Buy the Fosi Audio BT20A MAX if you want a remote, a subwoofer output, two RCA inputs and the newest Bluetooth in one small box, and you can live with a fan that never switches off. Choose the BT20A Pro or the AIYIMA A07 Pro for the same TPA3255 chip at roughly half the price, and decide between them on tone controls (Fosi’s reach a true flat position, AIYIMA’s do not) and Bluetooth codecs (AIYIMA adds aptX HD).
Quick answer
- Best for: the MAX for a small 2.1 system run from the sofa, the Pro for a budget desk or small room, the A07 Pro for the lowest price with aptX HD.
- Standout: ASR measured very low noise and distortion for the MAX on October 20, 2026 and recommended it, as it did the Pro in 2023.
- Watch out for: an always-on MAX fan, no USB or optical input on any of the three, and the need for a 48 V supply with 4 ohm speakers.
- Compared to: the Fosi ZA3 (balanced inputs, no Bluetooth), the AIYIMA A80 (USB and optical DAC) and the SMSL AO200 MkII (display and remote).
- Bottom line: pay for the MAX only if you will use the remote, sub output or second input. Otherwise a Pro or A07 Pro with a 48 V supply costs far less.
Fosi and AIYIMA store pages read on 2026-10-31, the independent reviews linked at the end and the owner feedback on our BT20A MAX product page. What we did not verify: we did not buy, test, measure or listen to these amps, and we cannot confirm the manufacturers’ power, noise or distortion figures. Fosi supplied the BT20A Pro and MAX units that ASR tested, and AIYIMA supplied Prime Audio’s A07 Pro. Store prices change often. Last checked 2026-10-31.
Specs from the manufacturer pages
| Spec | Fosi BT20A MAX | Fosi BT20A Pro | AIYIMA A07 Pro |
|---|---|---|---|
| Chip and rated power | TPA3255; 300 W x 2 at 4 Ω (180 W x 2 RMS) | TPA3255; 300 W x 2 at 4 Ω | TPA3255; 300 W x 2 at 4 Ω |
| Inputs | RCA1, RCA2, Bluetooth | RCA, Bluetooth | RCA, Bluetooth |
| Outputs | Speakers, subwoofer out | Speakers, pre-out | Speakers, line out |
| Bluetooth | 6.0, Qualcomm QCC3095 | 5.0 | 5.2, Qualcomm QCC304X |
| Codecs | SBC, AAC, aptX, aptX HD, aptX Adaptive, aptX Lossless, LDAC | SBC, AAC | SBC, AAC, aptX, aptX HD |
| Remote | IR remote, motorized volume | None listed | None listed |
| Tone controls | Bass and treble knobs, bypass mode | Bass and treble knobs | Bass ±12 dB, treble ±10 dB |
| THD and SNR (claimed) | THD+N ≤ 0.003%, SNR ≥ 112 dB | THD ≤ 0.005%, SNR ≥ 108 dB | THD 0.002%, SNR 90 dB |
| DC supply range | 32 to 48 V; sold with 48 V 5 A | 24 to 48 V; 32 V or 48 V, or none | 24 to 48 V; 32 V, 36 V or 48 V, or none |
| Fan | Built-in | None listed | None listed |
| Store price, checked 2026-10-31 | $249.99 with 48 V 5 A supply | $99.99 with 32 V; $129.99 with 48 V; $79.99 with none | $97 with 32 V; $108 with 48 V; $78 with none |
Sources, read on 2026-10-31: Fosi BT20A MAX page, Fosi BT20A Pro page and AIYIMA A07 Pro page. Power, THD and SNR are manufacturer claims, and prices are US store prices.
BT20A Pro or BT20A MAX: what the extra money buys
The name “Fosi Audio BT20A” covers three amplifiers. Fosi’s comparison table lists the original BT20A (2020, TPA3116 chip, 100 W x 2, Bluetooth 5.0), the BT20A Pro (2023, TPA3255, 300 W x 2 at 4 ohms) and the BT20A MAX (2025, TPA3255, Bluetooth 6.0). The Pro’s store title says “600W”, which adds its two 300 W channels together.
