Amplifying Your Voice, Shaping Our Innovation

At Fosi Audio, behind every innovation, there's a story. The birth of the ZA3 amplifier is just such a story, centered around our users. After the launch of the V3 amplifier, we gathered innumerable feedback from passionate audiophiles. They expressed a desire for us to develop an even better amplifier based on V3.

  • Input: RCA, XLR, ¼”TRS; Output: Stereo, Mono
  • SNR≥106dB; THD<0.006%; SINAD: 89dB; Frequency Response: 20Hz-20kHz (±0.1dB)
  • Rated Power Output: Stereo 180W*2 @4Ω; Mono 235W @4Ω

12V Trigger Sync Interface

Aluminum Alloy and One-Piece Molded Chassis

Logarithmic Potentiometer

Product details

Description
  • Dual-Mode Innovation: This new generation mini amplifier offers both stereo and mono modes, and adapts flexibly to your diverse needs, allowing seamless mode switching. In stereo mode, it delivers a robust output of up to 155W, while in mono mode, the power soars to a maximum of 235W. Pair two ZA3 units in mono configuration to create a powerful audio system, significantly enhancing your listening experience.

  • Richer Connectivity: Debut amplifier with balanced input and trigger in, the ZA3 features a balanced combo audio signal input connector supporting both XLR and 1/4" TRS plugs. This design minimizes interference and reduces noise floor. The 12V trigger-in connector enables synchronization with other devices, streamlining the process of turning on/off without individual operations.

  • Audiophile-Grade Components: The ZA3 features the TPA3255 high-end Class-D amp chip and utilizes premium Japanese NCC, ELNA, and German WIMA capacitors, and Japanese Sumida inductors for exceptional audio quality. With a SINAD rating of up to 89dB, an SNR of up to 106dB, and a low noise floor of only 150μV, it delivers exceptional clarity and low distortion.

  • Advanced Heat Dissipation: Based on V3's groundbreaking heat dissipation design, we upgraded ZA3's cooling system by featuring a larger chassis, moving vents to the sides, and adding dust covers to achieve better ventilation for a sustained and stable high power output.

  • Enhanced Scalable Fun: Personalize your audio experience with the op-amp rolling feature! The ZA3 stocks five swappable op-amps for left and right channel outputs, balanced input, and subwoofer output. Experiment with compatible DIP8 dual op-amps such as Sparkos SS3602, MUSES02, OPA2134PA, OP249, AD827, RM4558, LM4562, LME49720HA, etc. to fine-tune your sound to perfection.
Specifications
  • Chip Set: Texas Instruments TPA3255
  • Terminating Impedance: 2-8Ω
  • Input Mode: RCA, XLR, 1/4" TRS
  • Output Mode: Speaker Output (supports banana plug or bare wire connection), Active Subwoofer Output
  • Frequency Range: 20Hz - 20KHz(±0.1dB)
  • SINAD: 89dB
  • THD: <0.006%
  • SNR: ≥106dB
  • Dynamic Range: ≥106dB
  • Device Dimension: 15.49 x 18.39 x 5.08 cm; 1.78 Kilograms
  • DC Input Range: 24-48V
  • Power Supply: 32V/5A, 48V/5A
What‘s in the box?

Which Product is right for you?

Compare products to find the best one for your needs.

From €109.99

ZA3 Balanced Stereo Amplifier

Type
2.0 CH Amp
Amp Chip
TPA3255
MAX Power Output
2x 300W@4Ω
Input
RCA, XLR, ¼”TRS
Output
Passive SPK +Sub-out
Treble & Bass Control
No
THD+N
<0.006%
SNR
≥106dB
Terminating Impedance
2-8Ω
Power Supply
32V/5A, 48V/5A
From €119.99

V3 Mono Monoblock Power Amplifier

Type
Monoblock
Amp Chip
TPA3255
MAX Power Output
300W@4Ω
Input
RCA, XLR, ¼”TRS
Output
Speaker Output
Treble & Bass Control
No
THD+N
<0.006%
SNR
≥123dB
Terminating Impedance
2-8Ω
Power Supply
32V/5A, 48V/5A
From €89.99

BT20A Pro Bluetooth Stereo Power Amp

Type
Bluetooth 2.0 Ch Amp
Amp Chip
TPA3255
MAX Power Output
2x 300W@4Ω
Input
Bluetooth, RCA
Output
Speaker Output, Pre-Out
Treble & Bass Control
Yes
THD+N
≤ 0.005%
SNR
≥108dB
Terminating Impedance
2-8Ω
Power Supply
32V/5A, 48V/5A
From €79.99

