Fosi Audio ZA3 Amplifier Review

[doug s.]

It was not removed out of the box. I plugged my RCA cable into it, and the moment I moved the amp back it just fell right out. It doesnt look like there is any solder or anything on the connector. Not sure if there is supposed to be or not, but it doesnt stay in when I put it back in. The other RCA connector is tight and secure.

it could be the plastic inside is broken, and not holding the little 'teeth". may be time to return it for a replacement. i don't see the red plastic piece; should be there, just like the white one above it...

doug s.

 

[Fosi Audio]

Anyone else have this happen? First time using it today, plugged in my RCA, and the connector just fell out. View attachment 352081

Sorry for the inconvenience. Pls turn to our support team and we'll help you out.

 

[TwoEyedJack]

While I see your point, the volume control here gives you variable gain settings. In my testing I just set it to max and ran all the tests.

if you set a pot to max, aren't you effectively bypassing it ( i mean besides the wiper)?

How does a volume pot affect the gain of the amp? Isn't the gain of an amp fixed is most cases ?

 

[Psk]

Are most people using / considering a ZA3 as a replacement for a current "main" system or more as as secondary setup somewhere else.

Really interested to hear what people 's thoughts are in comparison to reasonably high end amps and if they compete or would it just be considered a great setup for a non critical listening scenario?

My current main system has an amp that has tested as well/better than the Fosi on ASR, so I don’t have a reason to consider the Fosi(or any other chip amp) as a replacement. I’m certainly interested in the potential of this tech, and I can appreciate energy efficiency in this age of increasing electric bills. I also appreciate the efficiency of physical space. But my current system works for me, and I have other projects.

Amp and speaker combinations are a funny thing. Some speakers are just designed for robust amps, even if they’re considered relatively efficient. I probably would not use a Fosi for those types of speakers, unless I have low expectations going in. I think it’s safe to say that most ’bookshelf’ size speakers will play well with Fosi amps. The measurements here on ASR only show the Fosi amp has tested well for low noise for what it outputs. Nothing more or less. How it plays with your speakers is a different matter.

 

[somebodyelse]

if you set a pot to max, aren't you effectively bypassing it ( i mean besides the wiper)?

How does a volume pot affect the gain of the amp? Isn't the gain of an amp fixed is most cases ?

It depends where you draw the boundary of the 'amp' - is it at the ZA3's external connectors, or some designated line on the PCB? Internally the power amp stage is usually fixed gain. The pot may be a simple attenuator, but in some cases it is part of an active volume control (Baxandall etc.) or just provides a value to a DSP.

 

[DSJR]

As I wrote in another thread. I had a Naim setup in excellent condition with Preamp, power amp and special PSU for it. When purchased a couple of years ago it retailed for 8000€. I really loved the system.

Then I bought a ZA3 for my office and was very happy with it and one day a put it in my main system and I was Shocked. It sounded better in many areas. The midrange and the warmth off the Naim is hard to beat. After some consideration I sold my Naim set up and bought two ZA3. I have been running it for a couple of week and I love it. As I sold the old equipment I have lots of money left to continue to buy and try new equipment. Whatever people are saying I am sure that the industry gonna change. I don´t say that the ZA3 is perfect but for the money it´s insane. I am really looking forward to see what´s gonna happen with this incredible fast evolution

As the new setup is smaller and much lighter and it´s easier to move around.

New system:View attachment 351901

Old system without same DAC as above
View attachment 351900

Naim *warmth?* - My word they've changed - for the better I should add But the costs are daft now.

 

[DSJR]

Anyone else have this happen? First time using it today, plugged in my RCA, and the connector just fell out. View attachment 352081

That amp needs repair or replacement.

PLEASE take care with general RCA cables, as some fancy looking plugs grip these basic RCA sockets far too tight and this kind of thing happens, especially when wiggling the plugs to remove them. UK made Audiolab amps used to suffer terribly here with sockets coming apart like this and in their case it was an entire socket bank.

 

[maty]

-> Sparkos Labs SS3602

Fosi ZA3 + Sparkos Op-amp - The real deal - Don't miss out !!!

 

[solderdude]

Where is the 2dB level difference coming from in the comparison ?
Was the recording of the Sparkos version deliberately 2dB louder ?

Obviously as the parts of the recordings are not the same (the music continues) one can wonder why all the comparisons were just about 2dB louder.
Probably to fool people into buying expensive Sparkos opamps which the reviewer probably got for free ?

 

[iLoveCats]

-> Sparkos Labs SS3602

Fosi ZA3 + Sparkos Op-amp - The real deal - Don't miss out !!!

View attachment 353706View attachment 353715

Can I ask what's the deal with leaving the subwoofer ones out? I don't use it and never will but they must affect the signal chain to be advised to leave out? Fosi had a video that showed what to change and it was only the two in the middle, it did not say to change the XLR one either. I have another op amp to swap into the XLR position too. I may try that.

