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Aiyima A07 Max Amplifier Review
- Thread starter amirm
- Start date
Well in order to measure the output of the amp you need to be using a differential probe for your scope. Are you? If you are, what is the channel balance of the probe?
Sure they are - but only when that quality exists in the frequency band to which they are sensitive. They are not sensitve to any frequencies at any level outside that bandwidth - especially 4 and a half octaves outside. The bio-meachanics of the ear literally has nothing to respond to them with. Even if the speaker were able to create a sound wave at that frequency - which they cannot.
But look - I've said that three times now in different ways, and you are not getting it. I suggest we stop. I will at least.
At idle (no input), for a class d amp, the duty cycle of the PDM output is 50%, i.e. a regular square wave at the switching frequency (see the PDM waveform near the zero crossings on the sine wave). Therefore, the output before the LC filter is this square wave alternating between the rail voltages.
Below is the output noise spectrum of the Topping PA5. (I spent a few minutes looking but failed to find a similar plot for a TPA 3255 amp). The TPA 3255 amp switching frequency was at ~450 kHz in the scope trace, so the output filter attenuation could be several dB less at than the 38 dB of the PA5. When we have a 48 VDC rail in BTL mode, a switching noise Vpp of ~1 V should be more or less typical. The pertinent question is what the speaker impedance is at the amp switching frequency, and that will tell us how much current and power go the speaker.
Below is the output noise spectrum of the Topping PA5. (I spent a few minutes looking but failed to find a similar plot for a TPA 3255 amp). The TPA 3255 amp switching frequency was at ~450 kHz in the scope trace, so the output filter attenuation could be several dB less at than the 38 dB of the PA5. When we have a 48 VDC rail in BTL mode, a switching noise Vpp of ~1 V should be more or less typical. The pertinent question is what the speaker impedance is at the amp switching frequency, and that will tell us how much current and power go the speaker.
Some thoughts:
I am using now two Aiyima A07 Max in dual mono as stereo amp
- so far so good (with stock power supply, enough for me for now for very reasonable price).
I hope Aiyima is monitoring this chat - thanks for such a good product and I'd like to suggest
- A07 Max has sliding switch on the bottom to change stereo and mono mode.
When you use this amp in mono mode - second pair of speaker terminals cannot be used - wasted.
It would be nice if this Amp also could have additional switch
next to stereo/mono one: only if Amp in mono - use 1st speaker or use 2nd speaker.
In this case Amp in mono mode will be able to use all available speaker terminals
to handle 2 speaker sets, similar to full size stereo amp.
I am using now two Aiyima A07 Max in dual mono as stereo amp
- so far so good (with stock power supply, enough for me for now for very reasonable price).
I hope Aiyima is monitoring this chat - thanks for such a good product and I'd like to suggest
- A07 Max has sliding switch on the bottom to change stereo and mono mode.
When you use this amp in mono mode - second pair of speaker terminals cannot be used - wasted.
It would be nice if this Amp also could have additional switch
next to stereo/mono one: only if Amp in mono - use 1st speaker or use 2nd speaker.
In this case Amp in mono mode will be able to use all available speaker terminals
to handle 2 speaker sets, similar to full size stereo amp.
Well, you can't. First, in mono mode the amplifier will use both positive terminals from both channels Why? Because it is using both channels as a one.
Do you want both channels outputing the same signal(left or right) to a 2 different speakers?. Are these speakers identical or with same sensitivity? If not one might sound louder than the other.
Let me tell a story. One day I was dissassembling the amp and inspecting what was inside, and by mistake I moved the mono/stereo to mono without knowing. After reassembling and connecting my RCA and speakers cables I noticed my speakers were playing really weird, I lost all the imaging and sounstage, i thought I broke the amp or something. I was getting mono from both speakers. Until I realized I moved the switch.
So, you can try exactly that, use mono mode, connect you RCA cable into the left channel on both amplifiers and use both speaker outputs from each amp for left and they other for right.
Tecnically this is not a true mono mode, because for a true mono you need to use both channels together to feed one speaker.
I really don't understand why you would like to do something like this in first place.
I really don't understand why you would like to do something like this in first place.
- Why full size stereo amp usually has terminals to handle 2 sets of speakers?
Why can't i have the same in case of A07 Max in dual mono (unless it is technically impossible)?
Looked for a good cheap small class D amp for my dad who is a bit hard of hearing. And the gain together with max power on his old amp wasn't giving him good levels on some stations. And yeah, it's the trusty Dayton DTA-1, so not a lot of real power. So I found this, measurements are okay, price is good, Amir even liked them on his Revel Salon, let's go.
Got it, hooked it up to my own system with two UniFi Reference floorstanders which so far have been powered by an IcePower 125ASX2. Thought it would sound about the same. Nope, there is a lot more resolution on tap across the whole frequency range. Plus, this drives much harder and bodily dynamics than the IcePower. With the IcePower, I heard the outlines of the drums cleanly but there was no body to the whole event.
Now, it's of course also the speakers, my Klipsch RP600m-II had no problem doing that with the IcePower amp. But now I also have some of it on my Elacs. Very impressed.
That said, I'll have to get used to this clarity a bit. Not sure if treble is 100% smooth. Could of course also be the tweeter, there is only so much you can get a non dimple, non ring cloth dome.
This is some amazing 120€ amplifier. Almost tempted to keep it so I can compare when I get a Hypex nCore later this year.
