Fosi Audio V3 Amplifier Review

[TheBatsEar]

2*130 real Watts into 8 hom under 500€

Not sure what the NC252MP module based amps deliver, but it should be somewhere over 100WPC/8R. Audiophonics sells one for less than 500€ i think, a lot less if you have less than 19% VAT.

 

[LeeRoy]

Not sure what the NC252MP module based amps deliver, but it should be somewhere over 100WPC/8R. Audiophonics sells one for less than 500€ i think, a lot less if you have less than 19% VAT.

You are right but here in France, you have it for 499€. Once again, pimping the V3 was fun and I hope now it will work a long way. For sureNC252MP is a simpler (ergonomy) and probably even better measuring alternative. Then, those Sparkos op amp are shining, not sure they are in the NC252.

 

[TheBatsEar]

It's safe to say the Sparkos op amps measure better than regular op amps, but i wonder how much of that can be measured at the other side of the power amp chip.
I hope someone lends his Modules to someone with measurement equipment.

@LeeRoy Would you send your opamps with or without amp to someone for measurement? For example this guy in France:
@VintageFlanker Would you be able to measure them in a meaningful way?

 

[LeeRoy]

It's safe to say the Sparkos op amps measure better than regular op amps, but i wonder how much of that can be measured at the other side of the power amp chip.
I hope someone lends his Modules to someone with measurement equipment.

@LeeRoy Would you send your opamps with or without amp to someone for measurement? For example this guy in France:
@VintageFlanker Would you be able to measure them in a meaningful way?

Hi TheBatsEar, sorry but I am just begining enjoying my new set up so I am not very enthousiast about sending these pricey op amps for measuring. Post office may be a poker run and I don't want to pay insurance for the send.

 

[dr_mick51]

It's not the title that determines how much one knows... I don't judge people who don't know, but I detest those who drag their education as justification for their qualification.



For a given physical object, there is linear relationship between those. It's call heat capacity...



Where did I suggest that?! You are changing assumptions only to prove your point...

The temperature of the heatsink will decrease, because on the microscopic level the air it interferes is on average colder... Looking on the whole system, by adding fan you are effectively increase the thermal conductivity of the cooling system. If the ambient temperature stays constant and the power to be dissipated is constant, the temperature of the heat source decreases.

That's exactly why we use fans on the radiators - to reduce the temperature of the heat source, exp. CPU.



Just heat it up before removal... What's more, it is twisting that is the safest way to remove CPU heatsink.

You said:
The temperature of element giving away the heat is always higher the better heat conductivity is.

Basically you are saying that a better heatsink will get hotter than a small heatsink. And I won't go deeper that that.

I knew this post will get me in trouble.

What is wrong with being a Mechanical Engineer?. That just proves that I know what I'm talking about. Or at least I studied in it College and passed the subject. Sorry if that offended you.


Back to the point. I'm still not sure if "I" need to apply that extra thermal paste between heatsink and enclosure as I did between chip and heatsink. Due to my low power draw on my particular case. Of course the higher the power consumption the more visible the benefit from better conductivity(thermalpaste).

Some thermalpastes get very sticky or dry (like glue) even after heating up and I'm afraid the case won't be able to be opened. There is no way to twist the heatsink while the pcb is inserted. I think I have valid (non-irational) concerns. And probably the same reason Fosi Audio did not use thermalpaste there.

 

[grogi.giant]

You said:
The temperature of element giving away the heat is always higher the better heat conductivity is.

I implied "all other things being equal". Agreed, it should be more explicit.

Basically you are saying that a better heatsink will get hotter than a small heatsink. And I won't go deeper that that.

I knew this post will get me in trouble.

What is wrong with being a Mechanical Engineer?. That just proves that I know what I'm talking about. Or at least I studied in it College and passed the subject. Sorry if that offended you.

Answer this: are you here to discuss audio and engineering, or assert your superiority? I hope the first... Give your best advice and lay down the knowledge for someone to take it. You don't need to bring the "Mechanical Engineer" to this.

Back to the point. I'm still not sure if "I" need to apply that extra thermal paste between heatsink and enclosure as I did between chip and heatsink. Due to my low power draw on my particular case. Of course the higher the power consumption the more visible the benefit from better conductivity(thermalpaste).

IMHO no, you don't need to. But I also believe one doesn't need to change or upgrade the cooling in this AMP at all.

Some thermalpastes get very sticky or dry (like glue) even after heating up and I'm afraid the case won't be able to be opened. There is no way to twist the heatsink while the pcb is inserted. I think I have valid (non-irational) concerns. And probably the same reason Fosi Audio did not use thermalpaste there.

Then don't do it. Worse thing you will come back and apply it if you find it overheats...

 

[Lux_ury]

I've had good results with the sticky blue pads for lappys.But every computer IT guy knows it's not the size of the cooler it's moving the heat away from it!

 

[PiobGuy]

I've had good results with the sticky blue pads for lappys.But every computer IT guy knows it's not the size of the cooler it's moving the heat away from it!

right on, not the size but the motion!

