Topping PA5 II Stereo Amplifier Review

[staticV3]

I have the PA5 II Plus version with balanced input sensitivity of 2.6 Vrms, and I will be feeding it signal from Topping D50 III Balanced DAC. Since the D50's TRS outputs are 4 V and 5 V respectively, is it best to use just the TRS 4V as this already exceeds the amplifier's input sensitivity and may result in distortion and overloading? Or should the best route is to use the RCA 2.5 V output of the D50 instead? Thanks!

You can safely use even the 5V mode.

As long as you don't max out the PA5's volume knob, nothing will clip.

 

[honn]

You can safely use even the 5V mode.

As long as you don't max out the PA5's volume knob, nothing will clip.

Is there a benefit in using the 5V instead of the 4V? What about in terms of distortion, which technically produces less distortion? which will yield in more "fidelity" so to speak? Thanks!

 

[antcollinet]

Is there a benefit in using the 5V instead of the 4V? What about in terms of distortion, which technically produces less distortion? which will yield in more "fidelity" so to speak? Thanks!

There is no difference to distortion except when the combination of input voltage and volume control causes the amp to reach and exceed it's maximum output voltage (clipping)

I would choose the 4V setting since this will maximise the range of volume control position you can use before this happens.

 

[staticV3]

Is there a benefit in using the 5V instead of the 4V?

The 5V mode has slightly higher SNR, technically.

 

[antcollinet]

The 5V mode has slightly higher SNR, technically.

by a maximum of 2dB

 

[honn]

by a maximum of 2dB

Understood, 4 V it is then!

 

[ICIETDIYEUR]

Hello staticV3 and antcollinet

You are talking about an interesting subject here.

Here are two presentations of measurements that I got on this forum which concern the TOPPING E70 DAC with 4 volts in output and then 5 volts in outputs ->

It is easy to see that SINAD is better at 5 volts but also some 'degradation' is observed in the harmonics (H2 and H3) and that H3 becomes 'dominant' when 5 volts are used as output.

What can we deduce (or not) in terms of 'SQ' with regard to these two modes of operation ?

Will this have an 'impact' in terms of measurements or listening when used in conjunction with the TOPPING PA5 II amplifier ?

Regards

 

[staticV3]

Will this have an 'impact' in terms of measurements

Yes, with good enough measurement equipment.

or listening

The difference between 4V and 5V, once level-matched, may barely be audible in extreme edge cases. Definitely not during regular listening.

Realistically, we're firmly in the realm of academic matters.

The reason why I'd personally use 5V with the PA5II, is because it does not hurt in any way.

In either mode, you can drive the Amp to clipping if you turn up the PA5II's volume too far.

 

[Sokel]

Hello staticV3 and antcollinet

You are talking about an interesting subject here.

Here are two presentations of measurements that I got on this forum which concern the TOPPING E70 DAC with 4 volts in output and then 5 volts in outputs ->

View attachment 424273

View attachment 424274

It is easy to see that SINAD is better at 5 volts but also some 'degradation' is observed in the harmonics (H2 and H3) and that H3 becomes 'dominant' when 5 volts are used as output.

What can we deduce (or not) in terms of 'SQ' with regard to these two modes of operation ?

Will this have an 'impact' in terms of measurements or listening when used in conjunction with the TOPPING PA5 II amplifier ?

Regards

You probably haven't played with input and output levels measuring DACs,
Not only the H2 and H3 are changing with every 100mV but the whole distortion structure as well,more so with input than output.
Down there at the abyss of -140dB does it really matters?

 

[Prosper Menière]

I'm interested about these small Class D amps with low distortion, noise, power usage, cost.... I get the impression most people use them in desktop setups and not as the main amp in a listening room setup. Why am I getting that impression?

 

[NTK]

I'm interested about these small Class D amps with low distortion, noise, power usage, cost.... I get the impression most people use them in desktop setups and not as the main amp in a listening room setup. Why am I getting that impression?

Welcome to ASR.

My guess is selection bias, as it is rather impractical to have a McIntosh or Accuphase on your desktop so you don't hear about those?

 

[Geert]

I'm interested about these small Class D amps with low distortion, noise, power usage, cost.... I get the impression most people use them in desktop setups and not as the main amp in a listening room setup. Why am I getting that impression?

Because you visit the wrong forums maybe?

 

[Bleib]

I'm interested about these small Class D amps with low distortion, noise, power usage, cost.... I get the impression most people use them in desktop setups and not as the main amp in a listening room setup. Why am I getting that impression?