And really wasn't prepared for the greater palpability and texture in the bass. Why is this there? Maybe different output impedance? So yeah, thanks to Amir for hooking it up to his Revel and making me pull the trigger
Got it, hooked it up to my own system with two UniFi Reference floorstanders which so far have been powered by an IcePower 125ASX2. Thought it would sound about the same. Nope, there is a lot more resolution on tap across the whole frequency range. Plus, this drives much harder and bodily dynamics than the IcePower. With the IcePower, I heard the outlines of the drums cleanly but there was no body to the whole event.
Now, it's of course also the speakers, my Klipsch RP600m-II had no problem doing that with the IcePower amp. But now I also have some of it on my Elacs. Very impressed.
That said, I'll have to get used to this clarity a bit. Not sure if treble is 100% smooth. Could of course also be the tweeter, there is only so much you can get a non dimple, non ring cloth dome.
This is some amazing 120€ amplifier. Almost tempted to keep it so I can compare when I get a Hypex nCore later this year.
And really wasn't prepared for the greater palpability and texture in the bass. Why is this there? Maybe different output impedance? So yeah, thanks to Amir for hooking it up to his Revel and making me pull the trigger
Turboscienziato
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Hello everyone, I've been lurking on the forum for a while and I'm writing from Italy. I own both the Fosi V3 Stereo and the Aiyima A07 MAX and I don't know if it's already been said but, the Aiyima is inverting, so the output is not in phase respect to the Fosi. if you use these amplifiers in multi-amplification after a DSP check the correctness of the phase.
I can confirm this info. I ran few polarity test tracks (which I found here) and with simple DC measurment on binding posts I was sure.
But to be frank, if I remember corectly, Fosi was in the same bucket with inverted phase too.
Btw hello to everyone here from Croatia, this is my first post too. I've been lurking around from 2017
Welcome to ASR!I can confirm this info. I ran few polarity test tracks (which I found here) and with simple DC measurment on binding posts I was sure.
But to be frank, if I remember corectly, Fosi was in the same bucket with inverted phase too.
Btw hello to everyone here from Croatia, this is my first post too. I've been lurking around from 2017
Thank you for sharing this diagram. I just bought a pair of used Klipsch RP-260F and I believe they are 8Ohm and the recommended power is 125W per speaker. I already had A07 Max with 48V/5A power supply. I believe that according to this diagram in mono mode this amp should be putting out max 125W exactly (midpoint between 100 and 150). I bought another amp just like that and I am planning to use two of these A07 Max 48V/5A to drive the two RP-260F speakers. Does that make sense? I tried it on one speaker and I think it sounds ok but I wanted to make sure I am not missing anything.Hi tommy6
Regarding the heat to the touch of your AIYIMA A07 MAX, what power supply do you have ?
Or rather, we should ask the question differently:
- What is the impedance of your speakers ?
- How much power do you need ?
Here is a table about PSUs ->
View attachment 387184
Explanation:
The TPA 3255 (amplifier chip) in your amplifier works best at its maximum frequency AND maximum voltage.
However, you have to take into account the heat dissipation surface (here the box in direct connection with the chip heatsink) of your amplifier which is rather small in consumer amplifiers (such as the FOSI AUDIO V3 for example).
So, what I say above is NOT APPLICABLE because indeed, and you have noticed it: your device will become too hot !
It is therefore advisable to take a power supply with the lowest voltage on the board according to your needs, which will limit this heat dissipation as much as possible.
You can also increase the space between the bottom of your amplifier and the surface it sits on, this helps a bit with cooling.
To cut off the power supply to your amplifier, the best thing to do is to do it manually while waiting for an additional box allowing the amplifier to be switched off without the presence of a signal or for manufacturers to integrate this original function into their device, a bit like the 12V TRIGGER socket that exists on some.
But if you search on AMAZON, there are TRIGGER 12V driven IEC sockets that could be a solution....
In my honest opinion - Klipsch RP-260F's sensitivity is 97 dB and my conclusion is that they are not hard to drive speakers at all. I can't imagine a situation where one needs 125 W per speaker of that sensitivity. In spec sheet it says " power handling: up to 125 watts RMS " , it's "up to" , not "recommended" , but still, you could power Klipsch RP-260F's with 50W RMS (even lower) per channel easy-peasy, still depends how loud you want to go.
About 07 Max, I got two of them, but using only one, powering my Monitor Audio Silver 100's. From power aspect we are talking about filling larger room with hearing damaging level's and my Silver's are harder to drive than RP-260F (adjusted dB on my dac which is 2V to match 1V input sensitivity of 07 Max).
No - only the output is shown, so there is no reference (input) signal shown from which to determine the inversion.
@amirm - that might be a nice and (I'm assuming) easy addition to the dashboard. It would be nice to know if an amp inverts output WRT to input.
Is it not the same output every other non-inverting amp has yielded? Why would the input for this unit suddenly be different from other amps he has tested?
staticV3
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The audibility of absolute phase is debatable.
Some can supposedly hear it on natural sounds like guitar notes, but in a busy mix it's a wash.
From what I've read, I'd place the audibility of absolute phase in the real of different DAC oversampling filters. Maybe below that.
Generally, as long as both channels are in-phase relative to each other, and the phase vs frequency response is flat(ish), you're not missing out.
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Whether audible depends on many factors. Chesky has some tracks on one or two discs that attempt to demonstrate any audible effects of inverted polarity.
BUT, the first graph of nearly every amplifier review here seems to show the output in absolute time (that bottom axis is time). Any inverting amplifier should show an inversion of this output signal, unless an inversion is being performed on the input signal and we're not being told (seems unlikely).
the problem comes if you use it with another non inverting amp.
For example if you use it with an AVR to amplify the L&R channels while using the AVR amps for the rest of the speakers.
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