This is my review of the new Fosi Audio V3 Mono Power amplifier, in its dual version.
I have tested both the original and modified versions, experimenting with different operational amplifier configurations using the Sparkos SS3602 and Muses02.
I must clarify that I’m not a purist audiophile, but rather a passionate music enthusiast in every sense. Besides playing various instruments (piano as my main instrument, guitar, saxophone, and harmonica), I love listening to good music with a keen ear. I demand high-quality audio reproduction from devices that accurately respect and reproduce the original details, without having to spend a fortune.
Over a year ago, I discovered Fosi Audio ( https://fosiaudio.com/ ), a brand I previously knew little about and underestimated, as I mentioned in other reviews. It’s often assumed that products from well-known, expensive brands will perform better, but I must confess that, as a consumer, my experience with Fosi Audio, and especially with their team, has been surprising—not only for the quality of their products but also for their excellent customer service.
Using Fosi Audio products, I realized something important: vintage, bulky, and renowned devices sometimes sound worse than lesser-known products like the remarkable Fosi Audio devices, which are compact, elegant, and high- performing.
I’ve even gone so far as to completely eliminate some of these vintage devices from one of my music setups. I sold a famous English amplifier I bought about a year ago for around 500 euros, as it had become redundant. With the proceeds, I purchased two ZA3 amplifiers, one SK01, and several operational amplifiers. Not only did I upgrade my setup at no extra cost, but I also gained space and sound quality, achieving a surprising level of acoustic versatility.
I must clarify that I’m not a purist audiophile, but rather a passionate music enthusiast in every sense. Besides playing various instruments (piano as my main instrument, guitar, saxophone, and harmonica), I love listening to good music with a keen ear. I demand high-quality audio reproduction from devices that accurately respect and reproduce the original details, without having to spend a fortune.
Over a year ago, I discovered Fosi Audio ( https://fosiaudio.com/ ), a brand I previously knew little about and underestimated, as I mentioned in other reviews. It’s often assumed that products from well-known, expensive brands will perform better, but I must confess that, as a consumer, my experience with Fosi Audio, and especially with their team, has been surprising—not only for the quality of their products but also for their excellent customer service.
Using Fosi Audio products, I realized something important: vintage, bulky, and renowned devices sometimes sound worse than lesser-known products like the remarkable Fosi Audio devices, which are compact, elegant, and high- performing.
I’ve even gone so far as to completely eliminate some of these vintage devices from one of my music setups. I sold a famous English amplifier I bought about a year ago for around 500 euros, as it had become redundant. With the proceeds, I purchased two ZA3 amplifiers, one SK01, and several operational amplifiers. Not only did I upgrade my setup at no extra cost, but I also gained space and sound quality, achieving a surprising level of acoustic versatility.
The Fosi Audio V3 Mono amplifier has truly exceeded my expectations, delivering a surprisingly impressive sound quality that competes in terms of tone and performance with much more expensive and renowned products, including old, bulky vintage amplifiers. In my opinion, this new V3 Mono offers three winning features: cost, sound quality, and performance.
For technical details, I refer you to the manufacturer's website ( https:// fosiaudio.com/products/fosi-audio-v3-mono-power-amplifier ) as I don’t have the appropriate equipment for precise measurements, and I find it pointless to copy-paste information that would only clutter the reading experience for those who are genuinely interested in what really matters—how it sounds.
The Fosi Audio V3 Mono is definitely designed to meet the needs of discerning listeners who care about quality and detail without breaking the bank, and I can say right away that it does not disappoint.
Even from the packaging, you can sense a new style: a design with clean lines, minimalist details and a subtle logo, reflecting a well- established professionalism.
The same goes for the Interior, where everything is neatly arranged without any excess.
The dual version includes a manual (almost unnecessary due to the simplicity of the device), two Fosi Audio V3 Mono monoblocks, and a single 48V 10A power supply with a power filter.
For technical details, I refer you to the manufacturer's website ( https:// fosiaudio.com/products/fosi-audio-v3-mono-power-amplifier ) as I don’t have the appropriate equipment for precise measurements, and I find it pointless to copy-paste information that would only clutter the reading experience for those who are genuinely interested in what really matters—how it sounds.
The Fosi Audio V3 Mono is definitely designed to meet the needs of discerning listeners who care about quality and detail without breaking the bank, and I can say right away that it does not disappoint.
Even from the packaging, you can sense a new style: a design with clean lines, minimalist details and a subtle logo, reflecting a well- established professionalism.
The same goes for the Interior, where everything is neatly arranged without any excess.
The dual version includes a manual (almost unnecessary due to the simplicity of the device), two Fosi Audio V3 Mono monoblocks, and a single 48V 10A power supply with a power filter.
The decision to purchase the kit with a single power supply favors placing the two units close together in a compact space.
