Fosi Audio ZA3 Amplifier Review

[solderdude]

Treble response above 10kHz is load dependent (the A800 is not and always peaks a 0.5dB @ 20kHz).
So depending on the impedance of the used speaker the upper treble (sharpness/air) can vary in level depending on the speaker.
When it is used for an active speaker (high section) it may be best to ensure the tweeter load impedance is around 4ohm frequencies > 5kHz.
Unless ... you want the treble peaking (to get more sharpness/air) then you could increase the tweeter impedance to get some extra upper treble.

The ZA3 with 4ohm tweeter load thus will sound less 'sharp' (1dB difference at 20kHz) than A800 and similar at 8ohm load.

 

[Pulkass]

Treble response above 10kHz is load dependent (the A800 is not and always peaks a 0.5dB @ 20kHz).
So depending on the impedance of the used speaker the upper treble (sharpness/air) can vary in level depending on the speaker.
When it is used for an active speaker (high section) it may be best to ensure the tweeter load impedance is around 4ohm frequencies > 5kHz.
Unless ... you want the treble peaking (to get more sharpness/air) then you could increase the tweeter impedance to get some extra upper treble.

The ZA3 with 4ohm tweeter load thus will sound less 'sharp' (1dB difference at 20kHz) than A800 and similar at 8ohm load.

Thanks, very kind of you, I am wondering how much signal will overdrive Fosi Audio ZA3 and Ayima A70, the case is the following, in my DAC Smsl do100 connected via Optical to PC ( Qobuz) and XLR to Both, even at volume set at 2, it s enough to drive my Floorstanders, rather good plentiful sound, but down stairs : Wiim pro to SMSL c100 dac connected via RCA to such amps, volume is very low, I have to set the knob at maximum, and still sound is rather weak, mistery !! Volume is 0 on dac, no attuenation, volume is Full on Wiim. I guess I could put a lot of signal in the down stairs system, I will try a pre amp before the Fosi and Ayima to feed them more.

 

[xanalog]

Treble response above 10kHz is load dependent...

You can now stop 'bad mouthing' this amp!
You've made me dislike my ZA-3s enough -and you were sooooo correct- after owning them for less than 4 months.
I ordered that replacement amp -you recommended- which was over 2.5X higher price.
Be on the look out for your post #801, because I may take away my Like... if the replacement amp is no better with my new floor-standers.

 

[Pulkass]

You can now stop 'bad mouthing' this amp!
You've made me dislike my ZA-3s enough -and you were sooooo correct- after owning them for less than 4 months.
I ordered that replacement amp -you recommended- which was over 2.5X higher price.
Be on the look out for your post #801, because I may take away my Like... if the replacement amp is no better with my new floor-standers.

Please quote the replacement amp.

 

[xanalog]

Please quote the replacement amp.

You are real close to it!
try the graphs of @solderdude post #786 and don't forget to give him a like for his BS&T

 

[Pulkass]

Thanks l de crypted the name. It s on AliExpress but with a different name. It seems the same though

 

[obsessive9119]

Thanks, very kind of you, I am wondering how much signal will overdrive Fosi Audio ZA3 and Ayima A70, the case is the following, in my DAC Smsl do100 connected via Optical to PC ( Qobuz) and XLR to Both, even at volume set at 2, it s enough to drive my Floorstanders, rather good plentiful sound, but down stairs : Wiim pro to SMSL c100 dac connected via RCA to such amps, volume is very low, I have to set the knob at maximum, and still sound is rather weak, mistery !! Volume is 0 on dac, no attuenation, volume is Full on Wiim. I guess I could put a lot of signal in the down stairs system, I will try a pre amp before the Fosi and Ayima to feed them more.

You haven’t mentioned which speakers you have upstairs and downstairs which makes it more difficult to guess what’s going on.

The WiiM Pro has a few ways that it can lower volume - pregain, EQ, line out level, max volume limit and of course volume control. Make sure you’ve checked them all.

