Fosi Audio ZA3 Amplifier Review

[gigantic]

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 just added a pair of the ZA3 to drive the woofers of my LaScala-derived, custom speakers. My first thought was that they sounded "wet" compared to the Alesis RA150 bridged mono amps that they replaced. The Class A/B RA150 sound very crisp and have a damping factor of 200. The FA3, driving a pair of JBL 2225 15" woofers sounds somewhat "boomy" by comparison. I haven't yet measured the decay, but I suspect the damping factor is not as good. Has anyone been able to measure the Damping factor of the ZA3?

 

[staticV3]

Has anyone been able to measure the Damping factor of the ZA3?

Here's the ZA3's output impedance, based on which you can derive the damping factor:

Source:

Fosi Audio ZA3 Balanced Stereo Amplifier Review

Fosi Audio ZA3 Balanced Stereo Amplifier Review

www.erinsaudiocorner.com

 

[amix]

you'd think they do away with the 1980s IR remote that require direct line of sight to work.

While off-topic, I feel the urge to stand up for "the properly engineered IR remote control (TM)":

It's the system remote control for the QUAD 66 system from the late 80's /early 90's. It consisted of a preamp, poweramp, cd player and FM tuner.
The remote has a dual IR transmitter which is so powerful, that I can hold the remote behind my back (transmitter facing my back) and it still functions. The whole room must be lit in infrared! It implements the Philips RC protocol. I think it's called RC5.

 

[EddNog]

While off-topic, I feel the urge to stand up for "the properly engineered IR remote control (TM)":

View attachment 359465
It's the system remote control for the QUAD 66 system from the late 80's /early 90's. It consisted of a preamp, poweramp, cd player and FM tuner.
The remote has a dual IR transmitter which is so powerful, that I can hold the remote behind my back (transmitter facing my back) and it still functions. The whole room must be lit in infrared! It implements the Philips RC protocol. I think it's called RC5.

Really wish the remote for my Schiit Freya worked that well. I have to aim it quite precisely for it to register.

-Ed

 

[amix]

Really wish the remote for my Schiit Freya worked that well.

There are products, that translate between IR and Bluetooth. You install an IR transmitter pointing to the Freya and control it via Bluetooth. You could also install an IR receiver in a place, that's more easy to reach with your IR RC and that will transmit to the other one, let's say, around the corner.

 

[zziplex]

I bought two ZA3 units directly from Fosiaudio in March 2024. After using them for roughly a month, and I never expected this issue to occur with my unit.
Interestingly, I saw a similar problem reported by others not long ago.

 

[howard416]

Oh, wow. That is not something that’s OK to have happen, no matter the price point.

 

[EddNog]

There are products, that translate between IR and Bluetooth. You install an IR transmitter pointing to the Freya and control it via Bluetooth. You could also install an IR receiver in a place, that's more easy to reach with your IR RC and that will transmit to the other one, let's say, around the corner.

I figured it out. I need to point the remote kind of low, as if I have a lazy arm. It works every time. Apparently the remote points higher than the body aims. ¯\_(ツ)_/¯

-Ed

 

[GK0]

Is it normal for sound to only come out of the right speaker when the volume knob is turned just a little(from zero)? If I turn it slightly more the left side starts to fade in, but even then it sound like the soundstage isnt quite centered. I'm using unbalanced Inputs from a Topping DX3 Pro.
I have tried different cables and flipping left and right inputs but the issue remains.

 

[Guddu]

Is it normal for sound to only come out of the right speaker when the volume knob is turned just a little(from zero)? If I turn it slightly more the left side starts to fade in, but even then it sound like the soundstage isnt quite centered. I'm using unbalanced Inputs from a Topping DX3 Pro.
I have tried different cables and flipping left and right inputs but the issue remains.

Its potentiometer anomaly, not uncommon with not-so-expensive component.
It shouldn’t have anything to do with DAC.

If you’re not seeing any channel balance issues turning it bit up further then I personally wouldn’t worry about it.

 

[staticV3]

Is it normal for sound to only come out of the right speaker when the volume knob is turned just a little(from zero)?

