Fosi Audio ZA3 Amplifier Review

[GWolfman]

With a sub out it’s missing a high pass mode for the speakers (adjustable crossover frequency would be ideal).

Otherwise decent performance for the price, and XLR(!); voted fine. Thanks Amir and Fosi.

 

[Fosi Audio]

a project with PFFB implementation

Yes, it's coming soon!

 

[Fosi Audio]

In US, where do you buy it at that price?
I have only seen non-XLR version?

The ZA3 comes standard with a 48V PSU at the price $149.99. You can also choose the 32V PSU version for $129.99.

 

[John Woo]

The ZA3 comes standard with a 48V PSU at the price $149.99. You can also choose the 32V PSU version for $129.99.

Please, Make it clear.

"Mono" on ZA3 means BTL, PBTL or just one-channel possible?

It is very confusing.

 

[AdamG]

The value proposition of an 2 channel amp with this level of power and performance was considered vapor ware just a dozen or so months ago. How far this technology has come is at breakneck speed. A 200 WPC Stereo amp for $150 bucks is difficult to imagine. Yet here it is in the flesh and ready to rock your budget 2 channel world and not cost you more than skipping your Starbucks coffee treat for a month. The forward momentum in this technology market is moving at light speed. All this performance for a Buck fifty is just incredible. Bravo Zulu to Fosi Audio Team. They came to play and they came to Win.

Amir thank you for your tireless efforts and commitment in driving this industry in the right direction of making performance finally leaping ahead of the Marketing Department. Some products sell themselves and this is a solid example of that. Performance out pacing Marketing. As I live and breathe.

 

[DanTheMan]

This is definitely a compelling set of features for the price! It essentially fits what I need for my keyboard/bedroom studio setup and the balanced connection sweetens the deal. If it had a high pass filter that engaged when the sub out was in use it would be absolutely ideal—especially if it had a variable crossover frequency. Large caps/coils aren’t out of the question but they’ll be expensive and I’ll just have to wait to see what the measurements dictate.

 

[Bruce Morgen]

I would never buy an amp with an external power brick. It's as big as the amp and you have to put it somewhere. It would be interesting to know how hot that external brick gets after an hour of use. Made in China Fire Hazard? I would certainly unplug the power brick when not in use.

If my experience is any guide, you can stand down from red alert on that issue. I power the two A07s in my system from a single 10A industrial SMPS, and it runs so cool that I disabled its fan with no ill effects. I doubt a suitably rated "power brick" would get anywhere beyond warm to the touch in normal audio use.

 

[pogo]

@amirm
No reactive load test, why???
Could the Fosi be damaged?

 

[amirm]

@amirm
No reactive load test, why???
Could the Fosi be damaged?

Two reasons:

1. Wanted to get the review out quickly as there as been so many requests for it.

2. These BTL amps are incompatible with my reactive load. As soon as I connect them, the load interface stops responding. I need to get one of these amps to the designer to troubleshoot.

But no, I don't think it will be damaged at all. The protection circuit in it is very robust as it is part of the IC they are using. I must have pushed it into that mode a dozen times during this testing and it has no trouble.

 

[Deleted member 48726]

It seems odd to me how a load dependent amplifier gets the praise it does.

And how the review only reflects the improved versions performance while many customers have bought the "rev. 1". Maybe I should look at this another way; that they actually took Amirs response in and made changes accordingly.

And how we still don't get the reactive approximations of real load testing with these amp types.

Oh well. I'm not in the market for these amps anyway and just thinking out loud.

 

[Glades]

It may be lacking some bright compared to the PA5 and Aiyima A07 in the exact same system. Purely subjective. It's my system and I listen to it every day and 'dark' was the first thing I thought when I played this amp, but like I said, it's probably just less bright.

I have the same subjective experience. I assume it's more laidback sounding (absolutely not muddied) vs my Audiolab 6Ka and paired with Wharfedale Lintons.

