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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 19.7%
  • 4. Great (golfing panther)

    Votes: 387 76.3%

  • Total voters
    507

staticV3

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So you assume it would be an audible difference? For the price of the Purif you could by 10+ Fosis
The difference in noise and output power may be audible, depending on your speakers' efficiency and listening distance.

The rest, probably inaudible.
 

Talisman

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So you assume it would be an audible difference? For the price of the Purif you could by 10+ Fosis
The purifi is a state of the art amplifier, with excellent performance in every area, however I doubt you will hear any difference other than power. The noise levels are also low enough to avoid problems even with high efficiency speakers in my opinion.
Clearly I wouldn't replace a purifi with a pair of V3 monos if I already had the purifi. But for those with a more limited budget or for a secondary system, Fosi monoblocks almost certainly provide transparent performance and it doesn't seem fair to me to call them "rubbish" or "landfill stuff" because up to now Fosi products have shown solid construction and There were no noticeable complaints about failures or problems.
 

serak

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Hello everyone,
I plan to purchase these monoblocks as a replacement for my oldschool AV-Receiver onkyo TX-SR700 (from 2002 at original price around 800$). I'm currently running it (in stereo mode) as a temporary replacement for my original power amp (same price range and even slightly older than the onkyo), which has definitely gone to silicon heaven.

Based on the parameters and amirm measurements, it should be a significant improvement for me. Unfortunately, I don't have personal experience with any D-Class amplifier yet. Is there a chance that even with these "cheap" boxes I will really move up in sound quality?
 

Doodski

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Based on the parameters and amirm measurements, it should be a significant improvement for me. Unfortunately, I don't have personal experience with any D-Class amplifier yet. Is there a chance that even with these "cheap" boxes I will really move up in sound quality?
You might hear a tiny difference but it in reality it is unlikely. Your Onkyo outputs a decent amount of power but it is not as 2 Ohm stable as the Fosi so you might hear something there but the differences might exceed your ears sensitivity.
 

staticV3

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Is there a chance that even with these "cheap" boxes I will really move up in sound quality?
Unless you have an actual issue with your current Amp, like strong hissing noise, obvious clipping at higher volumes, or an audibly skewed response, no new Amp is likely to move you up in sound quality.

$200 or $2000, Class D or Class A, doesn't matter.

The biggest improvements always come from buying new speakers, improving room acoustics, or adding DSP.
DACs and Amps are secondary.
 

Lednek

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Hello everyone,
I plan to purchase these monoblocks as a replacement for my oldschool AV-Receiver onkyo TX-SR700 (from 2002 at original price around 800$). I'm currently running it (in stereo mode) as a temporary replacement for my original power amp (same price range and even slightly older than the onkyo), which has definitely gone to silicon heaven.

Based on the parameters and amirm measurements, it should be a significant improvement for me. Unfortunately, I don't have personal experience with any D-Class amplifier yet. Is there a chance that even with these "cheap" boxes I will really move up in sound quality?
I think so! I am currently using a $200 SMSL AO200 for my 2 channel setup. If I remember correctly it rated at an honest 7owpc into 8 ohms. It sounds significantly better than my $1200 Dennon avr 3400x with a fluffed 100wpc channel rating. That being said, the fosi measures much better, with much more power.
 

Sokel

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Hello everyone,
I plan to purchase these monoblocks as a replacement for my oldschool AV-Receiver onkyo TX-SR700 (from 2002 at original price around 800$). I'm currently running it (in stereo mode) as a temporary replacement for my original power amp (same price range and even slightly older than the onkyo), which has definitely gone to silicon heaven.

Based on the parameters and amirm measurements, it should be a significant improvement for me. Unfortunately, I don't have personal experience with any D-Class amplifier yet. Is there a chance that even with these "cheap" boxes I will really move up in sound quality?
I would care more about the protections involved than anything else.
What happens if they decide to let the smoke out?What happens with hard clipping,or DC events,etc.
Cause nice speakers going off is a hard pill to swallow,amps is the immediate link to them.
 

serak

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I would care more about the protections involved than anything else.
What happens if they decide to let the smoke out?What happens with hard clipping,or DC events,etc.
Cause nice speakers going off is a hard pill to swallow,amps is the immediate link to them.

These are, of course, questions that I would very much like to know the answers to. (I suppose not only me.)
It is a pity that amirm does not include clipping behavior and basic protections in its tests.

Maybe someone from Fosi audio will comment on this.
 

Doodski

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It is a pity that amirm does not include clipping behavior and basic protections in its tests.
@amirm power draw/voltage and current draw metering would be very cool too. We could glean a lot of information from those measurements.
 

mike70

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Unless you have an actual issue with your current Amp, like strong hissing noise, obvious clipping at higher volumes, or an audibly skewed response, no new Amp is likely to move you up in sound quality.

$200 or $2000, Class D or Class A, doesn't matter.

The biggest improvements always come from buying new speakers, improving room acoustics, or adding DSP.
DACs and Amps are secondary.

That's the real thing :)
 

amix

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According to Fosi: No advantage. The 48V5A supply is enough to saturate the Amp.
Fosi Audio says this in their Kickstart FAQ:

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.
 

