• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Fosi Audio V3 Mono Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 7 1.5%
  • 2. Not terrible (postman panther)

    Votes: 11 2.3%
  • 3. Fine (happy panther)

    Votes: 95 19.9%
  • 4. Great (golfing panther)

    Votes: 364 76.3%

  • Total voters
    477

mrmeng430

Member
Joined
Aug 29, 2021
Messages
31
Likes
11
Am I late to the party? I don't see any time zones or discounts.
1713465626326.png
 

Anton D

Addicted to Fun and Learning
Joined
Mar 17, 2021
Messages
978
Likes
1,142
Kickstarter page is landing to 404 at the moment, either page is taken off (most probably) or down because of something like too much traffic or DoS/DDoS.
I got the email and the countdown timer says the offer ends tomorrow, but Kiskstarted says it hasn't launched yet.

I've tried clicking on the offer in the email, but it just transfers over to Kickstarter.

I'm hoping I am not screwing up. Kinda excited to get these!
 

antcollinet

Master Contributor
Forum Donor
Joined
Sep 4, 2021
Messages
7,981
Likes
13,553
Location
UK/Cheshire
Know this is subjective, which is verboten here, but do you think a pair of Fosi monoblocks would be an improvement sound wise over the XTZ-Edge A-300 that Amir tested here:

Have had the XTZ in my system and generally like it, very solid bass and well defined highs but maybe a little lacking in midrange, but wondering if the newer generations of class D represent a meaning improvement in sound.
Similar power, similare performance in other measures. I doubt very much you'd hear a difference if compared blind and level matched.
 

EddNog

Active Member
Joined
Mar 1, 2024
Messages
110
Likes
114
That's odd, it doesn't show on my end.
I tried to VPN in the US (I am in the UK), cleared browser cache but to no avail.
It doesn’t show the times anymore for me, either. They must’ve changed it (again).

-Ed
 

RobinOC

Member
Joined
Oct 29, 2022
Messages
5
Likes
1
This is a review and detailed measurements of the Fosi Audio V3 Mono class D amplifier. It was sent to me by the company. The price with the power supply I tested is US $139.99.
View attachment 360697
I must say the concept of a "monoblock" amplifier in such a small size runs foul of any expectation a longtime audiophile would have! But monblock it is even though it is a very small block. Controls are on/off/trigger audio and selection of XLR vs RCA inputs -- just like the big boys! :) I am not showing the sides of the amp but there are very large holes with attractive orange color grid showing through. Nice. Back panel is again a bit of a shock to the system seeing XLR input:
View attachment 360698

The power supply as noted, is quite beefy with 48 volts at 5 amps on tap (240 watts). The amplifier is stated to have PFFB implementation which for a class D amplifier means it should have no load dependency together with lower distortion. Let's see if we get these with our measurements.

Fosi Audio V3 Mono Amplifier Measurements
Let's start with XLR input:
View attachment 360699
Wow, I did not expect this class of amplifier to break through the 100 dB SINAD barrier but the V3 Mono does exactly that, placing it in our prestigious category of "excellent:
View attachment 360700
View attachment 360701

RCA input costs you some performance but I was relieved to not see any mains interference:
View attachment 360702

Distortion is still at provably inaudible -115 dB. I like that the gain is nominal 25 which is my new recommendation for amplifiers.

Noise performance is excellent and at full power, darn near approaches sate of the art:
View attachment 360703

Now the all important frequency response and load dependency test:
View attachment 360704

There is essentially no impact up to 20 kHz between the 4 and 8 ohm indicating very low output impedance, albeit with a bit of peaking. Compare that to non-PFFB amps such as Fosi Audio V3 stereo Amp:

index.php

Above we have 2 dB differential at 20 kHz.

Distortion is very low and only increases with frequency:
View attachment 360706

View attachment 360707

Let's see how much power we can get out of this little box:

View attachment 360709

View attachment 360710
Efficiency must be quite high as we get essentially the power we put in (the power supply likely has some headroom).