PA5 II has tons of power, far more than desktop should ever need

 

[Hipster Doofus]

I'm interested about these small Class D amps with low distortion, noise, power usage, cost.... I get the impression most people use them in desktop setups and not as the main amp in a listening room setup. Why am I getting that impression?

Not so…driving my B&W Matrix 80 with an PA5 from topping…no problems and play louder than I need. Cheers

 

[Yorkshire Mouth]

PA5 II has tons of power, far more than desktop should ever need

I think the point was whether there was enough power outside a desktop application.

For me, I listen ‘desktop’, it that’s a happy coincidence of listening nearfield.

 

[tmtomh]

I'm interested about these small Class D amps with low distortion, noise, power usage, cost.... I get the impression most people use them in desktop setups and not as the main amp in a listening room setup. Why am I getting that impression?

Welcome!

Class D amps generally come in two main size categories: very small ones that easily fit on a desktop, and larger ones that generally fall in a range between 1/2 the size to the full size of a traditional listening-room/hi-fi amplifier.

Up until a few years ago, the market for stereo Class D power amplifiers was pretty dominated by the small, "desktop style" amps, which are often called "chip amps" because they use a certain family of single-chip amplifiers at their core. There were certainly Class D powered full-size (or near full size) amps, but they were in the minority and their specs, while better than those of the "chip amps," were not considered as good as high-quality traditional Class A and Class AB amps (even though some of those Class A and AB amps don't measure that great themselves).

Over the past 5-7 years or so, a new wave of Class D amp has become common on the market, offering improved frequency linearity, distortion, and impedance handling capabilities. There are two main brands and several different models, but the point is that component-style or monoblock-style Class D amp that provides vanishingly low distortion, tons of power on tap, and impedance load invariance, is relatively new in the market, and while they are very popular and in many ways the norm at places like ASR, among certain hi-fi/audiophile communities they are still seen as a new thing or an alleged "unproven" thing.

Finally, the smaller, "desktop chip amp" category has not stood still either, and there have been considerable advances so that now it is totally feasible to use certain of the best models of those amps as perfectly respectable listening-room hi-fi amps driving conventional stereo speakers, as in @Hipster Doofus 's photo above.

 

[Ropeburn]

Welcome to ASR.

My guess is selection bias, as it is rather impractical to have a McIntosh or Accuphase on your desktop so you don't hear about those?

I had a large and beefy 20kg "oldschool" hybrid AB amp on my desk for 20 years. But then, it's an exceptionally large desk of 2.6x1m, so I guess that doesn't count. Nowadays there's just a smol Audiophonics Hypex amp sitting there, taking virtually no space - while being more powerful.

Size comparison for science:

 

[Roland68]

I'm interested about these small Class D amps with low distortion, noise, power usage, cost.... I get the impression most people use them in desktop setups and not as the main amp in a listening room setup. Why am I getting that impression?

That's probably up to you, because there are enough examples where the PA5, for example, is also used in large systems in the living room. But of course they are also used in desktop setups, precisely because of their size and price, but also because of their very low noise, for example.

The second, perhaps important point, if we leave aside the Purifi and Hypex amplifiers of recent years, the PA5 definitely has more power than the average amplifier sold in the hi-fi sector (Pioneer, Sony, Marantz, Onkyo, etc.).

The only limiting factor is people's imagination and the smaller number of inputs.

 

[mike70]

I'm interested about these small Class D amps with low distortion, noise, power usage, cost.... I get the impression most people use them in desktop setups and not as the main amp in a listening room setup. Why am I getting that impression?

Power ... is power.

The form factor is another stuff. Indeed, at the opposite of what you mentioned, I never (never) will use a 90lbs class A tube amp with the size of a tv to have 20 watts of power.

Take care with "audiophile" preconceived statements.

 

[totti1965]

Hello staticV3 and antcollinet

You are talking about an interesting subject here.

Here are two presentations of measurements that I got on this forum which concern the TOPPING E70 DAC with 4 volts in output and then 5 volts in outputs ->

View attachment 424273

View attachment 424274

It is easy to see that SINAD is better at 5 volts but also some 'degradation' is observed in the harmonics (H2 and H3) and that H3 becomes 'dominant' when 5 volts are used as output.

What can we deduce (or not) in terms of 'SQ' with regard to these two modes of operation ?

Will this have an 'impact' in terms of measurements or listening when used in conjunction with the TOPPING PA5 II amplifier ?

Regards

The second presentation shows k3 distortion at minus 138 dB! So this is about 50 dB to 60 dB from practical threshold of being audible and even 22 dB away from any theoretical, physical reasoned limit of being audible, which is minus 116 dB.
So both, 4 Volts and 5 Volts fully transparent by a huge margin.