Aiyima A07 Max - Aiyima's new TPA3255 amplifier with mono/stereo output

[Toku]

What I am concerned about with Aiyima A07 Max is the size of the main body.
According to HP's description, it is quite large at W265 x D240 x H65 mm, even though it does not have a built-in power supply.
But from the photos of the A07 Max, it doesn't look that big.
The A07 packaging carton box I have is exactly the same size as this one, so I think the HP's dimensions are wrong.

 

[Guddu]

What I am concerned about with Aiyima A07 Max is the size of the main body.
According to HP's description, it is quite large at W265 x D240 x H65 mm, even though it does not have a built-in power supply.
But from the photos of the A07 Max, it doesn't look that big.
The A07 packaging carton box I have is exactly the same size as this one, so I think the HP's dimensions are wrong.

I think it is as big as it needs to be to fit in the PCB.

 

[Guddu]

Can you please explain more on 63v cap requirements? What issues do you expect with 50v?
I am going to order one unit tomorrow and will see how well mono/stereo function in practice.

I realized later that Amazon's expected delivery is towards end of November, so will have to wait !!!

 

[AIYIMA]

There's some improvements compered to the old A07 like better cooling, mono option, substantial speaker terminals and higher quality parts. Still not "perfect" or best in class IMHO.

- Using 2200uF / 50V cap for filtering with 48V PSU is plain wrong! Fosi in their V3 amp uses two 2200uF / 63V and that is minimum voltage from safety and reliability point.

- Wima block capacitors in the output filter are 63V with 10% tolerance ("K" grade). In Fosi V3 we get 100V version with 5% tolerance ("J" grade). Both are far from ideal like some high pulse polypropylene caps (Kemet PHE426 comes to mind).

- We don't know the type of potentiometer used (Taper A or linear) and the overall amp gain. Everything matters...

- Their own THD measurements are about 0.0075%, roughly double or more compered with Fosi v3 (0.003%).

- We don't know if it's load independent or not. Maybe we just see 4 Ohm load, and not 8 Ohm with 20 KHz bandwidth. We get almost similar result with Fosi V3 if we ignore 8 Ohm plot.

View attachment 315423

Independent measurements from @amirm and pictures from the real finished product will dispel all the unknowns.

Our actual measured THD value is 0.007%, and the THD measured value given by the official chip is 0.003%.

 

[Guddu]

Hey @AIYIMA,
I have ordered one today on Amazon, hoping to get it in about 2-3 weeks.
All the components looks very good, but Can you tell us the capacitor value used in A07 Max?

 

[tmtomh]

Their freq. response chart shows they have figured out load-dependency issues.

It shows nothing of the kind. That's a single frequency response plot, which means it's with a single impedance load, and so by definition it cannot show whether or not the amp is load-dependent. As @BeQuietZen notes above, it's most likely that this frequency response sweep is with a 4-ohm load, in which case it's the same as the 4-ohm response for almost every load-dependent Class D chip amp Amir has reviewed.

So IMHO it's far likelier that this amp is load-dependent.

 

[Guddu]

It shows nothing of the kind. That's a single frequency response plot, which means it's with a single impedance load, and so by definition it cannot show whether or not the amp is load-dependent. As @BeQuietZen notes above, it's most likely that this frequency response sweep is with a 4-ohm load, in which case it's the same as the 4-ohm response for almost every load-dependent Class D chip amp Amir has reviewed.

So IMHO it's far likelier that this amp is load-dependent.

You might be right.

 

[AIYIMA]

Hey @AIYIMA,
I have ordered one today on Amazon, hoping to get it in about 2-3 weeks.
All the components looks very good, but Can you tell us the capacitor value used in A07 Max?

This capacitor is 50V, but the withstand voltage can reach 60V.

