The Fosi V3 Mono is a compact, budget-friendly power amplifier, typically used in pairs, capable of delivering high-quality stereo sound.
It features a solid, sleek metal case that feels great in hand and boasts a beautiful, minimalist design. The front panel is small, with quality switches, while the body is longer. The power adapter, which provides stable 48V 5A power, is actually larger than the amplifier itself. This high-quality adapter stays cool during operation.
The amplifier offers options for balanced XLR input and RCA input. The output can be connected using either speaker bare wire or banana plugs. I recommend using banana plugs because the bare wire connection is quite small. I use 12-gauge speaker wires and had to trim some of the bare wires to fit into
the tiny holes. I hope future versions of this amp come with larger wire connectors.
To set up a pair of these amps, you'll need a quality preamp to control the volume and shape the sound. For my initial testing, I used an NAD 1300 preamp, NAD CD C538 player, WiiM Pro Bluetooth receiver, JBL Studio 530 speakers, and Spotify.
I compared the sound of these amps with a pair of Aiyima A07 Max running in mono mode. The Aiyima amps use smaller Aiyima power adapters (36V 6A) that came with the amps.
The volume output between these two amps is similar, and both sound good. The Aiyima is smooth and balanced across high, mid, and low frequencies, making it great for sound reference. In contrast, the Fosi V3 Mono feels boosted in the high frequencies and especially in the bass. It delivers clean, powerful audio with minimal distortion. The bass is punchy, and the highs are crisp, making my music listening experience enjoyable. I was pleasantly surprised by the clarity of the double bass coming through my speakers.
As another point of reference, I also compared the Fosi V3 Mono to the Proton D1200, which has similar power at 8 ohms. The Proton, which is similar in sound to the NAD C268 power amp, falls into a higher price range than the V3 Monos. The sound from the Proton is generally warmer, more refined, and subtle.
I tested different genres of music through these amps, including Jazz, Classic Rock, Classical Music, Ethnic Music, and Avant-Garde Music. The soundstage of the V3 Monos is impressive, with present and clear audio.
The V3 Monos come with a well-written manual, though the print is quite small—I wish it were larger. The manual mentions that you can substitute different op-amp components on the motherboard, which will deliver different sound characteristics.
After two to three hours of use, the amp's temperature reaches around 38°C (+/- 2°C) and remains stable. While it runs warm, I recommend ensuring good open-air space around these amps for heat dissipation. Fosi also offers a matching fan on their website that helps keep the unit cool. I suggest Fosi consider making the case larger and adding longer feet to improve airflow. Personally, I would love to see a giant vintage-style UV meter on the front for nostalgia looks.
In the future, I’d like to try using four V3 Monos to bi-amp my speakers. I think it would make the speakers sound even more impressive. The V3 Mono is also a great choice for multi-speaker environments.
Overall, the Fosi V3 Mono is a fantastic choice for anyone looking to enhance their audio experience without breaking the bank. Its compact design, solid build quality, and impressive sound make it a worthy addition to any setup, especially for those who prioritize simplicity and value.
