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

[AIYIMA]

That seems wrong to me..
The amplifiers get left channel and right channel as input from the preamplifier.

It will those two different signals that goes to the chip input and those get amplified then on the chip output they bridge tie the load as ONE speaker output!

Seams wrong.. (and then just pass the left and right signal to the other amplifier and do the same wrong thing there. Two wrong make it not a right )

The question is two:
1. Does the switch that put the unit in BTL mode also switch so that one of the RCA inputs is sufficient to use?
2. If not and bothe of the RCA inputs is needed then surely then we need only one of the channels from the preamplifier and use a Y splitter so we feed the internal bothe amplifiers the SAME signal?

Probably easy to test with a Y cable, amplifier and a speaker I guess.

No, as long as the R/L channel is connected, it is recommended to add a tone preamp in front, adjust the A07MAX volume to the maximum, and control its volume output through the preamp.

 

[Guddu]

I have tested A07 Max in mono mode earlier, and only LEFT channel RCA input remains active in mono mode.
In case of 2 x mono operation, Pre-amplifier or DAC outputs should go to LEFT channel RCA on each mono A07 Max
I can only suggest @AIYIMA to update and clarify this on their selling pages.

 

[isaac507]

50v caps are not enough. I suspect it will shut down with protection like the a07 after just a moment when using a 48v psu.

 

[Jason Shep]

@AIYIMA
Any possibility of a version without a volume control?
It would better suit users with AVR’s/pre amps/ Minidsp flex etc etc.

 

[Toku]

View attachment 319825

No, as long as the R/L channel is connected, it is recommended to add a tone preamp in front, adjust the A07MAX volume to the maximum, and control its volume output through the preamp.

This picture is clearly strange. Has AIYIMA actually tested this connection?

 

[Subjective]

50v caps are not enough. I suspect it will shut down with protection like the a07 after just a moment when using a 48v psu.

No, that is not how it works.
The heat disapetion from the chip is what counts. If the chip can't offload heat in heavy usage then the heat is accumulated and the chip has a built in safety feature so it don't gets destroyed so it just shut down to be able to cool down.
The fosi v3 is lightyear better in transfer heat to the chassi outside. And will be able to have more or less no of these issues as the standard A07 has. When A07 shout down the fosi v3 is far from having any issues and just keep playing with lower temperatures at same load.. In testings I have seen.

Regarding the A07 MAX I have not looked at it heat disapaition solution but it should be better than the standard A07 when it is addressed in the MAX.

If your standard A07 is shut down because of heat. Then it is telling you that it can't get rid of the heat. And you should maybe address it with ether terminal coupund, bigger heat sink, more/bigger ventilation holes, active cooling, lower speaker load and so on..

The 50v rated caps has nothing with that to do. What can and may happen is that the cap is destroyed/ruined when there is no or very small marginals.

If a cap goes out it can do that in different ways with a little "explosion" that makes a mess in the enclosure. The unit will stop working.
And depending which and where in the circuit design the capacitor is located it may drag down other components also so they also got to be caput.
So there might me a great chance that the whole unit is getting scraped.

 

[Guddu]

This picture is clearly strange. Has AIYIMA actually tested this connection?

It might be possible that A07 Max aux out simply extends R-Channel RCA out only in mono mode, then the diagram might make sense.

 

[Toku]

It might be possible that A07 Max aux out simply extends R-Channel RCA out only in mono mode, then the diagram might make sense.

Looking at the connection between BTL and PBTL in the TPA3255 data sheet, in PBTL, one channel of the input is connected to ground, and the speaker output channels of L and R are connected in parallel. However, AIYIMA's monaural connection (PBTL) explanatory diagram does not show such a connection configuration. If you connect the speaker between the L/R + terminals as shown in the illustration, there should be no sound.

 

[Subjective]

I have tested A07 Max in mono mode earlier, and only LEFT channel RCA input remains active in mono mode.
In case of 2 x mono operation, Pre-amplifier or DAC outputs should go to LEFT channel RCA on each mono A07 Max
I can only suggest @AIYIMA to update and clarify this on their selling pages.

Thanks for the testing!
And verifying that only one RCA is in use when we run in mono.

So then that means that NO Y splitter is needed and the best way is to connect it as in my previous image.

