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Fosi Audio V3 Mono Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 13 2.0%
  • 2. Not terrible (postman panther)

    Votes: 21 3.2%
  • 3. Fine (happy panther)

    Votes: 128 19.3%
  • 4. Great (golfing panther)

    Votes: 501 75.6%

  • Total voters
    663
I have been listening to the V3 monos and ZD3 for a few weeks now. I think I am ready to move on. They are great for the price, but I like the Topping B100 monos (and the E70 Velvet) better.
 
I have been listening to the V3 monos and ZD3 for a few weeks now. I think I am ready to move on. They are great for the price, but I like the Topping B100 monos (and the E70 Velvet) better.
I'm using V3 Monos to drive a pair of ESS Heil AMT "Large" tweeters above 2000Hz, and contemplating Topping B100s instead. Looking forward to comparisons. I know ti measures quieter and cleaner, but audibly so? (I'm guessing not.)
 
No pop for me, but an individual V3 mono is significantly hotter than a ZA3 in stereo. Both with XLR and 48V/5A power supply from Fosi

V3 mono also a bit quieter than the ZA3 in identical setup (other than ZA3 being used in stereo)

Edit: just measured with my infrared thermometer, the top is at 53c when completely idle. The ZA3 at least had to be doing something to get a little warm. Concerning?
All other factors remaining constant, higher temperatures lead to a reduced lifespan for electronic components, particularly capacitors.

A temperature of 53 °C feels noticeably hot.

For metal surfaces on household appliances, 55 °C is the maximum permissible temperature for short-term skin contact (1–3 seconds).
 
With the price of the Fosis though, I’m not sure that reliability matters as much. If one blows, you’re not having to ship a heavy amp for repairs and be without for weeks/months. You could literally get a same day replacement from Amazon for the price of shipping a bigger amp, then look into warranty options for the dead one.

Given that amps are generally the least reliable component (thanks to high currents and other stresses), I think easy replacement is a big advantage.
 
With the price of the Fosis though, I’m not sure that reliability matters as much. If one blows, you’re not having to ship a heavy amp for repairs and be without for weeks/months. You could literally get a same day replacement from Amazon for the price of shipping a bigger amp, then look into warranty options for the dead one.

I understand, but I don't agree with the mindset.
Futile, I know.
 
I get it. I also like to buy-for-life where possible. That doesn’t really seem like an option with amps though? At minimum you’ll need a recap every 5-10 years, and you’d be lucky to get that done professionally for less than the price of replacement V3s.

When the measurements are great, and the costs are so low, it’s hard to justify the old approach (I say having recently switched out some old beloved amps for Fosi V3s).
 
I have been listening to the V3 monos and ZD3 for a few weeks now. I think I am ready to move on. They are great for the price, but I like the Topping B100 monos (and the E70 Velvet) better.

If you try a blind test, maybe you can find other result.
I mean, you have all the right to think the B100's better and it's ok (is what you "perceive") ... but ... it's a totally subjective opinion and maybe opposite to the truth.
That's all.
 
I am wondering if this amp (or looking for other suggestions) would be a good addition to my setup.

I currently use a Denon AVR but it can only power 9 channels and so it is running 7.2.2 but I am looking for a separate amp to get to the 7.2.4 setup that I want.

I initially was thinking of getting a cheap amp for my atmos speakers but now I am thinking why not buy an amp for the L+R channels (and use the AVR pre-outs) as that would free up a lot of the power on the AVR and probably sound better for the main speakers as well.

Anyway, I have been looking for cheap amps that would be an improvement over the Denon AVR and thought this might fit the bill.

I listen to music and home theater content 50:50
My speakers are DIYSG HTM 12v2 (sensitivity 91
I listen at 2m distance.

I have been looking into the 3e Audio A5/7 and the Fosi V3 Mono but wondering if people think those would work for me and if they thought one would be better than the other or if there are other amplifiers that I should consider.

Thanks for any suggestions!
 
I am wondering if this amp (or looking for other suggestions) would be a good addition to my setup.

I currently use a Denon AVR but it can only power 9 channels and so it is running 7.2.2 but I am looking for a separate amp to get to the 7.2.4 setup that I want.

I initially was thinking of getting a cheap amp for my atmos speakers but now I am thinking why not buy an amp for the L+R channels (and use the AVR pre-outs) as that would free up a lot of the power on the AVR and probably sound better for the main speakers as well.

Anyway, I have been looking for cheap amps that would be an improvement over the Denon AVR and thought this might fit the bill.

I listen to music and home theater content 50:50
My speakers are DIYSG HTM 12v2 (sensitivity 91
I listen at 2m distance.

I have been looking into the 3e Audio A5/7 and the Fosi V3 Mono but wondering if people think those would work for me and if they thought one would be better than the other or if there are other amplifiers that I should consider.

Thanks for any suggestions!
In your shoes, I'd be looking at exactly those amp.

I don't think there will be anything to choose between them sonically though.
 
