Topping PA5 II Stereo Amplifier Review

[RickS]

Hi folks!

Just a reminder to keep this thread on topic and take the rest to other threads or direct messaging please.

 

[Julf]

Why do you understand sighted listening? Is that what you understand? I didn't mention anything about sighted listening.

Because you didn't mention blind listening.

What is sighted listening for you?

Listening where you don't know which of the alternatives you are listening to.

The resolution of the final perceived sound is not only SNR. I explained in a previous post. Even the room can downgrade the resolution of the perceived sound.

No, you explained what you mean with the term. It seems your own private meaning of the word.

 

[lunaria]

That is the point though. Amps don't do that. They pretty much universally have ruler flat frequency response, low output impedance, and low distortion.

That's plain nonsense as a blanket statement. A lot of class D amps have a very poor frequency response with complex loads. With difficult to drive speakers, that can be several dB variation across the frequency band. I have difficult to drive speakers and have measured several different amps.

Class AB amps are generally very well behaved. Good class D implementations (e.g. Hypex, Purifi, ICEpower, good tpa325x PFFB implementations like PA5, ...) are also very flat.

 

[antcollinet]

Iam not affected by visuals, brands or whatever else.

Yes, you are - just like all other human beings are. Information from our sense are modified by our perceptive biases. It is happening all the time, we cant' stop it from happening, and even when we know how and when it happens we still can't stop it.

It is simply how our senses work.

It is why in all areas of science when human perception is tested, controlled blind testing is used. Without that it is impossible to know if what you are declaring as "different" is actually in the sound reaching your ears - or created in your unconscious brain by your perceptive biases.

So your talk of knowing how to do proper testing, and having the right equipment for it, is just an illustration that you don't.

 

[antcollinet]

That's plain nonsense as a blanket statement. A lot of class D amps have a very poor frequency response with complex loads. With difficult to drive speakers, that can be several dB variation across the frequency band. I have difficult to drive speakers and have measured several different amps.

Class AB amps are generally very well behaved. Good class D implementations (e.g. Hypex, Purifi, ICEpower, good tpa325x PFFB implementations like PA5, ...) are also very flat.

Yes, you are right - I sort of glossed over the cheaper class D's without good PFFB, because it is not really important to the point I was making.

Because even then - your 1 or 2 dB (or even 3 or 4) load dependency is small compared with room effects that can easily be +/- 10dB or more.

And have you ever taken a measurement of the frequency response of an amp, and found it reacts perfectly with your speaker to cancel out room modes and cancellations? Of course you haven't.

So the main point of my post, that amps don't "cover" a speaker's harshness is still valid. Even with the load dependent amps - where my ruler flat frequency response statement is not so accurate with some speakers. They are still not able to "synergise" with speakers to correct bad room interactions - or even bad speaker responses.

 

[MAB]

Yes, you are right - I sort of glossed over the cheaper class D's without good PFFB, because it is not really important to the point I was making.

Because even then - your 1 or 2 dB (or even 3 or 4) load dependency is small compared with room effects that can easily be +/- 10dB or more.

And have you ever taken a measurement of the frequency response of an amp, and found it reacts perfectly with your speaker to cancel out room modes and cancellations? Of course you haven't.

So the main point of my post, that amps don't "cover" a speaker s harshness is still valid. Even with the load dependent amps - where my ruler flat frequency response statement is not so accurate - with some speakers - they are not able to "synergise" with speakers to correct bad room interactions - or even bad speaker responses.

Yeah. Amps with unflat frequency response get measured and called out for their frequency response variations here. Your statement isn't nonsense at all, doubly so since I have never seen a Class D amp with a FR that could mask or somehow mitigate harshness.