Fosi Audio V3 Mono Amplifier Review

[SMen]

Sorry, May 1st to 5th are holidays here, so we were unable to respond promptly to your inquiries. Our R&D colleague on duty today sent the test result for the 48V/10A power supply, indicating that it can operate stably at 10A.

Additionally, our supplier Huntkey will provide us with the relevant test report for this power supply after they resume work tomorrow, and we will post update then.

View attachment 367686

Thank you for your clarification and follow up on this.

Could you publish noise and ripple from your supplier Huntkey also?

 

[quocheiser]

Sorry, May 1st to 5th are holidays here, so we were unable to respond promptly to your inquiries. Our R&D colleague on duty today sent the test result for the 48V/10A power supply, indicating that it can operate stably at 10A.

Additionally, our supplier Huntkey will provide us with the relevant test report for this power supply after they resume work tomorrow, and we will post update then.

View attachment 367686

So the power supply can output 10A current for a few seconds during a rather short 'test'.
What can we actually take away from this brief video?
How dependable is this kind of testing to gauge long-term performance and stability?

 

[Fosi Audio]

Please rest assured, we have conducted durability tests to ensure that this power supply can stably output 10A current for a long time.

So the power supply can output 10A current for a few seconds during a rather short 'test'.
What can we actually take away from this brief video?
How dependable is this kind of testing to gauge long-term performance and stability?

 

[iLoveCats]

Is everyone that switched to two 5 amp supplies gonna switch back? Fosi has always provided the receipts when pressed. Great job you guys.

 

[drmevo]

Is everyone that switched to two 5 amp supplies gonna switch back? Fosi has always provided the receipts when pressed. Great job you guys.

I don't think I will unless some new information comes out showing an added benefit to the 10A. The Aiyima I have in my system temporarily uses a 36V 6A PSU which is plenty of power for my medium-sized room, and that is a stereo amp.

Plus, if the 10A were to die, which is not unheard of with this type of PSU, you're out ~$100 for a new one. If a 5A dies, you're only out ~$50, although I suppose you do have twice the chance of that happening.

 

[amix]

I have heard, the chip would be current limited at some value below 10A. Does that mean, that the 10A PSU is a waste of money, because the current can't get through anyway?

 

[antcollinet]

I have heard, the chip would be current limited at some value below 10A. Does that mean, that the 10A PSU is a waste of money, because the current can't get through anyway?

This chart is from the datasheet from the PBTL ratings

To put out 450W into 2ohm, then it needs to deliver 15A.
240W into 4ohm needs 7.74A - so here we are voltage limited with the 10A supply.

(Oops - corrections made..)

So no, I don't think the chip is limiting the current.

.

 

[quocheiser]

Please rest assured, we have conducted durability tests to ensure that this power supply can stably output 10A current for a long time.

Thanks very much for that reassurance. It is great to have that in writing and reflects very well that you are prepared to do that.
As an aside: I am looking very forward to seeing the footage from the Fosi Audio stand at Munich High End 2024!

 

[quocheiser]

I have heard, the chip would be current limited at some value below 10A. Does that mean, that the 10A PSU is a waste of money, because the current can't get through anyway?

Where did you hear that?
If Fosi could confirm that their design is not current limited that would also be great.

 

[MCH]

The over current protection of the chip itself is programmable, and the values possible are high, even the lower ones.

 

[amix]

Where did you hear that?
If Fosi could confirm that their design is not current limited that would also be great.

I think it was in this thread, a few pages back.

 

[jvdburgt]

I couldn’t help myself and added 2x V3M and the SP601 speakers to my previous pledge for 3xV3M.

I have a 5.1 setup with a Marantz S6012 as receiver. My speaker setup is as follows:
- Fronts: Monitor Audio GS10 (relatively modest speakers)
- Center: Monitor Audio GSLCR
- Surrounds: the idea is to put the SP601 as surrounds.

Now, with 5 V3 Mono’s to play with, should I go for:
A. Each speaker its own amp
B. Bi-amp the fronts, and drive the surrounds with the S6012’s internal amp?

