Topping PA5 Review (Amplifier)

[restorer-john]

@Doodski Hint: they've never, ever measured an amplifier. They've read a few HiFi rags and re-gurgitated some dribble they heard.

They haven't looked at rails sagging after a half second or so. They haven't looked at the continuous rating vs the dynamic/peak rating, letalone the ripple and noise on those rails when the amp is at its limits. They certainly haven't wound up an amp only to see it clip hard, lock up and need to be "babied" back into normal operation.

 

[pma]

The trend for the past decades is to rate in WRMS. Are we to change overnight?

Just watts, W, Sir. Wrms is a nonsense. Power is calculated from rms voltage, rms current.

 

[david123]

The amp is last in the chain, and I for one want it to be taking the analog output of my expensive DAC and not messing with it. Why fool around with DSPs at this stage? That requires AD and DA chips. Better to do DSP upstream IMHO.

If topping releases a minidsp alternative, or a DAC with dsp, I will be happy too.

 

[Doodski]

@Doodski Hint: they've never, ever measured an amplifier. They've read a few HiFi rags and re-gurgitated some dribble they heard.

They haven't looked at rails sagging after a half second or so. They haven't looked at the continuous rating vs the dynamic/peak rating, letalone the ripple and noise on those rails when the amp is at its limits. They certainly haven't wound up an amp only to see it clip hard, lock up and need to be "babied" back into normal operation.

Yeah all prolly true. I did a calc on a Luxman the other day and it could hit something like 450WRMS peak capability. I've never heard a word about it in the 38 years I've been around this stuff. Not a thing. That's a shame because it's a beast.

 

[xrk971]

The last two letters of "ASIC" stand for "Integrated Circuit" -- IOW, an ASIC is "a chip," just not an off-the-shelf "jellybean" part that you can simply order from Digi-Key or Arrow like TI's monolithic "chip amp" solutions or an Infineon Class D driver/controller for discrete MOSFETs.

I guess I was thinking monolithic integrated chip amp. I suppose all semiconductors, IC’s, and even SMT resistors are “chips”. When I think chip amp, I think of having the output MOSFETs or BJTs integrated into the same chip for a simple low parts count monolithic solution (e.g., TPA32XX, TPA3116, LM3886, TDA7293, LM1875, etc). I don’t consider IRS2092 Class D amp driver a “chip amp”. But it’s all what you want to define as the chip amp system boundary.

 

[D700]

Small form factor, high performance DAC, HPA and AMP....all I need need now is a small footprint high performance rack to put this stuff on my desk to keep it in one place when I move a wire behind my desk....make it wall mountable..include a small LED downlight...optional power supply chassis with selectable outputs to occupy 1 slot and power everything from 1 cord

 

[Dennis_FL]

Small form factor, high performance DAC, HPA and AMP....all I need need now is a small footprint high performance rack to put this stuff on my desk to keep it in one place when I move a wire behind my desk....make it wall mountable..include a small LED downlight...optional power supply chassis with selectable outputs to occupy 1 slot and power everything from 1 cord

I said the same thing and someone pointed this out

 

[howard416]

Thanks!

You'll want an LC meter. You could buy a cheapie, a nice one, or build your own:

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[anphex]

I think it's hilarious how this little device devastates about the whole amplifier market. Even the good scientic amps measured here in ASR have little to counter considering the small price. Not to speak about stuff like McIntosh and Pass Labs... I feel sorry for the people who don't have discovered ASR yet and still will buy those expensive amps not knowing what they are doing and trusting baseless manufacturer claims.

 

[Koeitje]

I still don't get your point. Are confusing RMS with continuous? In class D anyway there is no dynamic momentary headroom, if it's what you are trying to say by "not RMS". What is peak output? For some it just means "RMS" watts time SQRT(2), which has no physical meaning because a Watt by definition is a function of time, a Watt is a Joule per second. For some peak power means momentary. It confuses people. ». Momentary headroom is still "RMS" if we are talking Watts, we shouldn't even have to call them Watts RMS, it confuses people, it's just Watts.

RMS output for most class D amplifiers is determined by thermal load. So a class D amplifier can generally deliver lower continuous Watt output. Yet it doesn't matter for real world performance, because the peaks it can handle are much higher. Just look at the data sheets for NCore for example. The continuous output is far lower than what the are advertised as. Why? Because in the real world it doesn't matter what the continuous output is as long as its not extremely low like 1 Watt. The measurements you see done by Amir also don't show continuous and peak power for class D. Those two measurements just show peak power. Because what he measures there are continuous still isn't continuous because it will run into thermal limits after a couple of minutes. So in the end RMS might be a useful metric for class A/AB, but it says nothing about real world performance of class D.

Lets say the average level of output during musical content is 6W and you get some nice dynamic material that has peaks of 20dB above the average musical level. That means I suddenly need 60W. I don't need a 60W continuous amplifier to provide that, I need an amplifier that can reach those peaks and can handle 5W 24/7.

