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

Jeromeof

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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 subwoofer (as expected).
 

ampguy

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I do think the stereo/mono switch on the front is a very poor design decision. The Aiyima placement of the same function on the MAX seems far safer to me for a daily use item, you're going to be using it one way or the other, not changing back and forth regularly.
Others have already mentioned it, but this would be a deal breaker for me. I've had many preamps, integrated amps, and receivers that had mono buttons, and mono meant both speakers, but mono mode, with no change in power output. Even with vinyl, sometimes mono is preferred (especially if combined with some wiring tricks that can cancel IGD).
 
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Guddu

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Some more observations, after more than 1 week of continuous use
-------------------------------------------------------------------------------

Power ON/Off -
Works fine, every time, no issues observed. However as I mentioned in original post, it is press and hold operation rather than a quick press click operation.
The supplied manual clearly says "press of 2 seconds" for power ON/Off, very well covered by @Fosi Audio but I won't be surprised if users start reporting that there is an issue as it really requires to press and hold for a couple of seconds or more if they don't miss it in manual.

Mono/Stereo Switching - works fine without any single failure every time
RCA/XLR Switching - works fine most of the times, however 2-3 times (out of 50+ attempts, probably) I had to power Off/ON after switching as I did not get output on speakers
Volume Control Knob - very smooth function, works like a charm, no issues observed.
12v Triggered input for ON/Off operation - works absolutely fine, tested with AVR triggered out to ZA3 amplifier and no issues or failure observed
Operating temperature of the case/chassis - very cool even after continuous use for hours, very impressive

Sound Quality - Same as I reported before, no changes after hours and hours of use. Sounds clean and powerful. PUNCHY, and it is kind of making it more suitable for low volume listening to me.

*** Controlling power ON/OFF by smart plug or smart wall socket - Some users would rather like to control power ON/Off by smart plug or smart wall socket, and there is some unexpected results here.
ZA3 amplifier does not maintain the power status/state after power off by power source.
This means that you can power off by cutting off the power on power strip or wall plug, but the amplifier will not regain power ON state when you switch ON the power strip (or wall socket, smart plug, etc.).
So, you can power off the smart plug to power off the amplifier, but you would need manual power ON operation (volume knob press and hold sequence) every time.
In my opinion, it provides a bit more safety (if any) but it is kind of inconvenient.
@Toku Hi Toku, can you give it a try as well please if possible, I just want to ensure that it's not just with my unit.

Overall, my opinion is that its very unlikely if someone won't like the way this amplifier looks and sounds. I could say I don't want stereo/mono in front, speaker connector size/spacing, etc. but these are just preferences and haven't posed any issues for me using it regularly for long hours.
 

TonyJZX

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this to me is really weird behavior

a amp like this should have no internal logic

the rca xlr switch should be just a relay right? so how can it not switch when you ask it to?

the vol. knob is that same kind if cam based pot and so how can it not fire up if the power circuit is not ON THE CAM (so to speak)

unless there's some microprocessor control underneath? no?

just weird. i am using a complete analog integrated and although it is chinese i see none of the behavior associated with any of these kinds of TPA based units
 
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Guddu

Guddu

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the rca xlr switch should be just a relay right? so how can it not switch when you ask it to?
It should and it does but I have had a few failures. I have topping E50 connected to ZA3 with RCA as well as xlr, and E50 outputs to both.
Changing from RCA to xlr (or vice-versa) works and I do hear a relay switching type sound, but a few times I didn’t get output. Power Off and ON fixed it.


the vol. knob is that same kind if cam based pot and so how can it not fire up if the power circuit is not ON THE CAM (so to speak)

unless there's some microprocessor control underneath? no?
There might be something controlling this behavior, probably because of 12v trigger input but can’t say for sure.
So basically it doesn’t stay powered ON if powered Off and then powered ON the wall plug or smart plug etc.

A different amplifier, let’s say Aiyima A07 Max, comes UP if powered off and powered on again on wall plug or smart plug.

Some users might want this, so I thought I will post it here.
 

MCH

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It should and it does but I have had a few failures. I have topping E50 connected to ZA3 with RCA as well as xlr, and E50 outputs to both.
Changing from RCA to xlr (or vice-versa) works and I do hear a relay switching type sound, but a few times I didn’t get output. Power Off and ON fixed it.



There might be something controlling this behavior, probably because of 12v trigger input but can’t say for sure.
Thank you for posting these details, might be important for some people.
There is something that could be a microcontroller, and even has a 4 pin header besides (firmware programming?)

Screenshot_2023-11-24-06-56-39-22_c0dc27f5c07cb0fb3541d6073dfd6932.jpg


A failing relay or firmware is not a good sign, most specially the amp being so new. It wouldn't matter for my use case but for someone using it as a preamp can be kind of a deal breaker.
 