With analog pots like what the ZA3 uses, yes. That's normal.

Solution is to reduce the volume on your DX3 Pro and turn up the ZA3 to compensate.

 

[Guddu]

Its potentiometer anomaly, not uncommon with not-so-expensive component.
It shouldn’t have anything to do with DAC.

If you’re not seeing any channel balance issues turning it bit up further then I personally wouldn’t worry about it.

Why do pots have channel imbalances at low volumes?

This is a question carried over from the L30 thread.

www.audiosciencereview.com

 

[Joe Smith]

Why do pots have channel imbalances at low volumes?

This is a question carried over from the L30 thread.

www.audiosciencereview.com

On my Fosi V3, there is very good channel matching all the way down to 0, basically. The pot on my Aiyima A07MAX is a little more uneven.

 

[EddNog]

On my Fosi V3, there is very good channel matching all the way down to 0, basically. The pot on my Aiyima A07MAX is a little more uneven.

Pretty sure this kind of thing varies from sample to sample, which is typical for inexpensive pots I like this.

-Ed

 

[Guddu]

On my Fosi V3, there is very good channel matching all the way down to 0, basically. The pot on my Aiyima A07MAX is a little more uneven.

I have 2 x A07 max and both are fine without this at the moment but I won’t be surprised if this starts happening.
Good thing is that it can be eliminated easily if not relying on pot to control volume.

 

[GK0]

Thanks everyone for the responses. I did some more testing and channel volume seems to be about even once I cross a certain threshold.

 

[patrick1112]

Hi guys, I'm pleased to share my experience to the community.
I have 2 ZA3 in mono mode for a couple a weeks now. Here is my feedback :
- switching from stereo to 2 mono gives 2 steps of improvements, not just 1, but really "2 steps". Seems incredible.
- removing all the opamp, expect the right channel, gave an additinal real step of improvement. All seems better, with the same tonality, but all better (precision, space, reality). At this point result is just astonishing, sound is so high quality, so real, giving me goosebumps.
- then I changed the original opamp with the SS3602 (around 200€ for 2). Additinal improvement is there, but more tricky. There is more precision, but it changes the tonality, giving more (too much ?) upper mi-range that gave me fatigue . I had to change RCA cable for a more nutral one to calm this disorder. And now I am happy

For info, my source is Eversolo DMP6 Master Ed. + LPSA6, speackers : Buchard S400 Mk2
If needed , I could share my experience of the Eversolo and change of power supplier LPSA6,

Happy to share listening to anyone arround Rennes, Britany, France

Thanks everyone for all your sharings

 

[mike70]

Seems incredible.

So incredible that you need to check it out.
Normally that's not happening and you need to remove all the "tricks" your brain made to maintain you happy.
That's an objective blind test, as an example.

Then, you can say if it's really better ... or you wanted in that way and your brain make it happen.

 

[Guddu]

Hi guys, I'm pleased to share my experience to the community.
I have 2 ZA3 in mono mode for a couple a weeks now. Here is my feedback :
- switching from stereo to 2 mono gives 2 steps of improvements, not just 1, but really "2 steps". Seems incredible.
- removing all the opamp, expect the right channel, gave an additinal real step of improvement. All seems better, with the same tonality, but all better (precision, space, reality). At this point result is just astonishing, sound is so high quality, so real, giving me goosebumps.
- then I changed the original opamp with the SS3602 (around 200€ for 2). Additinal improvement is there, but more tricky. There is more precision, but it changes the tonality, giving more (too much ?) upper mi-range that gave me fatigue . I had to change RCA cable for a more nutral one to calm this disorder. And now I am happy

For info, my source is Eversolo DMP6 Master Ed. + LPSA6, speackers : Buchard S400 Mk2
If needed , I could share my experience of the Eversolo and change of power supplier LPSA6,

Happy to share listening to anyone arround Rennes, Britany, France

Thanks everyone for all your sharings

You are in the wrong forum my friend, for your audiophile words at least.

 

[TonyJZX]

literally this

using rca cables to 'neutralise and calm the disorder' (???) from opamp abuse is i cant begin to even parse what this is