However, if you want to place the two amplifiers further apart, for example, to connect them to an audio interface with balanced outputs and use them with two home speakers as studio monitors, I strongly recommend purchasing two separate units, each with its own 48V 5A power supply. This setup will provide greater flexibility in positioning, allow for a customized arrangement, and reduce the risk of potential interference.
I tested the two amplifiers in various situations and configurations, with four different types of speakers (Kef, B&W, and Wharfedale), and I must say that I was consistently impressed by the sound quality and dynamics. The tonal character remained rich and full-bodied, adapting remarkably well to each set of speakers, highlighting the unique tonal characteristics and response of every configuration. If I had to choose a favorite, I found the best balance with the B&W CM5 S2, which offered particularly balanced and detailed playback.
The sound pressure was suitable and engaging, both in a large space like a living room and in a more intimate setting, such as a small home recording studio.
However, if you want to place the two amplifiers further apart, for example, to connect them to an audio interface with balanced outputs and use them with two home speakers as studio monitors, I strongly recommend purchasing two separate units, each with its own 48V 5A power supply. This setup will provide greater flexibility in positioning, allow for a customized arrangement, and reduce the risk of potential interference.
I tested the two amplifiers in various situations and configurations, with four different types of speakers (Kef, B&W, and Wharfedale), and I must say that I was consistently impressed by the sound quality and dynamics. The tonal character remained rich and full-bodied, adapting remarkably well to each set of speakers, highlighting the unique tonal characteristics and response of every configuration. If I had to choose a favorite, I found the best balance with the B&W CM5 S2, which offered particularly balanced and detailed playback.
The sound pressure was suitable and engaging, both in a large space like a living room and in a more intimate setting, such as a small home recording studio.
In addition to traditional use, the V3 Mono in dual configuration can easily be connected to a professional audio interface via its balanced inputs. This allows you to utilize existing passive speakers, avoiding the need to invest in dedicated powered monitors, while still maintaining high sound quality and offering exceptional operational versatility.
Another notable feature is its high portability, making it ideal for those who need to move it between different locations, such as a secondary home or a studio, without compromising on sound quality. The external chassis is made of anodized aluminum, a material that not only provides a pleasant tactile and visual experience but also ensures a solid and lightweight structure, while contributing to heat dissipation thanks to its thermal conductivity properties.
The interior, featuring a simple and clean design, is made up of high-quality components, assembled with great care and attention to detail.
Accessing the interior of the device is very easy: simply remove the two screws at the bottom and the ones at the back. Although a tutorial is available on the Fosi Audio website, it is almost unnecessary due to the simplicity of the operation. The internal board is housed snugly against the outer case, ensuring effective heat dissipation. Thermal paste is applied to the bottom of the board to improve thermal conduction with the chassis.
I recommend using a detachable support as a base to avoid direct contact between the board and the work surface, thus preserving the integrity of the thermal paste. During reassembly, it’s crucial to properly align the LED near the switch, ensuring it is positioned horizontally to match the opening in the case perfectly. There was no need to add more thermal paste during reassembly, as the case closed perfectly with excellent contact.
How Does It Sound?
Excellent.
The sound quality is top-notch: the output is extremely clean and detailed, with deep and controlled bass, rich and well-defined mids, and crystal-clear highs. An outstanding audio experience.
The amplifiers V3 mono adapt to the type of speakers they are connected to, transforming the sound and adopting new sonic characteristics.
I replaced the stock operational amplifiers, which were already of good quality, with the Muses02 and Sparkos SS3602. The result was surprising: the soundstage expanded significantly, opening up a whole range of new sonic possibilities.
I would like to highlight the efficiency and speed of the Fosi Audio customer service. The support chat proved to be extremely helpful: the representative was very knowledgeable and quickly addressed my requests, allowing me to receive both the Sparkos SS3602 and Muses02 at home within a few days. I recommend requesting chip sockets for the latter, with a minimal additional cost, as the pins are delicate and could be damaged during testing and replacement operations.
The sound quality is top-notch: the output is extremely clean and detailed, with deep and controlled bass, rich and well-defined mids, and crystal-clear highs. An outstanding audio experience.
The amplifiers V3 mono adapt to the type of speakers they are connected to, transforming the sound and adopting new sonic characteristics.
I replaced the stock operational amplifiers, which were already of good quality, with the Muses02 and Sparkos SS3602. The result was surprising: the soundstage expanded significantly, opening up a whole range of new sonic possibilities.
I would like to highlight the efficiency and speed of the Fosi Audio customer service. The support chat proved to be extremely helpful: the representative was very knowledgeable and quickly addressed my requests, allowing me to receive both the Sparkos SS3602 and Muses02 at home within a few days. I recommend requesting chip sockets for the latter, with a minimal additional cost, as the pins are delicate and could be damaged during testing and replacement operations.