TonyJZX

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i dont think its 'failing' as such

but in some circumstances the microprocessor, if it exists, is not allowing change or is not aware of a change being made

i would accept this as being a small price you pay for $100 amps

and tbf there's a fair few analog amps that have processor control and one would assume the TPA would be easily controlled in this manner
 

Toku

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Some more observations, after more than 1 week of continuous use
-------------------------------------------------------------------------------

Power ON/Off -
Works fine, every time, no issues observed. However as I mentioned in original post, it is press and hold operation rather than a quick press click operation.
The supplied manual clearly says "press of 2 seconds" for power ON/Off, very well covered by @Fosi Audio but I won't be surprised if users start reporting that there is an issue as it really requires to press and hold for a couple of seconds or more if they don't miss it in manual.

Mono/Stereo Switching - works fine without any single failure every time
RCA/XLR Switching - works fine most of the times, however 2-3 times (out of 50+ attempts, probably) I had to power Off/ON after switching as I did not get output on speakers
Volume Control Knob - very smooth function, works like a charm, no issues observed.
12v Triggered input for ON/Off operation - works absolutely fine, tested with AVR triggered out to ZA3 amplifier and no issues or failure observed
Operating temperature of the case/chassis - very cool even after continuous use for hours, very impressive

Sound Quality - Same as I reported before, no changes after hours and hours of use. Sounds clean and powerful. PUNCHY, and it is kind of making it more suitable for low volume listening to me.

*** Controlling power ON/OFF by smart plug or smart wall socket - Some users would rather like to control power ON/Off by smart plug or smart wall socket, and there is some unexpected results here.
ZA3 amplifier does not maintain the power status/state after power off by power source.
This means that you can power off by cutting off the power on power strip or wall plug, but the amplifier will not regain power ON state when you switch ON the power strip (or wall socket, smart plug, etc.).
So, you can power off the smart plug to power off the amplifier, but you would need manual power ON operation (volume knob press and hold sequence) every time.
In my opinion, it provides a bit more safety (if any) but it is kind of inconvenient.
@Toku Hi Toku, can you give it a try as well please if possible, I just want to ensure that it's not just with my unit.

Overall, my opinion is that its very unlikely if someone won't like the way this amplifier looks and sounds. I could say I don't want stereo/mono in front, speaker connector size/spacing, etc. but these are just preferences and haven't posed any issues for me using it regularly for long hours.
I agree with all your explanations.

However, in my ZA3
The basic power ON/OFF operation is to press and hold for 2 seconds, but sometimes that operation does not work. In such a case, it will not work unless you press and hold it for about 5 to 10 seconds.
I tested the 12V trigger again, but it still didn't work. My ZA3 seems to have some kind of problem with the power supply control circuit.
 

Toku

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Thank you for posting these details, might be important for some people.
There is something that could be a microcontroller, and even has a 4 pin header besides (firmware programming?)

View attachment 328942

A failing relay or firmware is not a good sign, most specially the amp being so new. It wouldn't matter for my use case but for someone using it as a preamp can be kind of a deal breaker.
The chip right next to the LED is the MCU chip, but there may be some mistake in this program.
 

Jeromeof

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I agree with all your explanations.

However, in my ZA3
The basic power ON/OFF operation is to press and hold for 2 seconds, but sometimes that operation does not work. In such a case, it will not work unless you press and hold it for about 5 to 10 seconds.
I tested the 12V trigger again, but it still didn't work. My ZA3 seems to have some kind of problem with the power supply control circuit.
I have noticed the 12V trigger is very dependent on the correct voltage (not all 12V triggers are the same) - I am going to run some more tests over the weekend. I did got it to work but not in a 100% consistent way.
 

MCH

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I have noticed the 12V trigger is very dependent on the correct voltage (not all 12V triggers are the same) - I am going to run some more tests over the weekend. I did got it to work but not in a 100% consistent way.
I asked fosi about this and they answered the voltage must be 12V. On the contrary to other triggers, lower voltages will not work (I posted their answer somewhere else some days ago).
 
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Guddu

Guddu

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i dont think its 'failing' as such

but in some circumstances the microprocessor, if it exists, is not allowing change or is not aware of a change being made

i would accept this as being a small price you pay for $100 amps

and tbf there's a fair few analog amps that have processor control and one would assume the TPA would be easily controlled in this manner

I would also say that it’s not failing in my unit, but a few times it didn’t work when amplifier was in operation. 2-3 times out of many many attempts for testing.
It worked every time when switched after powering it off, or when powered off/ON when it didn’t work.
I thought I will record a video but I couldn’t as it worked every time I tried to record.
I am looking to borrow another DAC with RCA+ XLR out to rule out my E50, but Topping PA7 never shoed this (I haven’t made those many attempts on PA7 though).
 