 

[AIYIMA]

1.±20% does not refer to the withstand voltage, but the capacitance value
2. Each power amplifier undergoes two 48V power supply tests before leaving the factory.
3. Professional electrolytic capacitors with very high accuracy in voltage resistance

 

[Guddu]

View attachment 316714

1.±20% does not refer to the withstand voltage, but the capacitance value
2. Each power amplifier undergoes two 48V power supply tests before leaving the factory.
3. Professional electrolytic capacitors with very high accuracy in voltage resistance

So I guess this answers all the questions and concerns raised earlier in this thread about not using 63v caps.
Thanks

 

[Talisman]

So I guess this answers all the questions and concerns raised earlier in this thread about not using 63v caps.
Thanks

This doesn't clarify any doubts, if anything it fuels them

 

[voodooless]

So I guess this answers all the questions and concerns raised earlier in this thread about not using 63v caps.
Thanks

No it doesn’t. We’ll just have to take their word for it? Industry standard is to take at least a 20% higher voltage margin. Why would it be different now?

A lot will depend on the type of power supply used. If it’s the type that is unregulated and just gives a factor of the input, this can be an issue. So if 230V gives 48V, then 253V (still within +10%, in the Netherlands according to NEN-EN 50160 ), would give 52.8V, which is beyond the caps rating. Cheap power bricks for higher voltages are often like this. What Aiyima delivers, I don’t know, but certainly with 3rd party bricks, this is a risk.

 

[Progronom]

I bought two pieces of AIYIMA A07 MAX.
I want to do a double Mono. That is,
- connect the Left channel from the source to one AIYIMA A07 MAX,
- connect the right channel from the source to another AIYIMA A07 MAX.
That's the point switching the AIYIMA A07 MAX to Mono mode!

See, for example, Attach. 1, how this is done in the Parasound amplifier.
1. The one speaker system is connected to two red (+) pins
2. The switch has been switched to Mono
3. The mono signal from the stereo source is fed to ONE RCA - R

However, on the AIYIMA A07 MAX brochures, for some reason in mono mode, a stereo signal is connected to the amplifier. What kind of idiocy is this?

To @AIYIMA - A simple question: How to send a Mono-signal to AIYIMA A07 MAX in Mono-mode?

 

[AIYIMA]

I bought two pieces of AIYIMA A07 MAX.
I want to do a double Mono. That is,
- connect the Left channel from the source to one AIYIMA A07 MAX,
- connect the right channel from the source to another AIYIMA A07 MAX.
That's the point switching the AIYIMA A07 MAX to Mono mode!

See, for example, Attach. 1, how this is done in the Parasound amplifier.
1. The one speaker system is connected to two red (+) pins
2. The switch has been switched to Mono
3. The mono signal from the stereo source is fed to ONE RCA - R

However, on the AIYIMA A07 MAX brochures, for some reason in mono mode, a stereo signal is connected to the amplifier. What kind of idiocy is this?

To @AIYIMA - A simple question: How to send a Mono-signal to AIYIMA A07 MAX in Mono-mode?

The right output connect to mono mode A07 max left input, the left output connect to mono mode A07 max left input.
So when A07 max is mono mode, all input are the left input port.

 

[Guddu]

Guddu ha detto:
Potete spiegare di più sui requisiti del limite 63V? Quali problemi ti aspetti con 50v?
Domani ordinerò un'unità e vedrò come funziona bene il mono/stereo nella pratica.

