I‘ve ran into multiple reviews of the A90D lately on YouTube where the reviewer critiziced the A90D for being „too perfect“. They say it is only built around measurements.
At the end of those videos they claim you essentially need a certain degree of distortion to even make the music enjoyable and how better amps sound which measure worse. They even claim those „worse“ amps are so much better and they even deliver better soundstage, more details, better bass etc…
Is this all the classic audiophile esoteric nonsense or do they have a point?
They have to have something to validate their review as far as their hearing is concerned, same as stereophile and all the rest, their idea of value add is to describe how in thier system at that moment in time the thing sounds to them. The problem comes when they review gear that is as transparent as the Topping, they are hearing what is on the recording but, still through their system at that moment in time. So, really unless you have their system and biases how can you take anything away from what they reviewed?
It has to be mentioned that measurements into a resistor are not the same as into a reactive load such as a headphone speaker for example. I am not knocking resistor measurements as they allow everybody to measure the same thing across the planet, but they way the device interacts with those reactive loads can make a difference in sound. The damping factor alone can make an audible difference depending on how poorly the speaker is engineered. So, there are variables, and hearing a difference is not some big deal, we can all hear differences.
The question is, how well does the amplifier amplify the signal without adding or subtracting anything, using your own speaker or headphones.
In other words, if the amp has a high damping factor (atleast 370) then you will not hear the interaction between the amp and the speaker connection, then how well does the amp provide the current needed to deal with the reactances in the speaker/phones and thus keeping the signal faithful.
So, yes, they do have a point, different amps certainly can sound different, but an amp such as the topping or benchmark or others, with super high specs to start with, and with good reserves of power, should be able to replicate a larger copy of the signal input to the amp at the speaker connectors with no additions of subtractions through out the audible band, but without measurements for that particular combination we are just going off of human hearing which is not much to go off of and certainly not objective enough.
The disconnect with measurements is when we just use a resistor and not the complex load of the headphone or the speaker, ie the transducers.
The next disconnect is not measurements but that even if the amp manages to produce an exact but amplified copy of its input at the speaker terminals (ie we measure at the speaker terminals) then now we are listening to the individual nuances and shortcomings of the speaker AND or our own biases of what we think things are supposed to sound like, even though the mix and master engineer already decided for us what they think sounds right. How can you win with so many variables in audio?
Can a certain degree of distortion sound better, of course it can. Stereo is a weak replication system of an actual event and that is a fact. It was great for the movies to show sound from the left or right side of the screen, but when you take away the visuals and let folks hearing and brains try to recover information from such a limited system, then often particular distortions or enhancements can make the illusion more fun if not more believable for some folks. Certianly the whole recording process is an exercise in intentional distortions, from mic placement to mixing to make the drums sound like drums etc.
The caveat of course is that the distortion if added by your device paints all incoming signals with the same brush, which may be good and may not, depends. For example, I enjoy SET sound, and I know I am not getting pure replication, but I enjoy the distortions and other effects that SET does for the sound of the music and dynamics. Sometimes, I want clean sound, such as what the A90D does, and I can certainly hear and enjoy the clean sound of this headphone amplifier and have never experienced any fatigue at all so that says a lot to me and my preferences.
I would love to see Amir add another measurement where he uses an actual real world "difficult load" and does a multi tone sweep and looks at the FFT of that to see what happens, this will show how much control the amp ( a voltage feedback amp for example) has over a real world device at really replicating an input signal at reasonable power levels from very low to pretty high as far as the rating of the amp goes.
Personally, one has to decide do they want an electronic device to pass the signal with the least harm or do they want it to be some sort of tone control. Or, as in my case, just choose which way you go depending on your mood at the moment.
Yes, a test some folks can do is listen to a cd test disc for example a 1Khz tone, then listen to the LP test disc 1Khz tone, and I bet for "pleasurable sound" the ever so slightly distorted version from the vinyl will be preferred, thus distortions can embellish and flesh out lots of recordings if you feel the mix and master engineers did not do enough of it for you when laying down the tracks.