 

[PlasticDoc]

Fosi ZA3 + Sparkos Op-amp - The real deal - Don't miss out !!!

These youtuber reviews reminded me of Alvin Gold's reviews in What Hifi (UK) magazine in the 80's~90's. His reviews of products from certain brands became so biased that other journalists began to refer to his articles/reviews as "gold has spoken" (we all got the feeling they were referring to the metal, not their colleague's voice).

Boutique op-amps do have its share of glowing reviews, and it is not unusual to come across high praise for brands like Muse or Sparkos, even on ASR.

It is possible that there may be gold within those op-amps. In which case it could be argued that 'gold speaks'.

 

[maty]

Can I ask what's the deal with leaving the subwoofer ones out? I don't use it and never will but they must affect the signal chain to be advised to leave out? Fosi had a video that showed what to change and it was only the two in the middle, it did not say to change the XLR one either. I have another op amp to swap into the XLR position too. I may try that.

Greg says that even if we do not have the subwoofer connected the opamps consume current.

 

[iLoveCats]

Greg says that even if we do not have the subwoofer connected the opamps consume current.

Yeah I am watching the whole video now. He just says that but it's more like an opinion. Also he didn't show the amp with empty sockets either. I don't know.
It is a well done video and he seems competent, Fosi gave him the stuff and funny enough you can hear a bigger soundstage even through YouTube.

 

[solderdude]

Greg says that even if we do not have the subwoofer connected the opamps consume current.

That small bit of extra current is not the issue. These opamps being $ 80.- a piece is the issue.
When using this cheap amp with RCA and without using the sub you only add $ 160 to the initial purchase price ($150) effectively doubling its price and you get the exact same performance but of course the owner knows he used the best opamps not realizing the class-D amp determines the sound.
When you replace the XLR and sub-out opamps as well you would put in an additional $ 240 which is not in use.

 

[DSJR]

Greg says that even if we do not have the subwoofer connected the opamps consume current.

And?..............

 

[DSJR]

That small bit of extra current is not the issue. These opamps being $ 80.- a piece is the issue.
When using this cheap amp with RCA and without using the sub you only add $ 160 to the initial purchase price ($150) effectively doubling its price and you get the exact same performance but of course the owner knows he used the best opamps not realizing the class-D amp determines the sound.
When you replace the XLR and sub-out opamps as well you would put in an additional $ 240 which is not in use.

And these people completely ignore the fact that their precious analogue recordings have been through arguably hundreds of plain vanilla 5532's or very similar!!!!!!!!!!!

This thing is a bargain bucket power amp with gain control on the front. Just use it as that on the way to a pukka pair of active monitors.

 

[maty]

It is a well done video and he seems competent, Fosi gave him the stuff and funny enough you can hear a bigger soundstage even through YouTube.

If the difference is so noticeable in a 4K video / AAC 192 kbps -> in that room it must be impressive. Those speakers use an expensive Mundorf AMT tweeter (acting as a dipole) that details the sound.

Air Motion Transformer Dipole

Air Motion Transformer Dipol

Einsatz als Super-Höchtöner für vorhandene Lautsprecher oder Dipol-Breitbänder.<br /> <br /> · Keine Schallwand notwendig<br /> · Linear bis 35 kHz

www.mundorf.com

 

[dweeeeb2]

@amirm fyi the ZA3 does not come up in the amp index if you search for fosi

 

[jokan]

Sample size of one......

The 48 volt power supply included with my ZA3 feels lukewarm in operation.

I've had the V3 for a month now, the only time it's been turned off along with the standard 48V brick has been to swap op-amps twice only to confirm what my ears like.
The brick is on my carpeted floor, it's never been turned off. The amp runs luke warm at most and it's turned all the way up as I use my RME ADI2 fs as a pre-amp. The brick is not even luke warm to the touch.

I believe that inferior quality chinese power bricks maybe a potential fire hazard, but certainly not with the Fosi Audio brick. I can't say anything about the GAN-FET one as I've not used it myself. A little too pricey for something that hasn't had a large number of reviews.

I run the V3 at 2 ohms all the time, It has zero issues even when I crank it up. The power brick is never an issue for heat even placed directly on a carpeted floor with no risers.
Hope that gives you some insight.

 

[doug s.]

Where is the 2dB level difference coming from in the comparison ?
Was the recording of the Sparkos version deliberately 2dB louder ?View attachment 353711

View attachment 353712

Obviously as the parts of the recordings are not the same (the music continues) one can wonder why all the comparisons were just about 2dB louder.
Probably to fool people into buying expensive Sparkos opamps which the reviewer probably got for free ?

maybe the volume wasn't touched at all, and the sparkos op amps themselves caused this?

it's an interesting point. i wonder what greg rulka would have to say about these graphs? i believe if this query about why 2db difference is presented to him in the youtube video's comments, greg will answer.

doug s.