Topping PA5 Review (Amplifier)

[aj625]

So I suspect that measurements alone don't sufficiently reassure you that it will sound good. I haven't heard it--it's a recent release and will take some time to make the rounds among the reviewers. I have been hanging around audio long enough that I can assure it will receive very good reviews. They will talk about an exceedingly solid choice at that particular price point, but is falls short of ultimate transparency, that requiring much. much more money. If they are smart, they will latch on to the misbehavior at high frequencies and will launch into a sermon about how this can lead to a certain edginess bordering on stridency with some recordings and when used with incompatible stable mates--those being the preamp or DAC of questionable pedigree.

And be assured also that misgivings will be expressed re the unusual input jack requirements that serve noone except the manufacturer who happens to use the same "quirky" cabling with the insinuation that it is coercive, and no truly reputable manufacturer would hamstring a buyer this way. This of course would completely overlook the almost preamp like functionality this ability to select from inputs provide.

In the end, they will have induced a case of audiophile nervosa, and the faint of heart will graze elsewhere. So prior to reading any reviews, understand the cabing is a nonissue (given the great price) but if using an unbalanced source, make certain it will swing 2 volts. Also acquaint yourself with the audibility of distortion at the frequencies affected here. Does it matter if it has 0.002% ? Good heavens no, but if there is any chink in the armor, this would be it.

Finally, you could always just take the plunge. I'm pretty sure Topping has a 30 day no hassle return. If not, buy it through Amazon. But bear in mind you'll have to trust your own ears. Also ear in mind that they, and not someone elses, should be the ultimate arbiter in any buying decision. Comes right down to these wizard/gurus can likely spot FR anomalies with greater precision than an untrained listener, but all the rest is just a fat bald guy behind the curtain pulling crap out of his own not so resplendent ass.

Measurements alone ? What else affects sound quality ? Looks, size, price, brand name or subjective reviews ?

 

[ModDIY]

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Finally, you could always just take the plunge. I'm pretty sure Topping has a 30 day no hassle return. If not, buy it through Amazon. But bear in mind you'll have to trust your own ears. Also ear in mind that they, and not someone elses, should be the ultimate arbiter in any buying decision. Comes right down to these wizard/gurus can likely spot FR anomalies with greater precision than an untrained listener, but all the rest is just a fat bald guy behind the curtain pulling crap out of his own not so resplendent ass.

I really don't like to read vulgarities.

 

[JRS]

Great design with measured performance that almost knocks the AHB2 off its throne.

My guess is that Topping is using a balanced input opamp or regular multiple opamps to achieve balanced input operation (probably OPA1642) and as driving the TPA32xx with custom optimized PFFB (optimized for extra low gain / higher feedback) as the power amp. Choice of higher Class D carrier oscillation frequency allows smaller inductors and capacitors to be used on the output filter and keeps ultrasonic noise leakage to a minimum in the audible band. The TPA32xx is capable of an extremely low noise floor, currently in the tens of microvolts with PFFB. Increasing level of negative feedback will bring the noise down even lower. TI’s factory designed PFFB white paper specifies 36v power rail, 600kHz carrier frequency, 12.75dB of gain when using TPA3251 and this gives 28.3uV noise. To drop that to 16uV requires modifying the factory PFFB settings for even higher feedback of about 1.75x more. This would make TPA3251 intrinsic PFFB gain close to only 10dB. To get 19.1dB overall gain, Topping is adding about 9dB gain in the input stage opamp, not an unreasonable request. They will probably use dual rail +/-15v supplies for the opamp to provide the high swing needed to drive a 10dB power stage to clipping at max of 68Vpp output. We will see once the insides are revealed…

The factory distortion vs frequency curve has an oddly similar shape to the measured one so this is another clue that we have a TPA32xx core with PFFB, well implemented.

Man I love when I hear dirty talk like this.

 

[TheTalbotHound]

Sure. I have to remember how to set it up as it is not a straightforward test (limitation in Audio Precision).

Have you figured out how to set it up yet?

 

[JRS]

Measurements alone ? What else affects sound quality ? Looks, size, price, brand name or subjective reviews ?

Pretty much nailed it. I'd add ergonomics--solid and silky feel of controls, being warm to the touch (not hot!), and a cool name, numbers are passe, I like names--the implied "great phucking amp" Adcom GFA555 and others excepted. Of course, a long and storied pedigree--preferably American but UK, Canadian or Danish will do. Japanese fine if it's old school, e.g. Denon, Yamaha, Onkyo but China ot so much--automatic deduction for fabrication and QC issues.

 

[pickyAudiophile]

The more I think about that device the more I doubt. There are some caveats. I mean, why is there no single-ended input? That's a little weird. It saves cost and a little bit of space inside. So far I understand. "Voltaic tidiness" kept inside shouldn't be an excuse.

