Overview

The iBasso Nunchaku is a portable DAC/amplifier released in 2024, featuring dual Cirrus Logic CS43198 DAC chips and a unique dual-mode architecture combining tube and solid-state amplification. Priced at 299 USD, it delivers up to 525mW output power and incorporates dual Raytheon JAN6418 vacuum tubes with a proprietary 22.5V anode power supply. The device measures 65×34.6×15mm and weighs 50g, targeting audiophiles seeking portable tube sound characteristics.

Scientific Validity

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Class AB mode demonstrates excellent measured performance with 130dB SNR and 130dB dynamic range, significantly exceeding transparent levels (105dB threshold) [1]. Tube mode achieves 107dB SNR and 110dB dynamic range, also exceeding transparent levels [1]. Output power of 525mW at both 32Ω and 320Ω provides adequate driving capability for most headphones [2]. Class AB mode achieves dead silent background while tube mode exhibits barely perceptible hiss with sensitive IEMs [3]. Both modes deliver performance well above audible thresholds, with Class AB mode matching top-tier portable amplifier specifications.

Technology Level

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The 22.5V anode power supply represents significant technical advancement over typical 5-12V portable implementations, enabling proper tube operation in compact format [4]. Dual-mode architecture with seamless tube/solid-state switching demonstrates sophisticated engineering integration [5]. APX555 tube matching with limited 50 pairs daily production indicates precision manufacturing standards [6]. PORON material tube suspension system effectively addresses microphonic issues inherent to portable tube designs [7]. Modern CS43198 DACs with FPGA processing and KDS femto-second oscillator provide contemporary digital performance [8]. Technical differentiation through unique portable tube implementation creates competitive advantage difficult for others to replicate.

Cost-Performance

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FiiO BTR17 (199 USD) provides superior output power of 650mW per channel at 32Ω (Desktop Mode) compared to Nunchaku’s 525mW, while delivering equivalent SNR performance of ≥126dB (A-weighted) with 130dB dynamic range matching Class AB mode specifications [10]. Equipped with dual ESS ES9069Q DACs and THX AAA 78+ amplification, the BTR17 offers equivalent-or-better audio performance metrics. However, BTR17’s Bluetooth connectivity represents a significant functional advantage absent in Nunchaku, requiring USB-C connection for operation. For wired portable DAC/amplifier comparison excluding Bluetooth functionality, the BTR17 provides superior measured performance at lower cost.

CP = 199 USD ÷ 299 USD = 0.7

Reliability & Support

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Standard 1-year manufacturing warranty period falls below industry average of 2-3 years [12]. Complex tube and solid-state dual-mode construction introduces potential reliability concerns compared to simpler solid-state designs. Support infrastructure relies primarily on dealer networks rather than direct manufacturer service. Vacuum tubes inherently have limited lifespan requiring eventual replacement. Warranty claims require retention of warranty card and receipt, with repair processing potentially taking several weeks to months depending on parts availability and international shipping requirements.

Rationality of Design Philosophy

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Design combines measurement-based engineering practices (APX555 testing) with appropriate integration of digital processing and analog amplification, demonstrating technical competence [6]. Dual-mode architecture provides measurable performance advantages with Class AB mode achieving 130dB SNR, placing it among top portable amplifier performance levels. However, tube mode implementation lacks scientific justification for claimed audible improvements beyond measured parameters, representing claims of audible effects for scientifically non-audible elements. Significant cost allocation toward tube aesthetics and “analog warmth” marketing rather than demonstrable transparent-level improvements. 22.5V anode power supply represents rational technical approach to portable tube implementation, yet the premium pricing for subjective sound characteristics conflicts with measurement-based value proposition.

Advice

Consider FiiO BTR17 (199 USD) as the more cost-effective option, delivering equivalent SNR performance (≥126dB) with superior 650mW output power and comprehensive connectivity including Bluetooth functionality absent in Nunchaku. The Nunchaku’s 100 USD premium over BTR17 specifically pays for tube mode functionality and analog aesthetic appeal without demonstrable performance advantages. Class AB mode provides excellent measured performance, yet BTR17 achieves equivalent specifications with additional wireless capability at lower cost. Tube mode appeals to enthusiasts seeking subjective sound characteristics beyond measured parameters. Evaluate whether the premium pricing for tube implementation justifies the cost versus superior-performing solid-state alternatives.

References

1. MOONSTAR Reviews, iBasso Nunchaku Review, https://moonstarreviews.net/ibasso-nunchaku-review/, accessed 2025-09-13, SNR/dynamic range measurements
2. Bloom Audio, Tube in Your Pocket? iBasso Nunchaku Review, https://bloomaudio.com/blogs/articles/tube-in-your-pocket-ibasso-nunchaku-review, accessed 2025-09-13, output power specifications
3. Headfonia, iBasso Nunchaku Review, https://www.headfonia.com/ibasso-nunchaku-review/, accessed 2025-09-13, noise floor evaluation
4. Ichos Audiophile Reviews, iBasso Nunchaku Review, https://ichos-reviews.com/ibasso-nunchaku-review/, accessed 2025-09-13, 22.5V power supply details
5. iBasso Audio, Nunchaku Product Page, https://ibasso.com/product/nunchaku/, accessed 2025-09-13, dual-mode architecture
6. Audiophile Heaven, Dual Raytheon Flagship Tubes Delight - iBasso AMP16 Amplifier Module for DX340, https://www.audiophile-heaven.com/2025/06/dual-raytheon-flagship-tubes-delight-ibasso-amp16-amplifier-module-for-dx340.html, accessed 2025-09-13, APX555 tube matching
7. Headfonics, iBasso Nunchaku Review, https://headfonics.com/ibasso-nunchaku-review/, accessed 2025-09-13, PORON suspension system
8. Bloom Audio, Tube in Your Pocket? iBasso Nunchaku Review, https://bloomaudio.com/blogs/articles/tube-in-your-pocket-ibasso-nunchaku-review, accessed 2025-09-13, DAC and processing specifications
9. iFi Audio, hip-dac 3 Product Page, https://ifi-audio.com/products/hip-dac3/, accessed 2025-09-13, <109dB balanced/<103dB unbalanced SNR specifications
10. FiiO BTR17 Product Page, https://www.headamp.com/products/fiio-btr17, accessed 2025-09-13, 199 USD pricing; FiiO BTR17 official specifications, dual ESS ES9069Q DACs, ≥126dB SNR (A-weighted), 130dB dynamic range, 650mW balanced output (Desktop Mode), THX AAA 78+ amplification
11. Kinemoss Tech, Apple USB-C to 3.5 mm Headphone Adapter review, https://www.kinemosstech.com/apple-usb-c-to-3-5-mm-headphone-adapter-review/, accessed 2025-09-13, 98dB SINAD/113dB SNR measurements
12. iBasso Audio, Policies, https://ibasso.com/policies/, accessed 2025-09-13, warranty terms

(2025.9.13)