Aiyima A07 PRO

[Daniel55]

Hello everyone. Good thing i read this thread before the store shipped out the A07 PRO. Already cancelled it and ordered the A07 non pro version instead. Thank you all for the review and insights, much appreciated.

 

[Scrufboy]

Not only that... I was being silly.... And not on purpose. For some reason dementia set in. I thought I was supposed to be seeing a pos & neg on the binding posts like you would with a set rca's. Which is odd considering how many speakers I've serviced over the years. After I posted, it took too long for me to realize the dumb shit I was saying and I couldn't edit the post and inform you all of that laughable gaff.

you can check again, 2 output pin of each op-amp are wiring to 2 10uf nichicon bp, there are 2 differential input.

 

[Scrufboy]

Well, It is a decent amplifier... I has grown on me. But as feature sets go. If you don't need or want tone controls or Bluetooth., Yes, the A07 is a great choice.

Both amplifiers benefit from competent op-amp swaps.

Hello everyone. Good thing i read this thread before the store shipped out the A07 PRO. Already cancelled it and ordered the A07 non pro version instead. Thank you all for the review and insights, much appreciated.

 

[Daniel55]

Well, It is a decent amplifier... I has grown on me. But as feature sets go. If you don't need or want tone controls or Bluetooth., Yes, the A07 is a great choice.

Both amplifiers benefit from competent op-amp swaps.

It's a decent amplifier for sure. What changed my mind is the dull RCA output reported here. Decided to settle with T9 Pro (BT with tone control) + A07.

 

[LDvo]

It's a decent amplifier for sure. What changed my mind is the dull RCA output reported here. Decided to settle with T9 Pro (BT with tone control) + A07.

Well, are we sure about this issue? Could someone else confirm the same to make sure it is the issue with A07 PRO and not single unit or setup problem?

 

[Scrufboy]

It's a decent amplifier for sure. What changed my mind is the dull RCA output reported here. Decided to settle with T9 Pro (BT with tone control) + A07.

Yep... I just went to check. Listening to Imagine That by Fatt Burger.

The picture shows where I have to put the tone controls to match the RCA DAC to the dynamic of Bluetooth.

It doesn't sound bad per se, just not as vibrant and crisp. The RCA seems "warmer" as in less Treble... Higher mids...

But remember, I did say I needed to test this with a different DAC. I'm using a Schiit Hel 2e currently to test.

So the Dull RCA is only my experience. The difference isn't subtle though.

But you, using the T9 would possibly be warmer sounding anyway. Probably close to the RCA of the Aiyima A07 Pro.
The T9 is using the same DAC chip and op-amp as the Schiit Hel and it's got that tube thing going on. Probably sounds great.

But whether or not your T9/A07 sound is similar to my Hel/A07 Pro - That's pure speculation on my part. I suspect it is similar. I would be interested if your setup sounds different through the Bluetooth vs internal DAC with a PC source or some such.

 

[Scrufboy]

With Sparkos SS3602's

 

[Scrufboy]

Well, are we sure about this issue? Could someone else confirm the same to make sure it is the issue with A07 PRO and not single unit problem?

Got a substantial raise, Won't kick in until mid Feb... I would be willing to purchase another unit to test. I'll get the second one from Amazon so I can return it. It will invariably be from the same lot. I ordered the day the email came out direct from Aiyima.

We also have to remember that the inclusion of Bluetooth means they had an intended audience. They very well could have tailored the output to be really dynamic to wow that crowd.

I wish it was possible to invest the money needed for full blown controlled testing. A07 vs A07 PRO stock and the two with the same op-amps rolled. Different DAC - All that Schtuff!

 

[Scrufboy]

Important to note... I think we're done here for now.

The two pics I have posted here are pretty close to being tone matched. Or at least reasonably similar.

The red knobs are from my active system. This is the tone control settings for my headphones and ultimately the speakers. It's a Schiit Loki Mini+. This chain has an A07 with 2 SparkosLabs SS3602's driving the speakers.

The tone controls shown with black knobs are the A07 pro. The two are pretty close to being tone matched as you can see.

When I switch the Loki to flat/neutral with what is an effective tone defeat, the system, for the most part, sounds the same as when the A07 pro has its tone controls at the 12 position, which is effectively no added tone/flat as well.

My observations are that the A07 Pro's Bluetooth output, is artificially tweaked to have a sound that is a bit more punchy and dynamic due to the raised highs and lows. A slight V shape if you will.

When I first posted the picture with the A07 tone controls with this setting, I stated that this was where we tuned it so the RCA input/output matched as close as it could the sound of the Bluetooth output with the knobs at 12/flat.

So these amplifiers, both the A07 and the A07 pro, when compared, sound pretty much the same. The A07 though has a better posted SNR and THD+n than this "Pro" unit. So it isn't really a "Pro" unit after all.

You can effectively introduce tone controls without adding this much noise to the system.

The Loki Mini, which costs $149 USD has an SNR of greater than 114db and a THD less than 0.0008%

You get a nice range of frequencies to play with in the 4 knobs the Loki Mini+ gives you. Based on my system. All the components have very close SNR and THD numbers. Things are quiet.