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Guddu

Guddu

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I agree with all your explanations.

However, in my ZA3
The basic power ON/OFF operation is to press and hold for 2 seconds, but sometimes that operation does not work. In such a case, it will not work unless you press and hold it for about 5 to 10 seconds.
5 - 10 seconds press and hold is really long, it’s not that long with my unit and it remains around 2-3 seconds.
 

Mike710

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OldTimer

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I don’t like sub woofer. I never find any subs on a music concert.
If you like subs then it means you don’t like any song you hear.
 

Idrago

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*** Note: No measurements are included in this thread ***

While I hope a Review with measurements comes through soon, I am putting together my observations here hoping to provide some clues to someone looking for ZA3 and quick comparison with Aiyima A07 Max.

Few other threads related to these two products:
Fosi ZA3: https://www.audiosciencereview.com/...3255-amplifier-with-mono-stereo-output.48226/
Aiyima A07 Max: https://www.audiosciencereview.com/...first-dual-mode-balanced-amplifier-za3.48552/

Fosi ZA3 amplifier joined my bench today, and currently placed alongside Aiyima A07 Max and Topping PA7

Quick visual inspection, and contents
* came in decent packaging, bigger than other Fosi amplifiers
* ZA3 amplifier, 48v 5a PSU, Manual
* Manual has all the basic information needed for connectivity

View attachment 326216

View attachment 326217

* ZA3 Amplifier Case & Construction
- Beautiful case, Orange volume knob like V3
- Slightly bigger than other TPA3255 amplifiers, quite a refreshing look
- Simple elegant look, don't think anyone would like to hide this amplifier
* PSU - Feels good build PSU
* Front
- ON/OFF and Volume Control Knob - Press and hold for ON/OFF
- Mono/Stereo Toggle switch
- RCA/XLR Toggle switch
* Back
- RCA Input: Single ended RCA input
- XLR/TRS: Balanced input accepts XLR as well as 1/4 TRS [@Fosi Audio It is really worth mentioning on product pages that ZA3 accepts 1/4 TRS balanced input, currently its XLR only everywhere]
- Sub Out: note: you will need to manage cut off frequency on the subwoofer itself
- 12v Tigger input
- Speaker Binding posts: Just like other Fosi amplifiers, small speaker connector binding posts. This is something Fosi could improve after V3 [Note: Plan to use 4mm banana plugs for safer and easy connection, there isn't enough space for spades or anything else]
- DC input jack, 24 - 48v PSU accepted: 5.5 x 2.1/2.5 mm connector

View attachment 326218
From: https://www.kickstarter.com/project...za3-hifi-stereo-mono-balanced-power-amplifier

My setup
Laptop >> Topping E50 DAC >> RCA & XLR to amplifiers >> Elac DBR62 speakers

Quick observations after powering UP and in-operation:
- With 48v 5a PSU, my ZA3 didn't even get warm. It ran very cool even after pushing to 84-86 db (from 3.5 - 4 meters).
- Idle power (powered ON but no music playing) remains around 8W
- Power ON/OFF, changing RCA/XLR makes click/relay-type sound
- Volume knob makes smooth volume transition
- Power ON/OF operation is push and hold sequence, don't need to change the volume knob position (thankfully) and so you don't loose volume level adjustment
- RCA and XLR inputs have different output levels, by SPL app showed around 5 db difference XLR being higher and RCA being lower

PE:
Sub-Out
- worked every time without any issues
- Volume knob controls sub pre-out level as well
- Only works when amplifier is powered ON

Quick listening with the setup mentioned above
- Sounds clean, powerful and good stereo separation
- ZA3 had no issues to make Elac DBR62 sing powerful
- 48v PSU makes you feel the power, if you are coming after other TPA3255 amps with 32v or 36v PSU
----------
***You can surely use the following comments as some pointers or completely ignore the following comments as its very subjective to my setup, in-room response and my taste:
- In my setup, time after time and track after track I kept of noticing slightly more punchier sound than my current regular amplifiers - Topping PA7 & Aiyima A07 Max.
All the recent Aiyima & Fosi TPS325x amplifiers measurements have shown flat response, at least up to 5-10K, and I am wondering why it felts like everything is slightly elevated (specially bass) in my setup/room with ZA3 while A07 Max and Topping PA7 don't. Its too bad that I don't have any way to measure.
- For me it's quite similar to SMSL SDB mode type sound, or loudness mode in traditional integrated amplifiers
- It surely has its own advantages, those who have heard SMSL SDB or loudness mode will be able to corelate easily, I hope
- It makes music listenable on low to moderate levels without feeling something is missing, but then it was a bit difficult for me to listen beyond 85-87 db
- Pls note that this could just be my room's response to this setup, rather than amplifier
- MusicBee 15 band EQ, lowering down 80 and 125 Hz a bit reduced/removed this loudness in my setup, but I liked it as it is
----------
Overall, It has everything to like. Its amazing for me that it is running cool while my other amps are at least warm to touch with similar output levels. PA7 even runs hotter all the time.

