Fosi Audio's First Dual-Mode Balanced Amplifier ZA3

[jagercola]

@Fosi Audio
These days, it is often more comfortable managing power through a smart plugs than cascading 12V triggers.
I also wanted to control the ZA3 through a smart plug, but I read a thread that said if you cut power to an amp that is on and then reapply power, the amp will be in a powered down state.
In order to power up the amp in that state again, I'd have to hold the knob down for a few seconds, and if I did, it would very likely change the volume it was matched to others when using it as dual mono.

Is this a difficult thing to fix? An easy to change mono/stereo switch is fine with me, but this could be a deal breaker for me.

I'm thinking of waiting for their monoblock amplifier without volume for this exact reason.

 

[somebodyelse]

Hi friend, there is LFP for the sub-out. The cutoff frequency is 300Hz.

I know, I'm just not sure how it helps although I think it's high enough not to do any harm. To integrate properly with the main speakers the sub will need its own adjustable LPF with a lower cutoff than that, probably between 120Hz and 50Hz depending on the speakers. Sub crossover is not an easy thing to do simply and well without some standardisation like THX have for home theatre speakers.

 

[Guddu]

@Fosi Audio
These days, it is often more comfortable managing power through smart plugs than cascading 12V triggers.
I also wanted to control the ZA3 through a smart plug, but I read a thread that said if you cut power to an amp that is on and then reapply power, the amp will be in a powered down state.
In order to power up the amp in that state again, I'd have to hold the knob down for a few seconds, and if I did, it would very likely change the volume that was matched to the other when using it as a dual mono.

Is this a difficult thing to fix? An easy to change mono/stereo switch is fine with me, but this could be a deal breaker for me.

I have tested this thoroughly, here: POST#23

Fosi ZA3 TPA3255 Mono/Stereo Switchable Amplifier, and vs Aiyima A07 Max

Balanced out shouldn’t be different than unbalanced wrt frequency response. I know but since I was measuring the V3 compared to the ZA3 in my room I thought I should measure both the balanced and RCA at the same time (in case someone asked). The only difference in FR was when I added the...

audiosciencereview.com

 

[K.Kevin]

I have tested this thoroughly, here: POST#23

Fosi ZA3 TPA3255 Mono/Stereo Switchable Amplifier, and vs Aiyima A07 Max

Balanced out shouldn’t be different than unbalanced wrt frequency response. I know but since I was measuring the V3 compared to the ZA3 in my room I thought I should measure both the balanced and RCA at the same time (in case someone asked). The only difference in FR was when I added the...

audiosciencereview.com

Nothing he said was inconsistent with your tests you mentioned there. In fact, he was most likely referring to your test.

Bottom line is that the ZA3 cannot be powered on with a smart plug.

 

[MCH]

You can use a 12V wallwart plugged to the smart plug and use that to turn on/off the fosi via the trigger.

Back to on after unplugging with a trigger input kind of half defeats the purpose of a trigger input for certain use cases.

Btw, strangely, audiophonics has it now as "out of stock" instead of in back order, maybe they won't be selling it?

 

[GNK]

Nothing he said was inconsistent with your tests you mentioned there. In fact, he was most likely referring to your test.

Bottom line is that the ZA3 cannot be powered on with a smart plug.

Exactly.

 

[Guddu]

You can use a 12V wallwart plugged to the smart plug and use that to turn on/off the fosi via the trigger.

Back to on after unplugging with a trigger input kind of half defeats the purpose of a trigger input for certain use cases.

Btw, strangely, audiophonics has it now as "out of stock" instead of in back order, maybe they won't be selling it?

View attachment 333754

Looks expensive to add a trigger this way, more than amplifier itself.

 

[MCH]

Looks expensive to add a trigger this way, more than amplifier itself.

Smart plug 10 eur, 12VDC wallwart 9 eur, mono jack plug 3.99 eur. Total 23 euros.
All three can be had for half these prices from AliExpress (I would do Amazon myself but if budget is tight....)
If for some reason you need a expensive fancy smart plug, well, you need it as well to plug the amp in directly, the only difference is the wallwart and the apator (12 eur in total).

https://amzn.eu/d/0vc4NCN

https://amzn.eu/d/87BxvEz

https://amzn.eu/d/2M5ynsK

 

[space_duck]

Hi friend, there is LFP for the sub-out. The cutoff frequency is 300Hz.

Wish it was adjustable, and that there was an adjustable high-pass filter for the speaker outs. That way it would be easier to integrate the speakers with a subwoofer.

 

[Fleuch]

The "pre-out" on the V3 can be used as an input to another amplifier (V3) in a bi-amping configuration, as it is simply a feedthrough of the input. Similarly the "Aux" output on the Aiyima 07MAX is also, I believe, a feedthrough of the input signal and can be used in the same way.

Moving on to the Fosi ZA3, the "Sub Out" output is derived from two opamps, which, presumably, cannot be used as an input to another ZA3. The obvious answer is to use the V3 for bi-amping and the ZA3 as monoblocks. Are there other bi-amping solutions using the ZA3, which I find is preferable to monoblock configuration??