From Armir’s review, the ZA3 clips at 1.2v input. I have pretty low sensitivity speakers (83dB) and even with EQ and negative pre-gain, the ZA3 easily drives them to 90dBA at 3m at around 3/4 volume.

 

[obsessive9119]

You can now stop 'bad mouthing' this amp!
You've made me dislike my ZA-3s enough -and you were sooooo correct- after owning them for less than 4 months.
I ordered that replacement amp -you recommended- which was over 2.5X higher price.
Be on the look out for your post #801, because I may take away my Like... if the replacement amp is no better with my new floor-standers.

I’m confused by this.

Depending on your speakers, you may see a 1db bump at 20khz. That should be barely perceptible, and even if it was, you could pull it down with EQ.

 

[xanalog]

I’m confused by this.
That should be barely perceptible, and even if it was, you could pull it down with EQ.

Some like it hot; others without the need for EQ or a volume control in the loop.

 

[Pulkass]

You haven’t mentioned which speakers you have upstairs and downstairs which makes it more difficult to guess what’s going on.

The WiiM Pro has a few ways that it can lower volume - pregain, EQ, line out level, max volume limit and of course volume control. Make sure you’ve checked them all.

From Armir’s review, the ZA3 clips at 1.2v input. I have pretty low sensitivity speakers (83dB) and even with EQ and negative pre-gain, the ZA3 easily drives them to 90dBA at 3m at around 3/4 volume.

Upstairs l have Magnat 709. Downstairs l have Magnat Bookshelf.

 

[obsessive9119]

Upstairs l have Magnat 709. Downstairs l have Magnat Bookshelf.

According to this https://hifi-wiki.com/index.php/Magnat_Quantum_709 the 709s have a sensitivity of 93dB so should be easy to drive. Do you know which model bookshelves you have or what their sensitivity is? Also how big is the room?

(Out of interest, I have a pair of Magnat All Ribbon 5s in my garage/gym - they were my main speakers for years until I bought the LS50s).

 

[Pulkass]

According to this https://hifi-wiki.com/index.php/Magnat_Quantum_709 the 709s have a sensitivity of 93dB so should be easy to drive. Do you know which model bookshelves you have or what their sensitivity is? Also how big is the room?

(Out of interest, I have a pair of Magnat All Ribbon 5s in my garage/gym - they were my main speakers for years until I bought the LS50s).

Downstairs, former wine making room and former bricks oven, dad and grandad s, I have Magnat 673, which I modded, adding mass internally and bracing, they are high efficiency to my opinion, so the reason of those two 'new' 3255 mini amps so low in volume, must be low voltage from Wiim pro, low voltage from SMSL c 100 dac, I will try next connected to marantz rca out cd player.

 

[Pulkass]

They are capable indeed of being loud, it depends on how much signal do we put in the input.

 

[Pulkass]

Yes! Connected both amps, to RCA out of Marantz cd player, the volume is enough at + 2 knob. Very loud. So both Wiim and Smsl dac, having volume set at max, dont put out enough volts. Mistery solved.

 

[motleypixel]

I'm curious for those using one of these as a main amp to drive two bookshelf speakers in a small listening area along with an active sub. Would you wired the sub up via LFE or high-level inputs on the sub if it had them? Everything I'm reading is there's better integration with 2.1 music setups using high-level inputs and outputs out to the mains vs mono LFE? Thank you.

 

[SoySalsaPicante]

I'm curious for those using one of these as a main amp to drive two bookshelf speakers in a small listening area along with an active sub. Would you wired the sub up via LFE or high-level inputs on the sub if it had them? Everything I'm reading is there's better integration with 2.1 music setups using high-level inputs and outputs out to the mains vs mono LFE? Thank you.

These Fosi amps don’t support high level sub connections—don’t do it.

