The CS43131 is a Cirrus Logic 32-bit DAC with an integrated ground-centered stereo headphone driver and headphone impedance detection, rated at 130 dB dynamic range and -115 dB THD+N in its datasheet. Since its 2017 release it has spread through USB dongles and Bluetooth receivers, and FiiO runs one per channel in the BTR13 receiver. A May 2025 comparative review at Audio Science Review measured eleven devices built on this chip and its sibling, found seven producing a level-dependent distortion artefact the author labeled the "Cirrus hump", and named the implementations it measured clean in the same test.
Figures on this page were checked October 2026. Every table row carries its source and access date, and every measurement claim stays attributed to the review that made it.
What the CS43131 is
The datasheet headline does the summarizing: a "130-dB, 32-Bit High-Performance DAC with Integrated Headphone Driver and Impedance Detection". The chip resolves 32 bits at sample rates up to 384 kHz, takes I2S, right-justified, left-justified, TDM or DSD-over-PCM input, offers five selectable digital filter responses including a low-latency mode, and carries a DSD path at up to 256Fs with a dedicated DoP interface. Control runs over I2C, and the part ships in a 40-pin 5mm x 5mm QFN or a 42-ball CSP package. The applications list runs from phones and tablets to digital headphones, powered speakers and AVR boards, which matches where the chip actually turns up.
Key specifications
| Field | Value | Source / as of |
|---|---|---|
| Dynamic range | 130 dB, A-weighted | CS43131 datasheet DS1155F2, 2026-10-13 |
| THD+N | -115 dB | CS43131 datasheet DS1155F2, 2026-10-13 |
| Interchannel isolation | 110 dB | CS43131 datasheet DS1155F2, 2026-10-13 |
| Analog output | Up to 2 V rms stereo, ground-centered | CS43131 datasheet DS1155F2, 2026-10-13 |
| Headphone power | 30 mW per channel into 32 ohm; 5 mW per channel into 600 ohm | CS43131 datasheet DS1155F2, 2026-10-13 |
| Resolution and sampling | 32-bit; up to 384 kHz | CS43131 datasheet DS1155F2, 2026-10-13 |
| DSD path | Up to 256Fs, with DoP interface | CS43131 datasheet DS1155F2, 2026-10-13 |
| Digital filters | Five selectable responses; low-latency mode; 110 dB stopband attenuation | CS43131 datasheet DS1155F2, 2026-10-13 |
| Control | I2C, up to 1 MHz | CS43131 datasheet DS1155F2, 2026-10-13 |
| Packages | 40-pin 5mm x 5mm QFN or 42-ball CSP | CS43131 datasheet DS1155F2, 2026-10-13 |
The integrated headphone driver
The feature that separates this chip from its sibling is on the analog side: ground-centered stereo headphone outputs come integrated, with DC and AC impedance measurement, plug-in detection and Popguard pop-noise suppression. The driver ratings are the two headphone power rows in the table above. The sister part, the CS43198, shares the digital core but swaps this output stage for pseudodifferential outputs, and its page carries the side-by-side.
Where you find it
| Device | CS43131 setup as reported | Result in the 2025 review | Source / as of |
|---|---|---|---|
| FiiO BTR13 | Dual CS43131, fully balanced; each channel processed by one CS43131 DAC; LDAC support; 220 mW rated unit output | Named affected | fiio.com product page, 2026-10-13; result per ASR review, 2025-05-21 |
| JCALLY JM20 | Single CS43131 | Named clean | ASR review, 2025-05-21 |
| JCALLY JM20 Max | Single CS43131 with an SGM8262-2 op-amp | Named clean | ASR review, 2025-05-21 |
| JCALLY JM20 Pro | Single CS43131 | Named affected | ASR review, 2025-05-21 |
| Shanling UA1 Plus | Dual CS43131 | Named clean | ASR review, 2025-05-21 |
| Tanchjim Stargate II | Single CS43131 | Named affected | ASR review, 2025-05-21 |
| TRN Black Pearl | Dual CS43131 | Named affected | ASR review, 2025-05-21 |
The two source types do different jobs. The FiiO page documents the BTR13 design; the review documents how that and six other CS43131 units measured. Neither source replaces the other.
The "Cirrus hump" measurements
The comparative review at Audio Science Review, published May 21 2025 by member jkim, tested eleven DAC and headphone-amp combo devices built on the CS43131 or CS43198 and found seven producing a distortion artefact under some conditions, which the author informally labeled the "Cirrus hump". In multitone testing the affected units show total distortion plus noise rising across a band of signal strengths, at up to 0.06 percent distortion in the worst case. The review measures with an E1DA Cosmos ADCiso interface in Grade A mono mode behind a Cosmos Scaler buffer, driven from REW v5.4 beta 80.
The author connects the behavior to the Dynamic Range Enhancement feature: a chip mechanism that raises low-level performance and measured dynamic range by adjusting the gain structure depending on signal strength. He notes that Cirrus Logic does not officially document the use of DRE anywhere, and that no datasheet register is clearly tied to the hump, so the mechanism remains his argument rather than a confirmed cause. A Class H amplifier interaction was tested and ruled out: the datasheet exposes a control register for it, and on units whose firmware can switch modes the behavior persisted in either mode. The review credits a published article at Reference Audio Analyzer, a Russia-based audio gear review site founded by Roman Kuznetsov, with examining and reporting the pattern, and closes with two hedged conclusions: any device on these two chips should be suspected of potentially producing the artefact, and it should be resolvable at the firmware design level. A reader poll attached to the thread drew 213 votes, with 50.7 percent choosing to buy only a device tested free of the hump. In a May 25 follow-up, member danadam showed the same JM20 unit distorting a C-major chord in a spectrogram, with a Samsung dongle alongside for comparison.