I condensatori elettrolitici utilizzati nei circuiti elettronici sono sensibili alla temperatura ambiente e vulnerabili alle sovratensioni.
Pertanto, è noto da tempo che i progettisti di circuiti utilizzano condensatori elettrolitici con una tensione pari o inferiore al 70% della tensione nominale.
Anche con i prodotti tecnologicamente avanzati di oggi, è necessario utilizzarli con un certo grado di libertà. Penso che sia auspicabile utilizzare anche le apparecchiature di consumo almeno all'80% della tensione nominale.
Se è un condensatore da 50 V, penso che dovrebbe essere usato a 40 V o meno. Per una tensione di alimentazione di 48 V, è necessario utilizzare un condensatore da 63 V. Inoltre, nel caso di piccoli amplificatori di Classe D, questi vengono spesso installati proprio accanto al dissipatore di calore, creando un ambiente termicamente difficile per i condensatori elettrolitici. Naturalmente il deterioramento continuerà.
L'utilizzo di un condensatore da 50 V su un alimentatore da 48 V comporta il rischio di esplosione a causa del minimo incidente nel circuito.
Ho sperimentato esplosioni di condensatori elettrolitici, ma la pulizia successiva è molto problematica.
I condensatori elettrolitici sono sempre dotati di valvola di sicurezza per ridurre al minimo le esplosioni. I piccoli condensatori elettrolitici hanno un segno X sulla parte superiore. Se si tratta di un condensatore a blocco grande, ci sarà un piccolo foro rotondo accanto al terminale. Quelle sono le valvole di sicurezza.

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Guddu said:
Can you explain more about the 63V limit requirements? What problems do you expect with 50v?
I'll order a unit tomorrow and see how well the mono/stereo works in practice.

Electrolytic capacitors used in electronic circuits are sensitive to ambient temperature and vulnerable to surges.
Therefore, it has long been known that circuit designers use electrolytic capacitors with a voltage equal to or less than 70% of the rated voltage.
Even with today's technologically advanced products, you need to use them with a certain degree of freedom. I think it is desirable to also operate consumer equipment at at least 80% of the rated voltage.
If it's a 50V capacitor, I think it should be used at 40V or less. For a 48V supply voltage, a 63V capacitor must be used. Furthermore, in the case of small Class D amplifiers, these are often installed right next to the heat sink, creating a thermally harsh environment for electrolytic capacitors. Of course the deterioration will continue.
Using a 50V capacitor on a 48V power supply poses a risk of explosion due to the slightest accident in the circuit.
I have experienced explosions of electrolytic capacitors, but cleaning afterward is very problematic.
Electrolytic capacitors are always equipped with a safety valve to minimize explosions. Small electrolytic capacitors have an X mark on the top. If it is a large block capacitor, there will be a small round hole next to the terminal. Those are the safety valves.

 

[Guddu]

Translated
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Guddu said:
Can you explain more about the 63V limit requirements? What problems do you expect with 50v?
I'll order a unit tomorrow and see how well the mono/stereo works in practice.

Electrolytic capacitors used in electronic circuits are sensitive to ambient temperature and vulnerable to surges.
Therefore, it has long been known that circuit designers use electrolytic capacitors with a voltage equal to or less than 70% of the rated voltage.
Even with today's technologically advanced products, you need to use them with a certain degree of freedom. I think it is desirable to also operate consumer equipment at at least 80% of the rated voltage.
If it's a 50V capacitor, I think it should be used at 40V or less. For a 48V supply voltage, a 63V capacitor must be used. Furthermore, in the case of small Class D amplifiers, these are often installed right next to the heat sink, creating a thermally harsh environment for electrolytic capacitors. Of course the deterioration will continue.
Using a 50V capacitor on a 48V power supply poses a risk of explosion due to the slightest accident in the circuit.
I have experienced explosions of electrolytic capacitors, but cleaning afterward is very problematic.
Electrolytic capacitors are always equipped with a safety valve to minimize explosions. Small electrolytic capacitors have an X mark on the top. If it is a large block capacitor, there will be a small round hole next to the terminal. Those are the safety valves.

Thanks Toku.

Seems like manufacturer (Aiyima, in this case) seems to be satisfies with 50v to be used with 48v psu.
I guess we can only suggest to upgrade it to 63v for better safety.
Appears like other Aiyima TPA3255 amps were also using 50v cap, like A07, A07 pro, etc.

 

[Bow_Wazoo]

But ugly as hell...

 

[Toku]

Thanks Toku.

