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Topping PA3s Review (Desktop Amplifier)

AudioSceptic

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I seem to recall some issues with those early Cambridge amps (crossover distortion?) - I no longer have the reviews which were tech based back then). The more powerful P80 'sounded' ok I remember but wasn't too good on the bench and we had to send an entire batch of newly launched P60's back as all were faulty... I suspect it was too clever a design and too slim a case coupled with components not quite up to it back then. The late 70's saw the beginnings of better components coming along I think (greater power and capability with less components needed) and I do regret our Uk market not exploiting the best of mid priced far eastern products back then - it was either contrived UK makers 'telling a story,' or a new wave of very expensive US gear with heavy build. I was trying to think Threshold was the first, but we had a good few others before, some of which came from the pro market, tried their luck and then returned to said market.
From memory, the P50II was a Stan Curtis design, unlike the earlier P40 and P50, and did "not" suffer from crossover distortion. Martin Colloms rated it highly both for measurements and for subjective SQ. BTW I still think those Cambridge amps were some of the best looking ever, although the slim design probably did compromise heat dissipation.

As a mere consumer, my impression at the time was that Japanese amps were starting to gain respect, but the serious brand was Crown/Amcron, or Phase Linear if you wanted huge power (200 or 350 W seemed incredible then). The Quad 303 was still the established top Brit amp but there were doubts about load tolerance and SQ.
 

JohnYang1997

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Thanks for the explanation, I will be looking forward to your design. As a small challenge, this is the same/similar kind of measurement on a small class AB amplifier with TMC compensation. I hope you will get better ;). I tried to keep the same scaling as @amirm for fast comparison.

View attachment 156842
(BTW I need more than 7 minutes for a single plot, these 4 plots take more than 30 minutes)
-----------------------

and Topping as per the review>
index.php
It's somewhat funny. When you see something doesn't measure exactly beautiful you challenge it with measurements. But when you see something measures perfect you then again argues what's audible.
And you also aren't shy comparing different classes of amplifier in the ability of the designer. How funny is that?
The output impedance of PA3S is 10mOhm across audio range. It will sound very good as it's not going to change frequency response.
 

MadMan

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Why is the dashboard SINAD notably worse than what @WolfX-700 got for 4R5W, about 92dB. https://www.l7audiolab.com/f/topping-pa3s-prototype/ Looking at the test details, he uses "Input1 ... AC (<10Hz) - 20kHz" versus "AC (<10Hz) - 22.4kHz". Does the extra bandwidth for your dashboard change it that much? It's hard to tell because the other distortion measurement (multitone) only shows to 20kHz. Also, you use 45kHz bandwidth (I assume 2x22.4 kHz) for Power v Distortion, would that change with 40 kHz bandwidth?
 

abdo123

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So, @JohnYang1997 according to your prices on Amazon you are selling this for EUR149 in Germany but also £149 (16% more) in UK. That is not going to endear you to us Brits.

probably because the UK doesn't have bilateral trade agreements with China after they left the EU or something. :p
 

pma

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It's somewhat funny. When you see something doesn't measure exactly beautiful you challenge it with measurements. But when you see something measures perfect you then again argues what's audible.
And you also aren't shy comparing different classes of amplifier in the ability of the designer. How funny is that?
The output impedance of PA3S is 10mOhm across audio range. It will sound very good as it's not going to change frequency response.

1) "When you see something doesn't measure exactly beautiful you challenge it with measurements" - sorry this is about measures, because the nonlinearity of PA3 is that high, frequency dependent, uneven and unpredictable that I am quite sure that it becomes audible. The nonlinearity shown in distortion vs. frequency plots is from -75dBr to -45dBr.

2) "But when you see something measures perfect you then again argues what's audible" - again about measures, yes distortion -120dBr vs. -110dBr or -100dBr is ridiculous and it is inaudible, though input impedance of 2k may make troubles.

I hope you can see the difference between -60dBr and -100dBr in (1) and (2).

3) "And you also aren't shy comparing different classes of amplifier in the ability of the designer. How funny is that?"
Sorry, power amplifier with THD+N vs. frequency profile as shown here speaks about ability of the designer and about his acceptable limits of engineering design work.
 

taisho

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Heres a comparison with more bargains, Aiyima a07 with the TI tpa3255 and Allo Volt+D with TI tpa3118.
Thanks. AIYIMA completely destroys its competition quality-wise and the price is unbelievable. It's a very budget choice even by less wealthy countries' standards. I myself have AIYIMA TPA3251 and in my small room, it has enough power to be loud and clean. On this level of performance, the real bottlenecks are room acoustics, the lack of a subwoofer, and in many cases the speaker distortion.
 

JohnYang1997

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1) "When you see something doesn't measure exactly beautiful you challenge it with measurements" - sorry this is about measures, because the nonlinearity of PA3 is that high, frequency dependent, uneven and unpredictable that I am quite sure that it becomes audible. The nonlinearity shown in distortion vs. frequency plots is from -75dBr to -45dBr.

2) "But when you see something measures perfect you then again argues what's audible" - again about measures, yes distortion -120dBr vs. -110dBr or -100dBr is ridiculous and it is inaudible, though input impedance of 2k may make troubles.