There is decent amount of power even with 8 ohm and with very low noise:
View attachment 360712

As note though, distortion does rise at higher frequencies:
View attachment 360713

Fortunately it is good where our hearing is very sensitive (below 5 kHz).

I also threw my suite of my punishing reactive loads at it:
View attachment 360717

Translating into watts:

View attachment 360716

Amazing that this little amplifier can handle even 2 ohm load! Note that these are short term power ratings.

There may be a bit of power on noise:
View attachment 360718

Conclusions
All I can say is wow! It is incredible how far these small amplifiers have come. It is the result of a manufacturer listening to our needs, implementing features such as balanced and trigger inputs, and proper feedback mechanism to essentially eliminate load dependency. I can't imagine asking for more from Fosi when it comes to such an amplifier. Everything is as good as you could possibly want.

It is my pleasure to recommend Fosi Audio V3 Mono amplifier.

-----------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
Have they mentioned that they make a new 48V GaN power supply? List is $90. How would this impact performance?
 

TheBatsEar

Major Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
3,243
Likes
5,291
Location
Germany
It will be possible to get them without the psu during the kickstarter campaign? I already have a 6 channel V3 setup I want to replace.
I doubt you will be able to sell a Stereo V3 without power supply for a fair price.
I for one will get a pair of the V3 Mono, but keep my V3 Stereo. Creeping towards a 6 channel setup, one chipamp-iteration at a time. :cool:

Have they mentioned that they make a new 48V GaN power supply? List is $90. How would this impact performance?
Power supplies are about voltage and amperes only. If two power supplies deliver the same amount of energy at the same loads, they sound the same.
GaN can be smaller while giving the same voltage and amperes, but i for one don't need smaller, i want cheaper.
 

Fosi Audio

Senior Member
Audio Company
Forum Donor
Joined
Sep 10, 2021
Messages
326
Likes
1,611
FWIW, those times don't correlate with the countdown timer in the emails they sent out.
The countdown timer in my email will hit zero at 6pm PDT.
Sorry for the inconvenience. Here is the correct time of the launch in different time zones
April 20th 8AM PDT
April 20th 11AM EDT
April 20th 5PM CEST
April 21th 1AM AEDT
 

EddNog

Active Member
Joined
Mar 1, 2024
Messages
110
Likes
114
I have my own psu so I'm not using the original ones. This is why I asked. So this upgrade wouldn't cost me much.
Yes, but his point is that once you order the new ones and they come in, if you order the new ones with power supplies, you will have an easier time recovering some of your costs by selling your previous amplifiers with power supplies rather than trying to sell them without one.

I originally bought my ZA3s without power supplies, and used 48V 5A ones I have already. When I saw V3 Mono’s test results here, I ordered a pair of 48V 10A ones and upgraded my setup to them, with the intent of including the 5A ones with the ZA3s when I sell them.

-Ed
 

YesChickenNuggets

Active Member
Joined
Nov 11, 2022
Messages
103
Likes
81
Guys, do you happen to know why RCA has a Sinad penalty? If the SU-1 can get to 116, why can't this fosi amp do the same sinad with RCA vs its XLR?

Will Fosi release an optimized version for RCA? SU-1 fans couldn't care less about XLR.
 

Bleib

Major Contributor
Joined
May 13, 2021
Messages
1,387
Likes
2,473
Location
Sweden
Guys, do you happen to know why RCA has a Sinad penalty? If the SU-1 can get to 116, why can't this fosi amp do the same sinad with RCA vs its XLR?

Will Fosi release an optimized version for RCA? SU-1 fans couldn't care less about XLR.
SU-1 balanced would do better than SU-1 single ended.
Otherwise the difference lies in the fact that one is a DAC whilst the other is an amplifier. It's a more difficult task to keep the signal clean with an amp.
 
Top Bottom