Seems like manufacturer (Aiyima, in this case) seems to be satisfies with 50v to be used with 48v psu.
I guess we can only suggest to upgrade it to 63v for better safety.
Appears like other Aiyima TPA3255 amps were also using 50v cap, like A07, A07 pro, etc.

sorry,
I received a question from an Italian friend and accidentally posted it here in Italian.

 

[Jeromeof]

I got an expedited delivery of a A07MAX and I have been listening and comparing it with my Fosi Audio V3.

And, I thought I would share my initial opinions:

So for me so far the advantanges of the MAX compared to the Fosi Audio V3:

1. New Design and the Board layout
I think the wider design on the MAX allows allot more space at the back of the Ampflifier - meaning cables are well separated - see photo below. They effectively redesigned the MAX so it's wide instead of deep.
2. Nicer binding Posts
The “offset” of the binding posts is much better and I think they have much higher quality binding posts than the V3,
3. Mono mode (and the switch)
This is a great option IMO - it shows off the upgradability - i.e. start with 1 A07MAX in stereo, then buy a second one and setup each as a Mono Block Amplifier (with a pre-amp controlling the volume)

The advantages of the V3 compared to the MAX:
1. Volume control has a “logarithm” taper Pot - so it has more subtle control over lower volumes
The MAX volume is nicer than previous Aiyima Amps but linear on the V3 really nice and it is very subtle with lower volumes
2. Lower THD+N / Higher SINAD value
The Aiyima published SINAD results for A07 MAX are slightly behind the V3 as far as SINAD / THD+N. Note: I did ask them to send a MAX to Amir for some official measurements so we can get AP definitive results - but I imagine Aiyima published results are accurate as they are in line with previous measurements.
3. Some may like the vent hole pattern on the top of the V3 - obviously both have the vent holes on the bottom and on the sides but the V3 vents on the top have a nice pattern ( though I do wonder about stacking components with the V3).

Note: I personally think both companies should look are providing pre-amps with their new 'house' designs (maybe ultimately DACs) as I would buy a pre-amp especially to control the volume of either as mono-blocks but especially if the pre-amp had a similar design.

I did some basic REW FR and distortion measurements matching the V3 with the MAX and mostly its no surprise they were exactly the same (this is using the same equipment and volume matching) - I did use the 36V that came with the MAX on both then I swapped the power supply to a 48V one I got with my V3 and used for both for some extra measurements) :

This was using the same 36V and volume matched they have identical FR (in my room - excuse the lack of Room correction and EQ as I kept the "stack" to a basic source, the amplifiers and speakers. Obviously they sounded the same to me.

Then I swapped the power supply (and thought it might be interesting to look at distortion - though again its almost identical):

A07-MAX - distortion:

Fosi Audio V3 distortion:

]]

I haven't take the MAX apart yet - though I did briefly open it up to see what might be accessible without removing the volume:

I plan to do more comparisons over the next few days and I will report back.

So in summary, so far I think it's a very nice upgrade over the A07 and IMO having this competition between manufacturers is a great way to move the industry forward.

 

[AIYIMA]

First of all, we use the same analog linear potentiometer as V3. If the sound source volume is the same
After testing V3 and A07 MAX under the same conditions, I feel that the volume changes of V3 are more subtle than that of A07 MAX.
This situation should be caused by the sensitivity of A07 MAX being twice that of V3. Relatively speaking, sensitive
The lower the degree, the smaller the change will be. Secondly, the distortion of A07 MAX in the case of THD is also
It can reach 0.003%, and our 0.007% is THD+N, THD is harmonic
Lost town, and THD+N is harmonic distortion plus noise.

Theoretically speaking, the higher the sensitivity of the machine, the better, which means the higher the technical requirements, especially
There are requirements for suppressing the noise floor of the whole machine, because the higher the sensitivity, the greater the noise floor will be.
Higher sensitivity means smaller signals can be amplified,