AIYIMA A07 TPA3255 Amplifier Measurements and Review - LM4562 (and OPA2134) option

[levimax]

I tend to agree but then again AIYIMA offers an "upgrade" opamp version of the A07 on their website. Do you think they tweak the circuitry for the "upgrade" opamp? I doubt it. Do they just do this for the uninformed?

They don't need to do anything as confirmation bias will make the upgraded op amp sound better to most people. Most if not all the differences would disappear if the comparison was done blind and level matched.

 

[Lräk]

I don't understand this opamp rolling. To my knowledge the circuit around the opamp needs to be designed specificly for the opamp used. Just because it fits mechanically and has the same pinout doesn't mean it fits the electric circuit i sits in. People don't go around 'rolling' different to-3 trannies in their amps, do they?

Nope. These designs have just been copied year after year. The NE5532 is a very old op amp. The fact that I could find at least 2 op amps from ADI that easily worked shows how easy it would be to try different ones. I actually thought the ADI chips did sound better.

 

[375HP2482]

Birds gotta fly, fish gotta swim, tweakers gotta tweak.

 

[ToMyr]

Birds gotta fly, fish gotta swim, tweakers gotta tweak.

Fools got to get fooled

 

[ToMyr]

Nope. These designs have just been copied year after year. The NE5532 is a very old op amp. The fact that I could find at least 2 op amps from ADI that easily worked shows how easy it would be to try different ones. I actually thought the ADI chips did sound better.

people tend to like tweaks that turns something neutral into not neutral, and especially if they tweak it themselves. There is nothing wrong with the 5532, and there is ofc possible that a pin matching substitute can sound better/better in the ears of the tweaker. Never the less: an opamp must have the circuit around optimized/adapted for it. It is possible to design the circuit so that it is less picky about what opamp is used, but that again means you're not getting the best out of it.

 

[375HP2482]

Considering the large amounts of negative feedback employed in the low-gain circuitry using the NE5532, the best one can hope for is an opamp with a lower noise figure, which would lower the noise maybe one dB or so -- a difference likely below perception.

As an aside, back in the sound reinforcement days of the early 70s we were making our own mixing consoles using mainly LM747s (dual 741s). We would have killed for something like the NE5532.

 

[LtMandella]

I bought two A07s, one to experiment with and one to listen to (and maybe eventually I will try bi-amping).

I own multiple preamps (Transcendent Grounded Grid, Hafler DH-101 x 2), Musical Fidelity preamp out from M1Clic, Musical Fideltiy preamp out from A1-2008, FIIO headphone out, etc, etc, etc.

Would there be any sonic advantage to bypassing the "preamp/input buffer stage/volume control" of the A07 and use my other preamps for line level gain and volume control, and the A07 just for power? Due to the A07 having only one input I am now always using external preamp so I juggle two volume controls.

If there would be a potential sonic improvement, what would be involved in a bypass effort?

Maybe just short the volume control?

 

[Zek]

Maybe just short the volume control?

The simplest way is to set A07 volume control to maximum and control the volume with the connected preamplifier.

 

[pma]

You might get a bit lower overall noise, however I do not think you will get any "improvement" in perceived sound that could be demonstrated in a DBT test.

 

[LtMandella]

The simplest way is to set A07 volume control to maximum and control the volume with the connected preamplifier.

I was thinking that would result in too much gain but worth a try.

 

[LtMandella]

You might get a bit lower overall noise, however I do not think you will get any "improvement" in perceived sound that could be demonstrated in a DBT test.

oh well, another dumb idea of mine to go in the circular file

But perhaps there is a flaw - or at least limitation - of the logic of DBT. It is quite possible that any one change might not improve distortion enough to be audible by itself in a DBT. So one could eschew multiple different changes in the presumption that any one change might not be audible. But couldn't they accumulate improvements? Such that eventually individual - and perhaps inaudible - improvements accumulate to the point a DBT would succeed in identifying a group of improvements.
But you would never get to that benefit if you bypass individual improvements in the presumption that each one on it's own would likely not be audible.

 

[Zek]

I was thinking that would result in too much gain but worth a try.

Or maybe you should set the A07 volume to the loudest you listen to (and a little more than that), then adjust the volume level on the preamplifier.

 

[LtMandella]

Or maybe you should set the A07 volume to the loudest you listen to (and a little more than that), then adjust the volume level on the preamplifier.

Yeah finding the sweet spot between the two is what I have been trying to do. Kind of a pain when switching sources with different output levels and no remotes anywhere

 

[Barbar]

In another topic, I wrote a couple of arguments about why some people hear the difference in OP and that even the most accurate measurements do not give a complete picture. In order not to repeat myself, I will post a link: https://audiosciencereview.com/foru...rent-are-that-many-confused.9245/post-2081117

 

[somebodyelse]

In another topic, I wrote a couple of arguments about why some people hear the difference in OP and that even the most accurate measurements do not give a complete picture. In order not to repeat myself, I will post a link: https://audiosciencereview.com/foru...rent-are-that-many-confused.9245/post-2081117

You fail to demonstrate that people can in fact hear a difference between opamps in situations where measurements show no significant difference in performance. It's like making arguments about why the earth is flat without first demonstrating that it is in fact flat.

 

[chasmo57]

Hi
I have an identical pair of Aiyima A07's and just discovered the this forum. As a result of reading, I obtained some LM4562's to upgrade one amp. I have tri-amplified speakers(w/subs) and am using one of the A07's for the 500Hz-3kHz range, and the other handling 125Hz-500Hz.
It is my experience in listening to my most familiar music that in going from the NE5532 to the LM4562, I hear a noticeable improvement in detail resolution and soundstage/imaging. This is most audible in the 500-3000hz band.
First I listened with 5532's, then switched to the amp with the LM4562's. I switched back and forth several times and at one point lost track of which amp was modded(covers in place).
A careful listen was all I needed to identify the one with better opamps. The venerable 5532 has been dethroned!

 

[chasmo57]

Post script:
Now to get some OPA2134's for the 125-500Hz amp!

 

[Svend P]

As a result of reading,

Certainly not on ASR...

Op Amp Rolling

In the review of the Fosi V3 (Fosi Audio V3 Amplifier Review), Amir wrote “There are replaceable op-amps for those of you who have nothing better to do than mess with the design.” For those who want to do just that, it is difficult selecting which op amps to “roll with”. Both the Fosi V3 and...

www.audiosciencereview.com

You are doing it wrong

And welcome to ASR.

 

[chasmo57]

Certainly not on ASR...

Op Amp Rolling

In the review of the Fosi V3 (Fosi Audio V3 Amplifier Review), Amir wrote “There are replaceable op-amps for those of you who have nothing better to do than mess with the design.” For those who want to do just that, it is difficult selecting which op amps to “roll with”. Both the Fosi V3 and...

www.audiosciencereview.com

You are doing it wrong

And welcome to ASR.

Apparently not,
as I got two gifts:
1. I'm happy with my sound, and 2. I got a warm, (cordial?) welcome from someone who apparently must care. Thanks(& peace)
p.s. what was this thread called, anyway?

 

[chasmo57]

"You are doing it wrong"

But it feels right..
by any measure.