Topping PA5 Review (Amplifier)

[TheWalkman]

Even the bargain basement Aiyima A07, with its notoriously poor thermal management, won't shut down while playing music at any but downright deafening levels -- music is not a steady sine wave from a piece of test gear!

Bruce,

I'm curious where you got, "notoriously poor thermal management" from. I have both an A07 and A04 which I switch between cranking them for hours on end (90 + db), driving a pair of Elac Reference speakers. I'm powering them both with a Mean Well, 36x 3.4A power brick. Neither amp gets even warm to the touch after extended play.

Granted, if you're running a sine wave, test signal through them, perhaps they would overheat. To the earlier point in this thread regarding power supplies, real world, listening scenarios would, I assert, need the full power of amps for a small amount of time and efficient, Class D amps like the Aiyimas or this Topping, I'd speculate, do a great job of supplying the transient power levels.

This, too, is the reason that a smaller, quality power brick can adequately power the amps (while confusing a lot of folks on how a 150 W power brick can power them adequately.

FWIW, I couldn't resist and pulled the trigger on a PA5 to add to my collection. It's on the plane now. I'll be curious to see how the PA5 stacks up to the Aiyimas i.e. can I tell any difference or am I chasing diminishing returns. With N+1 amps in my collection, I wonder if it would pay to open up a Class D Amp Museum? I certainly have enough relics to do so.

Fingers crossed, but I'm hoping this PA5 will be my endgame and I can resist the Siren's pull of the Benchmark.

Cheers

 

[Frank Sol]

Many of those same people won't EVER buy a tiny little Topping's amplifier no matter how well it measures.

Many of those "same people" may not like/enjoy their subjective opinion of the 'sound' they get from this PA5 if they listen to it in their system. I know subjectivism is not a happy subject here but it matters to many audiophiles

 

[Frank Sol]

Fingers crossed, but I'm hoping this PA5 will be my endgame and I can resist the pull of the Benchmark.

Cheers

There is no endgame

 

[DanielT]

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.

But take this amplifier for example:
NAD 3240PE: 40 W

Dynamic power 160 W in 8 Ohm, 200 W in 4 Ohm. It seems nice but in practice when you play music with many transients how do you know if the amplifier can handle them? How long is this temporary effect temporary that is? How do I know that it can withstand transient peak X that lasts for Y a long time? Also, how do I even know how long time Y is/last? Check song by song and see if it fits the amplifier? It's just too cumbersome.

Is not it better to choose a high enough RMS so you do not have to worry about it?

 

[TheWalkman]

But take this amplifier for example:
NAD 3240PE: 40 W

Dynamic power 160 W in 8 Ohm, 200 W in 4 Ohm. It seems nice but in practice when you play music with many transients how do you know if the amplifier can handle them? How long is this temporary effect temporary that is? How do I know that it can withstand transient peak X that lasts for Y a long time? Also, how do I even know how long time Y is/last? Check song by song and see if it fits the amplifier? It's just too cumbersome.

Is not it better to choose a high enough RMS so you do not have to worry about it?

Ah but I don't worry about it: most of the time I don't shake my windows when I listen to music at 85 - 90db.

My neighbors appreciate that.

How do I know if I'm going beyond the capabilities of the amp? Easy, but it is rather subjective: if the music sounds good and my ears don't scream, I don't smell smoke or see flames shooting out of the amp, it's working for me and hopefully the amp and speakers.

And if I need more, "loud" I can hook up my Niles or Denon and make the walls shake, my ears bleed and neighbors groan.

 

[pma]

Dynamic power

The only reason for that "dynamic power" is to make the product cheap, to reduce material costs. Just today I have run a 1 hour test with sine wave input close to maximum power with my UcD180 sample amplifier

Hypex UcD180HG HxR amplifier module analysis and review

Hypex UcD180HG HxR module analysis and review After buying and testing AIYIMA A07 amplifier (based on TPA3255 class D chip) in January 2021 I was quite disappointed with the frequency response modulated by speaker complex impedance and its audible consequences. This is, unfortunately...

www.audiosciencereview.com

and I could barely feel little warming of the heatsink at the end of the test. But nobody uses appropriate heatsink with class D, only smaller or bigger case or Al sheet. So then we have definitions like for 1 minute etc.

 

[aj625]

Let me understand…

• Is the R is the speaker?
• Is the r in the output impedence?

If ^that^ is correct, then we have 8.1 versus 9 ohms for the 0.1 and 1.0 ohm output impedance (respectively)?
Or am I missing something here?


What is a very low impedance for the speaker?
I thought that most 8 ohm speakers will only dip down to around 5-6 ohms at their lowest?

One could put a 5W 1 ohm power resister in series with speaker and test the hypothesis.
(^That^ should just handle the 20–40w RMS value, which I suspect is more like peak wattage(?) with the RMS being more like 1-2W RMS?)

Most 8ohm speakers specially those having bigger bass drivers can even dip below 4ohm and some even upto 2ohm. Higher output impedance will have difficulty in driving lower impedance (dynamic or on dynamic) loads just like you can't start your car with 8xAA batteries.

 

[Labjr]

Class D is cheap and efficient, so you don't need to worry about dynamic power reserves. Just get something with more power than you'll ever need.

