Fosi Audio V3 Amplifier Review

[Toku]

Hi Everyone,

I have a 2.0 setup (Klipsch RF7 III) with a big an bulky Pioneer SC-LX 87 AVR and a WiimPro. I want to replace the Pioneer with a Fosi V3. Do you think that it will have "enough" Power for the Klipsch? I just want to get rid of this big AVR because 95% of its features are unused.

Maybe I will also get a WiimPro+ for the better DAC and sell the Pro.
The Plan is to go digital in from the TV and RCA out to the Fosi.

Fosi V3 has a lot of power that cannot be imagined from its small size.
If you are still concerned, please choose a 48V power supply. I don't think you'll ever feel a lack of power in a typical home room.
However, Fosi V3 does not have digital inputs. RCA input only.

 

[ArdaDaMarda]

Thanks for your answers.

Yes, I will get it with the 48V GaN Power Supply anyway.
I will use the DAC in the Wiim Pro.

TV(digital) -> Wiim Pro (RCA) -> Fosi V3.

 

[coolstuff]

excellent review. many thanx. I am very pleased to have found this forum.

likely because of the power factor I had difficulties to measure real AC power consumption of the Fosi V3 with a cunsumer grade power meter.

Note that part of the heat is dissipated in the power supply and part in the amp. The X axis is power per channel, not total (amp is driven in stereo).

Would be nice to see overall efficiency including the AC SPMS running at both channels idle, at 5 watt and max power audio into 4/8 Ohm speakers and if possible make these results part of every review. Looking for power figures at idle load is very time consuming and not very transparent how this was measured.

 

[lamquin]

It took about 21 days to arrive here from Fosi Audios own shop instead of the estimated 5-15 days, but it's finally here and... it's really tiny compared to my old NAD 315BEE!

First impressions are a very positive with some minor annoyances. I got the 48V power supply to stay on the safe side, but using a wattage meter my speakers appear to take about 7W when listening at a comfortable volume (DALI Lektor 2). I'll simply view it as a bit of future proofing if I'd need to replace them in the future.

Same as someone mentioned earlier, the tweeters of my speakers also make a white noise while the amplifier isn't playing any music, but luckily the 0.5m distance I'm sitting away from them makes it all but inaudible.
As for the sound itself, it sounds the same to my ears as my old NAD 315, which is great!

The connectors for the speaker wire would've been daunting if several people didn't mention to also get the Banana plugs - thanks! The wire plugs were much smaller than I expected, so the wire probably wouldn't have fit easily. As for the banana plugs, the upper back "Red" one went in all the way as shown in the picture, while the other three have a very slight gap.
Should I forcefully push them further in, or leave as is?

The Fosi Audio V3 also powers on/off by using the volume knob and does not include a remote.
Would it be safe to use a remote controlled circuit breaker on the power as an On/Off switch while leaving the volume knob untouched in the On position?

Overall, having used it for three days - fantastic bargain for my current needs. Here's to hoping it lasts a few years!

 

[K.Kevin]

Would these would sound better or worse than the internal amps in a Denon X3800h?

I have a pair of used BMR’s, they droop down to 3ohm impedance for much of the bass frequencies. I tried the receiver up against an aiyima a07 32volt, I know there’s a huge power imbalance there, but I level matched them as best I could. I felt like the aiyima still provided crisper and tighter bass, like the bass guitar cut through the mix better than on the Denon. I did think the Denon had more pleasing mids and higher frequencies though. Is what I heard because these class D amps can provide more current at lower ohms, or that they’re more impervious to those droops?

I’m actually interested in two new ZA3’s in bridged, but they’re based on the V3 so it seems good to ask here

 

[Joe Smith]

It took about 21 days to arrive here from Fosi Audios own shop instead of the estimated 5-15 days, but it's finally here and... it's really tiny compared to my old NAD 315BEE!

View attachment 327790

First impressions are a very positive with some minor annoyances. I got the 48V power supply to stay on the safe side, but using a wattage meter my speakers appear to take about 7W when listening at a comfortable volume (DALI Lektor 2). I'll simply view it as a bit of future proofing if I'd need to replace them in the future.

Same as someone mentioned earlier, the tweeters of my speakers also make a white noise while the amplifier isn't playing any music, but luckily the 0.5m distance I'm sitting away from them makes it all but inaudible.
As for the sound itself, it sounds the same to my ears as my old NAD 315, which is great!