Loki Mini+
THD: Less than 0.0008%, 20Hz-20KHz, at 2V RMS in/out, pots centered, active stage enabled, less than 0.005% at any potentiometer setting

SNR: Greater than 114db, unweighted, referenced to 2V RMS

My Magni+ Heretic measurements as posted on the product spec page are:

THD+N:
High Gain: Less than 0.0002% (-112dB) ref 2V RMS at 300 ohms
Low Gain: Less than 0.0001% (-119dB) ref 2V RMS at 300 ohms

SNR:
High Gain: Greater than 115dB, unweighted, ref 2V RMS
Low Gain: Greater than 123dB, unweighted, ref 2V RMS

The A07 amplifier with stock op-amps
THD+N:0.008%
SNR:110db

The A3001 subwoofer amplifier
THD: 0.03%. - not great!
SNR: ≥106dB

And now you have the A07 pro.
THD: 0.002%
SNR: 90dB. <- Seriously?!?!


A correction - so to speak
The A07 pro overall is not dull... And I really shouldn't have said that. Because dull as compared to the sound through Bluetooth is not a statement about poor sound quality with the RCA sound.. But moreover a confirmation as to who Aiyima really wanted to sell this "Pro" unit to.

The A07 and the A07 Pro essentially sound the same.

It is my opinion that while they upgraded a few parts and added all those op-amp slots.. It really wasn't designed to be a true A07 upgrade.. An A07 owner has no need to purchase the "pro" unit because it is not an upgrade to that unit. It is just another product for them to sell... One with objectively worse specs than it's predecessor. But catered to the mobile crowd for sure.

A "Pro" version of anything should not be measurably worse than the preceeding non-pro model.

Why they did this is somewhat confusing because they essentially already gave us a TPA3255 unit with Bluetooth and tone controls in the A08 pro. With a different shape and that VU meter.

The A08 pro also supports LDAC! Why doesn't the A07 Pro support LDAC?

The A08 pro has tone controls and a posted SNR of ≥104db. They however do not post the THD+n measurements.

(Aiyima at one point also produced and released an A07 with Bluetooth with what appears to be an overseas market test of sorts. You can find it on AliExpress.)

The Aiyima A08 pro was reviewed by Amir - Here

So for me it is clear... The amps are all very similar and Aiyima does a good job for the most part with their TPA3255 implementation.

That being said, with the ability to add Bluetooth to any part of your chain with components such as the DAC, headphone amp, Pre or speaker amp, etc. You can inject that as you see fit. I have Bluetooth capability with my Aune X8 XVIII DAC and it does not artificially Amp up the frequencies like the A07 Pro does.

Aiyima just wants to have a product that can be marketed and sold to the most people. Which makes sense from a business point of view.

However, that said... This A07 Pro basically has no need to exist. None at all. They did not specifically design it to be a straight and true successor to the A07.

Right now... There are folks who have already put sagami inductors and better capacitors into their A07 and swapped out the op-amps. Some have even modified the case for convective cooling.

All the things I posted in my thread of what the current A07 needed.

We didn't need tone controls or Bluetooth. Although there is an audience for both. These things can be in your chain though with much better performance without adding to the noise floor.

Aiyima already make units with these features and the often suggest these other units be chained in front of the A07.

So while it is a good amplifier, the A07 Pro as it exists now... Doesn't need to exist. It doesn't do anything for the A07 user in regards to being a "Pro" version.

Not when you can modify your A07 to be a Pro unit for far less money by buying a few capacitors, a few inductors, some op-amps if desired and a better power supply.

I am very disappointed.. But not dissatisfied per se. Vote with your dollars and just buy the A07 if you are looking for a component to add to a simple stack.

But if you really are on a budget and just need a simple 2.0 system to drive speakers via Bluetooth... Then the A07 pro is all you need. You will like it.

Is the A08 pro better? Or the T9? Only a massive review thread with all the items measured, listened to and compared can we truly know...

My take..
Dump the Bluetooth, the tone controls... Make sure the SNR & THD is equal to or better than the A07... Then maybe you could call it an upgraded A07. But you have no business calling this a "Pro" anything.

I look forward to hearing more experiences with the A07 "Pro" from this fine community of audio enthusiasts.

It takes a village... Am I right?

 

[Scrufboy]

Douglas Blake in a YouTube thread offers us some clarity on the op-amp front.

Douglas writes:
The TPA3255 is actually 4 power-amps on a chip. When used in BTL mode, the left channel gets 2 and the right channel gets 2.

These pairs have to be driven out of phase to produce the kinds of power you get from it. That is when amp 1 is going positive amp 2 from the same pair has to be going negative.

The signals are identical, but one is inverted. The chip itself does not include the circuitry to do this, it is provided externally through the op-amps... Each chip (U2, U3, etc.) has two op-amps in them. One is physically on the left side of the chip the other on the right... So in total you have 10 actual op-amps in 5 packages.

So, from your description U8L is buffering the left channel input, U8R is buffering the right channel input. Similarly in the tone controls... U9L does left channel tone controls and U9R does right channel tone controls. Then again... U16L is driving the left channel line out and U16R is driving the the right channel line out. That's all pretty simple.

