Topping PA5 II Stereo Amplifier Review

[JDS]

This is a review and detailed measurements of the Topping PA5 II stereo balanced amplifier. It was sent to me by the company and costs US $219 (sale). There is a plus version with higher current power supply for $289.50.
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The fonts are hard to see but there is not much to read anyway. A power input button nicely lets you set trigger setup as well (so another device can power it on). The other switch lets you select between balanced and RCA which lets you use it as a pre-amp in a minimalistic system. I like the red ring around the volume control. There are large slots on each side for cooling (not shown). And regulatory certifications underneath (again, not shown). Back panel is what you expect:
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I like that the binding posts are separated allowing for my larger banana plugs to go in there with much more ease than typical desktop amps. As you see, balanced uses 1/4 connectors which are readily available. The external power supply I have is rated for 3.2 amps which I believe qualifies this as the normal version with Plus coming with 4 amp one.

Note: I put my college repairing a ton of power amplifiers. So take my word for it that amplifiers have much higher failure rate than other audio gear. To that end, this is a new amplifier and may have issues. In my testing, I pushed the unit very hard many times into clipping and shut down. A power cycle got it back working again. Heat was spread across the whole case which shows attention to that front. Still, large scale production may show issues that did not occur to my samples. So if you are risk averse, you may want to wait a bit or buy from a supplier that accepts easy returns.

Topping PA5 II Amplilfier Measurements
As usual we start with our dashboard:
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We expect superb performance from Topping even whey they use chip based class D amplifier and we get it here:
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Gain is fairly low but matches what we get out of desktop/modern DACs so not issues there. Using RCA input you actually get more gain:
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From here on, I will only be using XLR input starting with our SNR:
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My target for 5 watts is 96 dB or 16 bits and the PA5 II sails way past that. At full power, it reaches provably inaudible noise level even with very sensitive speakers.

A concern with lower cost chip based class D amplifiers is load dependency at higher frequencies. Topping has managed to make that essentially a non-issue:
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Distortion is extremely low but rises some at higher frequencies:
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Which causes some penalty for our 19+20 kHz test but still quite good:
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Power sweeps show the excellent levels of noise and distortion:
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Power is healthy for such a small package and lower tier power supply:
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The amp does get non-linear at higher frequencies which in the context of its very low noise, let's us see how:
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I was very pleased to see power on and off pop be well below my 1 millivolt threshold:
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Finally, the amplifier is stable on power up so no need to leave it on:
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Conclusions
I am not sure of the motivation for going from PA5 to PA5 II (reliability?) but whatever it is, we have another winner from performance point of view. The unit easily lands in our top 20 best amplifiers tested as far as combination of noise+distortion. I like the heat distribution and load independency. I would personally pay the other $70 and get the plus version but even here, you have good amount of power to drive a couple of bookshelf speakers.

I am happy to recommend the Topping PA5 II stereo amplifier.

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As always, questions, comments, recommendations, etc. are welcome. Click here if you have some audio gear you want me to test.

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Any idea what it can do with the bigger power supply?

 

[amirm]

Any idea what it can do with the bigger power supply?

Company advertises 40% more power at 4 ohm (140 watts instead of 100).

 

[Power Pop 23]

My PA3s and PA5 have been working fine with no issues. I moved the PA5 to a secondary location because I don't want to rely on it. I hope the Topping Audio PA5 II (Plus) speaker amplifier comes to be regarded as reliable by the marketplace - perhaps even to become known colloquially as the 'Phoenix' because this level of performance for these prices would be a 'game changer'

 

[amirm]

What causes this drop-off in this measurement?

Is it sampling rate chosen of the DA/AD ?

No, I don't think the signal is digitized in this platform. Just about every amplifier uses feedback to reduce distortion. This is done by sampling the output and comparing it with input. At sufficiently high enough frequency the phase inverts causing the feedback mechanism to become positive and hence, cause oscillations. So a low pass filter is included so that the response becomes less than 1 and hence, no oscillation.

