Fosi Audio V3 Mono Amplifier Review

[Hiten]

I contacted Fosi and they asked me to check my wiring and the RCA input so I did a few mores tests (My RCA and XLR inputs have the same phase and polarity) and sent them some measurement data

Can you share the measurement data ?
Thanks.

 

[Miley_B]

Can you share the measurement data ?
Thanks.

Edited to clarify that this is whole system phase response not the amplifiers in isolation.... just incase anyone couldn't tell!

 

[iLoveCats]

Fosi said in a Facebook post in one of the groups that both RCA and XLR are inverted.

 

[Sokel]

Fosi said in a Facebook post in one of the groups that both RCA and XLR are inverted.

If that's the case it's only a small mess and easy to fix,just reversing the speaker cables in both (XLR or RCA) cases.
The chart above your post also shows both to be inverted.

Now,considering that some users faced a different polarity between RCA and XLR a good sanity check would be to inspect their chains for any weird cables,previous (maybe) inverting amps or sources,etc.

That's too confusing.

 

[vuittion]

I've had a few Class D amps and have always found them harsh/clinical for my taste. How would you sum up the Fosi Audio V3 Mono sound.

 

[avdoc]

I've had a few Class D amps and have always found them harsh/clinical for my taste. How would you sum up the Fosi Audio V3 Mono sound.

My Magnepans are extremely revealing. Compared to the class D amps in my Pioneer SC-LX901 receiver, the V3M are much cleaner and smoother. There's no harsh digital "edge" to the sound like with the Pioneer. Also, the background is totally silent which is an improvement over the prior Fosi ZA3 I also own. The V3M are so revealing, that I'm currently auditioning new interconnects. I couldn't be happier with the V3Ms.

 

[DavidM1]

I've had a few Class D amps and have always found them harsh/clinical for my taste. How would you sum up the Fosi Audio V3 Mono sound.

I find it totally engaging… but I thoroughly enjoy detail.

 

[vuittion]

Thsnk you for your feedback.

 

[Borland]

The sound of my Fosis is neutral. No difference to other amps i use.

 

[antcollinet]

The V3M are so revealing, that I'm currently auditioning new interconnects.

Wow - that's peak...errr.... something.

Audiophillia perhaps.

 

[Stoutblock]

This was posted on FB by Fosi. Looks like the same statement posted here with the addition of the news that they will modify the polarity markings on the next production batch.


"Fosi Audio
3h ·
Official Statement Regarding the Inverted Phase of the V3 Mono
Dear V3 Mono Users,
Due to the implementation of the PFFB architecture, the phase inside the V3 Mono is inverted when the input signal is processed, which can help enhance the audio quality. The polarity markings on the V3 Mono's back panel align with the chip’s output and not the inverted phase. Normally, using two V3 Monos together won't cause any phase issues. However, if you integrate the V3 Mono with other equipment, please note that the phase might be inverted.
We apologize for any inconvenience this may have caused. This is indeed a shortcoming in our work, as we failed to clearly inform everyone about this design in advance. We will modify the V3 Mono and make the polarity markings match the phase in the next batch of production.
If you have any other questions or feedback regarding this statement or the V3 Mono, please feel free to contact [email protected]. Thank you for your attention and understanding.
Best Regards,
Fosi Audio Team"

I sure hope Fosi adds some sort of configuration ID between the inverted polarity and non-inverted polarity versions of the V3. If they don’t its going to be a huge opportunity to mess up a system if you have a mixture of both versions!

 

[TurtlePaul]

I sure hope Fosi adds some sort of configuration ID between the inverted polarity and non-inverted polarity versions of the V3. If they don’t its going to be a huge opportunity to mess up a system if you have a mixture of both versions!

I think it will be clear - it sounds like they are going to switch which speaker terminal is labeled "+" and "-".

 

[Bleib]

I think it will be clear - it sounds like they are going to switch which speaker terminal is labeled "+" and "-".

Hope they clearly label version number on the amps so we know which are fixed.

 

[TurtlePaul]

Hope they clearly label version number on the amps so we know which are fixed.

The ones with the red binding post on the right will be new and the ones with the red binding post on the left will be the old version, if you get what I am saying they will do.

 

[Rafaille]

Still a very bad idea if RCA and XLR inputs give different polarity...
Would be nice to know for sure whether this is the case or not.

 

[mike70]

Wow - that's peak...errr.... something.

Audiophillia perhaps.

Well, you don't know that you get what you paid? 2k / foot interconnects will add more transparency ... like lifting a veil from the speaker.

Sorry, I forget the amps are 150 USD each

 

[DavidMcRoy]

My four amps arrived the other day and all have red on the left, and no + or - label. This is not a big deal for me since they're all going to be used to drive 12" woofers in my new 7-way DIY dipole speakers. I have to check for phase among all the drivers, anyway and everything's done in DSP, so I'll just flip polarity or not depending on what I see in the crossover region frequency response.

 

[SMen]

I've had a few Class D amps and have always found them harsh/clinical for my taste. How would you sum up the Fosi Audio V3 Mono sound.

My impression of the V3 Monos is that they do not 'add' anything that could be judged harsh or clinical to the sound.
I enjoy many analogue recordings from the 50's / 60s / 70s. Some of these are bright, but many more have what many of us view as a 'warm' sound. Guess what. They sound warm.

So it's all about the source in my view with the V3 Monos - which is what I was hoping for when I bought them.

 

[Deleted member 72219]

My impression of the V3 Monos is that they do not 'add' anything that could be judged harsh or clinical to the sound.
I enjoy many analogue recordings from the 50's / 60s / 70s. Some of these are bright, but many more have what many of us view as a 'warm' sound. Guess what. They sound warm.

So it's all about the source in my view with the V3 Monos - which is what I was hoping for when I bought them.

Accurate.

-Ed

 

[Stoutblock]

I assume Fosi just switches the wires from the PCB to the output connectors? That's fine with me as its something I can easily DIY myself to make my current amps the same as the corrected ones from Fosi. Also easy to tell which configuration you have by having a peek inside.