The Fosi Audio ZA3 is a compact class-D power amplifier built on the TI TPA3255, with XLR/1/4-inch TRS balanced and RCA inputs and a stereo/mono switch, rated at 155W x 2 (or 235W mono) into 4Ω on a 48V/5A supply. It suits desktop and living-room systems with passive speakers fed by a DAC or preamp.
Who the Fosi Audio ZA3 is for
Passive speakers: Fosi rates it at 155W x 2 into 4Ω in stereo on the 48V/5A supply, and it supports speakers from 2Ω to 8Ω.
Balanced sources: Combo XLR/1/4-inch TRS inputs and RCA inputs, chosen with a front-panel XLR/RCA switch, connect a DAC or preamp without replugging.
Monoblock setups: Mono mode delivers 235W into 4Ω, so two ZA3s can drive a stereo pair as monoblocks.
2.1 systems: A subwoofer output feeds a powered subwoofer, and a 12V trigger input lets the ZA3 power on and off with other gear.
Op-amp rolling: Five swappable op-amps can be replaced with DIP8 dual op-amps such as the Sparkos SS3602, MUSES02 or OPA2134PA.
Skip it if: You need Bluetooth, a built-in DAC or a phono stage; the ZA3 takes analog line inputs only, Fosi says turntables need an external preamp, and the No PSU version needs your own 24–48V DC supply.
Fosi Audio ZA3 key specs
Amplifier: Texas Instruments TPA3255, Class D, stereo or mono mode
Rated power: 155W x 2 (stereo) or 235W (mono) at 4Ω on 48V/5A; 95W x 2 or 110W on 32V/5A
Inputs: XLR/1/4-inch TRS combo (balanced), RCA
Outputs: Speaker terminals (banana plug or bare wire), subwoofer out for a powered sub
Speaker impedance: 2–8Ω
Performance: SNR ≥106dB, THD under 0.006%, SINAD 89dB, 20Hz–20kHz (±0.1dB)
Power and control: DC 24–48V input; 12V trigger in; volume memory
Versions: With 48V/5A power adapter (black or orange knob), or without power supply (orange knob)
Size: About 184 × 155 × 51mm
In the box: ZA3 amplifier and user manual, plus a 48V/5A power adapter on the PSU versions
Genuine Fosi Audio stock. Free shipping on every order, 45-day returns.
Fosi Audio ZA3 vs similar options
vs Fosi Audio V3: Adds a 3.5mm pre-out in a smaller 166 × 105 × 35mm chassis; pick the ZA3 for XLR/TRS balanced inputs, a 235W mono mode, a subwoofer output and a 12V trigger.
vs Fosi Audio BT20A Pro 48V: Adds Bluetooth input and bass and treble controls; pick the ZA3 for balanced XLR/TRS inputs, mono mode and a subwoofer output.
Yes. Every unit we sell is genuine and brand-new, shipped in its original packaging, and backed by our 1-year TonePier warranty and 45-day returns.
Where does my order ship from, and how long does it take?
Every order ships from our warehouse in China, with full tracking, and most orders ship within 3 business days. Shipping is free on every order; most US orders arrive within 7–15 business days and most orders to other countries within 7–20 business days — see our shipping policy for details.
What if it isn't for me?
You get 45 days to decide. Keep the packaging, keep it in like-new condition, and send it back for a refund. Ear tips unsealed for hygiene reasons are fine — we expect you to actually listen.
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