The power rating is the same on the Pro and the MAX, so the difference is the feature list. Fosi says the MAX adds a second RCA input with its own selector button, a subwoofer output, a switchable high-pass filter (80 Hz, according to reviewers), a 12 V trigger, a motorized volume knob with an IR remote, a bypass mode that skips the tone knobs and PFFB (post-filter feedback), which Fosi calls a first for its stereo amps. It also has a fan. The Pro has a pre-out instead of a dedicated sub output and no remote, but its two op-amps are socketed.
Amir at Audio Science Review (ASR) tested a Fosi-supplied MAX with a 48 V, 5 A supply and posted his review on October 20, 2026. He found very low noise and distortion for the class and PFFB reducing load dependence, and he recommended it. He saw distortion rise with frequency a little more than he remembers for the class. He did not test Bluetooth, the high-pass filter or fan noise. His BT20A Pro review from April 2023 also ended in a recommendation, with tone knobs that reach a true flat detent. Both keep their figures in charts.
SoundPhile (May 2026, unit from Fosi) heard a neutral sound similar to other TPA3255 amps, plus an always-on fan and a case that runs warm at idle. A HiFiVision owner (March 2026) called the sound nearly neutral and punchy and also named the fan as the main drawback.
The AIYIMA A07 name covers more than one amp
AIYIMA’s store lists three A07 models today: the A07 Pro, the A07 MAX and the A07 Premium. The store has no plain A07 page today, although many older reviews cover that model. Only the A07 Pro lists Bluetooth (5.2, with SBC, AAC, aptX and aptX HD), alongside an RCA input, bass and treble knobs and a line out for an active subwoofer. The A07 MAX page lists a stereo/mono switch and no Bluetooth, and the A07 Premium page lists an RCA input only. For Bluetooth on an AIYIMA TPA3255 board, the Pro is the model.
ASR’s A07 Pro review (May 2023) found competent noise and distortion and a frequency response that shifts with the speaker. Its main complaint was tone knobs with no detent and no way to switch them out, and Amir said he would not buy it for that reason. Prime Audio (May 2023, unit from AIYIMA) liked the detail and listed the missing remote and undetented knobs as the cons.
Against the Fosi, Prime Audio heard the A07 Pro as airier and more precise and the BT20A Pro as fuller. A HiFiVision tester (September 2023) compared the original A07, which has no Bluetooth or tone controls, with the BT20A Pro in level-matched blind switching and heard no difference beyond slightly more bass from the Fosi. Two individual impressions that disagree make a weak basis for choosing.
Power supply and real output
The supply decides how much of the headline power an amp can use. Fosi lists 32 to 48 V for the MAX, which its store sells with a 48 V, 5 A adapter, and 24 to 48 V for the Pro. AIYIMA lists 24 to 48 V at 5 A or more for the A07 Pro.
Measured figures sit well below 300 W. ASR got 77 W into 4 ohms from an original A07 on its 32 V supply (ASR thread). Pavel Macura’s bench test (2024) rated an A07 on a 27 V supply at 64 W into 4 ohms. FutureAudiophile did not bench-test the BT20A Pro but reports about 70 W per channel into 4 ohms on 32 V and a rating near 150 W on 48 V. For the MAX, Amir wrote that power claims across this class are highly exaggerated, and he still called it a powerful little amp.
Read 300 W x 2 as a ceiling reached only with a big supply and an easy load. With 4 ohm speakers or a large room, take the 48 V option, which costs $30 more than 32 V on the Pro and $11 more on the A07 Pro as of 2026-10-31.
Weak points to check before you buy
Inputs: none of the three lists a USB, optical, coaxial or phono input. A TV that only has optical or HDMI out cannot connect directly.
- The MAX fan runs whenever the amp is on, and the case runs warm at idle (SoundPhile). ASR forum owners split between hearing the fan from several feet away and not hearing it.
- The BT20A Pro’s tone knobs have a working flat detent (ASR). The A07 Pro’s do not, and small turns change the tonality a lot (ASR, Prime Audio, HiFiReport).
