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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

ppdl3

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Hello there. Newbie here (this is my first post). Firstly, thank you so much to this amazing community; I've learned so much! I am, of course, still learning, so that's why I'm reaching out now. I've read all 84 pages of this thread and and still have two questions regarding this amp (one I think useful to the whole community and one that is selfish--please feel free to disregard the selfish one). So, if you have the chance to explain, I'd greatly appreciate it.

1. I've read enough about the difference in power supplies, but I'm still unclear: What would be the benefit of two 48v 10a over two 48v 5a power supplies? The price difference is significant enough to call this into question for me (as one person here explained it: it's enough to hurt the value proposition a bit).

2. (Selfish question). Prior to learning from this community, at the beginning of my audiophile journey I purchased a Musical Fidelity m2Si (fortunately used and for a great deal). Unfortunately, it hasn't been too well reviewed here. The gist is that the preamp is good, the power amp is not. So... would I be well served adding these mono blocks in an effort to better drive my Focal 615 towers? There is a sub question here that is perhaps philosophical: Should I instead invest in something different altogether? This is my main system, so I'm willing to invest, but I am a teacher and this is one of many hobbies, so I can't go too crazy spending several thousand. Many mention this as not something that will replace higher end gear, or wouldn't even be part of a main system. Well, why not? If the measurements are good, are there things not captured in the measurements selected that should mean going to class a/b or to a higher end class d like Apollon?

Thanks in advance!
 

Doodski

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1. I've read enough about the difference in power supplies, but I'm still unclear: What would be the benefit of two 48v 10a over two 48v 5a power supplies? The price difference is significant enough to call this into question for me (as one person here explained it: it's enough to hurt the value proposition a bit).
I will try to simplify while remaining accurate to the processes.

With one power supply:
As power is delivered to the speaker there are peaks in the power amp output and those cause the amp power supply to be depleted/drained of electrons and that can cause sound quality issues.

With 2 power supplies:
Higher speaker dynamic headroom is available due to there being more electron storage/drive in the power supply(s). As one channel draws more electrons the other is independent and not affected by the other channel.

If you would like a more technical explanation just ask and I'll elaborate on the subject. :D
 
Last edited:

staticV3

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What would be the benefit of two 48v 10a over two 48v 5a power supplies?
According to Fosi: No advantage. The 48V5A supply is enough to saturate the Amp.

We're still waiting for 3rd party testing to confirm this.

would I be well served adding these mono blocks in an effort to better drive my Focal 615 towers?
Only if you currently have some sort of issue, driving your Focals with the m2si. Something like too little power, or audible hiss at your MLP.

There is a sub question here that is perhaps philosophical: Should I instead invest in something different altogether?
The greatest return in sound quality you'll typically see with new speakers, room correction, or room treatment.
Electronics are secondary.
 

JeremyFife

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Hello there. Newbie here (this is my first post). Firstly, thank you so much to this amazing community; I've learned so much! I am, of course, still learning, so that's why I'm reaching out now. I've read all 84 pages of this thread and and still have two questions regarding this amp (one I think useful to the whole community and one that is selfish--please feel free to disregard the selfish one). So, if you have the chance to explain, I'd greatly appreciate it.

1. I've read enough about the difference in power supplies, but I'm still unclear: What would be the benefit of two 48v 10a over two 48v 5a power supplies? The price difference is significant enough to call this into question for me (as one person here explained it: it's enough to hurt the value proposition a bit).

2. (Selfish question). Prior to learning from this community, at the beginning of my audiophile journey I purchased a Musical Fidelity m2Si (fortunately used and for a great deal). Unfortunately, it hasn't been too well reviewed here. The gist is that the preamp is good, the power amp is not. So... would I be well served adding these mono blocks in an effort to better drive my Focal 615 towers? There is a sub question here that is perhaps philosophical: Should I instead invest in something different altogether? This is my main system, so I'm willing to invest, but I am a teacher and this is one of many hobbies, so I can't go too crazy spending several thousand. Many mention this as not something that will replace higher end gear, or wouldn't even be part of a main system. Well, why not? If the measurements are good, are there things not captured in the measurements selected that should mean going to class a/b or to a higher end class d like Apollon?

Thanks in advance!
Hi, and welcome :)

Just a thought on your second question - your Amp. The measurements weren't all bad, apart from clipping behaviour. If you don't hear unpleasant noises, and your amp isn't shutting down then it's probably not affecting your system. Don't worry about it.

If budget is limited (always is!) then perhaps invest in a measurement microphone and start understanding how your system is behaving in your room. That's a great platform to make changes from.

Changing the power amp won't improve your sound
 

edgar-bcn

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Newbie here, hello everyone!