Mono mode
- Front toggle to select mono/stereo
- RIGHT channel input and speaker output becomes ACTIVE in Mono mode
- I honestly don't know yet how it operates internally in mono, but seems like LEFT channel shuts down.
- Without changing anything in setup like same connections and same volume knob position in Mono mode, volume level/SPL was similar or marginally higher based on SPL app on iPhone. I will check it once again as I expect higher SPL
- Note: Amplifier does not show which input has Mono operation on the back panel, but it shows Mono Speaker output on RICHT channel binding post.
- I only have one unit and so did not test dual mono setup and operation, however it should work as expected


Some Comparisons
-----------------------

Power Supply

View attachment 326250

Fosi ZA3 vs Aiyima A07

View attachment 326251

View attachment 326252

View attachment 326253

View attachment 326256

Fosi ZA3Aiyima A07 Max
SummaryStereo Amplifier with balanced and unbalanced inputs
+ Nicer looking case
+ Power ON/OFF is Volume knob push and hold sequence, volume re-adjustment isn't an issue after ON/OFF as it can remain same
+ Runs cooler than others even with 48v PSU
+ 63v smoothing caps, ideal for 48v PSU
+ + Balanced input, more importantly an additional input
+ Balanced input accepts XLR as well as 1/4 TRS
++ 12v trigger input
+ Dedicated sub out, but no cut of freq. mgmt on amp, cab be used with an active subwoofer only
~ Speaker binding posts and spacing is tight, limits the compatibility with various bare wire gauges, spades, etc.

Sound: My setup and impression: Clean and punchy. You may ignore this as well.
Stereo Amplifier with unbalanced inputs
+ Case feels stronger
~ Power ON/OFF requires volume knob tuen down all the way, so volume re-adjustment requires everytime it is turned ON/OFF
~ Runs slightly warm with Aiyima 36v PSU
+ Runs cooler (or barely warm) like Fosi ZA3 with Fosi 48v PSU
~ 50v smoothing caps, although I have had no issues with 48v PSU but many would be skeptical about 48v PSU with this amplifier
+ Aux or line out, can be used with an active subwoofer with RCA input, and/or stereo signal input to another amplifier
+ Better binding posts with adequate spacing, no issues in using thicker wires or spades

Sound: My Setup and impression: Clean, balanced, non-fatiguing. You may ignore this as well.
Case size & appearanceBigger than A07 Max
Nicer looking case, feels premium for the price
Smaller than Fosi ZA3, but feels stronger
Nice looking case
Output Power (Stereo)Similar or close enough with same spec PSUSimilar or close enough with same spec PSU
Front PanelPower On/Off + Volume Control Knob
Power LED, orange/amber color, bright
Mono/Stereo Toggle Switch
RCA/XLR Toggle Switch
Power On/Off + Volume Control Knob, blue, brighter
LED showing Power ON with Stereo or Mono Mode
Back PanelRCA input
XLR/1/4 TRS balanced input
Speaker binding posts, slightly smaller and cramped
LFE type single port sub-out
12v trigger input
DC input jack, 5.5 x 2.1/2.5 mm connector

RCA input
Speaker binding posts, better quality and placement (very similar to Topping PA7/7 plus)
3.5mm AUX or Line Out
DC input jack, 5.5 x 2.1/2.5 mm connector
Air VentsOn both sides
no vents on top plate
On both sides
no vents on top plate
Any issues observed, or things to be aware ofSo far:
1) RCA/XLR switching did not work a few times until I powered ON/OFF
2) RCA/XLR volume output levels are different, 5db observed with SOL app on iPhone
Nothing really, other than slight warmer case when in operation
Pop Out Noise on Power ON/Off operation,
or with 12v Triger
Yes, it's faint but you can hear it when amplifier is powered ON/Off
Same is the case with 12v Trigger
Almost negligibly faint, not an issue at all

Again, I am hoping that a proper measurement based review comes through soon and these details might be used for quick product overlook and comparison.
Would also appreciate if you add anymore information based on your observation on this product.
Teacher's presentation documented and to the point, please indicate to me, in the cable chapter, which USB cable do you recommend, from your practical knowledge in the Laptop configuration to Topping E50 DAC and balanced TRS-XLR cable for ZA3, I intend to purchase the cables, thank you.
 
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