 

[Ultratek]

I've had good results with the sticky blue pads for lappys.But every computer IT guy knows it's not the size of the cooler it's moving the heat away from it!

They are very good too and do not usually have the sopping or hardening effect.

Thermal Pad - TP-2 ( APT2560 ) | Thermal Compound for All Coolers | ARCTIC

The ARCTIC Thermal Pad ACTPD00002A is a perfect bridger of unevenness for an even cooling surface | Easy to use and safe to handle | Fast processing and delivery | ARCTIC Store

www.arctic.de

 

[boz]

Hi

First post on this forum, a great resource Amir and all.
I got this amp yesterday with the 32V/5A supply. Currently have a Apple TV 4K -> Wiim mini - > SMSL SU-1 -> Aiyima A07 (32V) -> ELAC DBR62
Music I listen to is streaming Apple Music from the Apple TV in lossless, 24bit/48kHz is fine with me and my buddy Nyquist ; ) and my ears are good with even 256kbps alac for most.
The first thing I discovered is that the Fosi V3 is a lot quieter with the dials set in the same position on both amps, for some reason was expecting the V3 to be louder ? Not sure why I thought that though.
Also I don't hear a real difference in terms of audio quality with my ears, about the same I reckon. Same chip I guess, should I be surprised about this, probably not.
Thus due to lower volume than A07, no dedicated power switch, and not much discernible audio difference for my setup am returning it, and will save for something a little better for later on.

 

[fishmorganhammond]

Hi

First post on this forum, a great resource Amir and all.
I got this amp yesterday with the 32V/5A supply. Currently have a Apple TV 4K -> Wiim mini - > SMSL SU-1 -> Aiyima A07 (32V) -> ELAC DBR62
Music I listen to is streaming Apple Music from the Apple TV in lossless, 24bit/48kHz is fine with me and my buddy Nyquist ; ) and my ears are good with even 256kbps alac for most.
The first thing I discovered is that the Fosi V3 is a lot quieter with the dials set in the same position on both amps, for some reason was expecting the V3 to be louder ? Not sure why I thought that though.
Also I don't hear a real difference in terms of audio quality with my ears, about the same I reckon. Same chip I guess, should I be surprised about this, probably not.
Thus due to lower volume than A07, no dedicated power switch,...

The difference in "loudness" at the same volume knob position is due to different volume pot tapers in the A07 and V3. This was done purposely- check the Fosi Audio website for further explanation.

 

[Ultratek]

Hi

First post on this forum, a great resource Amir and all.
I got this amp yesterday with the 32V/5A supply. Currently have a Apple TV 4K -> Wiim mini - > SMSL SU-1 -> Aiyima A07 (32V) -> ELAC DBR62
Music I listen to is streaming Apple Music from the Apple TV in lossless, 24bit/48kHz is fine with me and my buddy Nyquist ; ) and my ears are good with even 256kbps alac for most.
The first thing I discovered is that the Fosi V3 is a lot quieter with the dials set in the same position on both amps, for some reason was expecting the V3 to be louder ? Not sure why I thought that though.
Also I don't hear a real difference in terms of audio quality with my ears, about the same I reckon. Same chip I guess, should I be surprised about this, probably not.
Thus due to lower volume than A07, no dedicated power switch, and not much discernible audio difference for my setup am returning it, and will save for something a little better for later on.

Hello welcome!
In my opinion, you should try it a little more. According to what I have read, this amplifier with a 32v source gets a little happier after 2 or 3 o'clock, then the differences with the Aiyima begin to be felt.

 

[boz]

The difference in "loudness" at the same volume knob position is due to different volume pot tapers in the A07 and V3. This was done purposely- check the Fosi Audio website for further explanation.

Oh yeah, I did not know that! thanks for pointing it out. It makes sense to how I'm hearing it as well, I have never driven any of them to full volume for my room, and so was thinking would it "catch up" if I cranked the V3, but never really tried. Maybe I will reconsider the device and get it back out of the box ; )

 

[boz]

Hello welcome!
In my opinion, you should try it a little more. According to what I have read, this amplifier with a 32v source gets a little happier after 2 or 3 o'clock, then the differences with the Aiyima begin to be felt.

Per my other reply, will now reconsider, did not go that far on the dial, my bad. All you folks making me reconsider, y'all work for Fosi ; )

 

[boz]

One other thing I noticed was that the L/R terminals are swapped, guess I got a mis-labeled or mis-wired unit as well.
On the subject of the volume, it was so low initially thought maybe was a phase issue, so its definitely not subtle difference either. Curious what it will sound like now past 3 o'clock.

 

[Lux_ury]

They are very good too and do not usually have the sopping or hardening effect.

