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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

yuki

New Member
Joined
May 2, 2023
Messages
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It would be great if you could put two of these amps inside the LC30 case!
My ramblings aside, thanks for the great amp!
 

staticV3

Master Contributor
Joined
Aug 29, 2019
Messages
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13,402
I am wanting to hook a pair of these up to my AVR. Its a yamaha RX A770. It doesnt have any preouts for the mains. Only for zone 2. Would something like this work acceptably to convert the speaker level output to a preamp level? https://www.audiocontrol.com/car-audio/factory-system-upgrade/lc1i/
Having the Yamaha's Line level signal be amplified by the built-in Amp, then brought back down to Line level via the adapter, then once again amplified to Speaker level by the Fosi, sounds extremely inefficient.

Instead, I'd try to modify the Yamaha by adding RCA Line outputs myself.

There's a service manual available online which guides you through the disassembly process and contains detailed block diagrams and PCB schematics.
 

sl1982

Member
Joined
Apr 20, 2024
Messages
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39
Why not use zone 2 line out?
The idea was to have multichannel audio still functional. I am not sure if you could have left and right on zone 2 preouts while utilizing all the other surround speakers. Granted i have never attempted it yet.
 

sl1982

Member
Joined
Apr 20, 2024
Messages
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39
Having the Yamaha's Line level signal be amplified by the built-in Amp, then brought back down to Line level via the adapter, then once again amplified to Speaker level by the Fosi, sounds extremely inefficient.

Instead, I'd try to modify the Yamaha by adding RCA Line outputs myself.

There's a service manual available online which guides you through the disassembly process and contains detailed block diagrams and PCB schematics.
After looking at the service manual i dont think this is in my skillset. While i do know how yo solder i have no clue where i would need to tap into.
 

Rafaille

Member
Joined
Dec 5, 2021
Messages
93
Likes
51
The idea was to have multichannel audio still functional. I am not sure if you could have left and right on zone 2 preouts while utilizing all the other surround speakers. Granted i have never attempted it yet.
According to the manual you can activate Zone 2 with a button. I would be surprised if it deactivated the main zone, only one way to find out though....
If it works, you will probably have to consider the delay between the different channels, that could be trickier.
 

EddNog

Active Member
Joined
Mar 1, 2024
Messages
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114
What is the difference between separate 5A power supplies and on 10A supply? What is the design benefit you mentioned? Thanks
There is actually a pretty decent answer to this in their newly posted FAQ:

IMG_2675.jpeg


-Ed
 

EddNog

Active Member
Joined
Mar 1, 2024
Messages
109
Likes
114
@Fosi Audio congratulations on landing APOS distribution!
 

SMen

Active Member
Joined
Jan 2, 2022
Messages
177
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91
Actually this is also answered differently. @great04

The "design benefit" is in bold from the FAQ
When powering a V3 Mono device, would using a 48V/10A power supply provide a higher power output than a 48V/5A power supply?

Based on our measurements, when powered by a 48V/10A power supply, there is no significant increase in power compared to using a 48V/5A power supply. This is because the power has essentially reached the maximum supported by the TI TPA3255 amplifier chip with a 48V voltage input. Increasing the current further does not directly enhance the power output. However, using a 48V/10A power supply compared to a 48V/5A power supply can provide a higher current capacity and greater safety margin for the amplifier. This increased current capacity effectively reduces voltage drops in power lines and internal circuits under high loads, improving the response of the amplifier when handling dynamically complex audio signals. Moreover, the higher current output means that the system is less likely to overheat or shut down due to current overload when facing peak loads, thereby enhancing the overall reliability and stability of the system. Additionally, opting for a more robust power supply can alleviate the operational stress on various components of the amplifier, prolong the lifespan of the equipment, and offer more flexibility for potential system upgrades in the future.

My small issue with this is that Aiyima have a 48V/10A GaN supply that is much less expensive than the Fosi 48V/10A.

So there is a design benefit, and a profit benefit, which is fine ... but in a marketplace ASR could assist in comparing the impact of these power supplies with regard to measurements of the complete amplifier units.

We could power two v3 Monos with two 48V/10A supplies from Aiyima for the reasons/benefits in bold from Fosi, but for much lower cost - if we had the measured performance information relating to the power supplies!

The power supplies cost as much as the amplifiers or more.

For good reason perhaps or not, I'm a 'believer' in the importance of power supplies.
 
Last edited:

wyup

Active Member
Joined
Mar 29, 2018
Messages
199
Likes
76
Location
Bilbao, Spain
Why not use RCA to XLR adaptors instead of RCA input for better performance?
RCA inputs have additional and innecessary gain as well as op-amp 'converter'.
XLR has enough input impedance to drive single-ended voltage.
 

drmevo

Active Member
Joined
Feb 10, 2022
Messages
137
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131
Why not use RCA to XLR adaptors instead of RCA input for better performance?
RCA inputs have additional and innecessary gain as well as op-amp 'converter'.
XLR has enough input impedance to drive single-ended voltage.
I was wondering this too but it seemed so obvious I figured I was missing something.
 

Abstracted

Member
Joined
Feb 14, 2024
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22
Anyone willing to bet we're NOT going to hit the $300K mark by the deadline?
 

hello_again

New Member
Joined
Apr 24, 2024
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1
Likely won't hit the $300k mark, but if they can pull another $25k in organic sales, the you just need to convince about 900 backers to add (1) Muse02 add on and your right at the $300k threshold... so I'm saying there's a chance. What's strange to me is there seems to be little participation from Japan or Korea. Would have figured there would be more interest, maybe Fosi needs to send some Asian influencers demo units.
 

Negatywny

Member
Joined
Jul 2, 2019
Messages
58
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77
Location
warsaw
what? We're at almost 85% to final goal of the campaign, and there's still 90% of the time left. So i'd say it shouldn't be a problem? I assume that there is more press/media coverage/attention coming in whole next month, and news in style of "spectacular success of kickstarter audio campaign, audiofile holy grail for normies, check it out, thers still time for you to pledge and be a part of history" ;).
 
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