WiiM Amp Ultra functional review: startup, ARC and source switching

Dated functional test · one recorded setup

A real usage log covers wake-up, streaming, TV audio, local inputs, multiroom and Sub Pro. The useful limits appear when playback changes source.

The 6 October 2026 log records successful standby wake-up, television sound and several music-input paths on one WiiM Amp Ultra. It also records three practical limitations: Google Cast did not resume after a ten-minute pause; returning from ARC to DLNA needed a fresh push or track selection; and returning to optical after another input produced no sound. Those observations deserve to sit alongside the successful checks.

This is a review of that dated functional record, not an electrical bench test or a claim about every Amp Ultra. The tested firmware was 5.2.829663. Later firmware has not been independently retested in this record, and manufacturer release notes cannot establish whether these particular observations have changed.

The setup and the limits of the method

The log identifies WiiM Home 3.6.10.092711, an iPhone 16 running iOS 27.0, and a TP-LINK TL-WDR5620 on 2.4 GHz Wi-Fi. Television playback used a Xiaomi L43M5-AZ through ARC with PCM selected. The passive speakers are recorded as 帝风 银河系, with a nominal 8-ohm impedance; a WiiM Sub Pro was also used.

The baseline form lists RoomFit and EQ as off, volume 30 and a volume limit of 75. These are not universal settings for every entry: the long DLNA session records volume 25, while a separate listening note records volume 20. Timing values below are the operator's recorded elapsed times. The log does not specify a calibrated start/stop method, uncertainty, or repeated series for each path; no averages or cross-service speed rankings are inferred.

The front-sheet fields for optical, line and USB sources say none, but the detailed tests identify a WiiM Ultra as the optical/RCA source and a USB drive. We retain those specific results while treating the summary form as incompletely synchronized. The WiiM Ultra is a separate source/peer, not the Amp Ultra under review.

The recorded timings

The first power-on-to-playback entry is 1 min 43.83 s, but the retained clarification says it includes initial installation and networking. It is excluded from a comparable startup benchmark. The second trial records playback at 41.26 s; the third playback field is blank. After power restoration, input and volume were retained, but automatic playback and queue retention were both marked no. The recorded playback times therefore must not be presented as automatic recovery.

Network playback: useful results, with handoff qualifications

One DLNA session explicitly records 60 minutes, a reported 96 kHz/24-bit stream and volume 25. Track-change failures and App discovery failures are each zero. Its interruption counter is blank, so this is not evidence of sixty uninterrupted minutes. The format entry also does not establish output bit depth or bit-perfect delivery.

The detailed handoff notes say that closing the App or disconnecting the phone from Wi-Fi allowed the current track to finish; after the Wi-Fi disconnection, playback then ended. Reconnecting required selecting the DLNA target and pushing again. A separate, blank-duration DLNA block says playback continued and records zero interruptions, but does not state the continuation period. Its counters cannot fill the missing long-session counter.

Cast and Spotify each record twenty track changes with zero anomalies. Spotify pause/resume, lock-screen playback and takeover from another device are marked successful. Cast lock-screen playback is also marked successful, but its ten-minute pause/resume check failed. No effective recovery action is recorded; a general no-anomaly note does not erase that specific failed check.

TIDAL records zero complete stops, zero progress-without-speaker-sound events, zero phone-sound-without-device-sound events and zero disconnections. Its sixty-minute completion field, twenty-track-change result and pause/resume result are blank. The thirty-minute completion fields for Cast, Spotify and the separate DLNA block are also blank. Those printed prompts are not completed endurance tests.

TV audio worked; ARC-to-DLNA switching needed a new selection

The ARC/PCM section records normal TV sound, automatic wake and HDMI selection, and no sudden high-volume event. It reports no obvious perceived picture/sound mismatch, which is a listening observation rather than a measured delay. The thirty-minute playback completion field remains blank.

The source-switching notes need their full qualification. Switching in both directions could be completed, but returning from ARC to DLNA required stopping and pushing again or selecting another track; otherwise the system was observed returning to ARC. The operator says this was reproduced multiple times, without a usable occurrence denominator. The log's five-switch line cannot therefore be reduced to five clean passes or converted into a failure rate.

The retained clarification treats the TV-remote/CEC-volume check as not applicable to this Xiaomi setup. Its ineffective remote-volume entry is not used as evidence of an Amp Ultra defect, and no universal CEC conclusion is drawn.

