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Topping PA5 Review (Amplifier)

howard416

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You get higher amplitude.
Tests dont need to be "real world like" they need to be reviling. and we need to have the knowlage to kow how to translate re results to real world.
SINAD a 1Khz is also not real world at al but it tells a lot.
You might not get a lot of >10 kHz periodic high amplitude signals but you sure get a lot of fast rise time signal wit high amplitude.

What signal will you get through an amp, that has a faster rise than a 20 kHz wave?

The 32 tone test is done at 5 W, so at least it's not like a 1 W test (admittedly, it's not a high power test but hey, maybe we should get 32 tone tests done at 20 W or 25 W too, right?) But keep in mind, the half-way point of low frequency energy vs high frequency energy happens around 350 Hz on average, depending on who you ask. Drum & bass, some hip hop, etc. will have even more of a skew towards LF.


Also, the amount of energy over 3 kHz in several kinds of music is quite low:

 

F1308

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The efficiency of 97dB is extremely high. The output noise of PA5 is very small, but if you use a 97dB speaker, you will feel the noise.
The efficiency of the speakers I use is 89dB, which is a common value for modern speakers. With a speaker of this level of efficiency, you will not hear any noise from the amplifier.
Either I am not understanding how the sound chain does work, from reading the source data to enjoying listening, or I think it is exactly the other way around...

Since you are aiming for a given loudness when auditioning, higher efficiency speakers will ask for a lower gain, decreasing noise...

NOISE= (DACnoise x 10^(AMPgain/20))^2+AMPnoise^2)^0.5

I am unable, for the time being, to mathematically establish a relationship between audition loudnes level, say 60dB, loudspeaker efficiency ranges, say 80 db to 105 dB, and the accordingly requiered change in AMPgain to keep loudness at the specified desired audition level, or ranges, as we walk along the available efficiency ranges, but I guess many other people can...
 
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AnalogSteph

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The efficiency of 97dB is extremely high. The output noise of PA5 is very small, but if you use a 97dB speaker, you will feel the noise.
Seems unlikely to me. -105 dB(A) relative to 5 W / 4 ohm is -101 dB(A) relative to 2.83 V. We'd be talking -4 dB SPL(A) @ 1 m, +2 dB SPL(A) at 0.5 m or +16 dB SPL(A) at 10 cm. In a nutshell, noise should be utterly inaudible unless you're virtually sticking your ear to the tweeter. These levels would be on par with the very quietest active monitors you can buy, e.g. Neumann KH310A.

I would recommend tweeters up to ca. 105 dB / 2.83 V depending on personal noise tolerance... things beyond 110 dB should probably be padded down.
 
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BDWoody

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Face the facts, data and listening go hand in hand.

Not here. At least not the uncontrolled kind, like what we see too often.

There are lots of places to go where you can get all the anecdotal information you can handle, but part of why we are here is to expose the fallacy of taking much, if any meaning from sighted, uncontrolled comparisons of subtle differences. The industry counts on a lack of rigor, and actively discourages the suggestion they are needed.

We aren't them. We don't want to be them.

If someone wants to try to influence the decisions of others by giving his subjective impressions while ignoring the need to control for bias, they should expect the 'Uh huh's ' they are likely to get.
 
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Toku

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Does the soundstage feel like the L or R speaker has reverse polarity? (disregarding the bass response)
Can you try to immediately switch the system to AIYIMA AO7 to check for soundstage differences?
I was not an audiophile, but an engineer who used to design professional equipment at a Japanese manufacturer. So if you have such a symptom, you'll know right away.
PA5 speculates that it uses the TPA3255 chip in my research. AIYIMA A07 also uses TPA3255. But there is a clear big difference in the sound of the two amps. I have purchased and tested a number of amplifiers using the TPA3255, but simply using a PFFB and high-end inductors and capacitors does not provide these characteristics. It's a mystery how Topping acquired this kind of technology.
At the same time I am very interested in the latest TPA3255 amps that have adopted your company's PFFB.
 

Lambda

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If we dont have data, then this place shouldnt and wouldnt exist. Face the facts, data and listening go hand in hand. You are clearly placing too much importance on data with the statement "if you have complete data you dont have to listen". That is pure bollocks.

Don't know what you don't understand?
We don't have enough data to exactly model and predict the amp for every input signal.

If we would have all this data we could calculate a virtual AMP and it would Null with the real amp.
at lest within the audible limits.

we don’t need to have a perfect model and all the data to say with high certainty that this amp is transparent.
So Casual listening impression cant add anything to the Data we already have.

What signal will you get through an amp, that has a faster rise than a 20 kHz wave?
It is not uncommon for modern recordings to have inter sample over.
The 32 tone test is done at 5 W, so at least it's not like a 1 W test (admittedly, it's not a high power test but hey, maybe we should get 32 tone tests done at 20 W or 25 W too, right?)
It is still energy spreed put over 32 frequency and not on 2.
testes don't need to be designed to be "real life" like they need to be reviling and reproducible.
and ideal give results in isolation from there you can calculate the impact on what ever your real life use case is

pre-compliance.jpg

187917-10916235.jpg


just a as an example of how far from real life some standard tests are but being this isolated is what makes them so comparable.
 

