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Fosi Audio V3 Mono Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 13 1.9%
  • 2. Not terrible (postman panther)

    Votes: 22 3.2%
  • 3. Fine (happy panther)

    Votes: 135 19.8%
  • 4. Great (golfing panther)

    Votes: 513 75.1%

  • Total voters
    683
Enjoying the sound?
Can't comment much on it. I was expecting more. However, the rest of my chain is pretty simple (WiiM Pro Plus streamer going directly, via RCA, to amps. Speakers are Dynaudio Contour 1.3 SE, so there will be a need for source (DAC) upgrade.
 
Probably not :)

The 5A and 10A power supplies are the same voltage so the idle/standby current and heat output would be identical for any of the power supply configurations.
not the ampere rating but the voltage. I'm comparing the 2 power supplies. The voltage from the supply ideally should be constant. So 48v generates more heat than 32v.
 
Cure, switch the wires.
You mean the V3 Monos have a hardware error, that I could solve by placing that part of the speaker wire, that goes into + into - and vice versa without damaging my speakers/monos?
 
You mean the V3 Monos have a hardware error, that I could solve by placing that part of the speaker wire, that goes into + into - and vice versa without damaging my speakers/monos?
Correct. It is fine.

-Ed
 
Shall I do this on the amp's terminal or the speaker's?
It does not matter, technically—the back of the speaker is likely more visible than the back of the amp, so probably better at the back of the amp.

-Ed
 
It does not matter, technically—the back of the speaker is likely more visible than the back of the amp, so probably better at the back of the amp.

-Ed
I'm not sure if i'm understanding the issue correctly, but am i going to be affected by it if i want to use two monos for, say, SMSL D6s acting as a pre-amp/dac in conjunction with ELAC DBR62s? Using RCA cables and banana plugs.
 
not the ampere rating but the voltage. I'm comparing the 2 power supplies. The voltage from the supply ideally should be constant. So 48v generates more heat than 32v.
Agreed. But the power supplies for the monos are all 48V whether 5A or 10A supplies are chosen so the heat generated (to address the original question) is going to be the same whichever option is chosen.

If you use a different non-standard power supply then yes, both amplification available and amplifier temperature are likely to change.
 
I'm not sure if i'm understanding the issue correctly, but am i going to be affected by it if i want to use two monos for, say, SMSL D6s acting as a pre-amp/dac in conjunction with ELAC DBR62s? Using RCA cables and banana plugs.
No, you won't be affected.

Use just a pair of monos and you'll be fine. It is only a concern if you are going to do something like use a mono for one channel and a different model of amplifier for another channel. If you do that you have a sort of 50:50 chance of getting mismatched phase, but even then all you have to do is swap over the +/- connections on one of your speakers.
 
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Agreed. But the power supplies for the monos are all 48V whether 5A or 10A supplies are chosen so the heat generated (to address the original question) is going to be the same whichever option is chosen.

If you use a different non-standard power supply then yes, both amplification available and amplifier temperature are likely to change.
i was comparing my BT20A which has the same amp chip with 32V supply instead of 48V
 
I'm not sure if i'm understanding the issue correctly, but am i going to be affected by it if i want to use two monos for, say, SMSL D6s acting as a pre-amp/dac in conjunction with ELAC DBR62s? Using RCA cables and banana plugs.
If you’re just driving two speakers with a pair of V3 Monos and nothing else, you have no problem.

If you’re blending in, say, an active subwoofer, then you may have an issue, or if you are using the V3 Monos as part of a surround system with the other channels driven by a different amp type, you may have a problem.

-Ed
 
I'm not sure if i'm understanding the issue correctly, but am i going to be affected by it if i want to use two monos for, say, SMSL D6s acting as a pre-amp/dac in conjunction with ELAC DBR62s? Using RCA cables and banana plugs.
Consider using just XLR though as the amp performs better in this mode
 
Can't comment much on it. I was expecting more.
Did you already have some other TPA3255 amps before you are comparing to Fosi V3 Monos? I don't think people were expecting noticeable subjective SQ improvement with the new V3 monos, were they?
 
Mine arrived yesterday and are also hot - and they seem hotter than my PA7 - warming them up now and will use my trusty COVID surface temperature thermometer. I will compare to PA7 and share findings.
I have seen some people just remove that orange-colored strip from the sides of the chassis for better ventilation, which sounds like a good idea, especially during these super hot summer months.
FosiV3Mono.PNG
 
I have seen some people just remove that orange-colored strip from the sides of the chassis for better ventilation, which sounds like a good idea, especially during these super hot summer months.
View attachment 382593
I don't have one, but the holes seem quite big in the picture. I wonder if dust could become an issue.
 
I got these from AE:

IMG_8990.png


Got 5 V3M’s lined up next to each other, and these holders put them at a nice angled position for better airflow (mine are in a cabinet with active ventilators, so looks are not an issue)
 
Consider using just XLR though as the amp performs better in this mode
Thank you for this suggestion, so i've read - may i ask how do i do that in aforementioned setup? I've never used XLR cables really, i'm still learning :/

Edit: nevermind, i think i got it :) going with the XLR then.
 
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It is difficult to get my head around this type of performance is such a small and inexpensive package. I have been looking to add an amplifier to my Onkyo RZ50 to drive my front speakers-ML Vistas (4 Ohm). I have no complaints with the RZ50, but the V3 Mono Blocks appear to perform better on the bench. I would be interested if people think that there would be a noticeable difference (Better or Worse) in sound quality.
In my case the Fosi sound clearly worse than my old Marantz SR6009 using the same streamer and DAC.
 
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