 

[Power Pop 23]

Fosi Audio dot com is now showing this page for the ZA3

Fosi Audio ZA3 Balanced Dual-Mode Class-D Amplifier

The ZA3 is a meticulously crafted high-performance balanced power amplifier designed with users' needs deep in mind. It supports XLR balanced input, offering strong interference resistance and effective noise reduction capabilities.

fosiaudio.com

BTW - the listiing for the Fosi Audio ZA3 at Audiophonics now says 'this product is discontinued'

FOSI AUDIO ZA3 Stereo / Mono Amplifier

This small Fosi Audio ZA3 integrated amplifier has the particularity of being able to operate in both stereo and mono mode. It incorporates two TI TPA3255 amplifier chips enabling it to deliver up to 2x150W or 1x240W @ 4Ω.

www.audiophonics.fr

I don't why the change was made. 'Maybe' it is because the knob is Black in color instead of Orange

 

[vicenzo_del_paris]

Fosi Audio dot com is now showing this page for the ZA3

Fosi Audio ZA3 Balanced Dual-Mode Class-D Amplifier

The ZA3 is a meticulously crafted high-performance balanced power amplifier designed with users' needs deep in mind. It supports XLR balanced input, offering strong interference resistance and effective noise reduction capabilities.

fosiaudio.com

BTW - the listiing for the Fosi Audio ZA3 at Audiophonics now says 'this product is discontinued'

FOSI AUDIO ZA3 Stereo / Mono Amplifier

This small Fosi Audio ZA3 integrated amplifier has the particularity of being able to operate in both stereo and mono mode. It incorporates two TI TPA3255 amplifier chips enabling it to deliver up to 2x150W or 1x240W @ 4Ω.

www.audiophonics.fr

I don't why the change was made. 'Maybe' it is because the knob is Black in color instead of Orange

I contacted audiophonics yesterday and they replied this morning that fosi insisted to have a worldwide retailer availability for December 20th.
Thus audiophonics temporary marked the item as "discontinued' to prevent pre-orders and will propose it again for ordering next week.
Don't worry .

 

[312elements]

Chiming in because I know that @Fosi Audio reads these. I don’t believe that a monoblock or amplifier for that matter should have high pass or low pass filtering. That’s a separate preamp product you should sell to those who want it. I very much look forward to the amp with PFFB, but filtered outputs even if defeatible would be a deal breaker as far as I’m concerned.

 

[Joe Smith]

Chiming in because I know that @Fosi Audio reads these. I don’t believe that a monoblock or amplifier for that matter should have high pass or low pass filtering. That’s a separate preamp product you should sell to those who want it. I very much look forward to the amp with PFFB, but filtered outputs even if defeatible would be a deal breaker as far as I’m concerned.

Agree! Looking forward to someone making a TRUE "baby" monoblock amp with internal power supply, front side off/on, standby mode, trigger or trigger option and capable of doing 100 real watts at 8 ohms. And nothing else, all else pushed to the preamp functions.

 

[K.Kevin]

Chiming in because I know that @Fosi Audio reads these. I don’t believe that a monoblock or amplifier for that matter should have high pass or low pass filtering. That’s a separate preamp product you should sell to those who want it. I very much look forward to the amp with PFFB, but filtered outputs even if defeatible would be a deal breaker as far as I’m concerned.

There is no indication the amplifier itself has filtering for the speaker outputs, can you point to where that is if that’s what you were meaning?

My understanding is it has filtering for the sub out, but what is your problem with that? It does not negatively impact you if you already have a preamp, because you can just go ahead and use your preamp and won’t need to use the filter. And if you don’t have a pre-amp, then you either don’t have subs in play, or if you do have subs then you would need the amp to have the output for the sub.

I understand Fosi reads these forums, and I understand they have shown a history of listening to feedback, but I think it becomes lame when every thread transforms into a wishlist thread where people just flood with these oddly specific or eccentric criterias they have. Maybe there should be a different format of threads dedicated to “Fosi feedback / wishlist” for these posts

 

[Fosi Audio]

Chiming in because I know that @Fosi Audio reads these. I don’t believe that a monoblock or amplifier for that matter should have high pass or low pass filtering. That’s a separate preamp product you should sell to those who want it. I very much look forward to the amp with PFFB, but filtered outputs even if defeatible would be a deal breaker as far as I’m concerned.

Thank you for your advice. Our R&D team have been focused on implementing PFFB for the past few months and has recently made significant breakthroughs. Stay tuned, as we might introduce a new amplifier supporting PFFB as early as next quarter.

 

[312elements]

There is no indication the amplifier itself has filtering for the speaker outputs, can you point to where that is if that’s what you were meaning?

My understanding is it has filtering for the sub out, but what is your problem with that? It does not negatively impact you if you already have a preamp, because you can just go ahead and use your preamp and won’t need to use the filter. And if you don’t have a pre-amp, then you either don’t have subs in play, or if you do have subs then you would need the amp to have the output for the sub.

I understand Fosi reads these forums, and I understand they have shown a history of listening to feedback, but I think it becomes lame when every thread transforms into a wishlist thread where people just flood with these oddly specific or eccentric criterias they have. Maybe there should be a different format of threads dedicated to “Fosi feedback / wishlist” for these posts

I was merely voicing an opinion in opposition to other posts requesting said features. Back off.

 

[Joe0429]

@Fosi Audio

The letter "D" in Class-D does not stand for "Digital".

 

[K.Kevin]

View attachment 334112

@Fosi Audio

The letter "D" in Class-D does not stand for "Digital".

Did they say it was?

 

[Joe0429]

Did they say it was?

https://fosiaudio.com/pages/balanced-dual-mode-class-d-amplifier-za3