bravomail

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I was not an audiophile, but an engineer who used to design professional equipment at a Japanese manufacturer. So if you have such a symptom, you'll know right away.
PA5 speculates that it uses the TPA3255 chip in my research. AIYIMA A07 also uses TPA3255. But there is a clear big difference in the sound of the two amps. I have purchased and tested a number of amplifiers using the TPA3255, but simply using a PFFB and high-end inductors and capacitors does not provide these characteristics. It's a mystery how Topping acquired this kind of technology.
At the same time I am very interested in the latest TPA3255 amps that have adopted your company's PFFB.
since u r an engineer - could u try to check polarity of signal in A07 vs PA5?
 

eardiggler

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After hearing the sound of PA5, I don't need any amplifiers other than PA3s anymore. Am I a little overstated?
Serious question: what are you hearing different in the PA5 vs any other mid-quality SS amplifier? I ask this because I can't hear any difference from one SS amp to the next except maybe floor noise (and I have to be looking for it). How much do you think seeing the measurements Amir posted influenced what you're hearing (or not hearing)? If you were told the PA5 measured poorly and you AB'd it against a 1991 Onkyo AVR do you think you would be able to tell the difference? Or is the sound so obviously transparent anyone with normal hearing can tell?
 

BoredErica

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Not here. At least not the uncontrolled kind, like what we see too often.

There are lots of places to go where you can get all the anecdotal information you can handle, but part of why we are here is to expose the fallacy of taking any meaning from sighted, uncontrolled comparisons of subtle differences. The industry counts on a lack of rigor, and actively discourages the suggestion they are needed.

We aren't them. We don't want to be them.

If someone wants to try to influence the decisions of others by giving his subjective impressions while ignoring the need to control for bias, they should expect the 'Uh huh's ' they are likely to get.
Most of the audio community to me is a total joke. A Headfi meet might as well be an astrology meet.
 

xrk971

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If you do drive a Class D amp at higher power and leave the output unconnected, it will destroy the amp chip (blow up in spectacular flames). This is because the back EMF generated by the inductor during the switching has to go somewhere, and the voltage can shoot well beyond what the internal MOSFETs can handle. I have had this happen under max power stress testing when I forgot to disconnect the input to one of the channels during the test as I only had a fan cooled 300W load resistor on the output of the other channel.

Some SMT rework to remove the dead TPA3255 and replace it worked well but it is not a job for every DIY’er.
 

howard416

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It is not uncommon for modern recordings to have inter sample over.

It is still energy spreed put over 32 frequency and not on 2.
testes don't need to be designed to be "real life" like they need to be reviling and reproducible.
and ideal give results in isolation from there you can calculate the impact on what ever your real life use case is
What does "inter sample over" mean?

Yeah, I know, it's literally called a 32 tone test, not a 2 tone test. My point is, the 32 tone test is more practically comparable (from an audibility standpoint) than the 18+19 kHz test. You haven't explained why the 18+19 kHz is so critical yet, nor have you shown that there's any kind of music that actually has more high-frequency energy than in the 32 tone test that Amir does. Exceptions: crash cymbals and the like: https://www.cco.caltech.edu/~boyk/spectra/spectra.htm

At this level of performance, does it make a difference to anyone listening to music? The IMD hash from the 5 W 32 tone test tops out at -110 dB, for crying out loud. Yes, Class D amps generally do more poorly on the 18+19 than other types of amps. Yes, the PA5 is not as good as the NC400 or the Purifi amp, and the designers of the latter amps should be loudly applauded for their engineering talents. Does it matter whether you have a PA5 or one of the latter amps, if you're just listening to music? I don't think so, as long as you're working within the power limit.
 
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MarkWinston

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Not here. At least not the uncontrolled kind, like what we see too often.

There are lots of places to go where you can get all the anecdotal information you can handle, but part of why we are here is to expose the fallacy of taking much, if any meaning from sighted, uncontrolled comparisons of subtle differences. The industry counts on a lack of rigor, and actively discourages the suggestion they are needed.

We aren't them. We don't want to be them.

If someone wants to try to influence the decisions of others by giving his subjective impressions while ignoring the need to control for bias, they should expect the 'Uh huh's ' they are likely to get.
So listening and asking for opinions are uncontrolled?
 

Lambda

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What does "inter sample over" mean?
Pleases go and educate yourself first.

At this level of performance, does it make a difference to anyone listening to music? The IMD hash from the 5 W 32 tone test tops out at -110 dB, for crying out loud. Yes, Class D amps generally do more poorly on the 18+19 than other types of amps.
just because this test uses this frequency don't men we can apply the knowledge from this test only to this frequency...
Its a test for Filter linearity.

Not made up by me but an industry standard recommend by AP.

does it make a difference to anyone listening to music?
We don't know we have no data...
it is fine at 5W with 32 tones
it is fine at single tone till 50W

Still some things we don't know its unlikely they are horribly bad. but is is just unknowen.
for example Inter modulation distortion.

https://www.audiosciencereview.com/...ation-audible-intersample-clipping-test.2231/
index.php


The waveform in the middle is what the AMP would see from a normal "legal" 44.1khz signal with send to an normal DAC at 0dBFS.
Lots of low stuff over 20khz...

So it is good to know if the output filter also "works" if it is closes to saturation for example low Frequency.
 

howard416

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We don't know we have no data...
OK. Go ahead and do a double-blind test with the PA5 and any other amp you like, then. I'll wait, and in the mean time, have nothing more to add.

If it matters, I don't own any Topping products, I'm not associated with Topping in any way other than merely discussing their stuff online, and generally do not favour import products.
 
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