Overview

The HiFiMAN HM-601 is a portable digital audio player released by HiFiMAN (then trading as Head-Direct) in late 2010, with the HM-601 Slim following in January 2012 at 199 USD (4 GB) and 249 USD (8 GB). It was positioned as the entry-level model in HiFiMAN’s HM-series DAP lineup, below the HM-602 and flagship HM-801, targeting users seeking a lower-cost dedicated portable player. The HM-601 uses the Philips TDA1543, a 16-bit multibit DAC introduced in the late 1980s, operated in a non-oversampling (NOS) configuration — a deliberate design choice for tonal character rather than measurement performance. A headphone amplifier with High/Low Gain switch drives headphones up to 150 ohms. The device supports FLAC, WAV, MP3, AAC, OGG, and WMA playback with microSD expansion up to 32 GB. The HM-601 is now fully discontinued and unavailable new; firmware support ended with v0.12 in January 2013 [1][2].

Scientific Validity

Reference Audio Analyzer (RAA) provides third-party numeric confirmation of frequency response at the headphone amplifier output: ±0.1–0.2 dB deviation from 40 Hz to 15 kHz into resistive loads [3][4], which is within the transparent range within that band. However, the measured output impedance of approximately 17 Ω causes severe frequency response coloration with low-impedance reactive IEM loads — RAA confirms swings of 7–11 dB with multi-driver BA IEMs such as the Campfire Andromeda (10.4–10.7 dB) and Fearless S8F (7.6–8.4 dB) [3]. For remaining primary metrics, only manufacturer-stated values are available: THD of 0.09% (test conditions unspecified) falls just below the 0.1% problematic threshold and is treated conservatively as borderline problematic; S/N ratio of 92 dB is mid-range between the 80 dB problematic and 105 dB transparent thresholds; line-output crosstalk of 74 dB meets the transparent threshold on line output only, with headphone output crosstalk unspecified. THD spectrum, dynamic range, IMD, and crosstalk are confirmed as graph-based plots on the RAA report pages but no numeric summary values are extractable from those images [1][3][4]. The composite profile, with THD borderline problematic, S/N mid-range, and severe real-world FR deviation with reactive loads, places performance at the midpoint between problematic and transparent levels.

Technology Level

The HM-601’s core DAC is the Philips TDA1543, a chip introduced in the late 1980s and discontinued approximately 15 years before this product’s 2010 release. Delta-sigma DAC alternatives — Wolfson WM8741, ESS Sabre ES9023, Cirrus Logic CS43122 — were commercially mature at the time and measured substantially better. The headphone amplifier uses commodity general-purpose op-amps (LM833, JRC4560, JRC5532) developed in the 1980s–1990s with no topology innovations [5]. HiFiMAN did make active per-product circuit decisions, selecting different op-amp configurations for the HM-601 versus the HM-602 to achieve different tonal character; this genuine in-house engineering work warrants a small positive adjustment. No proprietary patents for the HM-601 have been identified. The NOS TDA1543 topology is thoroughly documented in DIY audio literature and replicable by any competent engineer with no meaningful barrier. The HM-601 Slim (2012) introduced zero audio circuit changes over the original, confirming stagnant product-level development. The signal path is purely analog after digital decode with no DSP or modern digital processing.

Cost-Performance

The HM-601’s original MSRP is 199 USD (HM-601 Slim, 4 GB variant; used as the discontinued-product price basis) [1][2]. The Shanling M0 Pro, listed by Shanling at 129 USD, is the least expensive identified product with equivalent or better user-facing functions and measured performance [7]. It provides a 3.5mm headphone output with selectable gain, software-selectable analog line-out mode, microSD support up to 2 TB, FLAC/WAV/MP3 playback up to 32-bit/384 kHz, and hardware volume control [7]. Audio Science Review measured the Shanling M0 Pro at THD+N of 0.0006% at 32 Ω (versus the HM-601’s manufacturer-stated 0.09%) and SNR of 118 dB (versus the HM-601’s manufacturer-stated 92 dB) [6]; the Shanling M0 Pro demonstrably exceeds the HM-601 on all available measured performance axes.

CP = 129 USD ÷ 199 USD = 0.648 → 0.6

This comparison uses the HM-601’s official specifications together with RAA third-party measurement data, and uses Shanling official specifications together with ASR third-party measurements for the M0 Pro.

Reliability & Support

HiFiMAN provides a 1-year limited warranty for portable players including the HM-601, below the two-year industry norm, with coverage restricted to the region of original purchase and requiring proof of purchase [8]. Firmware support ended at v0.12, released January 15, 2013; no updates have been issued in over 13 years, and parts availability for a product discontinued roughly a decade ago is not officially committed to by HiFiMAN [9]. HiFiMAN does provide manufacturer-direct support rather than third-party only, and maintains an authorized dealer network across many regions, but the return-to-manufacturer repair process for a discontinued product with uncertain parts supply materially limits practical supportability [1][8].