Thermal Pad - TP-2 ( APT2560 ) | Thermal Compound for All Coolers | ARCTIC

The ARCTIC Thermal Pad ACTPD00002A is a perfect bridger of unevenness for an even cooling surface | Easy to use and safe to handle | Fast processing and delivery | ARCTIC Store

www.arctic.de

So true I use this brand which is same.
Some really good liquid paste gives great performance, but short life span. Artic silver is my go to as it does not go hard unless extreme overclocking or was it overcooking?
I can build phase coolers for you if worried about the amount of R&D that Fosi has spent (wink)Emoj as I'm too old to work out how to use them.
Getting interested in the low volume issue as mentioned on Amazon UK rub chin emoj.

 

[dr_mick51]

Hi

First post on this forum, a great resource Amir and all.
I got this amp yesterday with the 32V/5A supply. Currently have a Apple TV 4K -> Wiim mini - > SMSL SU-1 -> Aiyima A07 (32V) -> ELAC DBR62
Music I listen to is streaming Apple Music from the Apple TV in lossless, 24bit/48kHz is fine with me and my buddy Nyquist ; ) and my ears are good with even 256kbps alac for most.
The first thing I discovered is that the Fosi V3 is a lot quieter with the dials set in the same position on both amps, for some reason was expecting the V3 to be louder ? Not sure why I thought that though.
Also I don't hear a real difference in terms of audio quality with my ears, about the same I reckon. Same chip I guess, should I be surprised about this, probably not.
Thus due to lower volume than A07, no dedicated power switch, and not much discernible audio difference for my setup am returning it, and will save for something a little better for later on.

It is because of the Linear vs Logarithmic potentiometer. I also saw Amazon review of people complaining about this.
First you need to understand about input signal voltage, potentiometer position and amplifier gain. When Amir ran the test he had to use an input signal of 0.213V rms and the pot at max position to get 5W (at 4ohms) for the dashboard results for 1kHz test signal. This means a 26.5dB gain or 21.13 times the input voltage.
You need a higher input signal for example 1V rms to get 111.6W 1kHz test tone.
The problem is that music and test tones are not the same. And the input voltage from playing music is way lower than the voltage you get while playing test tones. It is like 10db lower in average. This lowers the total amplifier output voltage 10db. In summary you need higher input voltage 2V or more with music.

 

[Ultratek]

Per my other reply, will now reconsider, did not go that far on the dial, my bad. All you folks making me reconsider, y'all work for Fosi ; )

We just don't want to be the only ones to stick with a V3.
LOL

 

[amirm]

It's safe to say the Sparkos op amps measure better than regular op amps, but i wonder how much of that can be measured at the other side of the power amp chip.

Last time I tested a sparkos opamp in an amplifier, it actually measured worse: https://www.audiosciencereview.com/...-opamp-review-sonic-imagery-vs-sparkos.10325/

Distortion jumped up by 10 dB.

 

[maudio]

I now use the Fosi V3 as a power amp with the pre out of a Musical Fidelity m2si amp as source.
The initial target was increasing by 6db the Signal to noise Ratio against the power amp integrated in the m2si (88dB for the Fosi and 82dB for the m2si, measured by audiosciencereview)

Here are the steps I followed and a kind of review of each step

• First try with the m2si > Fosi V3 alimented by the 48V 5A Fosi PSU : dynamic is not terrible, sounds a bit flat. The m2si alone is better
• Second Try with the m2si > Fosi V3, original op amps replaced by a pair of Sparkos SS3602 (175€ for the pair) alimented by the 48V 5A Fosi PSU >> All is more dynamic, instruments sound natural, sound is cleaner than m2si alone but lacks a bit of bass compared to m2si alone
• Third Try with the m2si > Fosi V3, including Sparkos SS3602 alimented by the audiophonics 48V 7,3A PSU (120€)>> Now we talk, inprovement on all parameters compared to m2si alone. More power : ~130W into 8h instead of the original 72W into 8h of the m2si. Better sound at medium volume (65dB), instruments are more natural (birth of note and also decay), dynamic is good, 3D imaging excellent.

Note on ergonomy : natively, the fosi V3 turns off with the volume knob turned to 0. coupled with the audiophonics PSU, you can leave the volume button of the fosi V3 at the same position (the gain you choose, in my case volume at 3 o'clock) and turn it on and off through the button on the PSU. I read that the native fosi PSU triggered 6W/h even when the Fosi V3 was off, not the case with the audiophonics PSU.

Conclusion : for less than 400€, it is a good improvement upon the m2si alone.
The funny thing is that if Fosi creates a V4 in one year or two, with improvments in parts, the update will cost only the price of the new Fosi part. PSU and Sparkos could still be kept. At the moment, I am totally happy with V3 + Sparkos + 48V 7,3A PSU. Thanks Fosi

That's xactly what i am doin too! Xcept for 32V 10A PSU, also from alco..audiophonics. I thought it should be enough. Is your Fosi getting hot with 48V?
My goal is to get rid of Class A F7 clone during summer, that's why the smaller voltage. Also i will be using the xcellent Topping Preamp90.
Was it hard to deploy the Sparkos?