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

[MattCoyk]

Does your system work fine with the speaker cables connected to R+ and L+ as shown in the SMSL diagram?
I don't understand this speaker connection from the electrical operation of the TPA3255.

Yes, no problem with that configuration.

 

[MattCoyk]

Isnt it bad to Set amp to Max and dac to pretty low signal?
1. This would push the amp to max (possible distortion?)
2. Loses alot of DR because you have to lower DAC signal a lot.

I dont think there is anything wrong or bad with setting the amp at max in this config and just treating it as a power amp, but yes you are correct there will be a penalty from the DAC in dynamic range if your listening at lower volumes but it is unlikely to be audible as your volume is also low. I could improve this config by setting the amp volume lower allowing me to turn the DAC volume higher. The other option would be DAC in fixed volume, Amps Max volume and treat the Streamer as the pre running the volume control its just the SMSL offers a little finer control over the big jumps on the WiiM.

 

[Toku]

Yes, no problem with that configuration.

I have been involved with many TPA325x series amplifiers so far, and I think that if they work with AIYIMA's connection method, it is not a PBTL connection. Considering such a connection circuit, the output power should be the same as that of a 2ch BTL connection.
Could someone please explain electrically the internal connection circuit of AIYIMA A07 Max?

 

[MattCoyk]

I have been involved with many TPA325x series amplifiers so far, and I think that if they work with AIYIMA's connection method, it is not a PBTL connection. Considering such a connection circuit, the output power should be the same as that of a 2ch BTL connection.
Could someone please explain electrically the internal connection circuit of AIYIMA A07 Max?

I look forward to hearing more on this subject as well, when I said no problems that was more of a external configuration statement on setting these up rather than internal connection method.

 

[firestart3r]

Great effort Aiyima! Monoblocks are great to have more power and less crosstalk

My suggestion to make the device more simple to use is to:

ADD
- A variable/fixed volume switch

REPLACE
- The AUX output with a real RCA subwoofer output

My idea is that monoblock amps typically don't have volume control. You use a preamplifier with those (DAC, preamp, etc.)

It would remove my main concerns:
- Potential volume imbalance between left and right channel
- Running the amplifiers at max volume in mono mode
- Having a AUX output to daisy chain two mono amplifiers is weird and confusing.

One of the goals of having mono amps is to seperate the two channels early in the chain to diminish the crosstalk (compared to a stereo amp). Daisy chain two mono amplifiers?! Why?!?

 

[Jason Shep]

Great effort Aiyima! Monoblocks are great to have more power and less crosstalk

My suggestion to make the device more simple to use is to:

ADD
- A variable/fixed volume switch

REPLACE
- The AUX output with a real RCA subwoofer output

My idea is that monoblock amps typically don't have volume control. You use a preamplifier with those (DAC, preamp, etc.)

It would remove my main concerns:
- Potential volume imbalance between left and right channel
- Running the amplifiers at max volume in mono mode
- Having a AUX output to daisy chain two mono amplifiers is weird and confusing.

One of the goals of having mono amps is to seperate the two channels early in the chain to diminish the crosstalk (compared to a stereo amp). Daisy chain two mono amplifiers?! Why?!?

You DONT daisy chain them in mono mode!

They each connect directly to pre amp via their Left rca input when in mono mode.

A volume bypass would be very welcome & I'm just surprised that none of these little amps are available without a volume control, even though they are often listed as power amps.

 

[TonyJZX]

i'm thnking mandatory vol. ctrl. is a Chinese market thing

with a TRUE power amp then you limit the usuability... you must have a preamp or dac preamp etc.

and for these companies it limits the market - my feeling is the chinese market really does not get along with true power amps

the vast majority of people want to hook the amp up direct to a pc or whatever

 

[firestart3r]

You DONT daisy chain them in mono mode!

They each connect directly to pre amp via their Left rca input when in mono mode.

A volume bypass would be very welcome & I'm just surprised that none of these little amps are available without a volume control, even though they are often listed as power amps.

I really hope you're right !

I think this is what confused me:
https://www.aiyima.com/products/aiyima-a07-max?variant=46847926239508

Pretty sure there should be ONE RCA cable (not two).

 

[firestart3r]

i'm thnking mandatory vol. ctrl. is a Chinese market thing

with a TRUE power amp then you limit the usuability... you must have a preamp or dac preamp etc.

and for these companies it limits the market - my feeling is the chinese market really does not get along with true power amps

the vast majority of people want to hook the amp up direct to a pc or whatever

Good to know about that mandatory feature!

I still think there should be a variable/fixed volume switch on a monoblock amp with a potentiometer. They could set it at "variable" by default.

 

[Progronom]

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.

Absolutely the right question. In order to make PBTL from Stereo, it is enough to connect in the channels + and +, - and -. That is, a relay with two groups of contacts is enough to connect. The signal output will then be on any contacts L + - or R + -.
However, at Max we see that the signal output in Mono is at the contacts L + and R +. In order to make such a standard circuit, you need a relay with at least two groups of contacts for connecting, + one group of signal switching between two channels.
The relay standing on the Max board does not look like this.
So the question - how Max outputs the mono signal so strangely - remains open.

