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Help Shape Our Next Innovation: The ZA5 Balanced Power Amplifier!

Fosi Audio

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Audio Company
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Hello everyone, we are back seeking opportunities to co-create products with you.:D

Thanks to your continuous support, our ZA3, launched a few months ago, has been widely recognized by users. We greatly value the opportunity to discuss and develop new products with you. Now, we have started preparing the design for the next balanced power amplifier and hope you can continue to provide your valuable insights.

The new balanced model is ZA5, and we would like to get your opinions on a few aspects:
1. Choice of amplifier chip:
A. Hypex NCOREx
B. Purifi
C. TI TPA 3255
D. MOSFET class D amplifier (Do you have any recommended MOSFET brands?)
E. Other options

2. Based on the above options, what would be your price expectation for this product?
A. Around $200
B. Around $250
C. Around $300

If you have more suggestions, please let us know.
 

olieb

Senior Member
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Jul 1, 2023
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The TPA3255 looks like an economical and reliable choice with very good performance in the version with PFFB.
So my vote will be for 1C (TPA3255) + 2A(200€)
I do not need RCA inputs (even less so if SNR is inferior [like it seems the case with V3mono]) and no sub out either. But the option to daisy chain and a gain selector switch (maybe on the back side) 14dB +0dB/+6dB/+12 dB might be a good idea.

In any case I am looking forward to it.

EDIT: If this were a visit from the fairy godmother and I had three wishes, these would be 1B, 2A and of course an integrated power supply unit.
But I suppose it isn't. ;)
 
Last edited:

staticV3

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I'd say stick to TI, keep PFFB, work on high frequency distortion a bit, and add a Pre out and HPF upstream of the Amp for Sub integration.

Fosi Audio Mono V2 amplifier Multitone measurement (1).png Topping PA5 II Stereo Amplifier Audio Balanced Multitone Measurement.png
Fosi Audio Mono V3 19 20 khz intermoduation distortion amplifier measurement (1).png Topping PA5 II Stereo Amplifier Audio Balanced 19 20 kHz intermoduatlin distortion Measurement.png
Fosi Audio Mono V3 amplifier power 4 ohm vs frequency vs distortion measurement (1).png Topping PA5 II Stereo Amplifier Audio Balanced Power 4 ohm vs frequency Measurement.png

Untitled-1 (1).png

Important for the HPF:
The response needs to comply with standard crossovers filters (Linkwitz-Riley 12dB/Oct).

Do not do something like this:
AIYIMA A70 Class D Stereo Amplifier with PFFB balanced Subwoofer frequency response Measurement.png
 
Last edited:

Sokel

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I would also explore a nice AB ala LA90 with a decent 105-110db SINAD,,nice and even THD+N vs Frequency and power,efficient SMPS PSU,etc.
That's what's missing.
 

OldTimer

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Nov 24, 2023
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1. C
2. A

Those are known by people as affordable & reliable Texas Instrument.
 

JeremyFife

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Seems to me that;
The low, budget, end of the market is reasonably well covered with <200$ products - including by yourself.
The mid-upper end, > 700$, is good too with plenty of choice from good quality suppliers.
There's a gap in the market for the step up from budget.

The sort of behaviour that I'd be interested in is;
Frequency independent: 20Hz - 20 kHz
Stable into difficult loads: 2 Ohms (don't know enough to provide other specifications)
Powerful: 200W at 8 Ohm
Low noise, low distortion: anything around 100dB SINAD would be great
Low power use at idle

Features that would be interesting;
Selectable Gain
Trigger
Build quality
Good thermal management
Small size (my personal preference)
Decent quality connectors: option for Speakon

If you can do that for 300-400$ that would be really interesting.
The details (amplification class, amp chip etc) are secondary

I can buy a Topping PA 5II, or your own v3 monoblocks and get great amplification for not much money.
If I want more power then there are Hypex NC252 / NC502 options but that's a big step up in price and that tempts me to just go for a Purifi.
There's a gap in between these but I wouldn't be interested if it did not provide more power than the budget amps, but cleanly and it has to be capable of actually delivering that power (stable, cool)
 

Guddu

Major Contributor
Joined
Feb 10, 2020
Messages
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929
Hello everyone, we are back seeking opportunities to co-create products with you.:D

Thanks to your continuous support, our ZA3, launched a few months ago, has been widely recognized by users. We greatly value the opportunity to discuss and develop new products with you. Now, we have started preparing the design for the next balanced power amplifier and hope you can continue to provide your valuable insights.

The new balanced model is ZA5, and we would like to get your opinions on a few aspects:
1. Choice of amplifier chip:
A. Hypex NCOREx
B. Purifi
C. TI TPA 3255
D. MOSFET class D amplifier (Do you have any recommended MOSFET brands?)
E. Other options

2. Based on the above options, what would be your price expectation for this product?
A. Around $200
B. Around $250
C. Around $300

If you have more suggestions, please let us know.

