DAC / AmpOverreview

CrinEar Protocol Max

The most powerful $90 dongle on the bench and the reviewers' DAC/amp of 2025 — and a device whose equaliser, volume behaviour and quiet-unit reports every owner thread argues about.

31 sourcesUpdated
$90Typical US price

Score aggregates reviewer opinions across topics.

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CrinEar Protocol Max

The short version

What to know.

A $90 USB-C dongle DAC/amp whose measured output — about 500 mW into 32 ohms balanced, 4 V into a high-impedance load, an output impedance under an ohm — is the highest in its price class, with distortion and noise that an independent bench and the maker's own plots both put at transparent levels. Sources agree on those numbers and on the metal build. They disagree, sometimes sharply, about what the numbers are worth. On power, the bench and Boost-mode owners who run HD 600s, Sundaras and Edition XS planars from it face a run of owners who found it quieter than an Apple dongle; the explanations that surfaced are the Eco default (31 mW into 32 ohms balanced, 7.8 mW single-ended), a dongle volume that starts at minimum, iPhone current limits, and a few units that were replaced as faulty. On sound, most hear a neutral, transparent source; a measurement-minded minority say it is indistinguishable from any other CS43198 dongle including the cheaper FiiO KA15 it shares chips with; one listener heard it as lifeless next to a Chord Mojo 2. On the equaliser — the reason to buy it, by most accounts — the same accounts concede it can only be set from a Chromium browser on a computer, holds one profile, cannot be toggled off on the device, has no first-party app, and has gone offline with its web tool. Value splits along the same seam: benchmark for the money, or a KA15, a $35 TRN Black Pearl or a Qudelix 5K depending on what you need the equaliser to do.

About this product

The full-size dongle — dual Cirrus Logic CS43198 with dual SG Micro SGM8262-2 op-amps, 3.5 mm and 4.4 mm outputs, Eco/Boost gain switch, 10-band persistent PEQ. Not the 2026 Protocol Micro (a $10, 30 mW, 8-band sibling). Built on a TTGK/WalkPlay platform shared with the EPZ TP35 Pro shell and the BGVP MX1 board, which is why the WalkPlay app also recognises it. Firmware V1.4 as of this snapshot; behaviour of the equaliser depends on which browser tool you reach it with.

CrinEar's Protocol Max is a 17.9-gram black aluminium dongle with a window onto its circuit board, a 3.5 mm and a 4.4 mm output, three buttons, an Eco/Boost switch and a detachable USB-C cable. Inside are two Cirrus Logic CS43198 converters and two SG Micro SGM8262-2 op-amps, rated at 500 mW into 32 ohms balanced in Boost mode, with a 10-band parametric equaliser that lives on the device: you build a profile in the Hangout.Audio graph tool in a Chromium browser, push it over USB, and it stays applied on whatever you plug the dongle into next.

It appeared without announcement on 5 October 2025 at US$89.99 — the first source-gear product from the reviewer who spent years telling people the Apple dongle was enough — and within weeks it had a measured review calling it the dongle its author had been waiting for, a place on two 2026 buying lists, and a DAC/amp-of-the-year award. It also had, within weeks, a Reddit post titled shortcomings, another titled shockingly underpowered, and a comment section under the maker's own user guide asking why the equaliser could not be switched off. Nearly a year on, both halves of that record are still growing.

A good fit for

  • Owners of hard-to-drive full-size headphones who want one pocketable source for those and their IEMs
  • Anyone on iOS or a console who wants a fixed system-wide EQ applied in hardware, set once from a computer
  • Buyers who trust measurements and want the most output per dollar in a dongle
  • Daybreak, Reference or Dusk owners who want the maker's own EQ profiles loaded once and forgotten

Think twice if

  • You switch between several IEMs or headphones and want to change or disable the EQ from your phone — look at a FiiO KA15 or a Qudelix 5K
  • You listen at low levels on very sensitive IEMs and mostly single-ended — a smaller, built-in-op-amp dongle is quieter in practice and cheaper
  • You need microphone pass-through, multiple stored profiles, or a first-party app with a support record
  • You game on a PS5 and need a dongle that can override the console's USB volume cap

The reviewer consensus

Agreement &
disagreement.

