• 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: 8 1.6%
  • 2. Not terrible (postman panther)

    Votes: 12 2.4%
  • 3. Fine (happy panther)

    Votes: 100 19.8%
  • 4. Great (golfing panther)

    Votes: 384 76.2%

  • Total voters
    504

Zuiko

Member
Joined
Oct 2, 2023
Messages
20
Likes
22
How are you getting those calculations? You can't just assume that all the PSU power can be output to speakers.

My goal was 'simplified' power from the power supplies, not actual power to the speakers.
I get even that's theoretical. The comparison may still be useful in relative terms...
 

antcollinet

Master Contributor
Forum Donor
Joined
Sep 4, 2021
Messages
8,142
Likes
13,834
Location
UK/Cheshire
not actual power to the speakers.
Then you shouldn't state per channel power, and should clearly state you are only talking about PSU power output.

The comparison may still be useful in relative terms...
It isn't - it is misleading.
 

dr_mick51

Active Member
Joined
Mar 12, 2022
Messages
211
Likes
217
intersting.
Top: this ebay listing https://www.ebay.co.uk/itm/275540643117
Bottom: Guddu's review here in ASR:
most (all?) huntkey models, the three figures after the letters denote power in watts

View attachment 366964

have seen worse made though :p:
View attachment 366969
Both are the same power supply. The Model number (HKA30048063-7D which means 300W, 48V 6.3A) is the same, the input current is the same. The actual output power is the same. I think it's a little dishonest/misleading to state that the second PS provides 10A(max), people may believe this is a 480W power supply.
The real question is , do we really need all that power? With the 4Vrms input signal we provide at -12dBFS or even -14dBFS attenuation(x0.2 to x0.25) , and the total amplifier gain of 20.5dB or x10.6, the output voltage the amp can produce is 4V x0.20 x10.5= 8.4V, at 4Ohm we have 8.4^2 / 4= 17.64W

This means that a 8.4V DC/0.707 = 12V DC Power supply with 2A is more than capable of providing power for this particular use case. This is in "theory" because we know the TPA3255 needs at least 18V and 10.8V for the other digital circuitry:
1715698410498.png
 
Last edited:

gwing

Active Member
Forum Donor
Joined
Mar 19, 2022
Messages
193
Likes
181
I think it's a little dishonest/misleading to state that the second PS provides 10A(max), people may believe this is a 480W power supply.
Am I missing something here? Fosi have kindly shown on this forum that their supply is indeed capable of the claimed 48V 10A output, have you not read those posts or are you suggesting the supplied evidence and results are false/faked?
 

Talisman

Major Contributor
Forum Donor
Joined
Mar 27, 2022
Messages
1,036
Likes
3,073
Location
Milano Italy
Both are the same power supply. The Model number (HKA30048063-7D which means 300W, 48V 6.3A) is the same, the input current is the same. The actual output power is the same. I think it's a little dishonest/misleading to state that the second PS provides 10A(max), people may believe this is a 480W power supply.
The real question is , do we really need all that power? With the 4Vrms input signal we provide at -12dBFS or even -14dBFS attenuation(x0.2 to x0.25) , and the total amplifier gain of 20.5dB or x10.6, the output voltage the amp can produce is 4V x0.20 x10.5= 8.4V, at 4Ohm we have 8.4^2 / 4= 17.64W

This means that a 8.4V DC/0.707 = 12V DC Power supply with 2A is more than capable of providing power for this particular use case. This is in "theory" because we know the TPA3255 needs at least 18V and 10.8V for the other digital circuitry:
View attachment 369480
Before drawing this kind of conclusion it would be useful to continue reading....
 

amix

Member
Joined
Sep 20, 2020
Messages
80
Likes
47
ps. looks like 250 people or so are getting the 2x 48V 10A :D ... If you're here, what speakers are you driving or what are your reasons for 480W/channel?
Here!