@Fosi Audio
You already have excellent TPA3255 monoblack power amplifier Fosi v3 mono, so there is a space available for PFFB Stereo TPA3255 amplifier which you might already be working on.
With all the efforts you guys have put in for TPA3255 with your journey to PFFB, TPA3255 power amp is kind of a solved problem now.
For TPA3255, you can always explore "Integrated Amplifier" options with better subwoofer integration by including usable low pass filter / high pass filter (highly recommended) and inclusion of decent DAC in the same unit that could compliment your TPA3255 noise/distortion parameters. Display & remote control are other pleasing options.
To get some idea, look at the response WIIM Amplifier got so quickly.

For this balanced power amplifier, looking at your approximate cost from point 2, don't know how would you do it but HYPEX could be your next great option to explore. TPA3255 will always be limited by power output capabilities (and few other issues to resolve like IMD etc.), but HYPEX modules have better performance with more power already and better thermal capabilities. You already get many problems solved with HYPEX that TPA3255 (or others for that matter) have.
Aren't you already working on HYPEX though, I have seen a few posts on your FB!
 
Last edited:

Eleo

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Nov 7, 2020
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Location
Italy
In my experience, amplifier distortion is not a real problem, lack of power may be. Currently, I own a pair of Irs2092 monobloks: great power but a fair amount of load dependence. If you could design an IRS2092 power amp with PFFB, 800 watts, 85dB Sinad at less than 200$, it could be an interesting addition.
 

Chrise36

Major Contributor
Joined
Dec 23, 2018
Messages
1,078
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377
Hello everyone, we are back seeking opportunities to co-create products with you.:D

Thanks to your continuous support, our ZA3, launched a few months ago, has been widely recognized by users. We greatly value the opportunity to discuss and develop new products with you. Now, we have started preparing the design for the next balanced power amplifier and hope you can continue to provide your valuable insights.

The new balanced model is ZA5, and we would like to get your opinions on a few aspects:
1. Choice of amplifier chip:
A. Hypex NCOREx
B. Purifi
C. TI TPA 3255
D. MOSFET class D amplifier (Do you have any recommended MOSFET brands?)
E. Other options

2. Based on the above options, what would be your price expectation for this product?
A. Around $200
B. Around $250
C. Around $300

If you have more suggestions, please let us know.
A good measuring class ab with r2r vc
 

Jeromeof

Addicted to Fun and Learning
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Jul 25, 2021
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Location
Ireland
I would stick with the TI 3255 (with PFFB) and hopefully keep the costs down - until we all add lots of other features which will drive up the cost again ;)

So I would Vote 1C 2A

But if you can integrate a high pass filter on speaker output when the subwoofer is connected and some configuration for that crossover - I would then vote 1C 2B
 

Psinet

Member
Joined
Apr 26, 2024
Messages
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20
Location
Melbourne
I'd say stick to TI, keep PFFB, work on high frequency distortion a bit, and add a Pre out and HPF upstream of the Amp for Sub integration.

View attachment 365781 View attachment 365780
View attachment 365779 View attachment 365778
View attachment 365777 View attachment 365776

View attachment 365782

Important for the HPF:
The response needs to comply with standard crossovers filters (Linkwitz-Riley 12dB/Oct).

Do not do something like this:
View attachment 365783
This this, this. This this - this this this.

2x mono TI TPA 3255, balanced all the way through, upgraded PFFB, better high freq distortion figures, stereo pre-out with adjustable LPF.

That way we can purchase a ZA5 and a V3 mono for the ultimate 2.1 passive system.
 
Last edited:

TonyJZX

Major Contributor
Joined
Aug 20, 2021
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is hypex and purifi still selling fixed modules?

ie. all the resellers are doing is slapping it in a box and wiring up plugs?

where's the value add for these companies?

i always thought there's just not enough profit slice for a company that's not in the west?

the way i'm looking at it is that Fosi will be making something like the Audiofonics MPA-S250NC with a lower price... and maybe a vol. knob? and bluetooth lol?

that's fine too

but i really think that a stereo xlr pffb tpa3255 with or without vol. knob would be cool? that's all we want

hard/soft trigger - if not vol. maybe trim knobs, pre-outs, 80hz sub cut
 

JSmith

Master Contributor
Joined
Feb 8, 2021
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Algol Perseus
TPA 3255 with PFFB (done well), otherwise Purifi or Hypex for best price possible.

You would be the first well known audio Company from China to use Purifi/Hypex, which would make Fosi Audio stand out from the current companies using TPA 3255.

If Fosi could buy 1000 boards in bulk for a good price, I'd suggest they would sell very well as a completed product.


JSmith
 

Bleib

Major Contributor
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May 13, 2021
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Well, higher number so it should aim at a higher performance than V3 mono, exactly how I don't know.
 

Tom C

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Jun 16, 2019
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Wisconsin, USA
I think it’s really important to keep in mind that, in order to satisfy this lot, it doesn’t matter if you put Hypex or Purify or discrete or AB or class A or C or H on the case. What matters is what we see for $$$, FR, distortion and noise when the device is on the test bench. Power consumption at idle, looks, heat, and reliability can also help separate you from the competition.
 
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