 

[amirm]

Would be nice for you to show the switching noise, wide band plot, like you sometimes do for amps

It is the same as regular PA5:

 

[Power Pop 23]

Pa5iiplus and pa5 use same adapter

pa5ii and pa5iiplus share same pa5ii series board.

So if you have pa5 you can upgrade pa5ii to pa5iiplus.

Few members in Korea are setting up to test this.

Thanks for letting me know the external power supply of my (still working) PA5 has some salvage value

 

[dweeeeb2]

@amirm ”At full power, it reaches provably inaudible noise level even with very sensitive speakers” I see this written a fair bit. What test/graph demonstrates this in your speaker reviews? thanks

 

[Music1969]

It is the same as regular PA5:

thank you

 

[BeQuietZen]

Thanks for the review @amirm. You just forgot the crosstalk measurement to be complete. Not that I'm expecting any problems there.

Superior measurements aside, it's hard to ignore that Fosi V3 has double the power (141 vs 71 watts at 4 Ohms) for half of the price.
To each their own, I guess.

 

[amirm]

@amirm ”At full power, it reaches provably inaudible noise level even with very sensitive speakers” I see this written a fair bit. What test/graph demonstrates this in your speaker reviews? thanks

It is a longer topic. Briefly, if you have SNR of 120 dB, it means you can play at 120 dBSPL and the noise level would be at threshold of hearing (maximum dynamic range of our hearing). This amp can only reach 120 dBSPL with a very sensitive speaker and hence that qualification. The sensitivity rating of a speaker is the same as its frequency response in the speaker measurements. That number, say 86 dB, is achieved at 1 watt at 1 meter. There are calculators online which help compute at your distance how much power you need to arrive at 120 dBSPL (assuming that is what you want to do).

 

[Bleib]

How high of a voltage can this amp take, is it OK to give it more than 2 or 4 volts

 

[amirm]

You just forgot the crosstalk measurement to be complete. Not that I'm expecting any problems there.

Oops, just added to the review:

 

[amirm]

How high of a voltage can this amp take, is it OK to give it more than 2 or 4 volts

It will clip at 2.4 volts input at max volume over XLR. You can always turn that down and have it accommodate higher input voltage.

 

[Vovgan]

you have good amount of power to drive a couple of bookshelf speakers

Would be interesting to see how much power is enough to drive a pair of speakers of an average sensitivity if they’re crossed at ~ 80 Hz with subs. If most of the power demand is from bass and below, maybe this small Topping amp is actually enough for even large systems if bass is off-loaded to subs?

 

[Rja4000]

Thanks for the review.

Just a detail:
You use "XLR" everywhere, while there is none.
You meant "Balanced", of course.
I just hope it won't be confusing for some.

Will you also review the "Plus" ?

 

[Music1969]

As usual with Topping products, best to wait 6 months to buy it for any reliability issues to come up

But I suspect this Mk2 will be fine

 

[ralph]

chip based class D

Does anyone know which chip they are using?

So take my word for it that amplifiers have much higher failure rate than other audio gear.

Thanks @amirm for pointing this out. The only audio device I've owned that broke was an amplifier but that was like 30 years back. To me it looks like that the ones from many bigger companies (e.g. Japanese ones) are more reliable these days - or is this just my personal experience?

 

[Tangband]

Nice amplifier !

Now, I wonder how much extra it would cost to have a remote control on this amplifier ? . This performance is so good that its usable outside the desktop, maybe placed in a livingroom.

 

[viperxp]

I think there are reasons to upgrade. The RCA inputs can be very important for some people (me for example) as I plan to hook it up to my E30 II L30 II unbalanced stack.

 

[DWPress]

I haven't checked it against the original units graphs yet, but any advantage in IMD or distortion in this version for 3-20khz use?

To answer my own question - had the time to compare the original PA5 review with this one and in many respects across the board the original unit is marginally better according to the numbers.