Rationality of Design Philosophy

The HM-601’s design philosophy is explicitly oriented toward subjective tonal character. HiFiMAN selected the Philips TDA1543 NOS DAC for its warm, colored sonic character rather than measurement performance, at a time (late 2010) when delta-sigma DAC alternatives were commercially mature and measurably superior in both SNR and THD. The NOS topology deliberately omits the interpolation and reconstruction filter present in all modern DAC implementations, producing time-domain aliasing and gradual high-frequency roll-off — measurable deviations from neutrality that are design choices, not performance features. Additionally, the product advertises 24-bit/96 kHz hi-res playback, but the TDA1543 is a 16-bit DAC, meaning 24-bit source material is necessarily truncated to 16 bits at conversion; the “hi-res” label misrepresents the device’s actual conversion capability. The op-amp selection uses commodity parts roughly 20 years old at release, chosen for tonal character shaping rather than performance optimization. No DSP, modern signal processing, or measurement-focused engineering decisions are present. The HM-601 does provide genuine dedicated audio player functionality — hardware gain switch, expandable storage, line output — that distinguished it from general-purpose consumer players of the era, preventing a score below 0.1.

Advice

Purchasers considering the HiFiMAN HM-601 on the used market should be aware that the platform is now over 15 years old, with firmware frozen since January 2013, and no parts availability commitment from HiFiMAN for an entirely discontinued product line [9]. Product age and uncertain access to original replacement components add hardware risk. On objective measured performance grounds, the Shanling M0 Pro at 129 USD delivers ASR-measured THD+N of 0.0006% and SNR of 118 dB — substantially exceeding the HM-601’s manufacturer-stated 0.09% THD and 92 dB SNR — alongside Bluetooth 5.0 with LDAC, USB DAC capability, and microSD support up to 2 TB [6][7]. Users who already own the HM-601 may find it functional for straightforward playback into headphones with impedance above 150 Ω (where the 17 Ω output impedance has reduced impact on frequency response), but the case for acquiring one new is not supportable on cost-efficiency, measured performance, or support longevity grounds.

References

[1] HiFiMAN - HM-601(4G) Official Product Page - https://www.hifiman.com/products/detail/100 - accessed 2026-06-16

[2] SoundStage! Xperience - “HiFiMAN Express HM-601 Portable Audio Player” - https://www.soundstagexperience.com/index.php/equipment-menu/320-hifiman-express-hm-601-portable-audio-player - accessed 2026-06-16; price, specifications, format support

[3] Reference Audio Analyzer - “HiFiMan HM-601 Hi Gain” headphone amplifier measurement - https://reference-audio-analyzer.pro/en/report/amp/hifiman-hm-601-hi.php - accessed 2026-06-16; FR ±0.1 dB (40 Hz–15 kHz), output impedance ~17.2 Ω, IEM load FR deviation table

[4] Reference Audio Analyzer - “HiFiMan HM-601 Low Gain” headphone amplifier measurement - https://reference-audio-analyzer.pro/en/report/amp/hifiman-hm-601-low.php - accessed 2026-06-16; FR -0.1/+0.2 dB (40 Hz–15 kHz), output impedance ~16.9 Ω

[5] Headfonia - “Hifiman HM-601 and HM-602 Review” - https://www.headfonia.com/hm-601-and-hm-602/ - accessed 2026-06-16; op-amp identification (LM833, JRC4560, JRC5532), NOS DAC design

[6] Audio Science Review - “Shanling M0 Pro DAP Review” - https://www.audiosciencereview.com/forum/index.php?threads/shanling-m0-pro-dap-review.49351/ - accessed 2026-06-16; THD+N 0.0006% at 32 Ω SE, SNR 118 dB

[7] Shanling - “Introducing Shanling M0 Pro” - https://en.shanling.com/article-IntroM0Pro.html - accessed 2026-06-17; MSRP 129 USD, microSD up to 2 TB, Bluetooth 5.0, 32-bit/384 kHz support, output specifications

[8] HiFiMAN EU Store - Warranty Policy - https://eu.hifiman.com/pages/warranty-policy - accessed 2026-06-16; 1-year limited warranty for portable players

[9] HiFiMAN - HM-601 Firmware v0.12 Update - https://www.hifiman.com/articles/detail/262 - accessed 2026-06-16 (published 2013-01-15; final firmware version)

(2026.6.22)