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Fosi Audio V3 Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 10 2.1%
  • 2. Not terrible (postman panther)

    Votes: 44 9.0%
  • 3. Fine (happy panther)

    Votes: 231 47.4%
  • 4. Great (golfing panther)

    Votes: 202 41.5%

  • Total voters
    487
If Fosi make a V3 mark 2 there are a couple of improvements I would like:

1) Two sets of inputs. One should be XLR.
2) Reduce the high frequency variability with impedance
3) add a lower gain setting - my volume knob never goes above halfway and is usually between 10 o'clock and 11 o'clock.

Then it would be perfect.
 
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If Fosi make a V3 mark 2 there are a couple of improvements I would like:

1) Two sets of inputs. One should be XLR.
2) Reduce the high frequency variability with impedance
3) add a lower gain setting - my volume knob never goes above halfway and is usually between 10 o'clock and 11 o'clock.

Then it would be perfect.
I would add an RCA sub out and an optional, adjustable High Pass Filter on the main speaker outputs.
 
I obtained this for the princely sum of £72 including taxes and delivery, with the larger PSU, and I think it’s my favourite thing I’ve ever bought. All thanks to this site and the enthusiasts contributing to it!

These new class Ds have incredible treble, extended, smooth and detailed.

Most problems I thought I had with this amp have eventually been chased down as being due to another component. I have a tendency to blame the amp due to its extreme cheapness.

I hesitate to talk about burn in but it does seem to be better after a couple of months ordinary listening. Of course during that time I have been fussing with it, tweaking speaker position etc.

I think it’s more dynamic when the volume knob is around 75%, with volume reduced from the source. However, once you think you’ve identified some characteristic like that you are subject to confirmation bias. I think it’s flatter, as well as quieter, when the knob is lower. I’m not in fact sure exactly what the knob controls.
 
Anyone buy a fosi V3 recently notice that they changed the case? (I opened it and same internal pcb) Almost exactly the same but the logos are more of a gray than white now. The left is one from a year ago and the right is one I bought recently.

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I got yesterday the V3, and today is beeing returned, it was making like interference noises, coming from the 32V PSU. So nice components inside the amp but what components do they have in the PSU? . Luckily I bought it from Amazon.
My 1st and last Fosi device I will buy. I don want my house to burn down, if an amp make strange noises when I touch it I can not image what will happen in 1 or 2 years, if it manages to get that old.
I have and had smsl, topping and a loxje, all working fine, but this Fosi was a no for me. Maybe was just bad luck on this device.
 
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I got yesterday the V3, and today is beeping returned, it was making like interference noises, coming from the 32V PSU. So nice components inside the amp but what components do they have in the PSU? . Luckily I bought it from Amazon.
My 1st and last Fosi device I will buy. I don want my house to burn down, if an amp make strange noises when I touch it I can not image what will happen in 1 or 2 years, if it manages to get that old.
I have and had smsl, topping and a loxje, all working fine, but this Fosi was a no for me. Maybe was just bad luck on this device.
Almost certainly nothing to do with the amp or power supply (Did you hear noise with no input connected?) and most likely to do with ground loops (or other ground issues) in your system.
 
I have tested with 3 amps, and the electrical in the house is good. I have right now connected an Emotiva amp, and no issues.
Same for a loxje and an hypex.
Noises were there with only power connected, no speakers. The noises were not coming out from the speakers. If I touch the amp, only that, generate noise.
 
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I have tested with 3 amps, and the electrical in the house is good. I have right now connected an Emotiva amp, and no issues.
Same for a loxje and an hypex.
Noises were there with only power connected, no speakers. The noises were not coming out from the speakers. If I touch the amp, only that generate noise.
Was the noise coming from the amp or from the power supply? Could it be coil whine?
 
Hello friends,
I have b&w 683 (S1) attached to my tv in living room via old denon reciever avr2312. i use it for watching tv, movies, listening music on youtube ect. Before i have yamaha 1067 (now is broken) that sound much better than the denon that i use now. I have no experience with class d amps so i want to ask, is it possible to get good sound for my needs with a fosi v3, aiyima a07 or similar and connect with a smsl ps100 via hdmi arc with the tv? thanks
 
Noises were there with only power connected, no speakers. The noises were not coming out from the speakers. If I touch the amp, only that generate noise.
OK - fair enough. That is weird, and not right.
 
Well I bought three of the FOSI V3 Stereo Amps and integrated them with a MiniDSP Dlex Eight DSP controller driven by a WIIM Pro.
This system was to update/renew/refinish a set of B&W 802F speakers I have had with me since 1981. Over 43 years old. The 802s had been stored away. I decided on the above project because 3 FOSI V3s with 48V were affordable to couple with the MiniDSP Flex 8. This was to test whether I should go active with some Satori Textreme drivers on my main rig.
Long story short. Incredible, when I first set them up roughly just by ear before using REW and measuring my friend who own some Magicos jaw dropped.
The rise in output at the extremes high frequencies might actually be a BENEFIT to older domes. I confirmed this with my measurements on the old 802 which still used the soft domes and not the aluminum, or diamond tweets. I have these tuned to 25Hz in my room, tuned out the room resonances and with the headroom with the 48V PS and low end DSP control I have there is no issue at all.
Thanks FOSI and Aiyima for this category of amps.
 
Hey Im looking for some help.

I have an audio technica lp7 turntable and a Cambridge audio phono pre-amp.

When using my sansui integrated this setup works fine.

When plugging this into the fosi V3 I get a high pitched ground hum. I believe its called a 120 sine or something like that.

I have tried extra grounding from the tt to the preamp and then to the fosi but am having little joy in solving this issue.

Any tips would be appreciated.

Many thanks
 
what input do you use at the Fosi?

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Hey Im looking for some help.

I have an audio technica lp7 turntable and a Cambridge audio phono pre-amp.

When using my sansui integrated this setup works fine.

When plugging this into the fosi V3 I get a high pitched ground hum. I believe its called a 120 sine or something like that.

I have tried extra grounding from the tt to the preamp and then to the fosi but am having little joy in solving this issue.

Any tips would be appreciated.

Many thanks
How did you try grounding the Fosi?
 
The Aux output is not an alternative input for the small plug. That is why I ask. I had someone who thought this was just a second input.

Ah, yes, does it produce music through the speaker or only "hum". Hum usually is not high pitched, but a low frequency.

If there is normal music played with hum, unplug the phono-pre power supply. It should play on for a few seconds. Is the hum gone when the wall wart of the pre is plugged out?
 
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