View attachment 327793

The connectors for the speaker wire would've been daunting if several people didn't mention to also get the Banana plugs - thanks! The wire plugs were much smaller than I expected, so the wire probably wouldn't have fit easily. As for the banana plugs, the upper back "Red" one went in all the way as shown in the picture, while the other three have a very slight gap.
Should I forcefully push them further in, or leave as is?

The Fosi Audio V3 also powers on/off by using the volume knob and does not include a remote.
Would it be safe to use a remote controlled circuit breaker on the power as an On/Off switch while leaving the volume knob untouched in the On position?

Overall, having used it for three days - fantastic bargain for my current needs. Here's to hoping it lasts a few years!

Don't worry about the banana connectors not pushing 100% flush, that's normal for all of these amps, at least with the standard Nakamichi-branded plugs I use.

You can try turning off via the power strip with volume level knob kept up, but you may get more of a speaker pop when doing that way. See what it sounds like.

 

[Tenfilip]

Hi guys!

I can not decide wether I should buy this Fosi Audio v3 + a nice DAC or a integrated class D amp like the Audiophonics DA-S250NC DAC & Power Amp ... I tried to read as many ASR articles and comments as possible but could not find the answers to all my questions.

About my DAC+amp needs:
- it will have to power Focal Aria 926 floorstanding speakers
- it will be connected to my LG C1 TV via an optical cable
- it will have to be used via a controller from the couch (will sit in the TV bench)
- it has to be as reliable as possible, even if a bit more pricey

Here are my concerns:
- the Fosi Audio v3 doesn't seem to have a trigger jack input, does it mean I would have to manually turn it on by rotating the dial every time I want to listen to something on my TV?
- is a tiny amp like this Fosi Audio v3 really able to drive a 3-way (2x165mm bass + 1x165mm mid) bass-reflex floorstanding loudspeaker?
- do you think the power difference with the Audiophonics integrated amp will be noticeable?
- other options would be regular class A/B amps like Yamaha A-S701 or Marantz PM7000N. Do you think there are worth it compared to the class D amps I am considering?

Thanks a lot for your help!!!

Just use a master slave power strip. I use them for years. You could also use 2 smart sockets. But TBH, you could just leave it on.

 

[Tenfilip]

So, is this better than crown xls 2500 on lower volumes? Ignoring the DSP in crown, balanced in etc.

 

[joqueval]

So, is this better than crown xls 2500 on lower volumes? Ignoring the DSP in crown, balanced in etc.

I am waiting for a new power supply to test two V3 with 48v supply in the audio dj set.
There I use an Ecler XPA3000 stage, I'm really curious to know how far the V3s go.

Ecler DACORD 208H
2-way full range speaker
300W RMS /8 ohms – 600 W program
Efficiency 96dB SPL 1 W / 1 m Double 8” polypropylene woofer. 52mm coil

Ecler XPA3000
POWER 20-20kHz 1% THD:
4 Ohm Stereo: 295 WRMS
8 Ohm Stereo: 198 WRMS
8 Ohm Bridged: 590 WRMS
Peak power 2 Ohm Stereo: 600 WRMS
Frequency response (-1dB/-3dB): 10Hz/120kHz
High pass filter (-3dB): 30Hz/18dB oct.
THD+Noise @ 1kHz Full Power:
<0.05%
S+N/N 20Hz-20kHz @ 1W/4 Ohm: >78dB

Damping factor: 1kHz @ 8 Ohm: >300

Slew Rate: ±32V/ms

 

[Agapit68]

please tell me, what is the damping factor of Fosi V3 amplifier? What about the slew rate?

 

[Fhatway]

Maybe a dumb question, but it seems like so much of the negatives come down to the lack of volume-controlled sub output.....

Is it not possible to use a speakerlevel-->RCA module typical in cars like this:

Amazon.com

My understanding is this is so inconsequential to the speakers they wouldn't notice....am I wrong?

My cheap sub further doesn't even have two RCA inputs...just the one.
Can I additionally use an RCA splitter in reverse on the RCA outputs of the prior converter to mix both channels like this:

https://www.amazon.com/Splitter-Female-Audio-Video-Adapter/dp/B09YHDWVG8

The RCA converter has adjustable gain, so you can tweak it to not overdrive when mixed.