 

[192kbps]

Any plan for bigger one

AB

 

[Koeitje]

The only reason for that "dynamic power" is to make the product cheap, to reduce material costs. Just today I have run a 1 hour test with sine wave input close to maximum power with my UcD180 sample amplifier

Hypex UcD180HG HxR amplifier module analysis and review

Hypex UcD180HG HxR module analysis and review After buying and testing AIYIMA A07 amplifier (based on TPA3255 class D chip) in January 2021 I was quite disappointed with the frequency response modulated by speaker complex impedance and its audible consequences. This is, unfortunately...

www.audiosciencereview.com

and I could barely feel little warming of the heatsink at the end of the test. But nobody uses appropriate heatsink with class D, only smaller or bigger case or Al sheet. So then we have definitions like for 1 minute etc.

That's the difference between engineering something that works in all real world situations and something that works in all test bench scenarios. The latter is mainly a waste of resources.

 

[aschen]

Just need some company to democratize SOTA art speaker performance

 

[capslock]

Who would have thought we'd get two reviews in 3 days where a $350 amp had over twice the SINAD of a $1500 DAC!?!

What is the other amp? Or are you talking about a second review of the PA5?

 

[Walter]

What is the other amp? Or are you talking about a second review of the PA5?

Two reviews = 1 amp + 1 DAC

 

[SylphAudio]

Whoa! Congrats @JohnYang1997 !
Looks like a winner to me for price / performance ratio!

 

[SylphAudio]

Comparison between topping pa5 and JLE , JLE using tpa 3255 with PFFBView attachment 168637View attachment 168638

I too have a hunch that this is a TPA325X implementation, it is a very good performing chip even without PFFB so it has lots of potential for improving the sound quality and performance.

 

[ModDIY]

I too have a hunch that this is a TPA325X implementation, it is a very good performing chip even without PFFB so it has lots of potential for improving the sound quality and performance.

Check this: TPA3250

The pad are down.

 

[xrk971]

The power ratings for IcePower are very clear as to what is peak, maximum continuous, etc. I am not sure how other manufacturers are, but there is no ambiguity here for this Class D amp. If you take a look at the specifications table for the 1200AS2 section 8 datasheet, we see that max continuous power of 1200w for 1 channel driven without thermal shutdown is 15sec (120vac mains). But for continuous output without thermal shutdown is only 280w. It’s much better for 240vac mains so a lot of this appears to be limited by the on board PSU.

With the TPA3255 (assuming now, that’s what is inside the PA5) the specs depend on the rail voltage and the amount of THD one can tolerate. For 53.5v rail and 1% THD for a signal at 1kHz, TI states in the datasheet that the amp can provide 155w per channel. This assumes that adequate heatsinking is provided and that the PSU can provide the goods. I have done continuous sine wave testing in the TPA3255 with a good heatsink and sufficiently large 600w SMPS and can confirm that it will make 150w continuously. The heatsinking here is not trivial - using an CNC milled thermal transfer block to a large 6mm thick plate aluminum chassis floor. Those small finned heatsinks they bolt onto run of the mill TPA3255 amps from China will not dissipate 30w (strereo) continuously. But not to worry, the TPA3255 has built in thermal protection shutdown, and it will give a fault LED warning if it does so. It also tells you if it is clipping and also shut down if there is excessive clipping.

The PA5 has a PSU de-rated from the 53.5v max to 38v, so this will impact the max power. The way to estimate max voltage swing of a BTL amp is to take the rail voltage and multiply by 2x and subtract 8v (for 2x 4v dropout due to MOSFET output). This is 68v and matches what they state as max output swing. 68v / 2.83 is 24vrms output. Power is V^2/R so this is 72wrms. It appears that the 140w spec is for both channels into 8ohms. But 140w per channel into 4ohms.

So really, this is a 70w per channel amp for folks with 8ohm speakers.

That’s just the math behind the PSU voltage stated on the back panel.

 

[Doodski]

Dynamic power 160 W in 8 Ohm, 200 W in 4 Ohm. It seems nice but in practice when you play music with many transients how do you know if the amplifier can handle them? How long is this temporary effect temporary that is? How do I know that it can withstand transient peak X that lasts for Y a long time? Also, how do I even know how long time Y is/last? Check song by song and see if it fits the amplifier? It's just too cumbersome.

NAD 3240PE: 40 WRMS/ch w/2 ch driven.
I checked around and the amp will do ~500W peak stereo@2Ω for a short duration.
"With long 200-millisecond tone-bursts, representing the full duration of musical notes and chords, the 7240PE produces an impressive 100 watts per channel."

I crunched some numbers and if I am correct it can sustain 500w peak@2Ω/ch w/2 ch driven for ~10.9mS and then the power supply caps are drained to about ~0.8 of 1 RC time constant and the amp runs out of steam.
Don't quote me but if the transistors are in 100% saturation mode and the thermistors inline with the +/- rails are not resistive then we get that number.
If the transistors and thermistors are resistive then the time for duration for sustaining the 500w/ch @2Ω increases.

 

[Matias]

Check this: TPA3250

The pad are down.

Nice! And this should be the upcoming power amp too.

TPA3255 data sheet, product information and support | TI.com

TI’s TPA3255 is a 315-W stereo, 600-W mono, 18- to 53.5-V supply, analog input Class-D audio amplifier. Find parameters, ordering and quality information

www.ti.com

 

[TheWalkman]

We all seem to be tippy-toeing around this so what the heck, I'll take the plunge.

Hey @JohnYang1997 : are you using the TPA325X in the PA5? If not, what? Enquiring minds want to know!

(John: based on this darned review, I just purchased a PA5 AND an E50 this weekend, so be nice: I'm your customer! Please don't make me void my brand new warranty for the sake of science and curious ASR readers! )