Though it's not about the 480W/channel, especially since Fosi doubts, the 10A will give much more output power.

I did so, since I suffer from bad synergy of my speakers and my amplifier (QUAD 66 Pre + QUAD 306 PA) for far too long. The speakers are Dynaudio Contour 1.3 SE. It is generally believed, all across the forums I visited so far, that Dynaudios want not so much power as they want current. I still don't understand the technical aspects behind it, but I had enough and took the chance to get the higher current supplies.

Dynaudio's customer support recommended an amp with high reserves.
 

Fosi Audio

Senior Member
Audio Company
Forum Donor
Joined
Sep 10, 2021
Messages
329
Likes
1,631
Both are the same power supply. The Model number (HKA30048063-7D which means 300W, 48V 6.3A) is the same, the input current is the same. The actual output power is the same. I think it's a little dishonest/misleading to state that the second PS provides 10A(max), people may believe this is a 480W power supply.
The real question is , do we really need all that power? With the 4Vrms input signal we provide at -12dBFS or even -14dBFS attenuation(x0.2 to x0.25) , and the total amplifier gain of 20.5dB or x10.6, the output voltage the amp can produce is 4V x0.20 x10.5= 8.4V, at 4Ohm we have 8.4^2 / 4= 17.64W

This means that a 8.4V DC/0.707 = 12V DC Power supply with 2A is more than capable of providing power for this particular use case. This is in "theory" because we know the TPA3255 needs at least 18V and 10.8V for the other digital circuitry:
View attachment 369480
Hello there, please ignore the model number on the power supply. This 48V/10A power supply is custom-made with Huntkey, and we will correct the model name. We have previously released the relevant test report and test video for this power supply. For details, please refer to here.:)
 

jvdburgt

Member
Joined
Apr 17, 2024
Messages
15
Likes
8
IMG_8610.jpeg
Fosi posted details about their SP601 speaker, asking users’ inout on which calibration they prefer.

Thoughts?
 

Sokel

Master Contributor
Joined
Sep 8, 2021
Messages
6,522
Likes
6,714
I see they use an LMS analyzer though.
Results should be comparable between measurements.
 

ovi

Member
Joined
Mar 6, 2023
Messages
18
Likes
9
Last edited:

staticV3

Master Contributor
Joined
Aug 29, 2019
Messages
8,753
Likes
14,124
Thanks for the formula it helped me understand a lot more about this subject :)
Check this out, may be useful:
 
  • Like
Reactions: ovi

Rover

Active Member
Joined
Apr 21, 2020
Messages
133
Likes
92
Hello there, please ignore the model number on the power supply. This 48V/10A power supply is custom-made with Huntkey, and we will correct the model name. We have previously released the relevant test report and test video for this power supply. For details, please refer to here.:)
Hi.When will the Fosi Audio M3 Mono be available?
 

Atryx10

New Member
Joined
May 17, 2024
Messages
1
Likes
0
I'm new here, so IDK if this should be in its own thread or not, but how would you connect these up in a 2.1 surround setup? I was considering getting a DAC and headphone amp (that could be used as pre-amp), so I'd have something that I could use for both headphones and speakers, but I don't understand how it'd be possible to connect that with three Fosi V3 Mono for a 2.1 setup, since as far as I can tell, headphone amps don't seem to have the capability for more than 2.0. I was thinking of getting a FiiO K19, but maybe I should just give up on trying to get this to work...
Would greatly appreciate help with understanding more about this.

