Fosi Audio V3 Mono Amplifier Review

[Down South]

Lots of houses are built using outdated materials. In a lot of European houses they use terrible clay blocks with a hard plaster finish and tiled floors creating a really harsh reflective sound. In the USA I watch programmes showing just how flimsy the construction is and interior walls about 4" thick using single skin plasterboard with rock wool insulation, incredible. No wonder both types require 'room correction'.

 

[r3uba6HBHa2Ye7F]

is there much sonic difference when using 2x 48V 5A VS 2x 48V 10A? or is it more about having more available supply in case the amp needs it? (to prevent clipping maybe?)

thanks

 

[r3uba6HBHa2Ye7F]

Hahh this is exactly what I'm doing. I don't say it is an improvement but my dac has only balanced outs. I was thinking to get the monos but why should I when I can simply add a balanced xlr pigtail to my v3?
CMRR get a small hit but the wire is very short and double shielded so doesnt matter.

View attachment 371756
In case someone needs it:
Pin1 +
Pin4 gnd
Pin7 -

question please, are you saying you connected the XLR input directly to the DIP8 socket?

Also, did you have to do anything to the XLR socket (like maybe cutting the pins so they are not soldered to the PCB? Thanks

 

[r3uba6HBHa2Ye7F]

5. In comparison to the aforementioned Fosi monoblocks, the Fosi 3 PFFB STEREO represents a superior value proposition for the average home audio consumer, particularly in the context of power supply overloading and beat interference.

Is "Fosi 3 PFFB STEREO" the ZA3 model? thanks

 

[Guddu]

Is "Fosi 3 PFFB STEREO" the ZA3 model? thanks

No, ZA3 is non-PFFB topology.
Fosi’s PFFB stereo topology hasn’t come out yet.

 

[Guddu]

is there much sonic difference when using 2x 48V 5A VS 2x 48V 10A? or is it more about having more available supply in case the amp needs it? (to prevent clipping maybe?)

thanks

There are lots of posts on this topic in this thread, but summary is that there isn’t any considerable difference in performance.
If you are keeping units far apart then consider the splitter cable length.

 

[Megaken]

Is there a way to tell when my unit would be shipped

 

[Deleted member 72219]

Is there a way to tell when my unit would be shipped

They said 6/15 on the last Kickstarter update.

-Ed

 

[staticV3]

Is there a way to tell when my unit would be shipped

 

[Marss72]

Does anyone have experience with swapping op amps on the Fosi V3/ZA3? I am curious which op amps you guys rolled and what it did with the sound?

 

[Talisman]

Does anyone have experience with swapping op amps on the Fosi V3/ZA3? I am curious which op amps you guys rolled and what it did with the sound?

...... I hate you @Fosi Audio

 

[antcollinet]

Does anyone have experience with swapping op amps on the Fosi V3/ZA3? I am curious which op amps you guys rolled and what it did with the sound?

This is not how op amp circuits work.

it doesn't matter what op amps are used. If they are compatible they wont alter the sound in any meaningful way. in the worst case, they'll not be compatible, and they will destabilise the amp.

 

[joostdh]

Does anyone have experience with swapping op amps on the Fosi V3/ZA3? I am curious which op amps you guys rolled and what it did with the sound?

There are multiple videos on YouTube, including by Fosi itself, that demonstrate this. Be aware of the limitations of audio over YouTube when comparing though. I would recommend this video by Virtual Hifi as the maker also offers an audio uncompressed download.

 

[joostdh]

in the worst case, they'll not be compatible, and they will destabilise the amp.

Luckily Fosi itself provides a list of opamps they have tested and deemed as working. Whether or not they alter the sound in any meaningful way is surely up to everybody to judge for themselves.

 

[gwing]

Does anyone have experience with swapping op amps on the Fosi V3/ZA3? I am curious which op amps you guys rolled and what it did with the sound?

I suspect you'll get several opinions soon on what, if any, difference the Muse 02 op amps make in the V3 mono.

 

[Marss72]

I suspect you'll get several opinions soon on what, if any, difference the Muse 02 op amps make in the V3 mono.

I'll keep an eye on that

 

[SMen]

This is not how op amp circuits work.

it doesn't matter what op amps are used. If they are compatible they wont alter the sound in any meaningful way. in the worst case, they'll not be compatible, and they will destabilise the amp.

Coming to this from the aspect of learning over the past while, this is my understanding, namely, that op-amps in certain circuits need to have certain characteristics in order to conform: to be fit for purpose. The argument that there is no point in changing op amps, when the circuit has been optimized is a totally strong one. I've been reading with great interest @Michael Fidler 's view on this in the context of phono pre-amps.

With these buffer stages in the class D's I have the impression of a rather 'standardised buffer' approach - but it is just an impression. If a designer stuck their head above the parapet and said "this buffer has been optimized specifically for use with this op amp" I'd believe them, but I am not sure that they in fact have optimized a buffer circuit! Instead it is a pretty "standard" circuit.

And so let the customer subjectively play!

I am not advocating swapping or otherwise: it is just an observation regarding these designs.

 

[rgruber]

Don't be silly, people here don't actually listen to their equipment, they just measure it

This guy has tested a bunch of op amps in the Fosi amps and has made good quality recordings that you can listen to and decide for yourself if you hear a difference:

Does anyone have experience with swapping op amps on the Fosi V3/ZA3? I am curious which op amps you guys rolled and what it did with the sound?

 

[Sokel]

Don't be silly, people here don't actually listen to their equipment, they just measure it

This guy has tested a bunch of op amps in the Fosi amps and has made good quality recordings that you can listen to and decide for yourself if you hear a difference:

Oh,these guys.
Right

(didn't even have to play it,obviously)

 

[DavidM1]

Never underestimate the ability of human psychology to create difference when none exists. Welcome to the world of branding.

These videos aren’t tests in any genuine sense of the word. If you can’t identify op amps without the benefit of labels then accept there is no difference… even if pricing suggests there should be.