Fosi Audio ZA3 Amplifier Review

[Power Pop 23]

Hello there,
can someone tell me if the Fosi ZA3 is an improvement against my current setup?

Current setup is Project-Audio DS2 Amp Box -> Polk ES60

I use the Power Amp for Music (Wiim Ultra) and on the Front PreOuts from the Marantz Cinema 70s for Movies. I think the Project-Audio Speaker Noiselevel is kinda extreme. So compared with each other, would be the Fosi ZA3 better as the Project-Audio DS2 Amp Box Noiselevel- and Powerwise?

Sorry for my bad english

Hi,

I am uncertain you will hear a difference with the ZA3. Perhaps you can sample a ZA3 with return privileges.

 

[asa_g]

Works fine for two weeks but after I've noticed that right channel is louder then left one. Have changed everything and localize that the problem is in the Amp. Here is link to reddit with the same problem

https://www.reddit.com/r/BudgetAudiophile/comments/1cwj6ul/fosi_audio_za3_issue_right_input_louder

It will be nice if information with such common issue will be added to first post.

 

[obsessive9119]

Works fine for two weeks but after I've noticed that right channel is louder then left one. Have changed everything and localize that the problem is in the Amp. Here is link to reddit with the same problem

https://www.reddit.com/r/BudgetAudiophile/comments/1cwj6ul/fosi_audio_za3_issue_right_input_louder

It will be nice if information with such common issue will be added to first post.

I’m not sure it is common, unless you’re in the very low end of the volume control?

 

[asa_g]

As for me it almost independent from the gain of Amp but more depends on volume level. I clearly heard this issue till the 40% of the volume knob.(Didn't tried more high levels of amplification)

 

[TheRealLGC]

This might be the right time (for U.S. customers) to try out the ZA3 w/48v 5a adapter, from Amazon. Currently on sale & there's an additional 10% coupon listed on the landing page. Brings the total to $114.74 pre tax.

 

[Good Vibes]

Hi,

How detrimental to the sound is the load dependency overshoot of this amplifier? I have been thinking of building a 2nd system on a tight budget and have been considering the ZA3 but the frequency response looks problematic.

 

[Talisman]

Hi,

How detrimental to the sound is the load dependency overshoot of this amplifier? I have been thinking of building a 2nd system on a tight budget and have been considering the ZA3 but the frequency response looks problematic.

What speakers would you like to use them with?

 

[Good Vibes]

What speakers would you like to use them with?

I don’t have any as of yet, I am keeping an eye on the used market with a maximum budget of £200.

 

[TheRealLGC]

Hi,

How detrimental to the sound is the load dependency overshoot of this amplifier? I have been thinking of building a 2nd system on a tight budget and have been considering the ZA3 but the frequency response looks problematic.

I see the Fosi amps (either the ZA3/V3 Mono) as a gateway between low budget (minimum requirement) and mid level audio equipment. By giving you a decent taste of monoblocking, with separate AC adapters. I have two ZA3 setups, both setups use a WiiM streamer and or T.V.'s, as a source.

1. 2x ZA3 running in mono, feeding a pair of Polk R200, bookshelfs & a couple Definitive Technology SuperCube subs.
2. 1x ZA3 stereo, feeding a pair of Polk LSiM 703, bookshelfs

No issues with clipping, during playback, on either setup. Unless you're running some 2 ohm speakers or your goal is for critical listening, you won't have a an issue.

 

[Good Vibes]

I see the Fosi amps (either the ZA3/V3 Mono) as a gateway between low budget (minimum requirement) and mid level audio equipment. By giving you a decent taste of monoblocking, with separate AC adapters. I have two ZA3 setups, both setups use a WiiM streamer and or T.V.'s, as a source.

1. 2x ZA3 running in mono, feeding a pair of Polk R200, bookshelfs & a couple Definitive Technology SuperCube subs.
2. 1x ZA3 stereo, feeding a pair of Polk LSiM 703, bookshelfs

No issues with clipping, during playback, on either setup. Unless you're running some 2 ohm speakers or your goal is for critical listening, you won't have a an issue.

Hi

Thanks for sharing. I am 5 years into this hobby and still very much learning. The HF rise on the measurement of the ZA3 seems counterintuitive to me, isn’t it a bad thing? How would that affect the sound? From what I know those polks have a bit of a rise in the HF department. Is it essential to attenuate the effect of the ZA3 with EQ?

 

[somebodyelse]

Hi,

How detrimental to the sound is the load dependency overshoot of this amplifier? I have been thinking of building a 2nd system on a tight budget and have been considering the ZA3 but the frequency response looks problematic.

It depends on how the impedance and output of the speakers varies with frequency. A speaker with an impedance peak around 20R at 2kHz might see increased output around 0.5dB from what I remember of measurements on similar amps. A bigger impedance peak, or a peak at a higher frequency, would have more of an output increase. 0.5dB is probably audible, but also probably no worse than the variation between left and right speaker from manufacturing tolerances. If the speaker has a dip in response there then the increase would actually help. Conversely if there's already a peak in response at that frequency a further increase is worse.

 

[Good Vibes]

It depends on how the impedance and output of the speakers varies with frequency. A speaker with an impedance peak around 20R at 2kHz might see increased output around 0.5dB from what I remember of measurements on similar amps. A bigger impedance peak, or a peak at a higher frequency, would have more of an output increase. 0.5dB is probably audible, but also probably no worse than the variation between left and right speaker from manufacturing tolerances. If the speaker has a dip in response there then the increase would actually help. Conversely if there's already a peak in response at that frequency a further increase is worse.

That has helped me to get my head around it and understand it better. Thank you.

Not ideal but not overly detrimental.