Edit: Thanks for the answers! That has made me get some additional questions, but as it's going to stray from the main topic of this thread, it's better for me to wait with replying until this gets moved to its own thread :)
Though, from what I gather so far, it's going to be for the best if I get a separate DAC and headphone amp, with the headphone amp having pre-amp capabilities and a sub out. If my understanding is correct, I should be able to make do with my FiiO Q15 as the DAC, and just try to find a headphone amp with a sub out. Perchance
Now, I wonder how cursed it would be if I were to use a FiiO K19 plugged into a Denon AVC-X3800H, that then plugs into the Fosi V3 Mono amps. ;) This stack would after all have the ability for IEM and headphone driving, alongside the ability to do surround up to 7.4.4
 
Last edited:

antcollinet

Master Contributor
Forum Donor
Joined
Sep 4, 2021
Messages
8,142
Likes
13,834
Location
UK/Cheshire
Options:

1 - You need a Dac or other device with a built in crossover, and output for a sub. One example would be a mini DSP flex.
2 - You split the 2.0 output, and send it both to the main amps, and to the sub. Then use the low pass filter on the sub to perform the crossover. No high pass for the main speakers this way though.
 

DTTOM37

Active Member
Joined
Jul 3, 2020
Messages
202
Likes
292
Location
French side of Europe
I'm new here, so IDK if this should be in its own thread or not, but how would you connect these up in a 2.1 surround setup? I was considering getting a DAC and headphone amp (that could be used as pre-amp), so I'd have something that I could use for both headphones and speakers, but I don't understand how it'd be possible to connect that with three Fosi V3 Mono for a 2.1 setup, since as far as I can tell, headphone amps don't seem to have the capability for more than 2.0. I was thinking of getting a FiiO K19, but maybe I should just give up on trying to get this to work...
Would greatly appreciate help with understanding more about this.
Hi, Bienvenue ;-)
1rst: Usually the .1 may be an active subwoofer, which means it already has integrated amplifaction. You would only need a third amplifier in case you use a third passive speaker/sub (unamplified)

2nd: In case you use an active sub, you could get a DAC (like the SMSL D6/6s) that allows dual full range signal output via a) balanced/TRS and b) unbalanced/RCA outputs, which could feed a) you speakers with the Mono V3 and b) the active sub. Imho, one of the cheaper options, and quite doable if your sub does low pass filtering.

3rd: Alternatively you could look at the WIIM range, which may - with the all new WIIM Ultra - may allow pre-amp functionality & 2.1 output.
Afaik, it's still assumed that its parametric EQ will receive high pass / low pass functionality quite soon. (pehaps it already has and I am not up to date ?)

Means: HP: Signal above selected frequency will be outpt to the speaker amp, LP: Signal below selected frequency will be sent to subwoofer only.

As often, the more you invest the better are your options for your specific use case. AFAIK
 

rvsixer

Addicted to Fun and Learning
Joined
Apr 6, 2018
Messages
635
Likes
442
Location
Somewhere at the base of the Rockies....
I'm new here, so IDK if this should be in its own thread or not, but how would you connect these up in a 2.1 surround setup? I was considering getting a DAC and headphone amp (that could be used as pre-amp), so I'd have something that I could use for both headphones and speakers, but I don't understand how it'd be possible to connect that with three Fosi V3 Mono for a 2.1 setup, since as far as I can tell, headphone amps don't seem to have the capability for more than 2.0. I was thinking of getting a FiiO K19, but maybe I should just give up on trying to get this to work...
Would greatly appreciate help with understanding more about this.
IMO should be in its own generic thread, but onwards:
1) 2.x, by definition, is not a surround setup (you need surround speakers for that, 2.x is just front/left/x subs)
2) Headphones (generally) only support 2.0 (no sub input or output). Of the few that do support a "sub" inside of them, the crossover is internal to them so still only need 2.0 input.
3) Many ways to skin this cat, what I would setup:
- miniDSP Flex Eight as already mentioned (assuming all your sources are digital).
- Fosi mono blocs for the 2.x output to speakers (make sure your passive sub(s) are okay with the Fosi output limits, otherwise just use a different amp for the sub(s)). If your subs are active that negates the need for external amp(s).
- Headphone amp for your headphones
- Would make for a very compact and versatile base setup, easy to change up amps/speakers etc. in the future
- Always use more than one sub but that's a whole other discussion :)
 
Last edited:
Top Bottom