 

[Joe Smith]

I have yet to get mine from Aiyima, but I am going to use it strictly for stereo. I remain hopeful that one of these manufacturers will make true monoblocks at some point, amp with no V/C, just input for one channel power, with volume controlled by a matching style preamp that has 3 inputs, a good stepped volume pot, remote control, volume display LED.

 

[NoMoFoNo]

I have yet to get mine from Aiyima, but I am going to use it strictly for stereo. I remain hopeful that one of these manufacturers will make true monoblocks at some point, amp with no V/C, just input for one channel power, with volume controlled by a matching style preamp that has 3 inputs, a good stepped volume pot, remote control, volume display LED.

While I agree that would be great, I have to think the market for genuine mono blocks, with one tap going in and feeding one channel only, appeals to a very small market. Also, the amount of power typically cranked through mono blocks by 'enthusiasts' is much higher than the vast majority of users ever call for, making for a niche market IMO. I think that the sweet spot for these manufacturers is probably something akin to the A07 Max or the upcoming Fosi ZA3, hopefully with load independence.

 

[Jason Shep]

Without volume controls, either mono blocks or stereo models would make great value home theatre amps, especially if one has already dropped a small fortune on a nice processor & doesn’t have funds remaining for a sexy mega multi channel power amp.

I will be using mine in mono for an Auro3d top channel, but I could just keep adding them for all channels & switch my AVR to processor mode.

 

[carpman]

I really hope you're right !

I think this is what confused me:
https://www.aiyima.com/products/aiyima-a07-max?variant=46847926239508
View attachment 320355
Pretty sure there should be ONE RCA cable (not two).

Yes I saw that and that's why I thought it summed the two RCA channels when in mono mode. But it looks like just the left channel is used.

 

[Guddu]

I couldn't understand the operation of AIYIMA A07 Max's monaural mode, so I looked into the TPA3255 data sheet in detail. I also found out that the TPA3255 has four operating modes depending on the combination of M1/M2 pins.
Its four operating modes are
1. 4ch SE connection mode
2. 2ch BTL connection mode
3. 1ch BTL connection mode
4. 1ch PBTL connection mode
There are 4 types.

The strange thing about A07 Max's monaural mode
1. Normally, with PBTL connection, the output load is allowed up to 2Ω, but there is no mention of 2Ω load, and the display remains the same as BTL connection.
2. The output power in monaural mode has not increased much from 2ch BTL. Normally, if you use monaural with PBTL connection, you can get twice the output of 2ch BTL.
3. Adoption of a speaker output connection method that is unimaginable with PBTL

Previous monaural Class D amplifiers used PBTL connections, but the A07 Max seems to use BTL monaural mode from the catalog data.
This operation mode completely stops one channel of the BTL 2ch stereo mode and operates as 1ch monaural.

Looking at the spec data of A07 Max, normally in PBTL monaural mode, the output is twice that of BTL stereo mode, but the output in A07 Max's monaural mode has not increased much from 2ch stereo. There is no mention of PBTL 2Ω in the output load. All of these points can be explained by using BTL monaural mode.
This is just my personal opinion. The actual circuit is unknown.

Now I am wondering why Fosi’s new amplifier have even lower published specs in mono, even lower than A07 Max.

 

[damarfi]

I ordered two 07 Max and waiting for delivery. Here is part of their web page and description of the amp. Did anybody try to connect that way: Mono Max Output Power(switch mono mode)：600W/ 2Ω（48V/12A）
(R+ connect to speaker +, L+ connect to speaker -)

L+ to speaker - (??)

 

[Jason Shep]

I ordered two 07 Max and waiting for delivery. Here is part of their web page and description of the amp. Did anybody try to connect that way: Mono Max Output Power(switch mono mode)：600W/ 2Ω（48V/12A）
(R+ connect to speaker +, L+ connect to speaker -)

L+ to speaker - (??)

I don’t think that’s unusual when bridging an amp?

 

[T&T]

I have owned both Aiyima 07 and 07Pro and never have a problem shutting down using 48v 5a power supply, used for several hours in a day, I am not a DJ, so I don't need to place the volume at max and that can be a problem maybe.

 

[Joe Smith]

While I agree that would be great, I have to think the market for genuine mono blocks, with one tap going in and feeding one channel only, appeals to a very small market. Also, the amount of power typically cranked through mono blocks by 'enthusiasts' is much higher than the vast majority of users ever call for, making for a niche market IMO. I think that the sweet spot for these manufacturers is probably something akin to the A07 Max or the upcoming Fosi ZA3, hopefully with load independence.

You are probably right, but I continue to hope that Fosi will release some "pure" amps without a volume pot. I'd like to be able to control via one preamp, one volume pot for both channels. If not monoblocks, then something that would be the Class D answer to the Schiit Vidar 2 but coming in the $200-300 range. Much higher than that, and it would be too close to the Hypex 2-channel builds, such as Buckeye, VTV, etc.

 

[TonyJZX]

i personally think the $500 it takes for a basic XLR 250NC amp is far away above these units.. its another class... i mean these are only $100 base.

i think Aiyima is the winner so far with the MAX seemingly the best out of this. I mean we will see closer to Xmas when new models come out form the competition.