TB10D Stereo Audio Amplifier

Type
2.0 Ch Amp
Amp Chip
TPA3255
MAX Power Output
300W x2
Input
RCA
Output
Passive Speakers
Treble & Bass Control
Yes
THD+N
≤ 0.3%
SNR
≥ 90dB
Terminating Impedance
2-8Ω
Power Supply
32V/5A, 48V/5A
From €79.99

Fosi Audio V3 Mini Stereo Amplifier

Type
2.0 Ch Amp
Amp Chip
TPA3255
MAX Power Output
2x 300W@4Ω
Input
RCA
Output
Passive Speakers, Pre-Out
Treble & Bass Control
No
THD+N
<0.003%
SNR
≥110dB
Terminating Impedance
2-8Ω
Power Supply
32V/5A, 48V/5A

FAQs

Please read our FAQs page to find out more.

Stereo Mode

Replacing the op amps for both left and right channels in stereo mode, regardless of RCA or XLR inputs, will notably enhance sound quality.
Mono Mode: Only replacing the op amps for the right channel.

XLR Input

Using XLR input mode allows for further sound quality enhancement by replacing the op amps for the XLR channel.

Subwoofer Channel

If a subwoofer is connected, there's the option to replace the op amps responsible for the subwoofer channel.
Note: Carefully align the notch/the number '1' on the chip's cover with the 'O1' mark on the PCB.

Here is a tutorial video for your reference: https://youtu.be/VvYYwxAfBi4

  • 5 stars: 4 (100%)
  • 4 stars: 0 (0%)
  • 3 stars: 0 (0%)
  • 2 stars: 0 (0%)
  • 1 star: 0 (0%)
P
Phdejo

Ordered the ZD3 and ZA3+48V/5A PSU (no Op-Amp rolling), dug up my Monitor Audio Studio 10’s from good 30 years ago, added Fosi’s XLR cables (30 cm) and GEARit Premium Braided Speaker Wire (4.57 m, 2 x 2.5 mm2/14AWG, black), connected my iPhone 16 via Bluetooth and already enjoyed the results. These things are tiny, fit easily on top of one of my speakers and are a beauty to behold. Monitor Audio was the first British speaker company to offer metal-dome tweeters (aluminium/magnesium and gold-color anodized finish). The woofer uses an aluminium-alloy cone. It all sounds neutral, has a smooth treble, excellent soundstage depth, and a good feeling of low-frequency authority. In my living room of about 16 m2 there is nothing to be ashamed about. My first digital setup. I’m a happy camper.

Z
Zdenek Skoda

I have been a Fosi Audio fan for a couple of years, and their gear is in my daily listening. My first piece was the ZA3, bought at launch, and it was my first real step into Hi-Fi. Since then I have built up to the full Fosi stack, ZD3 into ZP3 into ZA3, all running Oracle II op-amps, paired with my own 3D printed speakers. My passion is drum and bass, so that is how I judge everything. This setup delivers raw, deep, clean bass into the low 30 Hz range with no subwoofer, and it still makes me want to dance every time. It is remarkable what sound is possible at these prices, and it is exactly why I keep coming back to Fosi, quirks and all.

ZA3 (amp)
A great little amp with excellent sound and solid build, and a playful streak, because it comes apart so easily for OPA rolling. Simple to use, outstanding value, and in my opinion the perfect first step into Hi-Fi.

Plus
- Astonishing sound and build quality for the price
- Easy OPA rolling
- Stereo and mono versatility, strong power output
- 12 V trigger
- Great customer support

Minus
- Early units ran hot (resolved on my newer unit, and my first one died from it but was replaced under warranty)
- The Oracle II op-amps are not fully happy in the ZA3. They give occasional artifacts and cracking and eventually die, so their reliable lifespan here is short if you listen a lot

A
Anonymous

Výborný zesilovač, který předčil mé očekávání. Zvuk zní skvěle, poslechově baví. Velká výhoda je jeho velikost, kdy je možné ho bez problému umístit i za televizi. Zesilovač nahradil můj Hifi zesilovač který váží 18 kg. V kombinaci s DACem od firmy Fosi se pro mě stala tato sestava více než uspokojivá.

F
Faustino Sevilha

Good amplifier I go use in mono mode to drive a subwoofer. I have another ZA3 and a ZD3.