Of course I’ll experiment, but happy to hear your thoughts on this

 

[rvsixer]

I see they provided specs on the SP601 speakers. On paper they look quite good, anyone has an idea how they perform against well known speaker brands (like Monitor Audio)?

Now that you have the SP601's coming your way, suggest sending one (and your comparison speaker) in to ASR for testing to answer the question .

 

[jvdburgt]

Now that you have the SP601's coming your way, suggest sending one (and your comparison speaker) in to ASR for testing to answer the question .

Haha! I think I’ll take the egoistic route here, and hope that Fosi will send a fresh pair to ASR anyway

 

[antcollinet]

I couldn’t help myself and added 2x V3M and the SP601 speakers to my previous pledge for 3xV3M.

I have a 5.1 setup with a Marantz S6012 as receiver. My speaker setup is as follows:
- Fronts: Monitor Audio GS10 (relatively modest speakers)
- Center: Monitor Audio GSLCR
- Surrounds: the idea is to put the SP601 as surrounds.

Now, with 5 V3 Mono’s to play with, should I go for:
A. Each speaker its own amp
B. Bi-amp the fronts, and drive the surrounds with the S6012’s internal amp?

Of course I’ll experiment, but happy to hear your thoughts on this

A.

Bi-amping is a waste of money, both on amplification, and on cable. There are no audible benefits to be had, unless you are removing the crossovers from the speakers, and going fully active with digital crossovers upstream of the amps.

 

[SMen]

My humble opinion is to run these with lower voltage to be safe and have peace of mind,somewhere in the 35-40V region and no more.
Unpopular opinion,I know but I have learn to respect limits and a little extra that this.

(note that the above charts shows power at 10% THD which is ridiculous,no one will push the amp to such a limit,even if the chip allowed to do so)

I think you might be right on this - especially with 8 ohm speakers. I think that I am right that 8ohm speakers favour amps as a priority? I might be wrong.
I'm using another 3255 happily with 36v. I'm going to do a comparison with matched gain to see when the v3 monos arrive, and see if I detect any difference at up to 14 khz ... my limit I am pretty sure at 57! ...

 

[ninetylol]

I think you might be right on this - especially with 8 ohm speakers. I think that I am right that 8ohm speakers favour amps as a priority? I might be wrong.
I'm using another 3255 happily with 36v. I'm going to do a comparison with matched gain to see when the v3 monos arrive, and see if I detect any difference at up to 14 khz ... my limit I am pretty sure at 57! ...

higher Ohm need higher voltage because theres more resistance.

you can see that in amirs review on page1 too.

most amps struggle with lower Ohm because you need to push more current to achieve the same power which means more heat

 

[quocheiser]

A.

Bi-amping is a waste of money, both on amplification, and on cable. There are no audible benefits to be had, unless you are removing the crossovers from the speakers, and going fully active with digital crossovers upstream of the amps.

The value of time and money is in the ear of the beholder.
Feel free to listen to this video where the poster (ironically) can't hear a difference.

Despite the poor room acoustics and recording quality, to my ears and on my modest listening setup the bi-amping off the same AV receiver (rather than via separate monoblocs etc) is better. There is more depth, separation and weight to the different layers in the music which I'm sure would show up via a FR graph.
In saying that, I'd say most people (80-90%) won't hear the difference or enough of one.
Furthermore, synergy between the different parts of the audio chain will have a big say on the end result.
FWIW I'm definitely planning on a bi-amped system if/when I upgrade my speakers and would happily share measurements of the results when that happens.

 

[Lednek]

What do you guys think about setting these amp upside down with some taller adhesive feet and applying these heatsink over the chip? Also considering applying new thermal compound to the chip itself. @Fosi Audio, any thoughts?

 

[antcollinet]

I'd say most people (80-90%) won't hear the difference or enough of one.

I'm saying there is nothing to be heard in the sound waves reaching your ears. If you are hearing what you are saying you are, it is most likely happening in the wetware between them.

There is no physical way for an audible difference to happen - unless in the single amped case, the relatively small amount of power going to the tweeter is pushing the amp over the edge of its power capacity. This seems to me to be a fairly unlikely edge case, and can be solved by using an appropriately rated amp.