7 / 7topics divide opinion
7 Divided opinions

Common ground5

  • On the balanced output in Boost mode it measures about 500 mW into 32 ohms and 4 V into high impedance — desktop-class for a dongle — and it drives HD 600-class and planar headphones with headroom
  • Distortion and noise measure at transparent levels, and even the listeners who dislike it call it neutral and uncoloured
  • Output impedance under 0.6 ohms on both jacks; no audible noise floor with sensitive IEMs on a healthy unit

Points of contention7

  • Power in practice: desktop-class, or too quiet — Eco vs Boost, 3.5 mm vs 4.4 mm, iPhone current limits and a few faulty units drive the split
  • Noise: a silent background, a spec sheet that oversells it, or crackle and static in the field
  • Sound: a transparent source that gets out of the way, or one indistinguishable from any other CS43198 dongle — or, to one listener, lifeless

A closer listen.

7 topics · 7 divided
Left: criticalRight: positiveTighter lines: more agreement

Power

Leans positiveDivided opinions
Reviewer sentiment21 supporting sources
CriticalNeutralPositive

Band: opinion spread · Dot: weighted average

Sources split, and the split tracks the mode switch. On the bench and in Boost mode on the balanced output there is near-unanimity: GoldenSound measured about 500 mW into 32 ohms from a phone — more than a Mojo 2 or Hugo 2 — and owners run HD 600s, HD 650s, HD 800 S, Sundaras, Edition XS and even Susvara from it with headroom; Amazon's own tally is twelve positive mentions to one. Against that sits a run of reports — some from returned units — that it was quieter than an Apple dongle or a Moondrop Dawn Pro, and a video reviewer who needed 60 of 100 for an HD 600 and called it powerful but not powerful enough. Four things explain most of the gap: Eco is the default and rates only 31 mW into 32 ohms balanced and 7.8 mW single-ended; the dongle's own volume starts near minimum and must be raised separately from the phone's; iPhones cap USB current; and at least two units were confirmed faulty. A third, measurement-side view says the headline is overstated anyway — the Protocol Max clips only 3.2 dB louder than a Qudelix 5K into 32 ohms.

Measured

GoldenSound (Audio Precision, Android host): about 500 mW into 32 ohms balanced, up to 4 V into a high-impedance load, output impedance just over 0.5 ohms balanced and about 0.25 ohms single-ended. Maker's table: balanced 500 mW at 32 ohms and 54 mW at 300 ohms in Boost, 31 mW at 32 ohms in Eco; single-ended 125 mW at 32 ohms in Boost, 7.8 mW in Eco, 13.5 mW at 300 ohms. jkim: 4.3 Vrms balanced before clipping versus 3.0 Vrms for the Qudelix 5K — 3.2 dB. Host draw measured by PhonoPhi at 132–135 mA in both Eco and Boost, 33 mA idle.

Where it splits
desktop-class power for a dongle — drives planars and 300-ohm headphones in Boost74%

“everything else I tried sounded great on this and I did not feel like they were being limited at all.”

GoldenSound · The Headphone Show (8:33)
underwhelming or too quiet in practice — Eco mode, the 3.5 mm jack, iPhones, some units18%

“On 3.5 it’s still more powerful than the apple dongle but it’s not the powerhouse it’s said to be.”

Benaudio · r/headphones
the headline power gap is smaller than it sounds8%

“However, in reality, the maximum power output difference b/w these devices is not practically substantial.”

jkim · Audio Science Review
Link to this topic

The hardware

Specifications.

Checked

Design

Form factor
Portable
DAC
Dual Cirrus Logic CS43198 · Delta-sigma
Amplifier
Solid-state

Output

Output power
Single-ended: 500 mW @ 8 ΩBalanced: 600 mW @ 16 Ω
Signal-to-noise
132 dB
EQ
Parametric

Connection

Headphone outputs
4.4 mm, 3.5 mm

Manufacturer-published figures, not measurements · from crinear.com.

Follow the evidence

Sources 31

1–6 of 31 sources

Read with context

Limitations & method.

As of

What to keep in mind 7

  1. A read of where the reviews land as of September 2026. CrinEar has promised a companion app since launch and the web tool changes without notice, so the equaliser complaints here describe the product as it was, not necessarily as it will be.

  2. No independent lab has published a full bench of the Protocol Max. The power, distortion and noise figures come from one measured video review and from the maker's own plots; the two agree, but the spec sheet's SNR claim is contested and the reader should treat the maker's headline numbers with that in mind.

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