Fosi Audio V3 Mono Amplifier Review

[Peternz]

Finally an amp that looks worth considering. I am truly interested. I know Topping has made some amps but they always seem to have something about them that I don't like.

I am interested in this because it does not have a volume control knob. Yes, that is a big deal to me, I can control the volume with my computer, dac and pre amp. That is plenty.

It has an external power supply. That means that the box can be small and unobtrusive and to me that is a huge plus.

It is mono. The channels are totally separated from each other and that can only be a good thing.

Bravo.

 

[activewire]

Thanks for the review.
@amirm have you had the chance to experiment with the audio sense feature? Is it sensitive enough?
Monoblock without trigger input, if the auto on doesn't work properly it would be a cosmic fail. But if it does, this little amp is perfect!

Agreed. I don't understand why new Monoblock design has dropped the 12V trigger - meanwhile Fosi's existing (mono-bridgable) ZA3 already has the 12V trigger. WHY on earth would Fosi drop this from a design that otherwise screams out to a higher end (XLR inputs ... Nichicon caps ... Swappable op-amps) user?

 

[Overseas]

Swappable op amps as in let's dump the price benefit for questionable audible advantage? Is that a feature?

 

[TonyJZX]

I am interested in this because it does not have a volume control knob. Yes, that is a big deal to me, I can control the volume with my computer, dac and pre amp. That is plenty.

fosi still have two complementary devices to come

the PFFB conventional stereo unit most likely with vol. ctrl. and xlr (similar output to older products so 70-90w)

the ZD3 matching analog preamp w/ remote (maybe with some crossover support?)

but yeah... there's still some holes in the market for them and others to patch

be interested to see what partner preamps fit well with this

 

[ehabheikal]

The high frequency distortion performance looks poor to me.

 

[Overseas]

fosi still have two complementary devices to come

What about very good measuring RCA amp?!

 

[TonyJZX]

if you're after a plain stereo single input rca amp w/ vol. ctrl. AND pffb like all the 'classic' units i'm not sure these guys want to go back to that?

 

[Overseas]

I am after the first post where Amir shows quite serious differences between XLR vs RCA.

 

[Billy Budapest]

one might ask if any measurement improvements would be audible

That’s highly doubtful. In fact, I believe the measurements right now are below the threshold of audibility, so I don’t think it’s going out on a limb to say “no.”

Still, cumulative noise and distortion from source, preamp, and speakers all interact and can be additive, so it’s important to have clean signal reproduction throughout the playback chain.

 

[Bruce Morgen]

From tpa3255 datasheet:

The large capacitors used in conjunction with each full-bridge, are referred to as the PVDD Capacitors. These capacitors should be selected for proper voltage margin and adequate capacitance to support the power requirements. In practice, with a well designed system power supply, 1000 μF, 80 V supports most applications.
The PVDD capacitors should be low ESR type because they are used in a circuit associated with high-speed switching.

That tells me what TI recommends and most TPA3255 implementations follow, not what Fosi Audio actually did in this particular product. If indeed those big capacitors are doing the PVDD function, why almost four and half times the capacitance of TI's recommended value?

 

[rvsixer]

I am after the first post where Amir shows quite serious differences between XLR vs RCA.

The inaudible 6dB SINAD difference?

 

[Overseas]

The inaudible 6dB SINAD difference?

Take your query to Amir.
The almost SOTA measured XLR specs that makes the unbeateable quality/ price ratio, if you were not on Earth last 2 days...

 

[MCH]

That tells me what TI recommends and most TPA3255 implementations follow, not what Fosi Audio actually did in this particular product. If indeed those big capacitors are doing the PVDD function, why almost four and half times the capacitance of TI's recommended value?

I understand it is a minimum recommended. TI themselves use 2x4700uF in the evaluation board. I don't think there is any mystery behind, the reasons are explained in the text. But I might be mistaken. TI website has a support forum where they answer questions. Maybe this has been addressed there.

 

[rvsixer]

Take your query to Amir.
The almost SOTA measured XLR specs that makes the unbeateable quality/ price ratio, if you were not on Earth last 2 days...

I did not query Amir, but I have my answer in your answer.

 

[Overseas]

I did not query Amir, but I have my answer in your answer.

Good.
I have my answer in your answer to my answer.
Happy 6dB to you.

 

[antcollinet]

Sorry if this has been asked before:

- The v3 mono is not on sale anywhere yet, is it?
- The v3 stereo is nowhere near as good (spec 88 dB SINAD). What are the differences? No PFFB for the stereo?

1 - yes

2 - lower Sinad - but probably still audibly transparent for real world listening.

 

[Golf]

- The v3 mono is not on sale anywhere yet, is it?

Correct. Nevertheless more than 350 members of this heavily science devoted community firmly believe that can rate it right now

 

[Billy Budapest]

Correct. Nevertheless more than 350 members of this heavily science devoted community firmly believe that can rate it right now

I think they believe they can subjectively rate the results of the objective performance testing by Amir.

 

[Golf]

I think they believe they can subjectively rate the results of the objective performance testing by Amir.

Maybe. But the title of that poll was Rate this amplifier ...

 

[staticV3]

Maybe. But the title of that poll was Rate this amplifier ...

Good point actually.

@amirm I remember the poll being a point of contention when people discuss ASR's ethos.

Wouldn't it be sensible to change the poll title from "Rate this Amplifier/DAC/whatever" to "Rate the measurements"?

Not only would it be a more accurate title, it'd also remove a low-hanging fruit for those criticizing ASR.