INSTRUCTIONS FOR REPLACING THE OPERATIONAL AMPLIFIERS
I have conducted several tests under various conditions, with diverse listening experiences, some of which were even surprising.
It is not necessary to replace all three operational amplifiers: replacing just one, preferably the second, is enough to notice a significant change in tonal character. Replacing both amplifiers enhances the improvement even further. However, removing the third operational amplifier, which manages the balanced signal, does not bring additional significant benefits, as the system reaches its optimal balance with the first two upgrades. Therefore, it is advisable to keep the original chip in this position, as removing it may degrade the overall sound quality.
If both operational amplifiers are replaced, I recommend using the same type of model for both to ensure optimal tonal coherence.It is not necessary to replace all three operational amplifiers: replacing just one, preferably the second, is enough to notice a significant change in tonal character. Replacing both amplifiers enhances the improvement even further. However, removing the third operational amplifier, which manages the balanced signal, does not bring additional significant benefits, as the system reaches its optimal balance with the first two upgrades. Therefore, it is advisable to keep the original chip in this position, as removing it may degrade the overall sound quality.
When testing with Muses02 or similar models, it is highly recommended to use chip sockets to prevent damage to the delicate pins during insertion and removal.
I also suggest using good quality interconnect cables: it is not necessary to opt for overly expensive options, but it is wise to avoid very cheap ones. The cables offered by Fosi Audio are an excellent choice in terms of quality-to- price ratio.
SPARKOS SS3602
With the Sparkos SS3602 operational amplifiers, the sound of the Fosi Audio V3 becomes much more precise and detailed. The bass is deep and well-defined, delivering powerful impact while remaining under control. The high frequencies are also very clear and bright, without ever being harsh, while the mid frequencies maintain remarkable clarity, highlighting voices and instruments.
Compared to standard operational amplifiers, the Sparkos offer greater dynamics, meaning they handle transitions from quiet to loud passages more effectively, and they have much lower distortion, resulting in a cleaner and more natural sound. Essentially, they allow you to enjoy music with a higher level of detail, satisfying both those who love to focus on sonic nuances and those who seek a more immersive and enjoyable listening experience.
Compared to standard operational amplifiers, the Sparkos offer greater dynamics, meaning they handle transitions from quiet to loud passages more effectively, and they have much lower distortion, resulting in a cleaner and more natural sound. Essentially, they allow you to enjoy music with a higher level of detail, satisfying both those who love to focus on sonic nuances and those who seek a more immersive and enjoyable listening experience.
MUSES02
With the Muses02 operational amplifiers in the Fosi Audio V3, the sound becomes very musical and refined. The bass is smooth, deep, and pleasant, without ever being too dominant or boomy. The mid frequencies, such as vocals and acoustic instruments, are reproduced with great clarity and warmth, making them sound very realistic. The highs are delicate and rounded, never harsh or piercing. Overall, the listening experience is very harmonious and immersive.
WHICH OPERATIONAL AMPLIFIERS TO CHOOSE?
It's hard to say. Each set offers a different and personalized musical experience, and it really depends on your personal taste.
The Sparkos provide greater resolution and sonic transparency. The bass is more punchy and defined, the mids are detailed, and the highs have a more pronounced brightness. On the other hand, the Muses02 deliver a warmer and more musical sound, with a more enveloping emphasis on midrange coherence.
In summary, I believe the Muses02 are well-suited for those who seek a warm and musical sound, with sweet and rounded highs that create a relaxing listening experience. Meanwhile, the Sparkos SS3602 are ideal for those who prefer a more transparent, dynamic, and analytical sound, revealing every subtle detail with brighter and more prominent highs.
The Sparkos provide greater resolution and sonic transparency. The bass is more punchy and defined, the mids are detailed, and the highs have a more pronounced brightness. On the other hand, the Muses02 deliver a warmer and more musical sound, with a more enveloping emphasis on midrange coherence.
In summary, I believe the Muses02 are well-suited for those who seek a warm and musical sound, with sweet and rounded highs that create a relaxing listening experience. Meanwhile, the Sparkos SS3602 are ideal for those who prefer a more transparent, dynamic, and analytical sound, revealing every subtle detail with brighter and more prominent highs.
IN CONCLUSION
The V3 Mono is truly a small powerhouse that redefines the concept of accessible Hi-Fi. It offers exceptional performance with an impressive price- to-quality ratio considering its power, versatility, and sound quality. Despite its compact size, it delivers sound quality that surpasses many more expensive and bulkier devices. It’s the perfect solution for those seeking high performance in small spaces, without sacrificing quality or budget. It definitely deserves attention, especially for anyone looking for a high-quality audio system at an affordable price.