Straight forward and symmetric as in the same is done on left and right channel and when we use them as mono blocks that is the primary goal then to do the exact same thing on left and right channel!

If you decide to connect like in the other way by using the dazy chain the two amplifiers of some unknown reason.

Then be very very carful so you connect it correctly! There is then a huge risk that you connect it so you have two left cannels or two right ones! (verify the connection with test track that play left and right sounds.)

And you now have asymmetric setup:
* one channel directly driven from its RCA input and that drive the speaker
* the other channel is going into the same amplifier RCA. But then to the "AUX" output and into another wire and then to the next RCA input on the other amplifier. (is the extra connections and soilder joints that the first amplifier don't have in its signal path. =asymmetric.) And here is the question which of the two RCA males is the other channel that we want to amplify.. As I mentioned above..

It is a bad and error prone way to do the connection if we analyze it closer.

 

[robertospeed]

This image I made it , and Aiyima told me it is right , then I don't know because I should have another A07 to do the test and see if it works right

 

[Der Immolator]

To address your concerns with my previous post.

For context - Fosi and I have been exchanging emails for quite some time. I have been testing these types amplifiers ever since the initial release of the A07.

I posted simply to inform.

Two days ago, I produced three very crude diagrams for FOSI Audio. After several video exchanges and dozens of email exchanges, it was these diagrams that ultimately enabled them to recreate the issue and respond accordingly. It is a known issue. The problem is - it is a repeating issue and that should not be the case.

With that, my testing is quite accurate and Fosi, being able to recreate the error with the backfed signals, crossfeeding between the V3 and their M-03 and M-04. They have responded and have decided to issue a revision that will address this issue. Aiyima is next.

In the testing, the results are the same when using the A07 & A07 MAX in conjunction with the Aiyima A3001 and A1001

The A07 MAX operates no differently in this regard than the original A07 and the FOSI V3. Perspective buyers should be made aware so they can make an informed choice.

The error is not in the subwoofer amplifier. The error occurs between the two units. Because of the design of each and how they interact.

As some have responded. - Obviously you cannot experience this error with a secondary stereo amplifier connected to the AUX of the MAX.

The issue ONLY presents when connecting to a summing amp like the Aiyima A3001, A1001 or Fosi equivalent. It also ONLY happens with an amplifier like the A07, V3 and the A07 MAX. It does not happen when these subwoofer amplifiers are paired with the A07 Pro, BT20A Pro, etc. It will also not happen with the upcoming Fosi ZA3.

In regards to the A07 pro and the opamp solution they provide that does avoid this issue. The Fosi BT20A Pro does not use an opamp based circuit for their pre-out. Reports suggest that it is a true pre-out with variable volume control. So the pre/line/aux output of these amps obviously can be implemented in others ways.

The concern is that both Aiyima and Fosi advertise these amplifiers as being able to connect to active and passive subwoofer through their 3.5mm aux/pre/line outputs.

This error affects people with passive subs that do require the use of a subwoofer amplifier. It stands to reason that users would choose what the brand already offers.

This also affects people who choose to use one of these subwoofer amplifiers as a data transfer unit to an active sub. Keeping the level and frequency control at the desktop. While this scenario is not as common. It is still a relevant issue, as it is an advertised use case. Both companies advertise and market these desktop amps as usable and capable in each scenario.

Workarounds have already been tested and established. My post was simply to inform the community of the facts so they can make an informed decision. I have had and continue to have discussions with the manufacturers of these units.


This prevalent issue was already discussed in several forums and noted as a known issue with the original A07. This is my concern.. As it makes no sense to copy known issues into new offerings.

Aiyima could have easily offered this max unit with a true line out. They did with the A07 pro.. Fosi did with the BT20A Pro and will again with the ZA3.

The ZA3 however, has its own slew of issues in regards to having its 5 opamps designated in the ways they intend. That is a different discussion though.

Thank you for your attention and your comments.

 

[Der Immolator]

Yes - I think maybe 30% of users would like this as a pass through and maybe 70% of users would want a proper line out. I would also prefer a proper line out.

I am in that 70% camp as well. The A07 pro does this quite well.

 

[Guddu]

Thanks for the testing!
And verifying that only one RCA is in use when we run in mono.