- The BT20A Pro has tightly spaced speaker posts that take banana plugs best, and its pre-out is a 3.5 mm jack (FutureAudiophile).
- ASR’s power-cycle tests show a pop at power-off on both the BT20A Pro and the MAX.
- SoundPhile noticed a MAX spec sheet naming a TPA3225 chip, while Fosi’s product page lists the TPA3255.
Which one fits your setup
For a living room with a subwoofer and a sofa remote, only the MAX fits. For a desk where you sit an arm’s length from the amp, the fan makes the Pro or A07 Pro easier to live with, and between those two the choice is detented tone controls (Pro) against aptX HD (A07 Pro). iPhones do not support LDAC (What Hi-Fi?), so an iPhone-only household gains little from the MAX’s codecs. A turntable without a phono preamp, a PC you want to connect by USB or a TV with only optical out needs a different amp, such as the A80 below.
Reviewers used ELAC DBR62, Revel M16 and ELAC Debut B2.6 speakers. Match a speaker’s rated impedance to the 2 to 8 ohm range Fosi lists or the 4 to 8 ohm range on AIYIMA’s page, and browse our speakers for pairs.
Alternatives we list and when each is the better pick
| Model | What the manufacturer page lists | Store price, checked 2026-10-31 | Pick it instead when |
|---|---|---|---|
| Fosi Audio ZA3 | TPA3255; RCA, XLR and TRS inputs; subwoofer output; no tone controls or Bluetooth listed (Fosi page) | $109.99 with no supply; $149.99 with 48 V 5 A | You feed it from a DAC or preamp, want balanced inputs and never use Bluetooth. |
| AIYIMA A80 | TPA3255 with an ES9038Q2M DAC; Bluetooth 5.1; USB, optical, coaxial and TRS inputs; PFFB (AIYIMA page) | $199.99 with no supply; $229.99 with US supply | You need USB, optical or coaxial inputs for a PC or TV, and can pay more than for any of the three. |
| SMSL AO200 MkII | Infineon MA5332 chip; Bluetooth 5.0; subwoofer pre-out; remote; color LCD (SMSL page) | Not shown on SMSL’s page | You want a remote and front display from a non-TPA3255 design. Check SMSL’s manual for power and inputs. |
More options are in our class-D amplifier picks under $250, and our product pages carry the full listings: Fosi Audio BT20A MAX, Fosi Audio BT20A Pro and AIYIMA A07 Pro.
Owner feedback summarized from retailer reviews
Our BT20A MAX product page summarizes retailer and forum feedback. Owners use the MAX mostly for phone-to-amp Bluetooth listening, often with a modest subwoofer, as a second system or a step up from a soundbar. Listed downsides are no Wi-Fi streaming (owners feed it from a streamer such as the Fosi Audio S3 over RCA), no balanced input, and Bluetooth quality that depends on the source phone’s codecs. The summary also calls the amp cool-running on enclosed shelves. SoundPhile’s warm case and always-on fan, and fan complaints in customer reviews on Fosi’s own store page, point the other way, so leave room for airflow. We hold no owner summary for the BT20A Pro or the A07 Pro.
Where to buy
Some links on this page are affiliate links, including the buttons above. As an Amazon Associate we earn from qualifying purchases. This does not change what we write, and the stores set the prices.
Independent reviews and measurements used
Audio Science Review: BT20A MAX (2026-10-20), BT20A Pro (2023-04-10), A07 Pro (2023-05-20) and A07 (2021-01-01), plus the MAX forum thread. Also SoundPhile (2026-05), HiFiVision MAX review (2026-03), HiFiVision Pro vs A07, FutureAudiophile, Prime Audio, HiFiReport and pmacura.cz.
Update log
- 2026-10-31: First version, with specs and prices read from the Fosi and AIYIMA store pages and ASR’s BT20A MAX review of 2026-10-20.
- 2026-10-31: Added our own product pages for the Fosi BT20A Pro and the AIYIMA A07 Pro and linked them here.