I initially was thinking of getting a cheap amp for my atmos speakers but now I am thinking why not buy an amp for the L+R channels (and use the AVR pre-outs) as that would free up a lot of the power on the AVR and probably sound better for the main speakers as well.
I did exactly that... and then upgraded my centre and surround speakers to 4Ω models that my AVR couldn't handle, so I ended up with 7 Fosi V3 Mono channels. It's been great! The auto-sensing feature is particularly nice. Here they are in a 3D-printed stand:
IMG_5915.jpeg
 
I did exactly that... and then upgraded my centre and surround speakers to 4Ω models that my AVR couldn't handle, so I ended up with 7 Fosi V3 Mono channels. It's been great! The auto-sensing feature is particularly nice. Here they are in a 3D-printed stand:View attachment 422193
This looks awesome and I think I will end up copying this.

What are the thermals like for this setup?
 
The temps are fine; there’s a space below the Fosis for air to flow in, but no fan. They don’t get noticeably hotter than many other things.
 
I guess I am wondering if class a/b rated at 60 watts per channel is cleaner than class D at 100+ watts per channel especially at extreme volumes both soft and loud. The reviews seem to suggest listening at loud volume causes distortion above 85 db. Or is this a stupid question?
I think you would find any of these Stereo Digital Amplfiers would be more than adequate to fill you room with sound at all volumes and certainly better than most average AB Amplifiers of 60 watts. We have used Aiyima A04, A07 and D03 and Fosi amplfiers with great success with a range of bookshelf or at least smaller speakers from KEF, Mission and others. I have also used them with EV ZX1 PA Speakers also with no complaints at really high volumes for events.

I have just purchased a Stereo Fosi V3 to add to my amplifier collection and with probably purchase a 3e Audio A5 or A7 soon.
 
I am wondering if class a/b rated at 60 watts per channel is cleaner than class D at 100+ watts per channel especially at extreme volumes both soft and loud.
The class is not a determination of being cleaner. It is the implementation of the design that matters and so one cannot just say this class is better than that class for cleanness of output. Both class AB and class D can be done poorly or very well. So it is a case by case basis. There is more to the sound quality than the cleanness of output as you say.
 
I did exactly that... and then upgraded my centre and surround speakers to 4Ω models that my AVR couldn't handle, so I ended up with 7 Fosi V3 Mono channels. It's been great! The auto-sensing feature is particularly nice. Here they are in a 3D-printed stand:View attachment 422193
Cool. Have you shared the 3D printed stand design on Thingiverse or elsewhere?
 
Would you guys recommend a V3 Stereo or 2x V3 Mono’s for my setup? I have a Wiim Ultra as source which would go into a V3 Stereo or 2x V3 Mono’s which would power my Elipson XLS 15 passive speakers. Speakers are rated 200W @ 6ohm 92db sensitivity (dropping down to 3.2ohm). From the measurements I’ve seen, both the Mono and Stereo output around the same power per channel, so not entirely sure what the benefits of running 2x Mono’s would be over a Stereo, other than better channel separation
 
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Would you guys recommend a V3 Stereo or 2x V3 Mono’s for my setup? I have a Wiim Ultra as source which would go into a V3 Stereo or 2x V3 Mono’s which would power my Elipson XLS 15 passive speakers. Speakers are rated 200W @ 6ohm 92db sensitivity (dropping down to 3.2ohm). From the measurements I’ve seen, both the Mono and Stereo output around the same power per channel, so not entirely sure what the benefits of running 2x Mono’s would be over a Stereo, other than better channel separation
The original stereo V3 gets a SINAD of only 88 whereas V3 Mono hits 100. Also, the V3 Mono’s PFFB implementation means that it is fully flat across the audible frequency spectrum, whereas the original V3’s lack of PFFB results in load-dependent frequency response in the ultra high frequency range.

-Ed
 
Would you guys recommend a V3 Stereo or 2x V3 Mono’s for my setup? I have a Wiim Ultra as source which would go into a V3 Stereo or 2x V3 Mono’s which would power my Elipson XLS 15 passive speakers. Speakers are rated 200W @ 6ohm 92db sensitivity (dropping down to 3.2ohm). From the measurements I’ve seen, both the Mono and Stereo output around the same power per channel, so not entirely sure what the benefits of running 2x Mono’s would be over a Stereo, other than better channel separation

I'd be going mono.

It has max power of 243 compared with 161 of the stereo (into 4 ohms - your speakers are 6 dipping to 5 so will have some of this benefit), and has oodles of current capability to drive dips in the impedance characteristic of any speaker.

More importantly it has post filter feed back which essentially eliminates the load dependency of the v3 stereo.
 
The original stereo V3 gets a SINAD of only 88 whereas V3 Mono hits 100. Also, the V3 Mono’s PFFB implementation means that it is fully flat across the audible frequency spectrum, whereas the original V3’s lack of PFFB results in load-dependent frequency response in the ultra high frequency range.

-Ed
I'd be going mono.

It has max power of 243 compared with 161 of the stereo (into 4 ohms - your speakers are 6 dipping to 5 so will have some of this benefit), and has oodles of current capability to drive dips in the impedance characteristic of any speaker.

More importantly it has post filter feed back which essentially eliminates the load dependency of the v3 stereo.
Thanks guys, V3 Mono it is!

Would it be worthwhile getting 2x 48V/10A power supplies, or would the 5A suffice?
 
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