Review Fosi Audio V3 Mono with different Speakers

The Fosi Audio V3 Mono is a 1-channel Class-D mono power amplifier based on the TI TPA3255 amplifier chip. With a 48V/5A power supply, an output power of up to 240W at 4 ohms is possible. Even when selecting the components used, emphasis was placed on an audiophile character. Capacities from Wima and ELNA, as well as filters from NICHICON and inductors from Sumida are used. By integrating the PFFB Post-Filter Feedback Technology, independence from the connected load is to be achieved. The OpAmps used (NE5532) are interchangeable, so that the user can influence the sound characteristics according to his taste. The housing concept is designed for maximum cooling and uses the entire housing including ventilation openings for this purpose. Due to its arrangement, the cooling works according to the fan principle. The connection options on the back include an RCA/input and XLR/input (selectable via toggle switches on the front) as well as connection terminals for a speaker and the power supply. The RCA/input also has a gain switch with 31dB/25dB. On the front is the aforementioned RCA/XLR toggle switch and the the other switch with the positions ON / AUTO (automatic shutdown after 10 min) / OFF. An external power supply with 48V/5A is used for each V3 Mono. A 48V/10A power supply with splitter cable is also offered to supply both monoblocks with one power supply.

The following configurations were chosen to test the two power amplifiers:
1. Streaner WiiM Mini + 2 x Fosi Audio V3 Mono + DALI Spektor 1 speakers
2. Streamer Blusound Node 130 + 2 x Fosi Audio V3 Mono + DALI Opticon 2 MK2 speaker
3. Streamer WiiM Pro Plus + 2 x Fosi Audio V3 Mono + Speaker Piega PL 4
So there should be something for every budget.

The following combinations served as a reference:
Amplifier Advance Paris X-i75 (Class A/B 2x110W at 4 Ohms) + Streamer WiiM Pro Plus + Speaker Piega PL4
Atoll 100 Signature Amplifier (Class A/B 2x140W at 4 Ohms) + Blusound Node 130 Streamer + DALI Opticon 2 MK2 Speaker
Streaming Amplifier WiiM Amp + Speaker DALI Spektor 1

MP3 files with 250-320 Mbit from the NAS of different music genres served as music material.

Alan Taylor "Colour to the Moon"
Genesis "Mad Man Moon"
Bazzi "Paradise"
Hans Zimmer "Wheel of fortune"
Kari Bremnes "Kanskje"
Nils Lofgren "Keith don't go"
TOOL "Pneuma"

1. 2 x Fosi Audio V3 Mono + Streamer WiiM Mini + DALI Spector 1 Speaker
Very cost-effective and compact streaming solution. Since the DALI Spektor 1 have a relatively low efficiency of 83 dB, they need quite a bit of power to sound powerful. Here the V3 Mono have absolutely no problems driving the speakers. In all musical genres, the bass was crisp, the mids pronounced and the trebles present. Overall, a very good tuning based on small compact speakers. The achievable, distortion-free volume is above what makes your neighbor sleep. If you want to create a good-sounding combination with a limited budget, you are on a very good path here. This is very suitable as a desktop solution or in rooms up to approx. 15 square meters with limited space. In my opinion, the V3 Mono in conjunction with the Wiim Mini are a good alternative to the WiiM Amp, with somewhat limited connectivity.

2. 2 x Fosi Audio V3 Mono + Streamer Blusound Node 130 + DALI Opticon 2 MK2 Speaker
Streaming solution that already reaches a high level in terms of costs. Here, the V3 Mono did a good job. It was fun to listen to the V3 Mono's, regardless of the chosen music genre. Whether bass-heavy party music, classical passages or quiet acoustic delicacies, the V3 Mono coped with every style of music. The sound was predominantly neutral without emphasis on frequency ranges. The Atoll 100 integrated amplifier served as a reference here (certainly a bit unfair). However, the V3 Mono cannot replace this. Despite your good sound performance, you subjectively lack tonal substance. The difference is already clear, not like day and night, but audible. However, we are also talking about a price difference of almost 1000.00€ here. The compact DALI Oberon 3 would also be a loudspeaker alternative here. This also keeps the price within a more moderate range without having to make big compromises in terms of sound.

3. 2 x Fosi Audio V3 Mono x Streamer WiiM Pro Plus + Speakers Piega PL 4
Living room streaming solution with the use of floorstanding speakers.
The V3 Monos have no problems with the Piega speakers and come very close to the Advance Paris X-i75 integrated amplifier. However, you cannot catch up with him or overtake him. Here, too, you subjectively lack a little tonal substance in the sound. In any case, I was amazed at how well the V3 Mono's got along with the ribbon tweeter of the Piega. Due to the quite good efficiency of the Piega (89dB at 4 ohms), the V3 Mono's are also suitable for larger rooms (40 - 50 sqm) in combination with similar loudspeakers.

Summary:
The V3 Mono convinced me quite a bit. The sound you can get for a moderate price today is great. At the same time, the Fosi Audio V3 monos sound extremely neutral without highlighting any frequency ranges. In the right combination of amplifier/speaker/streamer, you get solutions that inspire and are easy on the wallet. Based on the V3 Mono's, a solution is possible for every taste and price. Since compact speakers are probably used for the most part, the V3 Monos are suitable as a desktop solution or for medium-sized rooms. The RCA input was generally operated with 31dB gain. The playback via XLR was therefore a bit quieter with the same volume setting (the connection was made via the XLR/RCA adapters shown). Subjectively, I couldn't hear any difference in sound between RCA and XLR. The speaker connections are kept quite compact. The use of 4 mm banana plugs is recommended here. On the front switches, I would like to see a few different colored LEDs (XLR/RCA).
As speakers for the Fosi Audio V3 Monos, I can also recommend the following additional compact speakers from my subjective opinion (the pair between 150-550€). I borrowed these from friends for a short test (Q Acoustics 3020i, Fyne Audio F300 or F301, Acoustic Energy AE100 MK2, DALI Oberon 3)

Pros.
Compact and stable housing
Very good sound (based on the price)
Harmonize with different speakers
Interchangeable Opamps
Various inputs RCA/XLR

Cons.
Limited connection options In/Out
Relatively large power supplies
Case: Fingerprint sensitive
Heating of the housing even at low load and operating time
Speaker jacks a bit small, but usable with 4 mm banana plug