I hope you can see the difference between -60dBr and -100dBr in (1) and (2).

3) "And you also aren't shy comparing different classes of amplifier in the ability of the designer. How funny is that?"
Sorry, power amplifier with THD+N vs. frequency profile as shown here speaks about ability of the designer and about his acceptable limits of engineering design work.
Topping PA3s Measurements Multitone Balanced Amplifier.png

OI (1).jpg


And multitone at different output power/load:
 

DHT 845

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sarumbear

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Unfortunately, Hypex Ncore and Purifi remain the only well behaving class D amplifiers. Still a lot to learn, @JohnYang1997 .
Have you compared the prices? Maybe it is nothing to do with learning?

I expect technical people to be nice to each other...and members of a science orientated forum to be sensible not to offer 6kW power amplifier worth $10,000 for comparison on a $150 power amplifier review.
 
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sarumbear

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Thanks for the explanation, I will be looking forward to your design. As a small challenge, this is the same/similar kind of measurement on a small class AB amplifier with TMC compensation. I hope you will get better ;). I tried to keep the same scaling as @amirm for fast comparison.

View attachment 156842
(BTW I need more than 7 minutes for a single plot, these 4 plots take more than 30 minutes)
-----------------------

and Topping as per the review>
index.php
What is that "small AB amplifier" make & model or specs, please?
 

sarumbear

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Sorry, power amplifier with THD+N vs. frequency profile as shown here speaks about ability of the designer and about his acceptable limits of engineering design work.
Rubbish! Price has the most affect on the quality of an amplifier (like for like).
 
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PeteL

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LM3886 is a class AB design, Neurochrome (Modulus-XXX) modules also use a separate opamp error contol circuit on top of the LM3886 and are in quite higher price range. So they are also quite a different animal.
I agree that we shouldn't compare products that aren't in the same price range ore maybe more, in the same "Price per Watt" range, but hey whether it's class AB, whether there is a different feedback topology, error correction, and such, it's of course interesting to note but in the end all have the same job to do. It's not how you get there, it's how good, and that include how energy efficient, you are at amplifying an audio signal. I don't think we can only compare class D or other topology separately, in the end the expected result is the same.
 

JohnYang1997

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Why is the dashboard SINAD notably worse than what @WolfX-700 got for 4R5W, about 92dB. https://www.l7audiolab.com/f/topping-pa3s-prototype/ Looking at the test details, he uses "Input1 ... AC (<10Hz) - 20kHz" versus "AC (<10Hz) - 22.4kHz". Does the extra bandwidth for your dashboard change it that much? It's hard to tell because the other distortion measurement (multitone) only shows to 20kHz. Also, you use 45kHz bandwidth (I assume 2x22.4 kHz) for Power v Distortion, would that change with 40 kHz bandwidth?
This corresponds to about 2dB of SINAD. I personally measured the unit before sent to Amir. Under Amir's settings it should be both 0.002x%. I think it's the difference low pass filter used. I use simple RC lowpass between the amplifier output and AP.
 

sarumbear

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I agree that we shouldn't compare products that aren't in the same price range ore maybe more, in the same "Price per Watt" range, but hey whether it's class AB, whether there is a different feedback topology, error correction, and such, it's of course interesting to note but in the end all have the same job to do. It's not how you get there, it's how good, and that include how energy efficient, you are at amplifying an audio signal. I don't think we can only compare class D or other topology separately, in the end the expected result is the same.
The main issue is you must put the price into the comparison. Many in this thread are simply stating chip names or topologies without actually giving any model names that compare with this amplifier in review.
 

sarumbear

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Why is the dashboard SINAD notably worse than what @WolfX-700 got for 4R5W, about 92dB. https://www.l7audiolab.com/f/topping-pa3s-prototype/ Looking at the test details, he uses "Input1 ... AC (<10Hz) - 20kHz" versus "AC (<10Hz) - 22.4kHz". Does the extra bandwidth for your dashboard change it that much? It's hard to tell because the other distortion measurement (multitone) only shows to 20kHz. Also, you use 45kHz bandwidth (I assume 2x22.4 kHz) for Power v Distortion, would that change with 40 kHz bandwidth?
Is a 2dB lower SINAD notably worse?
 

PeteL

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The main issue is you must put the price into the comparison. Many in this thread are simply stating chip names or topologies without actually giving any model names that compare with this amplifier in review.
Yes
 

Oukkidoukki

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Out of topic, but does anyone know sinad numbers for amps in active monitors? For some reason many manufactures are hiding them......for example yamaha hs8. Can't find it. Or neumann, genelec, adam......I assume better sinad more transparent they are.
 

MZKM

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Out of topic, but does anyone know sinad numbers for amps in active monitors? For some reason many manufactures are hiding them......for example yamaha hs8. Can't find it. Or neumann, genelec, adam......I assume better sinad more transparent they are.
Some companies give this spec if I recall. However, at the end of the day it’s how much distortion/noise/etc. comes out of the speaker. It doesn’t matter if the internal amp they use has a SINAD of 100dB (0.001% THD) is the speaker as a whole is outputting 1% THD.
 
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