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 €71.99

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: 352 (91%)
  • 4 stars: 34 (9%)
  • 3 stars: 0 (0%)
  • 2 stars: 0 (0%)
  • 1 star: 0 (0%)
A
Andr��s C.
Excellent amplifier with impressive power and detail

I've been using the ZA3 in a desktop hi-fi system paired with Wharfedale Diamond 12.2 speakers, and the performance has exceeded my expectations. The amplifier delivers plenty of clean power, excellent channel separation, and a very low noise floor.

The balanced XLR input works flawlessly with my ZD3 DAC, creating a clean and dynamic sound with tight bass, detailed mids, and smooth highs. Even at higher listening levels, the sound remains controlled and effortless.

Build quality is outstanding, the case feels solid, and the volume control has a premium feel. The 48V power supply provides more than enough headroom.

For the price, I honestly think the ZA3 competes with amplifiers that cost significantly more. Highly recommended.

M
Michael B
ZA3 - Good power for the buck

I've had my ZA3 for a couple weeks now, and I've been really happy with it.
Running it along with the S3 streamer, and it has been powering my bookshelf speakers without a problem! Using the XLR inputs, I get a really clean signal. Really like the 12v trigger, so I can power on my S3 and the ZA3 powers on right along side. Haven't tried rolling op amps yet, but maybe in the future. But I'm really happy with it right now!

J
John Skelly
The Fosi Audio ZA3 amplifier completely transformed my HiFi setup.

The Fosi Audio ZA3 amplifier completely transformed my HiFi setup. It pushes plenty of clean power, and my Elac 3.0 DB63 speakers and B&W ASW608 subwoofer sound absolutely amazing running off of it. The build quality is fantastic, and I��m already planning to complete the ultimate stack by adding the matching Fosi ZD3 DAC and Merak CD player next. Highly recommend!

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

p
phdejo
ZD3/ZA3 and Monitor Audio Studio 10

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 and fit easily on top of my left speaker. 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.

B
Ben X
Great value for the price

bought another ZA3 after tried my first one for several months, the extra power of mono/mono configuration improved the sound quality noticeably in terms of dynamics and sound stage for my 4om/200wRMS speakers.

E
ERIK
Get two

Get two and run these in mono for L/R, use XLR cables and never look back.

P
Peter S.
Simple and powerful

With the 12V trigger and small footprint it is easy to integrate to a convenient and good sounding system. It has enough power to drive my Q Acoustics 3030i and retain a decent headroom. It is also a great option to have a sub out as well. No complaints whatsoever.

D
Darko
Great in my setup

Using two ZA3 units as monoblocks in my custom 5.1 setup completely changed the system.
The biggest improvement was not just power, but control, separation and effortless dynamics. Stereo imaging became more precise, vocals cleaner and bass tighter without sounding exaggerated.

What impressed me the most is how relaxed and stable everything sounds even at higher volumes. The amps never feel stressed. Small details stay clear while the whole sound becomes bigger and more immersive.

I originally planned to use one ZA3 for center/LFE duty, but after trying them as monoblocks for FL/FR, I immediately kept them that way. The sense of space, instrument positioning and transient response became addictive.

Excellent amps for both music and movies, especially in active or multi-amp systems.

J
Jay
Love this!

Decided to upgrade my office music setup and bought this amp (along with the Fosi Audio Box X5 Phono Preamplifier and Fosi cables), and couldn't be happier. Sounds great, was relatively affordable, shipped quickly, and looks cool next to my turntable. Highly recommend.

J
Joma tha
Love this one

Idk but this is so good

G
Guillermo
Good upgrade path or just go all in?

First time Fosi buyer, never heard them or tested. Was going to just start small and test but ended up getting two of them to use in mono mode, then got the birding audio classic op-amps.

Do to the shipping getting split into multiple packages I first got one and tested it, then took the sub op-amp out and tested, then got the second one and tested with sub and left op-amps out, then got the Burson classic op-amps and put them in.

At every stage I heard a tangible improvement, and now I��m left with one amazing system that is truly impressive, not just for the price but at any level.

Wish I could say the same thing about the Streamer they sell, as that is a complete mess and will leave a review in the future as soon as they fix what is wrong with mine, but this amp is solid and recommended if you can afford it to just go all in from the start.

Cheers!

P
Peregrine
Very happy with this purchase!

Amazing performance from such a handsome tiny amplifier. It arrived nicely packaged and in perfect condition. It was easy to set up with the power supply and connections to the Fosi DAC and preamplifier. It��s very pleasant to look at as well as the listening experience. I��m curious about opamp options, but it sounds very good to me right out of the box. I��ll live with it for a while before making any decisions regarding modifications.

A
Ash V
Small Package, Big Sound

Love it! Wide soundstage, great stereo separation, stays tight even cranked up. Build quality is solid too - the toggle switches have a satisfying click and the volume knob feels premium. Seriously good value for what you're getting.

I
Ian L
As good as it gets - so I got two

I bought two ZA3 amps and have them as mono amps and quite frankly I don't think that you can get a better quality setup for the money.

Absolutely delighted with the amps.

O
Octavian Dumitrescu
Superb!

Curently I use this amplifier in stereo mode and I am very satisfied. I intend to buy another one for MonoBlock for better chanel separation and for separate 48V power supply. I am in love with the design and sound.

G
GB
good choice

I've bought 1 LC30 VU, 2 ZA3 with Burson V7C chipsets and 1 ZD3. It sounds on a Polk Audio ES15 loudspeaker. I satisfied.

D
DGJ
Good.

Good amplifier.

T
Tony P
ZA3 Power Amplifier

bought with ZD3 as bundle, connected with xlr cables and trigger. Great value with balance output.