Implementations the review found clean
The same review names units it measured without the artefact, including the MEIZU Hifi Audio Pro, Tanchjim Space, TempoTec Sonata BHD Pro and the JCALLY JM20. That list and the affected list above come from one author's measurements; this page reports both without ranking, and the BTR13 row shows why the setup source and the measurement source have to stay separate.
FAQ
A 32-bit audio DAC from Cirrus Logic, introduced in fall 2017 per the comparative review below. Its datasheet headline is "130-dB, 32-Bit High-Performance DAC with Integrated Headphone Driver and Impedance Detection", and the ratings are 130 dB dynamic range (A-weighted), -115 dB THD+N and up to 2 V rms stereo output.
FiiO documents a dual CS43131 design in the BTR13 Bluetooth receiver, one chip per channel. The Audio Science Review comparative review adds the JCally JM20 family, the Shanling UA1 Plus, the Tanchjim Stargate II and the TRN Black Pearl, with the configurations as reported by that review. Device pages change, so each row on this page keeps its own source.
An informal label coined in the May 2025 comparative review at Audio Science Review, for a level-dependent rise of total distortion plus noise across a range of signal strengths in multitone testing. Seven of the eleven devices tested showed it. It is not an official Cirrus Logic term, and the link the author draws to the undocumented DRE feature is presented as his argument, not as a confirmed cause.
The chip integrates a ground-centered stereo headphone driver rated at 30 mW per channel into 32 ohm and 5 mW into 600 ohm, with DC and AC impedance measurement and plug-in detection. How any given product performs depends on the implementation around the chip, which is why whole-device measurements, not silicon ratings, are the record to check.
blafili B3 Bluetooth Receiver
Dongles are not the only path: the B3 pairs the QCC5125 Bluetooth chip with an ESS ES9018K2M DAC, and outputs over XLR, RCA, optical and coaxial with an OLED front panel.
- Cirrus Logic, CS43131 product page: datasheet listing "CS43131 Product Data Sheet, DS1155F2 (PDF), Dec 16, 2022". cirrus.com/products/cs43131/, accessed 2026-10-13
- Cirrus Logic, CS43131 datasheet DS1155F2 (156 pages, copyright 2015-2022): headline "130-dB, 32-Bit High-Performance DAC with Integrated Headphone Driver and Impedance Detection"; features "130-dB dynamic range (A-weighted)", "-115-dB total harmonic distortion + noise (THD+N)", "110-dB interchannel isolation", "Up to 2-V rms stereo output", "30 mW per channel into 32 ohm" and "5 mW per channel into 600 ohm" (ohm values normalized from the symbol in the source), "Headphone DC and AC impedance measurement", "Headphone plug-in detection", "Popguard technology eliminates pop noise", 32-bit resolution, "Up to 384-kHz sampling rate", DSD "Up to 256Fs", I2S/right-justified/left-justified/TDM/DoP serial audio input, "40-pin 5mm x 5mm QFN or 42-ball CSP package options". statics.cirrus.com/pubs/proDatasheet/CS43131_DS1155F2.pdf, accessed 2026-10-13
- FiiO, BTR13 product page: "Dual CS43131 fully balanced", "Each channel processed by one CS43131 DAC", "Dual high-end CS43131 DACs", "Supports HD Bluetooth codec LDAC", "Powerful 220mW output". fiio.com/btr13, accessed 2026-10-13
- Audio Science Review forum, thread "On the Distortion of Cirrus Logic CS431xx-Based Devices: A Comparative Review" by jkim, May 21 2025: TL;DR "Eleven DAC/HP amp combo devices adopting either the Cirrus Logic CS43131 or CS43198 were tested, and seven of them were found produce [sic] the distortion dubbed a 'Cirrus hump.'"; device list "FiiO BTR13 - QCC5125, dual CS43131, no op-amps", "JCally JM20 - SA9312, single CS43131", "JCally JM20 Max - SA9312, single CS43131, SGM8262-2", "JCally JM20 Pro - CB5100-Pro, single CS43131", "Shanling UA1 Plus - CT7601, dual CS43131", "Tanchjim Stargate II - CB5100-Pro, single CS43131", "TRN Black Pearl - CB5100-Pro, dual CS43131"; DRE described as adjusting the gain structure depending on signal strength with "the use of DRE is not officially documented by Cirrus Logic anywhere"; worst case "0.06% distortion"; measurement chain E1DA Cosmos ADCiso (Grade A Mono Mode) with Cosmos Scaler buffer, REW v5.4 beta 80; reader poll of 213 votes at 50.7 percent for "only if tested free of the Cirrus hump"; clean implementations named "MEIZU Hifi Audio Pro, Tanchjim Space, TempoTec Sonata BHD Pro, JCALLY JM20, etc.". audiosciencereview.com/forum/index.php?threads/on-the-distortion-of-cirrus-logic-cs431xx-based-devices-a-comparative-review.63038/, accessed 2026-10-13
- Same thread, follow-up by member danadam, May 25 2025: spectrogram of a C-major chord played through the JCally JM20 showing the distortion in real content, with a Samsung dongle for comparison. Same URL, accessed 2026-10-13