So then that means that NO Y splitter is needed and the best way is to connect it as in my previous image.

Straight forward and symmetric as in the same is done on left and right channel and when we use them as mono blocks that is the primary goal then to do the exact same thing on left and right channel!

If you decide to connect like in the other way by using the dazy chain the two amplifiers of some unknown reason.

Then be very very carful so you connect it correctly! There is then a huge risk that you connect it so you have two left cannels or two right ones! (verify the connection with test track that play left and right sounds.)

And you now have asymmetric setup:
* one channel directly driven from its RCA input and that drive the speaker
* the other channel is going into the same amplifier RCA. But then to the "AUX" output and into another wire and then to the next RCA input on the other amplifier. (is the extra connections and soilder joints that the first amplifier don't have in its signal path. =asymmetric.) And here is the question which of the two RCA males is the other channel that we want to amplify.. As I mentioned above..

It is a bad and error prone way to do the connection if we analyze it closer.

On the topic of using Aux out for RIGHT channel, It definitely looks "not required" to me (and surely to many of us).
But I think its probably easier and more similar than different from connectivity point of view for many not-so-familiar users.
Look at this used case, my RCA cable limits me and I have to keep amps on top of each other which I don't like. Aux out is the best possible option in this case.

 

[Guddu]

Looking at the connection between BTL and PBTL in the TPA3255 data sheet, in PBTL, one channel of the input is connected to ground, and the speaker output channels of L and R are connected in parallel. However, AIYIMA's monaural connection (PBTL) explanatory diagram does not show such a connection configuration. If you connect the speaker between the L/R + terminals as shown in the illustration, there should be no sound.

I was not planning but now I am curious and will test connections with Aux out.

 

[Guddu]

This image I made it , and Aiyima told me it is right , then I don't know because I should have another A07 to do the test and see if it works right

View attachment 319901

I think it might work, I am going to test it.
By the way, how did you find A07 Max sounding with your favorite music? I am just asking to ensure I am not hallucinating with my results.

 

[carpman]

Well this is all very confusing.

I want an amp (was hoping for either Fosi ZA3 or Aiyima A07 MAX) that does something I thought was simple:

1. I want an RCA line level stereo (dual L + R RCA) going into the ("CLASS-D") amplifier's RCA inputs (no problem so far)
2. Then I want the CLASS-D's pass-through AUX 3.5mm output to (function whether the amp is powered or not, and) go into the standard RCA stereo inputs of my headphone amp ("HA") - I'm one of the 30% in this case.
3. I want the CLASS-D amp to output a genuine mono (sum of its L + R RCA inputs) to a single passive speaker (not a sub).

So one passive speaker is driven by one CLASS-D amp and plays a genuine mono signal (not just the left RCA input channel).

I thought both of these amps did this, but after reading the last few pages of this thread, now I'm not so sure.

Anyone know what the actual state of play is with the Aiyima A07 MAX (or Fosi ZA3) simply acting as a stand-alone (i.e. not 2 mono-blocks) true MONO amp is?

Any help much appreciated.

C.

 

[NoMoFoNo]

This image I made it , and Aiyima told me it is right , then I don't know because I should have another A07 to do the test and see if it works right

View attachment 319901

I really hope the above is wrong and that mono requires one input RCA to each A07 Max because the above is complicated enough that many/most users would not get it right. Much simpler to effectively turn each amp into a 'one-side-only' affair without the need for kludgey 3.5mm-to-RCA cable between the amps themselves. I cannot see myself buying amps that would require such wiring.

Left input RCA to one amp, right input RCA to the other amp, each amp to its respective speaker. If Aiyima hasn't made it thus it's a loser.

 

[voodooless]

Left input RCA to one amp, right input RCA to the other amp, each amp to its respective speaker. If Aiyima hasn't made it thus it's a loser.

Of course it will work like this. It’s equivalent to the picture you reacted to, just saves one cable.

 

[robertospeed]

I think it might work, I am going to test it.
By the way, how did you find A07 Max sounding with your favorite music? I am just asking to ensure I am not hallucinating with my results.

I made a video:

 

[Guddu]

Left input RCA to one amp, right input RCA to the other amp, each amp to its respective speaker. If Aiyima hasn't made it thus it's a loser.

See my testing on this: