Topping PA5 Review (Amplifier)

[amirm]

Our ears are much more sensetive to IMD than HD. There is of course a reason 18-19 khz is a standard test.

What standard? AP software has no built-in IMD test set of 19 and 20 kHz. It can be done but it is a custom test. In sharp contrast, there is SMPTE and CCIR IMD tests.

 

[Mulder]

Well, the argument was strange. You don't want to diminish the value of measurements in one breath, and in the other say we should measure even more stuff that is even harder to show the value of.

???? What I wrote, or at least tried to say, was that the term "realism" is a fairly arbitrary argument.

 

[TNT]

Because harmonics of 1 kHz tone land where our hearing is most sensitive and has the highest chances of being heard. 19+20 kHz does not at all represent that. There is just no argument for why it produces anything useful. Any perceptual analysis will nullify its value.

No but these 2 tones may produce a tone that is in the most sensitive region - as you just mentioned. But still, what kind of music has any energy here. Its a clinical measurement - but isnt that what this site is all about

Its a pity that the measurements was not really carefully picked out at the advent of ASR as, as of now, on cant compare different products really...


//

 

[Walter]

https://www.audiophonics.fr/en/integrated-amplifier/topping-pa5-balanced-class-d-amplifier-2x125w-4-ohm-black-p-15847.html

Correct, PA5 costs €349 in Europe (with tax and duties) and Audiophonics NC122 amp costs €399 with tax.

Yeah, with that pricing, I'd let my usage decide. If I needed the smaller size or volume knob, PA5. If not, NCore.

 

[DanielT]

Yes he does https://www.stereophile.com/content/nad-c-298-power-amplifier-measurements

Hm, did that square wave look so good? What can be deduced from that regarding the performance/ sound in the NAD C 298?
I post a picture to compare with. A vintage receiver Harman Kardon 330C. Measured square wave. See attached picture with occiloscope.
(not me who carried out that measurement)

 

[pma]

Hm, did that square wave look so good? What can be deduced from that regarding the performance/ sound in the NAD C 298?
View attachment 170807

Here is a measurement of a 70's receiver Harman Kardon 330C even such an old one, it looks better:

View attachment 170808

Please use the same time division. The upper plot is in 20us/div, the oscilloscope shot is in 200us/div (0.2ms/div). This is not a fair comparison. You have 10kHz square vs. approx. 1kHz.

 

[Frank Sol]

I am not a fan of that test since both tones will be full amplitude at levels that are not remotely realistic.

"Fan" ? Interesting

The test is just an Objective measurement... Nothing to be a fan of or not

 

[DanielT]

Please use the same time division. The upper plot is in 20us/div, the oscilloscope shot is in 200us/div (0.2ms/div). This is not a fair comparison. You have 10kHz square vs. approx. 1kHz.

Aha, missed it. It is important to compare the apple with the apple. Good thing you raised it.

In any case, it is very interesting how to measure class d amplifiers. I follow when you (all) who are doing measurements sort out how you should and can measure and how you can interpret the results.

 

[PierreV]

"Fan" ? Interesting

The test is just an Objective measurement... Nothing to be a fan of or not

A lesson in using a figure of speech as a strawman argument for no purpose at all...

 

[Mulder]

Hm, did that square wave look so good? What can be deduced from the current sound in the NAD C 298?

OK. But it was this figure and measurement I wanted to show. This is from @John Atkinson measurements in Stereophile. It is about NAD:s implementation of the Eigentakts Purifi-module. And I really would like to se the same measurement of this new Topping class D.

"With an equal mix of 19 and 20kHz tones and the signal peaking at 200W into 4 ohms, intermodulation in stereo mode was extremely low (fig.14).

 

[Dogcoop]

It is, I just refuse to pay the ASR Sinad tax.



I will, when the need arises.

Please use the same time division. The upper plot is in 20us/div, the oscilloscope shot is in 200us/div (0.2ms/div). This is not a fair comparison. You have 10kHz square vs. approx. 1kHz.

And what have you deduced about the performance/sound from the measurement?

 

[ergre]

Because harmonics of 1 kHz tone land where our hearing is most sensitive and has the highest chances of being heard. 19+20 kHz does not at all represent that. There is just no argument for why it produces anything useful. Any perceptual analysis will nullify its value.

Is a 1khz tone not also a result of 19+20 kHz intermodulation?

 

[Frank Sol]

A lesson in using a figure of speech as a strawman argument for no purpose at all...

However , the purpose is clear as day. If Amirm does not want to do that measurement thats his business but someone will soon.

 

[DanielT]

And what have you deduced about the performance/sound from the measurement?

Here are the measurements on the HK 330C, various measurements. Starts 4:20 into the video. If it helps to get more information on how that person performed the measurement ?:

 

[Mulder]

A teardown and some further comments about the ASR testing: https://www.diyaudio.com/forums/class-d/380233-topping-pa5-tpa325x-modification-worth.html

 

[Papaya_X]

A teardown and some further comments about the ASR testing: https://www.diyaudio.com/forums/class-d/380233-topping-pa5-tpa325x-modification-worth.html

The pictures are from this topic indeed, nothing new

 

[Walter]

Its a pity that the measurements was not really carefully picked out at the advent of ASR as, as of now, on cant compare different products really...

Whatmakes you think Amir did not carefully choose the tests he runs? I suspect that he did. The fact that some people feel additional tests would be helpful has no bearing on that whatsoever.

 

[Papaya_X]

Hey, is it better to max the volume of the amp (PA5) or max the volume of the DAC (EX5) ?

 

[KSTR]

Hm, did that square wave look so good? What can be deduced from that regarding the performance/ sound in the NAD C 298?
I post a picture to compare with. A vintage receiver Harman Kardon 330C. Measured square wave. See attached picture with occiloscope.
(not me who carried out that measurement)

The NAD shows a textbook square response which is filtered by a 2nd-order lowpass (typically right at the amp's input), most probably a Butterworth response, that's where the "overshoot" is coming from. It does NOT tell you anything about how it sounds.

Square wave response == frequency response... unless you run into slew-rate limiting and other large-signal artifacts.

 

[daniboun]

Hey, is it better to max the volume of the amp (PA5) or max the volume of the DAC (EX5) ?

I think that you will get the best THD Figure with the amp @ Max volume.
I would play with my preamp or DAC volume instead