 

[Maciekw]

I have read the discussion about this amplifier. Unfortunately I did not find there any information about how the input of the amplifier is constructed. We only know that it is balanced, but we do not know if there is a differential amplifier at the input, which would enable feeding an unbalanced signal using a suitable adapter from RCA to mono jack. However, if the design is a simple bridge amplifier from the input, feeding an unbalanced signal could be problematic. Does anyone have any information about this?

 

[PeteL]

RMS output for most class D amplifiers is determined by thermal load. So a class D amplifier can generally deliver lower continuous Watt output. Yet it doesn't matter for real world performance, because the peaks it can handle are much higher. Just look at the data sheets for NCore for example. The continuous output is far lower than what the are advertised as. Why? Because in the real world it doesn't matter what the continuous output is as long as its not extremely low like 1 Watt. The measurements you see done by Amir also don't show continuous and peak power for class D. Those two measurements just show peak power. Because what he measures there are continuous still isn't continuous because it will run into thermal limits after a couple of minutes. So in the end RMS might be a useful metric for class A/AB, but it says nothing about real world performance of class D.

Lets say the average level of output during musical content is 6W and you get some nice dynamic material that has peaks of 20dB above the average musical level. That means I suddenly need 60W. I don't need a 60W continuous amplifier to provide that, I need an amplifier that can reach those peaks and can handle 5W 24/7.


View attachment 169043

I understand all that, I just disagree with your usage of the term RMS.

 

[D700]

I said the same thing and someone pointed this out

Topping already makes a linear power supply...it wouldn't be a stretch for them to complete the vision of a high quality, mini-stack rack mount system. Throw in a streamer that has Airplay 2, Room integration with DSP and we'll have a Topping Tower.

Not a fan of the plexiglass look but that's the idea.

 

[Koeitje]

I understand all that, I just disagree with your usage of the term RMS.

And I disagree with your statement that there is no momentary dynamic headroom. Because the 200W@8ohm stated for the NC400 is momentary dynamic headroom if you only use the standard passive cooling. Power output is time limited by thermal load. Of course momentary dynamic headroom is not a couple of ms but more in the range of 30 seconds to a couple of minutes.

 

[nhs]

I can not find the input impedance of this amp. Does any one know it?

 

[NTK]

I can not find the input impedance of this amp. Does any one know it?

Please see this post.

Topping PA5 measurements )

A real amplifier: Here are the benefits: Cheaper Contains a respectable D/A converter Similar power in real terms Inbuilt phono stage 6 inputs Tone controls, bass, treble and direct switch Absolutely perfect channel balance through the entire volume range. Motorized remote control volume...

www.audiosciencereview.com

 

[nhs]

Please see this post.

Topping PA5 measurements )

A real amplifier: Here are the benefits: Cheaper Contains a respectable D/A converter Similar power in real terms Inbuilt phono stage 6 inputs Tone controls, bass, treble and direct switch Absolutely perfect channel balance through the entire volume range. Motorized remote control volume...

www.audiosciencereview.com

Ah about 10k, thank you.

 

[eardiggler]

I think it's hilarious how this little device devastates about the whole amplifier market. Even the good scientic amps measured here in ASR have little to counter considering the small price. Not to speak about stuff like McIntosh and Pass Labs... I feel sorry for the people who don't have discovered ASR yet and still will buy those expensive amps not knowing what they are doing and trusting baseless manufacturer claims.

Many of those same people won't EVER buy a tiny little Topping's amplifier no matter how well it measures. The industrial design just doesn't apply to their lifestyle and it will look silly on their $8000 African Mahogany audiophile rack.

 

[PeteL]

And I disagree with your statement that there is no momentary dynamic headroom. Because the 200W@8ohm stated for the NC400 is momentary dynamic headroom if you only use the standard passive cooling. Power output is time limited by thermal load. Of course momentary dynamic headroom is not a couple of ms but more in the range of 30 seconds to a couple of minutes.

OK, you can't stay there all the time, understood, with a test signal. But it's still the rated power of the amp and the only one that matter because, as you say music or content will only reach that for short transient. That's the metric that matter, the "non taking account thermal load" rated power. It's different than what is usually refered to has "dynamic headroom" but let's not get lost in semantics. That's the max power of the amp before clipping. The rated power.

 

[Koeitje]

OK, you can't stay there all the time, understood, with a test signal. But it's still the rated power of the amp and the only one that matter because, as you say music or content will only reach that for short transient. That's the metric that matter, the "non taking account thermal load" rated power. It's different than what is usually refered to has "dynamic headroom" but let's not get lost in semantics. That's the max power of the amp before clipping. The rated power.

The problem is that the 'dynamic headroom' stuff stems from a period well before class D became relevant. The only thing I care about is if an amplifier can drive my loudspeakers to the playback level that I want and can do that for as long as I want to. And an old concept like continuous output is not the metric you want to use for that.