Jim Taylor

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It is a pity that amirm does not include clipping behavior and basic protections in its tests.

Amir is testing equipment that belongs to other people. I seriously doubt that the owners of these amps would appreciate it if their property was damaged or destroyed.

Testing can proceed, if necessary, to destruction. However, that's not the purpose of this site.

Jim
 

Kimbrough Xu

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Search interface in Audio Electronics here: https://www.audiosciencereview.com/forum/index.php?pages/Reviews/

Not much different than using active studio monitors with audio interface.

Is there any multichannel movie audio processor preamp people use with monoblocks?
What is a multichannel movie audio processor preamp?

A processor like Emotiva BasX MC1 https://emotiva.com/collections/processors/products/basx-mc1-13-2-channel-dolby-atmos-dts-x-cinema-processor?
 

Rob_in

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Or... you could install a nice volume pot inside Fosi monoblocks.... if you know a bit about electronics. Even a 6-stepper attenuator will do nicely in preventing fully blasting the speakers by accident. Of course, you'd lose the warranty...
For an amplifier with such a huge amount of power on tap I think some kind of attenuation (even stepped as mentioned) would be useful.

For example, I have a pair of Q Acoustics Concept 20. 88dB, 4-6ohm, 75W max recommended power. Currently these are driven by an SMSL AO200 (original, not Mkii). Source is an SMSL DO100 which I use as a pre-amp (selecting source/volume) - I never touch the volume on the AO200 which is set at around 45 (out of 70) and is plenty loud for my tastes. For a 'budget' system I'm pretty happy with this.

From what I read here a pair of these Fosi V3 Mono amps would (should?) be an upgrade on the AO200, and at a similar cost. And with the option to be able to drive just about any speaker one cared to upgrade to in the future? Great, right?

However, I imagine that with no attenuation in the V3 the pre-amp would rarely get above 20-30% (on it's 0-99% scale) so surely this would loose a load of dynamic range in the signal from the pre-amp? I guess someone might argue that using a DO100 in 0-30% versus 0-100% isn't going to be audible? But still, there would be a loss of granularity in the volume control (and the chance of damaging speakers if one slipped on the volume) at the very least?

Another point is that from what I can tell (and please excuse this simplification) Class D amps are not at their best anywhere close to their rated output power so wouldn't it make sense to provide some what to limit the amp to it's sweet spot when the maximum power is not required. Yes, I know, you're going to say, "Sure - it's called a pre-amp" ;)

Final point is, I guess if one is worried about their speakers being overpowered with the 48V/5A (per channel) PSU they could downgrade to a 32V, but imagine most people here would say that is a very silly idea?

... or please correct me if I've misunderstood something here.
 

serak

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Amir is testing equipment that belongs to other people. I seriously doubt that the owners of these amps would appreciate it if their property was damaged or destroyed.

Testing can proceed, if necessary, to destruction. However, that's not the purpose of this site.

Jim
I would say that torturing the amp into a two ohm load will be a significantly greater risk to the amp than clipping or DC protection testing.
Of course, borrowed samples from private users should be treated with more caution than pre-sale samples provided by the manufacturer itself :)
 

Paffi

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The purifi is a state of the art amplifier, with excellent performance in every area, however I doubt you will hear any difference other than power. The noise levels are also low enough to avoid problems even with high efficiency speakers in my opinion.
Clearly I wouldn't replace a purifi with a pair of V3 monos if I already had the purifi. But for those with a more limited budget or for a secondary system, Fosi monoblocks almost certainly provide transparent performance and it doesn't seem fair to me to call them "rubbish" or "landfill stuff" because up to now Fosi products have shown solid construction and There were no noticeable complaints about failures or problems.
That´s the point - sure, Purifi is measurable better. But if it´s only better on paper but not audible better, it makes no sense for me, to pay the premium for being better on paper. Sure there will be a significant loss, when selling my apollon, but in the end there will be still a solid amount of cash left.
 

Cal_Cobra

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Guys, this is throw away stuff. I know that irritates many people. I've been apart of the PA5 debacle with 3 units and Topping didn't miss a beat. Keep on producing and minimize the problems. These companies seem to have found the market is resilient to possible reliability problems as long as top performance, cheap gear gets released quickly. I'm ok with it. I was really upset when I had $2500 worth of broken NAD gear. I was only annoyed with a $350 Topping amp. I won't blink an eye is a Fosi V3 mono takes a dump and I'll buy the next equivalent thing.
Totally agree. Plus with these bargain basement prices, we have the opportunity to try far more products. That's a win-win scenario in my book.
 

rgruber

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I schlepped my $1000 Rotel receiver from Brooklyn to Stereo Exchange in Manhattan several times as one channel kept blowing till finally it was replaced with a new unit.

Let's not pretend that big name companies and high dollar A/B components didn't also fail. And they were much heavier to carry/ship.

That and the fact that my first Class D amp blew the Rotel out of the water sound wise.

Totally agree. Plus with these bargain basement prices, we have the opportunity to try far more products. That's a win-win scenario in my book.
 
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