What am I missing?

This all said....by the time you purchase the v3 ($80) + the 48V supply ($60) the RCA converter ($10 ...... at what point do you just get a more traditional amp with integrated supply and pre-out instead?

 

[dingbat]

Right now the limit of the pa3s is the low output power, but according to what you said it's not a problem for you.
the pa3s although having a slightly lower sinad than the V3, has a lower noise level with 16 bits full of dynamic range at 5 watts and up to 18 at full power, it is substantially a little less noisy than the V3, which having very sensitive speakers is preferable. Furthermore, pa3s is load invariant, thus another point in its favor.
Basically, since the great advantage of the V3 over the Pa3s is the great power, and you don't need it, if I were you I would go to Topping

Hi. I have a pair of AE109 speakers. I’ve tried both of these power amps but I am a complete newbie. What do you mean by “lower noise level”?

 

[Talisman]

Hi. I have a pair of AE109 speakers. I’ve tried both of these power amps but I am a complete newbie. What do you mean by “lower noise level”?

This refers to the basic noise level of the amplifier when it is not reproducing a signal. Basically you put the volume at maximum without playing anything and you gradually move closer to the tweeter until you hear a hiss or at least a noise. Clearly the greater the sensitivity of your speakers, the more audible it will be or it will be audible from a greater distance. In the vast majority of cases and modes of use an amplifier like the V3 will offer noise performance good enough that you won't have to worry about it

 

[dingbat]

Currently swapping between a Topping PA3S and the Fosi V3. They are both cracking little amps, with the Fosi able to crank up that bit more.

However, the Fosi is always quite warm even when not playing (i.e. just while plugged in). In comparison the Topping has yet to hit any sort of temperature.

Is this sort of heat from the Fosi V3 normal?

 

[Joe Smith]

Currently swapping between a Topping PA3S and the Fosi V3. They are both cracking little amps, with the Fosi able to crank up that bit more.

However, the Fosi is always quite warm even when not playing (i.e. just while plugged in). In comparison the Topping has yet to hit any sort of temperature.

Is this sort of heat from the Fosi V3 normal?

Depends greatly on the power brick. With a 32v Fosi brick, the amp feels just slightly warm to the touch.

 

[Steven Holt]

what is the damping factor of Fosi V3 amplifier?

That partly depends on the impedance of your speakers. Rest assured, with any modern amp -- AND ESPECIALLY CLASS D -- the DF is more that adequate. In fact, it's a non - issue.

What about the slew rate?

Again, with any modern amp, it's a non - issue.

 

[dingbat]

Depends greatly on the power brick. With a 32v Fosi brick, the amp feels just slightly warm to the touch.

It's the 48v Fosi brick.

 

[dingbat]

I've had this amp for a couple of days now. I didn't expect it to run so hot while idle! I left it switched on overnight and this morning the chassis was 40c sat in a cupboard with a 29c ambient temp. The Topping PA3s never felt more than warm to the touch, but perhaps it just doesn't conduct the heat to the chassis as effectively. I'm now considering a smart plug to turn it off when not in use.

This is exactly my experience. The Fosi V3 seems too hot to leave switched on 24/7.

 

[Agapit68]

That partly depends on the impedance of your speakers. Rest assured, with any modern amp -- AND ESPECIALLY CLASS D -- the DF is more that adequate. In fact, it's a non - issue.

Again, with any modern amp, it's a non - issue.

Ok, you've given me hope! However, somewhere I came across rather pessimistic measurements to an amplifier based on the same 3255 chip. I’ll try to find now http://archimago.blogspot.com/2023/04/measurements-fosi-audio-tb10d-upgraded.html?m=1

 

[Steven Holt]

Ok, you've given me hope! However, somewhere I came across rather pessimistic measurements to an amplifier based on the same 3255 chip. I’ll try to find now http://archimago.blogspot.com/2023/04/measurements-fosi-audio-tb10d-upgraded.html?m=1

'Rather pessimstic measurements'?? Your blog-guy measured it out at 28 times at 4R!! Anything over 10X at 4R is considered more than adequate! Buy this little amp with confidence and don't worry one whit about DF or SL. And this : if they were important then Amir would measure them. And welcome to ASR, audio taught right!