” establishing the evaluation that “one should not expect proper service from Topping.” Despite the ability to develop technically excellent products, insufficient quality control and after-service systems represent fatal flaws for products intended for professional use.

Rationality of Design Philosophy

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The E2x2’s design philosophy is highly rational. Focusing on measurable performance improvements, it achieves a design that meets or exceeds transparency levels across all major indicators. By incorporating NFCA-LE technology in the headphone amplifier, it achieves the difficult balance of high output and low distortion that conventional audio interfaces struggle to realize. The ultra-linear design of the microphone preamp also provides scientifically meaningful improvements. Features like 48V phantom power, 192kHz/24bit support, and low-latency design represent rational decisions from both practical and measurement performance perspectives. The approach of eliminating occult elements and purely pursuing measurement result improvements represents an ideal approach for modern audio equipment development. However, quality control issues hinder the realization of this design philosophy.

Advice

The E2x2 is a technically excellent and cost-effective audio interface, but careful consideration is required before purchase. Its measurement performance and headphone amplifier capability are top-tier in its price range, making it highly attractive for high-impedance headphone users and those seeking high-quality recording. However, Topping’s reliability and support system issues cannot be overlooked. For users prioritizing failure response and after-service, we strongly recommend choosing brands with established support systems like the Focusrite Scarlett 2i2 or SSL 2. If choosing the E2x2, it’s important to verify the retailer’s warranty period and replacement policy in advance, and plan purchases considering the possibility of initial defects. Make your decision after thoroughly comparing the technical merits against the risks.

(2025.7.30)