Fosi Audio Fosi Audio ZA3 Balanced Stereo Amplifier

• PBTL Mono Mode Support
• XLR Input / 12V Trigger in
• Op-Amp Rolling: SS3602, MUSES02, OPA2134PA
• Replaceable Knobs: Black Knob

Fosi Audio ZA3

The next generation balanced dual-mode Class-D power amplifier. Fosi Audio's first amplifier supporting both stereo and mono modes.

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

TI TPA3255 Amp Chip Integrated​

Enabling superior sound and ultra-low distortion across the audio band with Class-D efficiency.

Swappable Op-Amps

Compatible with DIP8 dual op-amps. Roll them to get your preferred sound signature.

Advanced Heat Dissipation Design

Enhanced cooling with larger chassis, whole-body heatsink, and side ventilation with dust covers.

Separated Digital & Analog Modules

Optimized circuit board layout protects core audio modules from interference for a purer sound.

• 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.

• ZA3 Power Amplifier x 1
• 32V/5A or 48V/5A Power Adapter x 1
• User’s Manual x 1

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.

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