Fosi Audio ZA3 Amplifier Review

[howard416]

Man, where is the “dislike” button…

 

[musicforcities]

That is how my current system is set up. I have a Benchmark DAC2 with XLR out to a Buckeye Hypex 252 amp and then onto the mains. The RCA out goes to a 12" sub with the cross over set at 65Hz. This works really well and sounds great, however, the mains are playing at full range, as is the Buckeye amp driving them.

With a cross over imbedded in the DAC, or the sub out in the amp, you can alleviate the stress the lower frequencies place on both the amp and the main speakers. If you have a powerful amp and tower speakers it not so important, however, for a 2.1 system incorporating bookshelf mains and a sub it is extremely useful, especially if your measuring with REW software.i

Just had a funny vision of a bechmark dac plugged into a $150 fosi chip amp…

 

[OldTimer]

$150 za3 vs $70 v3. Balanced connection is expensive

 

[Toni Mas]

$150 za3 vs $70 v3. Balanced connection is expensive

And brings no improvement to the measurements.

 

[Bruce Morgen]

$150 za3 vs $70 v3. Balanced connection is expensive

So is a power brick, which will not be supplied with a V3 at $70 ($80-90 is more typical AFAICT) -- the comparison ought to be with a ZA3 alone, not one with a bundled 48V/5A power brick at $150.

 

[rj2wells]

It's a $30 difference between the za3 and the v3 on the fosi website, with the same power brick, either 32v or 48v.

 

[Bruce Morgen]

It's a $30 difference between the za3 and the v3 on the fosi website, with the same power brick, either 32v or 48v.

...and if you need balanced inputs, the mono mode, and/or a usable subwoofer output, that $30 may well be worth it.

 

[Petevid]

...and if you need balanced inputs, the mono mode, and/or a usable subwoofer output, that $30 may well be worth it.

And a trigger input which was the clincher for me , works seamlessly with a Wiim Pro and it’s remote.

 

[Bruce Morgen]

And a trigger input which was the clincher for me , works seamlessly with a Wiim Pro and it’s remote.

Point taken --thanks! As usual, it's all about the use case. In my particular case, neither the ZA3 nor V3 have enough potential advantages over what I currently have to be worth the (admittedly modest) cost of an upgrade

 

[Fosi Audio]

With respect, that's a low pass filter (and I can't fathom how 300Hz is of any use to anyone). They were asking about a high pass filter for the main output that engaged when the sub was in use, preferably with a variable crossover frequency.

Hi there, are you suggesting that you would like the device to offer a high-pass filter with selectable frequency ranges? Could you please recommend which frequency ranges you would prefer to have as options, such as 120Hz-20kHz, 200Hz-20kHz?

 

[MCH]

Hi there, are you suggesting that you would like the device to offer a high-pass filter with selectable frequency ranges? Could you please recommend which frequency ranges you would prefer to have as options, such as 120Hz-20kHz, 200Hz-20kHz?

The aim is to cross a sub, so best at low frequencies, say 60 to 200 Hz?

 

[Svend P]

The aim is to cross a sub, so best at low frequencies, say 60 to 200 Hz?

For a budget amp, I think a fixed crossover at 80 Hz would be sufficient.

 

[Talisman]

Hi there, are you suggesting that you would like the device to offer a high-pass filter with selectable frequency ranges? Could you please recommend which frequency ranges you would prefer to have as options, such as 120Hz-20kHz, 200Hz-20kHz?

It's a strange question. Many of us have asked this several times, I asked it myself in a previous confrontation. The low pass filter is useless, it is integrated into any active subwoofer, we need a high pass for the speakers to be able to correctly integrate a sub.

 

[Toni Mas]

For a budget amp, I think a fixed crossover at 80 Hz would be sufficient.

Why limit features and performance if better ones can be achieved at budget price?

What these small amps demonstrate is that It makes little sense to pay more to get top performing gear.

Btw, of course the merit of this performance belongs mainly to the TPA chip, and the price to manufacturing conditions whatever the brandname, the circuit being datasheet based...

 

[staticV3]

Hi there, are you suggesting that you would like the device to offer a high-pass filter with selectable frequency ranges? Could you please recommend which frequency ranges you would prefer to have as options, such as 120Hz-20kHz, 200Hz-20kHz?

Basically what we want is:

(please excuse the poor drawing)

For the High-pass filter, I can think of a few reasonable options:

• OFF/80Hz -> less expensive to build/design
• OFF/60/70/80/90Hz -> same as what some studio subs provide, e.g. KRK S10.4
• OFF/60/80/100/120Hz -> higher corner frequency might be good for very compact Main speakers, e.g. Monoprice THX Satellite

The frequency control could be continuously variable, or just switch between four distinct steps.

If the steps allow for a less expensive or higher quality implementation, then that would be my choice.

 

[memphiskat]

Hi there, are you suggesting that you would like the device to offer a high-pass filter with selectable frequency ranges? Could you please recommend which frequency ranges you would prefer to have as options, such as 120Hz-20kHz, 200Hz-20kHz?

YES! In my experience anyone running a 2.1 system would realize the greatest real world sound quality benefit from using matching high/low pass filters over any of the other minor increases in SINAD discussed here. I have never failed to hear audible benefits when I add a high pass filter, rolling off bass to a pair of bookshelf speakers, and a matching low pass filter on the signal to a sub - as apposed to running the bookshelfs full range and tryin to match the sub using the subs built in low pass filter. It's not a subtle difference. An adjustable filter from 50hz to 150hz would be great.

A Fosi amp that had a the sound quality and power output of the V3 or ZA3, a subwoofer output with a lowpass filter, a matching highpass for the mains? At the price point of the ZA3, I would buy that amp immediately. Even faster if it was the price of the V3! ;-)

 

[howard416]

in most use cases I would suggest a fixed 80 Hz crossover would be good enough. Preferably 4th order electrical to minimize distortion in the mains/monitors

 

[memphiskat]

Basically what we want is:
View attachment 350519
(please excuse the poor drawing)

For the High-pass filter, I can think of a few reasonable options:

• OFF/80Hz -> less expensive to build/design
• OFF/60/70/80/90Hz -> same as what some studio subs provide, e.g. KRK S10.4
• OFF/60/80/100/120Hz -> higher corner frequency might be good for very compact Main speakers, e.g. Monoprice THX Satellite

The frequency control could be continuously variable, or just switch between four distinct steps.

If the steps allow for a less expensive or higher quality implementation, then that would be my choice.

THIS! With the a matching low pass to the sub out. I know every powered sub sold has a built in adjustable low pass filter, but why try to use the rotary knob on the sub to match the cut off frequency on the high pass filter? That's an unnecessary headache in my experience. Unless that was implied in staticV3's post already, in which case ignore this LOL

A fixed 80hz high/low pass would work too.

 

[staticV3]

The ideal implementation would be something like what the WiiM Amp does:


One knob controls the frequency of the High-pass filter built into the Speaker output and the frequency of the Low-pass filter built into the RCA Sub output.

Though I think that'd be pretty difficult to implement purely in the analog realm.

For a pure analog solution, I think the most realistic options would be:
A) Fixed 80Hz crossover (LPF&HPF), either ON or OFF
B) Sub out is unfiltered, Speaker out has adjustable HPF.

 

[rj2wells]

I would prefer a device that has a high pass filter, as described above, and no low pass filter. Active subs already have the LPF it's the HPF that I'm missing.

Right now I'm searching reviews of active HPF and not finding anything better than the $260 miniDSP to put between my wiim pro and my fosi v3 (sub would then be upstream of the fosi).