 

[TNT]

I need to get one of these amps to the designer to troubleshoot.

Please hurry.

//

 

[Berwhale]

The other button is key in book which is support for balanced XLR input to help in avoiding ground loops:

I think you mean the other button (switch?) is 'input'.

 

[Glades]

I would never buy an amp with an external power brick. It's as big as the amp and you have to put it somewhere. It would be interesting to know how hot that external brick gets after an hour of use. Made in China Fire Hazard? I would certainly unplug the power brick when not in use.

I use two ZA3's for mono and like the other comment, the bricks get lukewarm at best. I did notice the ZA3's (while running in mono) feel a bit warmer, although nothing to be concerned of.
Personally, I don't have an issue with the external PSU's. In my cabinet I only see two small units and the bricks are tucked away behind it. Running them for a few months now daily and so far no smoke.

 

[PlasticDoc]

Yes, it's coming soon!

Lets see if it comes close to the 3e audio 260-2-29A amplifier, as this seems to be the "state of the art" for TPA3255 based amplifiers.

Regarding this ZA3:
a) it measures worse than the V3
b) it costs more than the V3
c) it has a poor XLR implementation
d) it has a poor mono implementation
e) it seems to have better heat dissipation (and cabinet)

Simply adding a gold anodised knob and a few more switches does not constitute audio engineering; it is merely a lazy marketing tactic to boost sales.

Innovation is defined as something new that brings satisfaction and value to the customer. Therefore, an audio company should focus on providing genuine value to the customer.

Consumers do not typically perceive gadget features, lower specifications, and higher prices as innovation. Good engineering is what truly constitutes innovation.

Fosi Audio had to balance innovation with marketing for both the Chinese and global markets.

 

[Petevid]

Lets see if it comes close to the 3e audio 260-2-29A amplifier, as this seems to be the "state of the art" for TPA3255 based amplifiers.

Regarding this ZA3:
a) it measures worse than the V3
b) it costs more than the V3
c) it has a poor XLR implementation
d) it has a poor mono implementation
e) it seems to have better heat dissipation (and cabinet)

Simply adding a gold anodised knob and a few more switches does not constitute audio engineering; it is merely a lazy marketing tactic to boost sales.

Innovation is defined as something new that brings satisfaction and value to the customer. Therefore, an audio company should focus on providing genuine value to the customer.

Consumers do not typically perceive gadget features, lower specifications, and higher prices as innovation. Good engineering is what truly constitutes innovation.

Fosi Audio had to balance innovation with marketing for both the Chinese and global markets.

But in practical terms the ZA3 amp has features I need and use that the V3 doesn’t

 

[Bob101]

I can't understand the filtered sub out. An unfiltered pre out is more flexible, subwoofers have their own filter anyway.

I never got it either. It seems so unnecessary.

 

[Bob101]

Please, Make it clear.

"Mono" on ZA3 means BTL, PBTL or just one-channel possible?

It is very confusing.

From my understanding the mono mode just shuts down one channel, resulting in more power to the other one with the same PSU. No bridging is done.

 

[DSJR]

+1 to that!
Volume should come out of the DAC.
Power amp should have zero volume control, and (at worst) MAYBE three gain settings (lo / med / hi)

I kind of disagree, as I'd rather have up-to full level coming down the interconnects and decide the overall level of attenuation on the power amp (which I do currently myself as my power amps have level controls on them). Fifty years ago, noise could be an issue but maybe far less of an issue now perhaps?

 

[DanielT]

Thank you for your review Amir.
_____

Oh and the frequency response is shockingly bad.

It seems odd to me how a load dependent amplifier gets the praise it does.

Quite important with an amp that is not load dependent, has good FR (the most important criterion?). But okay, if you want to color the sound, why not.

What if a speaker exhibits, say, 15-20 Ohms at 8-10 kHz, what would this amps FR look like?