Fosi Audio V3 Mono Amplifier Review

[antcollinet]

I don't have one, but the holes seem quite big in the picture. I wonder if dust could become an issue.

I'd be more concerned with metallic objects getting into the amp and killing it.


A great way to replace a non problem (amp temperature) with a real problem (broken amp)

 

[DavidM1]

Any ideas about this thing? It arrived with my V3 monos.

 

[DavidM1]

My V3s have also arrived
But they get very hot and I wonder when hot is too hot....

I have now ordered an infrared thermometer.

Edit:
Do they perhaps get so hot because I use 10A power supply units? Is it better to use a splitter cable and only one power supply?

I really wouldn't worry. Amps give off heat, it's one of their charms. Fosi has posted a video on the V3 monos and they point out that the entire case is a heat sink and it's going to be warm to touch. Not a problem and a good sized heat sink is a wonderful thing.

 

[GDK]

I really wouldn't worry. Amps give off heat, it's one of their charms.

I agree. I think the simplest fix for this perceived heat issue is for people to stop touching their amps.

 

[Bleib]

Ok. Got this information/ confirmation through Fosi
"Hello There,
Our R&D team has confirmed that the V3 MONO is a single-channel unit without positive and negative phases. Its circuit design differs from conventional designs: it operates positively when paired with another V3 MONO. When one V3 MONO paired with other models, it may result in a reverse phase. In such cases, simply swap the positive and negative output lines of the V3 MONO. This unique product design aims to achieve superior performance parameters."

 

[Sokel]

Any ideas about this thing? It arrived with my V3 monos.View attachment 382672

Someone in the factory must be searching for it's screwdriver now

Ok. Got this information/ confirmation through Fosi
"Hello There,
Our R&D team has confirmed that the V3 MONO is a single-channel unit without positive and negative phases. Its circuit design differs from conventional designs: it operates positively when paired with another V3 MONO. When one V3 MONO paired with other models, it may result in a reverse phase. In such cases, simply swap the positive and negative output lines of the V3 MONO. This unique product design aims to achieve superior performance parameters."

²

 

[Bleib]

Someone in the factory must be searching for it's screwdriver now


²

Yeah, well, it's still PR talk

 

[jvdburgt]

Yeah, well, it's still PR talk

Actually, that's one of the perks unlocked as part of the KS campaign

 

[Borland]

I agree. I think the simplest fix for this perceived heat issue is for people to stop touching their amps.

Yes, you can do it like that ...
But Fosi talks about (I think) 33 degrees in the video.
Mine are getting hotter, but I haven't been able to measure it yet because the thermometer hasn't been delivered yet.

What happens when they reach 60 degrees (Celsius )?
Just don't touch them and don't think about it?

 

[antcollinet]

Ok. Got this information/ confirmation through Fosi
"Hello There,
Our R&D team has confirmed that the V3 MONO is a single-channel unit without positive and negative phases. Its circuit design differs from conventional designs: it operates positively when paired with another V3 MONO. When one V3 MONO paired with other models, it may result in a reverse phase. In such cases, simply swap the positive and negative output lines of the V3 MONO. This unique product design aims to achieve superior performance parameters."

Well that is a bunch of nonsense, other than confirming the phase inversion, but without the specific information confirming RCA, XLR, or both.

Specifically, phase inversion has nothing to do with:

This unique product design aims to achieve superior performance parameters."

Which I'm assuming to be about the PFFB.

@Fosi Audio please can you get some valid and accurate technical information into this topic, and leave out the marketing spin. It doesn't wash here.

Thanks.

 

[gelo_mc]

Well that is a bunch of nonsense, other than confirming the phase inversion, but without the specific information confirming RCA, XLR, or both.

Specifically, phase inversion has nothing to do with:


Which I'm assuming to be about the PFFB.

@Fosi Audio please can you get some valid and accurate technical information into this topic, and leave out the marketing spin. It doesn't wash here.

Thanks.

This should be stated in the technical specification online and in the paper included in the box.

 

[somebodyelse]

This should be stated in the technical specification online and in the paper included in the box.

I agree it would be a good thing to see in specs, but I don't remember ever seeing it from any manufacturer. From time to time a manufacturer will make a point of preserving absolute phase in marketing material, but that's the exception rather than the rule.

 

[Petrushka]

I agree it would be a good thing to see in specs, but I don't remember ever seeing it from any manufacturer. From time to time a manufacturer will make a point of preserving absolute phase in marketing material, but that's the exception rather than the rule.

Just speculating, but most amps are stereo, and you expect the two channels to match. I remember years ago, talk about absolute phase and thinking it was BS.

It never occurred to me until recently that absolute phase would be an issue.

 

[gelo_mc]

Just speculating, but most amps are stereo, and you expect the two channels to match. I remember years ago, talk about absolute phase and thinking it was BS.

It never occurred to me until recently that absolute phase would be an issue.

most likely because they are monoblocks and part of the usecase is to extend power in home theatre setup or just stereo with sub.

 

[Sokel]

most likely because they are monoblocks and part of the usecase is to extend power in home theatre setup or just stereo with sub.

Lets put it simple.
If we,for example,have 3 fosi monos of which the 2 of them use the XLR input and one of them uses the RCA input,the later will be in inverted phase relatively to the other two.

See,they don't even mix even if no other amp is involved.

 

[gelo_mc]

If they are non inverting it should be easy to integrate.

Let say you have an existing 5.1 receiver from reputable manufacturer. It will be safe to assume all output are in phase otherwise the room correction software would have complained.

if you want to use the same setup for music but looking for more power and cleaner amp then you can use another amp

 

[gwing]

Lets put it simple.
If we,for example,have 3 fosi monos of which the 2 of them use the XLR input and one of them uses the RCA input,the later will be in inverted phase relatively to the other two.

See,they don't even mix even if no other amp is involved.

Unless of course your XLR source and RCA sources are themselves in different phase. Then the Fosis would sort it all out for you rather than being a problem, the world isn't in a completely nice and tidy state so you have to look at the whole audio chain

It would be helpful to have a phase inversion switch for the RCA inputs though, or even an internal mod to match phase between RCA and XLR, especially for folks who might often switch between RCA and XLR inputs if they have multiple sources. Most folks need to either do nothing or just swap speaker connections though.

 

[GDK]

What happens when they reach 60 degrees (Celsius )?

Tell people you have the world’s smallest Class A amps

 

[Bleib]

This should be stated in the technical specification online and in the paper included in the box.

Exactly, people need to know how their amps work.

 

[Sokel]

Unless of course your XLR source and RCA sources are themselves in different phase. Then the Fosis would sort it all out for you rather than being a problem, the world isn't in a completely nice and tidy state so you have to look at the whole audio chain

It would be helpful to have a phase inversion switch for the RCA inputs though, or even an internal mod to match phase between RCA and XLR, especially for folks who might often switch between RCA and XLR inputs if they have multiple sources. Most folks need to either do nothing or just swap speaker connections though.

Not only I check every component and the chain,I measure them also.
And I have yet to meet a source or a pre with a reversed phase (but some gave the choice )

The problem is not what it does with the rest of the chain,the problem is that the same device has reversed phases between it's own inputs and no warning about it.
Going further,when fosi was asked about it they seem to not even know what this is,same as with the el. crossover at the other thread where I had to explain what that is.

Is not exactly giving you confidence.