Fosi Audio's First Dual-Mode Balanced Amplifier ZA3

[K.Kevin]

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

…….You just… pasted a link to the entire web page.

What specific part features Fosi stating class D meant digital? Because it sure wasn’t in the screenshot you previously posted either

 

[Joe0429]

…….You just… pasted a link to the entire web page.

What specific part features Fosi stating class D meant digital? Because it sure wasn’t in the screenshot you previously posted either

I didn't say Fosi claimed that Class-D amplifiers are digital. I was just pointing out that the part of their diagram labeled as "digital" is not actually digital.
So please don't put words in my mouth. There are already many discussions about Class-D on ASR, so please refer to the relevant articles.
https://www.audiosciencereview.com/forum/index.php?threads/class-d-amplifiers-101.7355/

 

[Fleuch]

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.

If an amplifier supporting PFFB is available "as early as next quarter" , does this make the ZA3 a "dead duck" in the marketing sense?

My intention is (or was) to sign up for the ZA3, maybe two for using as monoblocks. With the possibility of an improved version coming so soon, I probably will put that on hold.

The provision of an active, filtered "Sub Out" limits the available options to extend the use of the ZA3. An input feedthrough, as on the V3, is preferable. Removing the active output reduces the chip count, which should help to keep costs down. Please consider using a feedthrough rather than an active output in the design of the PFFB project.

Is this another Kickstarter project?

 

[K.Kevin]

I didn't say Fosi claimed that Class-D amplifiers are digital. I was just pointing out that the part of their diagram labeled as "digital" is not actually digital.
So please don't put words in my mouth. There are already many discussions about Class-D on ASR, so please refer to the relevant articles.
https://www.audiosciencereview.com/forum/index.php?threads/class-d-amplifiers-101.7355/

I didn’t say you claimed Fosi claimed Class D amplifiers *are* digital, did I?

You said, “The letter "D" in Class-D does not stand for "Digital"”

That’s what I asked about. I asked, where did they state class D meant digital?

I wasn’t putting words in your mouth. You saying “I was just pointing out that the part of their diagram labeled as "digital" is not actually digital.” Is not necessarily the same as what you initially said.

 

[MCH]

If an amplifier supporting PFFB is available "as early as next quarter" , does this make the ZA3 a "dead duck" in the marketing sense?

My intention is (or was) to sign up for the ZA3, maybe two for using as monoblocks. With the possibility of an improved version coming so soon, I probably will put that on hold.

The provision of an active, filtered "Sub Out" limits the available options to extend the use of the ZA3. An input feedthrough, as on the V3, is preferable. Removing the active output reduces the chip count, which should help to keep costs down. Please consider using a feedthrough rather than an active output in the design of the PFFB project.

Is this another Kickstarter project?

Don't give them reasons to delay the next release
It is already taking ages to finally make the za3 available to the masses since the Kickstarter tease

 

[Fleuch]

Don't give them reasons to delay the next release
It is already taking ages to finally make the za3 available to the masses since the Kickstarter tease

Quite agree; but which way should I travel => invest in the ZA3 now or wait for the PFFB improved version? Perhaps the "Sub Out" issue is the decision-making tipping point!!

By the way, my other wish is offset spacing for the speaker terminals, as found on the Aiyima 07MAX; otherwise "Fosi is fab".

 

[zeluxao]

Glad to see balanced inputs.

PFFB is the next step in performance.

Stereo/Mono switch should not be so easily accessible, better on the back, but in front On/Off switch.

Usually people use active subs which already have variable low pass filter. What sets apart is having variable high pass filter for the speakers, as this is undoable for the regular user.

Looks like the orange knob is here to stay. Became somewhat like your brand distinction, which is nice to have. But still regular all black option is important, as not everyone wants something shiny.

I like the orange with the black, but yeah, maybe no need to have the whole knob in orange. But orange accents are a nice touch against the black box. Maybe the dot on the knob that informs where the volume's at could be in orange, together with some of writings in the box. I actually think it'd be nice it those dots and other switches indicators that don't have leds could have somethink like that paint that glows in the dark or something so i could see it in the dark. Some thing like that would be great. Also maybe switching the orange for that kind of bronze colour used in the vents, etc. could be nice.

 

[zeluxao]

It would be nice to have a bypass switch to use it with an external preamp.
With that integrated power on / volume pot you need to power on the amp and then to set the volume at max.

Maybe you can left the pot at max position and use the switch at the power strip to power on / off ... that method can be safe?

The bypass switch would also be great to use two as monoblocks. That way it would be easy to volume match. Just turn that switch on!