 

[Gwreck]

I'm curious for those using one of these as a main amp to drive two bookshelf speakers in a small listening area along with an active sub. Would you wired the sub up via LFE or high-level inputs on the sub if it had them? Everything I'm reading is there's better integration with 2.1 music setups using high-level inputs and outputs out to the mains vs mono LFE? Thank you.

I am using this amp for a small set with with the wiim ultra as the preamp. I have an RSL 10e sub and Martin Logan lx16 bookshelves. I prefer the wiim crossover and bass management than coming off the amp as the wiim has except bass management options and some auto eq features. Sounds better also.

 

[motleypixel]

These Fosi amps don’t support high level sub connections—don’t do it.

All their amps? Because I'm using my BT30D Pro this way. The BT30D Pro does has a set of passive sub binding posts to drive a passive sub but I don't have one. It does have a 3.5mm full-range pre-out which I could connect to my low level inputs RCA L/R on my DefTech SuperCube II active sub but I found when the amp is off the signal still passes through to the sub if there's a signal coming from my DAC which is sort of odd, but led me to connect my headphone amp which works great now when I switch off the BT30D I can listen to wired headphones. I'd really like to know if this is for all Fosi amps then why because aren't high-level inputs on active subs that have them just sending the high level to a crossover ckt and passing what ever is above that at the amplified signal level sent from the amp on out to the mains? Thank you.

 

[SoySalsaPicante]

All their amps? Because I'm using my BT30D Pro this way. The BT30D Pro does has a set of passive sub binding posts to drive a passive sub but I don't have one. It does have a 3.5mm full-range pre-out which I could connect to my low level inputs RCA L/R on my DefTech SuperCube II active sub but I found when the amp is off the signal still passes through to the sub if there's a signal coming from my DAC which is sort of odd, but led me to connect my headphone amp which works great now when I switch off the BT30D I can listen to wired headphones. I'd really like to know if this is for all Fosi amps then why because aren't high-level inputs on active subs that have them just sending the high level to a crossover ckt and passing what ever is above that at the amplified signal level sent from the amp on out to the mains? Thank you.

At the very least the V3 Monos. I am not 100% sure for ZA3, but definitely the case for V3 Mono. Either way, subwoofers are not nearly as well-integrated when not high-pass filtering the main speakers. To get the cleanest hand-over, you want to apply the same type of crossover slope for the subs and the speakers, in most cases 4th order (24dB/octave). You also improve/reduce IMD for the speakers by handing more bass frequencies to the subwoofer, especially with smaller speakers. It is impossible to run a high-pass on speakers if you're relying on the high level inputs to the amps for the sub.

As for your last question, no, the high level inputs on subs do not do this at all. Only subwoofers that have an actual speaker output that is high-pass filtered will do what you're talking about, and those are always low level outputs to the speaker amps (example KEF KC62 has such high-passed outputs). The high-level inputs on subwoofers never send a signal back to the speakers/amps. They are solely inputs, and not outputs. They pass through the sub's low-pass filter.

 

[obsessive9119]

I'm curious for those using one of these as a main amp to drive two bookshelf speakers in a small listening area along with an active sub. Would you wired the sub up via LFE or high-level inputs on the sub if it had them? Everything I'm reading is there's better integration with 2.1 music setups using high-level inputs and outputs out to the mains vs mono LFE? Thank you.

My sub (SVS SB1000) has a line level HPF, fixed at 80Hz. Initially I set this up as:

WiiM -> Sub (HPF) -> ZA3 -> mains

There were a couple of flaws though - I wanted to cross the sub over a bit higher, and the sub was adding some audible noise to the mains.

Now I’ve switched it to

WiiM -> ZA3 -> mains
WiiM -> ZA3 -> (LFE) Sub

So, the mains are no longer high passed, however I get around this a little with EQ. Basically I have the sub volume set about 10dB higher than it needs to be, then pull it down with EQ in the WiiM. That way the mains end up getting -10dB.

I haven’t tried high level to the sub. I’m not sure why that would integrate better than line level, unless the sub HPF’s the high level output.