However, buying that amp implies signalling to the industry "O.K. I give in, 'don't need single-ended any longer."
Personally I don't see the point of going from 2V to 4V with no audible benefits whatsoever. Plug types can be discussed, I am open to all, I could even get along with Pentaconn only, too. But the 2V vs. 4V problem is really annoying and it's persistent.

I never felt more pressure on me and my beloved single-ended gear (than after this review came out). And the pressure keeps growing, slowly but steadily. I don't know. I could ignore it all and buy a $449 "Emotiva XBas A2" instead to try something else "contemporary" of 2021. That one received raving subjective reviews. However, we still don't know how it measures.

 

[JRS]

I reported my listening test results. It sounds superb.

But you don't count. As an objectivist you must clearly be biased.

 

[TimF]

I have a question. There is speculation that the PA5 uses a Texas Instrument Class D amplifier chip. I see that other Chinese and non-Chinese Class D amplifiers use chips by Texas Instruments and by Infineon. I think that Bel Canto has primarily used ICEpower chips. The Class D amplifier chip is a technologically complex product like the DAC chip, and therefore they are made by big tech corporations and are made in high volumes. Question: do the Hypex and Purifi amplifier IC boards have a Class D amplifier chip?

 

[JRS]

I really don't like to read vulgarities who shamelessly lie for profit, nor do I mince words when I feel maximum emphasis is called for.

What pickles my member are those who profit through bald faced lies. Excuse me if my outrage is showing.

 

[brandonhall]

Yep, it's a pretty nice feature to have. But, it's also a great beginning-level DIY project... an inline active xover + summing box with a basic DC power supply, proto-board, and a few opamps will do the job and is only a few hours of work if you have a soldering iron and some basic tools.

Which is not to presume that anyone is ready or willing to embark on DIY, of course.

Do you know of any examples or tutorials? That would be a fun first project for me

 

[gvl]

Question: do the Hypex and Purifi amplifier IC boards have a Class D amplifier chip?

They are discrete Class D designs afaik, same for ICEPower.

 

[Bruce Morgen]

They are discrete Class D designs afaik, same for ICEPower.

There's rumor going around that "entry-level" ICEpower modules are built around TPA3255 chips, but I've yet to encounter a credible confirmation of that.

 

[Bruce Morgen]

What would happen if one tried using a power supply / adapter with a higher voltage? Say 48V and 3A?

I don't know other than the fact that you'd almost certainly void the warranty -- the back panel clearly specifies "DC 38V."

 

[amirm]

Have you figured out how to set it up yet?

No... running on empty these days with so much going on.....

 

[SDC]

That toggle switch. Really makes me want to use power sequencer for turning on and off. I wish there are SSRs inside that but for the price its just dreaming...

 

[aj625]

Pretty much nailed it. I'd add ergonomics--solid and silky feel of controls, being warm to the touch (not hot!), and a cool name, numbers are passe, I like names--the implied "great phucking amp" Adcom GFA555 and others excepted. Of course, a long and storied pedigree--preferably American but UK, Canadian or Danish will do. Japanese fine if it's old school, e.g. Denon, Yamaha, Onkyo but China ot so much--automatic deduction for fabrication and QC issues.

Are you serious ? If measurements alone not affect sound quality then what else affects ?

 

[audiophileonabudget]

Actually, for about $100 you can get a Focusrite Solo and REW software. I have a Howto thread on how to do it. Limitations will be the inherent distortion of the sound interface but getting 0.001% THD capability is quite easily achieved with modern mid-priced consumer equipment.

Y'all are very helpful and I am thankful for that, but you and the others keep missing the point: multiple people would love (and would PAY) to have this feature in a ready-to-purchase product. There are plenty of DIY and paid hack-y (miniDSP, inline filters) solutions out there, yet it would be GREAT if there were a high resolution DAC with a digital crossover option so you could set a frequency to high pass your speakers and low pass your subwoofer. (There's some SMSL DACs with sub-out but doesn't appear to filter anything).

Apologies for the tangent that really doesn't have much to do with this amplifier so let me end by saying this amplifier looks fantastic, performs well above expectations, and is very reasonably priced. Well done to Topping!

 

[Moosi]

How much power does it consume in on/standby? And why is there no sub out? In any case this is the last bit of evidence I ever needed to be confident that there is no 2000$+ amp on earth actually being worth the money from a technical standpoint.

 

[Bruce Morgen]

why is there no sub out?

It's marketed as a power amp, very few -- if any -- of which have that feature.

 

[Rottmannash]

Full power with what? Sine wave? Couple of minutes probably. Music? 24/7. Full power RMS is the most useless specification ever.

Music, what else?