 

[Baltima]

The Power of the ZA3 in PBTL Mode are 1x 235 Watt @4Ω.
In the Datasheet of the TPA3255: PBTL-Mode = 1x 480 Watt @2Ω 1% THD+N

Both Datainfos are PBTL-Mode, with different Power. Which is the correctly Data ?

 

[somebodyelse]

Both Datainfos are PBTL-Mode, with different Power. Which is the correctly Data ?

Both. Note the different loads. If the amp can deliver the necessary current then the power should double if the load is halved.

 

[PlasticDoc]

Seen @ Fosi Audio site:
* V3 specs: Power 300Wx2 @4Ω, SINAD 88dB, THD 0.003%, SNR ≥110dB
* ZA3 specs: Power 155Wx2 @4Ω, SINAD 89dB, THD 0.006%, SNR ≥106dB

Something feels wrong at those specs:
* Regarding Power: one or both of the stated values seem wrong
* Regarding SINAD vs THD: SINAD increases AND THD increases too? If I am not wrong, when THD increases SINAD decreases (and vice versa), as they are representations of the same physical and measurable property.

Based on the values published at the Fosi site, Fosi ZA3 amplifier will be a worse amplifier than the Fosi V3. All this happens as some TPA3255 boards start to measure really well here at ASR (for instance: 3e audio TPA3255 260-2-29A).

A sugestion at @ Fosi Audio:
a) take a serious look at 3e audio TPA3255 260-2-29A, that seems to be the golden standard right now; can you sell us a box that does just that?
b) sell us a FOSI V4 with proper PFFB TPA3255 board + a good internal 39V/10A power supply + a metal case / dissipator (like you have done with the ZA3). Forget about sub-out and multiple front switches. Leave a back switch to switch between 2ch and 1ch output (this is the other reason to have a proper builtin 10A power supply).

I will be among the first to buy such an amplifier (just for the fun of it)

 

[PlasticDoc]

If an amplifier supporting PFFB is available "as early as next quarter" , does this make the ZA3 a "dead duck" in the marketing sense?

Clearly a case of "Osborne effect"

 

[mike70]

It depends ... you need to know the price tag of that theoretical new product

 

[MCH]

ok guys, the ZA3 is available at Audiophonics....... at 149 euros

Second price increase at day one of launch, not bad

 

[NoMoFoNo]

I signed up at Fosi's site for a 20% 'launch' discount but they are still not showing pricing. I'll be surprised if the price is more than $120-130 with the discount.

 

[nastynick]

I'm hoping it's at worst $149 usd - 20% = $119.20.

 

[abbazaba]

Anyone have an idea on timing tomorrow?

 

[abbazaba]

Anyone have an idea on timing tomorrow?

Just went live on Amazon, but the 20% early bird coupon doesn't work yet

Edit: 20% Coupon working on ebay, stacks with the 10% offered on the page

 

[OldTimer]

Seen @ Fosi Audio site:
* V3 specs: Power 300Wx2 @4Ω, SINAD 88dB, THD 0.003%, SNR ≥110dB
* ZA3 specs: Power 155Wx2 @4Ω, SINAD 89dB, THD 0.006%, SNR ≥106dB

Something feels wrong at those specs:
* Regarding Power: one or both of the stated values seem wrong
* Regarding SINAD vs THD: SINAD increases AND THD increases too? If I am not wrong, when THD increases SINAD decreases (and vice versa), as they are representations of the same physical and measurable property.

Based on the values published at the Fosi site, Fosi ZA3 amplifier will be a worse amplifier than the Fosi V3. All this happens as some TPA3255 boards start to measure really well here at ASR (for instance: 3e audio TPA3255 260-2-29A).

A sugestion at @ Fosi Audio:
a) take a serious look at 3e audio TPA3255 260-2-29A, that seems to be the golden standard right now; can you sell us a box that does just that?
b) sell us a FOSI V4 with proper PFFB TPA3255 board + a good internal 39V/10A power supply + a metal case / dissipator (like you have done with the ZA3). Forget about sub-out and multiple front switches. Leave a back switch to switch between 2ch and 1ch output (this is the other reason to have a proper builtin 10A power supply).

I will be among the first to buy such an amplifier (just for the fun of it)

Agreed. The sub-out should be eliminated because more components more distortion. Take a look at Schiit even no volume knob.

 

[nastynick]

Just went live on Amazon, but the 20% early bird coupon doesn't work yet

Edit: 20% Coupon working on ebay, stacks with the 10% offered on the page

Its not working for me. It does the 10% off $149.99 = $134.99 and the discount code takes off $13.50 for a total of $121.49.

What final price did you see?