Optical, RCA, USB storage and Bluetooth

Optical audio initially played from the WiiM Ultra source. After changing to another input and returning, the result was not normal; the retained clarification specifies silence on return. The source output format is missing, and neither a cause nor a verified remedy is established. This does not mean optical never worked or that every source is affected.

RCA input from the WiiM Ultra played with correct left/right channels. No audible hiss, hum or distortion was reported in that check, but source output level and the fifteen-minute completion field are absent. These notes are not noise-floor or THD measurements.

A 32 GB FAT32 USB drive containing FLAC was recognized, browsed and played, and was recognized after reinsertion. The ten-track-change result is blank. This was a storage-playback check, not a computer USB-audio-input or external USB-DAC-output test.

Bluetooth records the connection times in the table, zero interruptions and successful return after network playback. The fifteen-minute completion field and codec are blank; the record does not support a codec-quality or full-duration stability verdict.

Speaker controls, multiroom and Sub Pro

The speaker checks report correct channels/test-tone assignment, working balance and mute controls, no obvious low-volume channel imbalance, and no audible noise at the usual level. A short listening note reports no obvious distortion, protection stop or unexpected restart at volume 20 and 2.5 m. Its track is unspecified and its duration is ambiguously written, so it is not used as a precise timed or comparative listening test.

The owner clarified that a separate WiiM Ultra participated in multiroom. Group creation took 2.15 s; this section explicitly records thirty minutes without the group dropping, synchronized volume and normal operation after ungrouping. No obvious synchronization problem was heard. That subjective observation is not a millisecond synchronization measurement; the service and peer firmware are missing.

Wireless Sub Pro pairing took 3.05 s. The log marks operation during Cast, Spotify, TIDAL, HDMI, optical and line input, with reconnection after standby wake and power restart. It notes that App setup was needed. USB/Bluetooth coverage, a delay result and a bass-tail result are not supplied. Wired Sub Pro output, audible crossover adjustment, subwoofer level control and settings retention are also recorded as working, without crossover frequencies or response measurements.

Manufacturer capability is separate from these observations

WiiM's model-specific manual describes HDMI ARC, including connection to a TV's ARC/eARC port; the TV label does not make the amplifier an eARC device. It lists PCM and Dolby Digital, but this test log covers PCM only. The manual supports USB storage and USB output to a DAC, not USB audio input from a computer. It lists Cast, Spotify Connect and TIDAL Connect; AirPlay 2 is not supported. These are manufacturer-documented capabilities, not additional SPL test results.

The current Sub Pro setup page was revised after this test date and includes a latest-firmware exception alongside a wireless Cast restriction, without naming a minimum version. It cannot retrospectively certify every path on 6 October or prove that a later release resolved an observation here. The dated Sub Pro results above remain limited observations of the recorded setup.

What this record does not establish

There are no supplied calibrated output-power, THD+N, frequency-response, noise-floor, difficult-load or thermal-limit results. The nominal 8-ohm speaker label is not a measured resistive bench load. UT61E and UMIK-1 are listed as available equipment, but no corresponding instrument readings or calibration records are supplied.

EQ/RoomFit outcome fields, REW curves, temperature and power-consumption results are unfilled in this copy. Photo/screenshot filenames and exact repeat counts are also missing. That describes the evidence available here; it does not prove that no later tests or media exist. Existing editorial photographs are separate from measurement evidence.

What to take from the functional test

This log supports a useful account of everyday wake-up, PCM TV sound and several input paths on the tested unit. Its most decision-relevant limits are source handoff, recovery and optical return. Those deserve a clearly dated account rather than either a blanket pass or a claim that no testing exists.

If a system decision depends on room correction, demanding speaker loads, objective sound performance or long-term reliability, this record does not settle it. No score, maturity promotion or model-wide repair claim follows from these functional checks.

Sources and evidence scope

1. SoundPath Lab retained functional log dated 6 October 2026, with subsequent owner clarifications. The original text is retained editorially; private hardware identifiers and internal file references are excluded from this article.
2. WiiM Amp Ultra User Manual, v1.0.5, dated 13 April 2026; model-specific manufacturer documentation, checked 4 November 2026.
3. WiiM: devices supporting AirPlay 2, checked 4 November 2026.
4. WiiM Sub Pro setup guide, revised 27 October 2026; later documentation, checked 4 November 2026, not an independent retest.