I need something to drive my LCR speakers, at first I was looking for 3-channels power amps like the Emotiva BasX A3.

How this compares with others budget AB amplifiers?

Thanks!
 

AdamG

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druskys

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I’ve been reading a lot (focused mostly on trying to figure out Sinad/distortion/etc.) and feel like I’ve gotten nowhere… so, I’m just going to accept I need to ask and see if someone here can explain.

I’m strongly considering the wiim ultra (over 120 sinad per company specs) paired with the Fosi monoblocks (over 100 sinad with xlr but mid 90s with rca).

1. If RCA is used (wiim doesn’t have xlr), SINAD is such that the amp is no longer in the excellent category, right?
2. In general, what is the point of having a DAC with 120+ SINAD score if amps reviewed here aren’t getting that high? Seems like you’ll always be at the mercy of the amp sinad?
3. If I use the wiim ultra, am I losing that sought after SINAD score as soon as it hits the Fosi monoblocks via rca?

I realize after reading that sinad is more complicated than just a number and actually takes into account a couple of things. That being said, I was really excited for the above pairing until I realized how far different the SINAD scores were. Seems like I should just wait for the wiim amp pro to come out (claiming 120 SINAD).

Also, sorry for the novice questions. I’ve been trying to do my due diligence, but am not getting good answers. Thanks!
 

Sokel

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I’ve been reading a lot (focused mostly on trying to figure out Sinad/distortion/etc.) and feel like I’ve gotten nowhere… so, I’m just going to accept I need to ask and see if someone here can explain.

I’m strongly considering the wiim ultra (over 120 sinad per company specs) paired with the Fosi monoblocks (over 100 sinad with xlr but mid 90s with rca).

1. If RCA is used (wiim doesn’t have xlr), SINAD is such that the amp is no longer in the excellent category, right?
2. In general, what is the point of having a DAC with 120+ SINAD score if amps reviewed here aren’t getting that high? Seems like you’ll always be at the mercy of the amp sinad?
3. If I use the wiim ultra, am I losing that sought after SINAD score as soon as it hits the Fosi monoblocks via rca?

I realize after reading that sinad is more complicated than just a number and actually takes into account a couple of things. That being said, I was really excited for the above pairing until I realized how far different the SINAD scores were. Seems like I should just wait for the wiim amp pro to come out (claiming 120 SINAD).

Also, sorry for the novice questions. I’ve been trying to do my due diligence, but am not getting good answers. Thanks!
I'll puzzle you a little more by pointing out that if the SINAD is your aim the numbers you read are usually for the full output of the DACs and for a specific frequency (that's for all).
I would urge you to study the Power vs Distortion charts (all of them,for amps) and the IMD vs level and THD+N Ratio vs Frequency for DACs,for starters.
 

druskys

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I'll puzzle you a little more by pointing out that if the SINAD is your aim the numbers you read are usually for the full output of the DACs and for a specific frequency (that's for all).
I would urge you to study the Power vs Distortion charts (all of them,for amps) and the IMD vs level and THD+N Ratio vs Frequency for DACs,for starters.
Haha thanks. I watched Amir’s videos yesterday on the subjects and have been doing some reading. There’s probably a reason I didn’t become an engineer :)

Most important to me: will it be completely out of the audible range whether or not I use rca or xlr with the Fosi? In that case, I don’t care and will go for that setup as it is easy/cheaper than other options I’m considering…

If it matters, my setup is a pair of bmr monitors from philharmonic audio and a rhythmic l12 sub.
 

antcollinet

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Most important to me: will it be completely out of the audible range whether or not I use rca or xlr with the Fosi? In that case, I don’t care and will go for that setup as it is easy/cheaper than other options I’m considering…

Yes - with one proviso. The main point of XLR is noise immunity - particularly ground loop noise (a system, not a component problem, related to how all the components are grounded and interconnected)

As long as you don't have a noise problem, then yes, the difference will be out of the audible range.
 

Kimbrough Xu

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Any idea what the longevity of the Fosi Audio V3 Mono amp should be compared to Hypex or Purifi amps? I have always stayed away from external power supplies in the past as they typically have been the weakest link in my experience.
They have 24 months warranty, so the longevity can be at least 24 months.
 

iLoveCats

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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.
 

Snoopy

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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.

Yeah let’s keep adding stuff to the landfills with more and more throwaway stuff. :)
 

Paffi

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Seeing this brings the idea of selling my Apollon Purifi 1ET400 and buy a bunch of these instead into my head o_O
 

amper42

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That would be a trade from quality to trash. Downgrade in performance and longevity not to mention the Purifi runs much cooler.
 
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