Overview

The iBasso Audio A01 is a compact portable headphone amplifier released in Japan in December 2011 and distributed domestically by Hibino Intersound at a launch price equivalent to 61.80 USD. Measuring 37×10×64.5 mm and weighing 28 grams, the A01 was positioned to drive headphones from DAPs and smartphones via an internal lithium polymer battery rated for approximately 38 hours of continuous operation. The product succeeded the T3 Hj in iBasso’s portable amplifier lineup and is discontinued; as of 2026 it is absent from the current iBasso product catalog and available only on the secondhand market.

Scientific Validity

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Manufacturer specifications indicate a frequency response of 20Hz–100kHz within ±0.5 dB and an S/N ratio of 98 dB [1]. THD, IMD, and crosstalk are not provided in any available documentation for this product. No independent third-party measurements for A01 were identified. All available figures are unverified manufacturer claims and are therefore treated conservatively.

Technology Level

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The A01 is an in-house iBasso design, confirmed by distributor documentation describing revised circuitry from the predecessor T3 Hj [1]. The circuit employs op-amp analog amplification in a symmetrical single-ended configuration, an ALPS potentiometer for volume control, and a lithium polymer battery. These technologies were fully mature and widely adopted in the portable amplifier market well before the A01’s December 2011 release. Evaluated from a 2026 standpoint, they are thoroughly obsolete; modern USB-C DAC/amplifier dongles are the more relevant current technology comparison when an analog input is unnecessary, while the closer like-for-like analog portable-amp comparison is handled in Cost-Performance. No proprietary patents or novel circuit techniques were identified. The design contains no digital processing, wireless connectivity, or software components, and the same architecture is trivially replicable without proprietary licensing. The in-house design origin is the product’s only meaningful technical strength.

Cost-Performance

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The A01 has no current retail price. For price comparison, this review uses its historical Japanese street-price equivalent of 61.80 USD, converted at the USD/JPY exchange rate of 161.5 as of the review date [1][5].

The FiiO A1 portable headphone amplifier, available at 27.99 USD [4], provides equivalent user-facing functions: analog 3.5mm input and output, battery-powered portable operation, USB charging, and volume control. Reference Audio Analyzer measurements [3] and FiiO’s official specifications [2] confirm equivalent-or-better performance on all available metrics:

• S/N Ratio: FiiO A1 ≥100 dB vs A01 98 dB (both manufacturer specifications; FiiO A1 equal-or-better)
• Frequency Response Deviation: FiiO A1 −0.2 to +0.0 dB at 40Hz–15kHz (measured [3]) vs A01 ±0.5 dB (manufacturer specification, bandwidth unspecified)
• Crosstalk: FiiO A1 −62.1 to −67.2 dB @ 1kHz (measured [3]) vs A01: not specified

This comparison is provisional; no A01 third-party measurement data was identified, and all A01 figures are unverified manufacturer specifications.

CP = 27.99 USD / 61.80 USD = 0.45

Rounded to one decimal place, the result is 0.5.

Reliability & Support

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Any original warranty from the 2011 launch period is long expired. The analog circuit is structurally simple with few components susceptible to early failure; however, the built-in lithium polymer battery presents an inherent long-term degradation risk in a device now over 14 years old. The A01 is discontinued and absent from current product listings; no A01-specific official repair path was identified, so buyers should not assume manufacturer repair availability. Public user reviews note the analog potentiometer’s low-volume channel-imbalance risk [5].

Rationality of Design Philosophy

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At the time of the A01’s December 2011 release, smartphone headphone output stages were generally inadequate for demanding headphones, and a dedicated portable amplifier offering 38-hour battery life addressed a genuine user need that general-purpose alternatives could not then satisfy. Solid-state op-amp amplification is the technically appropriate implementation for this use case, and costs are directed toward functionally relevant components: the metal chassis, ALPS potentiometer, and lithium polymer battery [1]. The design approach is, however, decidedly conservative — the A01 employs no novel technique, no DSP integration, and no published performance targets, and no innovative element distinguishes it within the category.

Advice

The iBasso A01 is a vintage product from 2011, and no reliable current new-stock availability through ordinary retail channels was identified. Anyone seeking analog-input portable headphone amplification today can obtain equivalent or superior measured performance at approximately half the A01’s original converted price from currently available alternatives such as the FiiO A1; if analog input is unnecessary, modern USB-C DAC/amplifier dongles are the more relevant comparison. For those already in possession of an A01, the unit remains functional as a basic portable amplifier provided the lithium polymer battery retains adequate charge capacity, though buyers should not assume manufacturer repair support and the long-term battery condition of any 14-year-old unit should be assessed before relying on it.

References

[1] Hibino Intersound - “iBasso Audio ‘A01’ を発売” - https://www.hibino-intersound.co.jp/information/2766.html - Accessed 2026-06-22 (Official distributor announcement; iBasso A01 product page returns 404 as of review date)

[2] FiiO - “FiiO A1 Parameters” - https://www.fiio.com/a1_parameters - Accessed 2026-06-22

[3] Reference Audio Analyzer - “FiiO A1 measurement report” - https://reference-audio-analyzer.pro/en/report/amp/fiio-a1.php - Accessed 2026-06-22; frequency response, crosstalk, and output impedance measured at 15.8Ω and 100Ω loads

[4] Amazon.com - “FiiO A1 Silver Portable Headphone Amp” - https://www.amazon.com/FiiO-A1-Silver-Portable-Headphone/dp/B01CPUVPEM - Accessed 2026-06-22; price 27.99 USD

[5] Kakaku.com - “iBasso Audio A01 [Black]” - https://kakaku.com/item/K0000311375/ - Accessed 2026-06-22

(2026.6.28)