But, when you get to U2 and U3 something different is happening... U2L is set up as a non-inverting driver for the power amp's left-1 input, U2R is set up to invert and drive the power amp's left-2 input. Remember, they have to be out of phase for that to work... U3L and U3R perform similar duties for the right channel's power amps, 3 and 4.

Personally, I would not have done it that way, but from what you describe, that's the way Aiyima did it. I hope that helps....

 

[conradj]

That's interesting, that the A07 amps are set up that way. So, changing just those 2 op amps will directly affect the sound of the unit. Guess i should change them all anyway.

i just received my A07 Pro 2 days ago, have it connected to a Topping E30 II that i received the same day. It takes a few days for the amp to run in and sound its best, is that so?

i have its tone controls zeroed out and volume at max. Using the E30 II to control volume.

When i first powered it up the A07 Pro was a bit mushy with orchestral music. That cleared up quickly. No complaints or other observations so far. This amp and the E30 II seem to be a good match.

Wanted a line out for the sub, so got this model rather than the A07.

 

[Scrufboy]

Wanted a line out for the sub, so got this model rather than the A07.

Both the A07 and A07 pro have a 3.5mm jack for output to a sub, or another amplifier. The A07 though is really more of a pass through and can be used as input instead of the RCA jacks. But it is there. I have my A07 connected to the Aiyima A3001 subwoofer amplifier.

 

[conradj]

o yes: my bad. The pass through in the A07 isn't controlled by the volume knob, and the line out in the A07 Pro is. Of course, that doesn't matter the way i've set it up now. Did intend to use the volume knob on the unit when i made the purchase.

Dug out an old baggie of AD827SQ/883B and swapped them in. i don't have golden ears; more like tin cans with strings. Do hear a more dynamic sound and better details in the highs. The stuff in the middle sounds thicker. The drums in the orchestra're better defined. A mild improvement tho will take time to figure out whether i like it.

 

[conradj]

ok, just experimented and found that the line out in the A07 Pro isn't tied to the volume control. It's a pass through.

Finding the AD827SQ/883B nicer than the NE5532 but is still suboptimal. For one the line out is a lot quieter and i have to crank up the subwoofer quite a bit. Also had to redo the speaker EQ, which is neither here nor there, but interesting.

Don't have anything else on hand so will start looking around.

 

[Scrufboy]

ok, just experimented and found that the line out in the A07 Pro isn't tied to the volume control. It's a pass through.

Finding the AD827SQ/883B nicer than the NE5532 but is still suboptimal. For one the line out is a lot quieter and i have to crank up the subwoofer quite a bit. Also had to redo the speaker EQ, which is neither here nor there, but interesting.

Don't have anything else on hand so will start looking around.

Well in the Pro it is pass-thru and it isn't. With the A07 - The two in/outs are basically wired together. Either can be used as inputs. Older units actually had the L&R reversed.

With the pro... Whatever the unit does to "pass-thru" it still goes through the U16 op-amp. So while it isn't connected to the volume knob, I would be interested to see just how much of the signal is affected...

Like If I connected an A07 to the one out of the A07 pro... Ran speakers only from the A07, would the tone controls affect it... Or is the signal only affected by other particular processes and the U16.

The signal has to be passing through more than just the op-amp... At least I believe it is... I could test this out...

Wanting to vent the chassis first though...

Thanks by the way for joining the thread and posting your experiences!

 

[conradj]

o i'm just a user, not like you folks. Haven't any testing equipment more sophisticated than a simple multimeter. And no metal working tools; can't cut a straight line so won't try venting the case.

Think i'll try some OPA1656 next, on those little adapter boards. Have an Aiyima DAC-A1 coming and hopefully the NE5532's in that will be swappable with the OPA1656 as well.

 

[Scrufboy]

o i'm just a user, not like you folks. Haven't any testing equipment more sophisticated than a simple multimeter. And no metal working tools; can't cut a straight line so won't try venting the case.

Think i'll try some OPA1656 next, on those little adapter boards. Have an Aiyima DAC-A1 coming and hopefully the NE5532's in that will be swappable with the OPA1656 as well.

I'm just a user too. There are slight improvements any user can make to add to the longevity of the amplifier or slightly tweak the sound. Thermally bonding a heatsink is not a big deal. You're already swapping op-amps.

The case, yeah, daunting and time consuming. And my results so far are less than stellar. At the time of posting I am only halfway through with the pilot holes.... Some of them had a bit of drift... So my symmetry is off a d the look won't be as professional as I would like...

But the heat will escape... So this, in my mini rack won't even be seen.

 

[T&T]

I just get the Pro, be extremely careful, this opamps are hard to get it out...so the bottom line sounds better than 07...I have quite some opamps, so I tried all 5 opa1656, some opa627, muses 02, lme49860 and some other opamps...I am tired... so concluding 3 opa1656 and 2 opa2604 for now sounds better like I said for now

 

[Scrufboy]

 

[Joe Smith]

I wish Aiyima would offer ventilated cases...even a few holes would help. Nice work, yours turned out great to my eye.