Topping PA5 Review (Amplifier)

[Walter]

I'd argue that peak output at some low distortion level (less than 1% for sure) is more important. You will never run an amplifier at its RMS level with music because it wont be able to handle the peaks. It wont even come close to handling the peaks. RMS gives some indication of what an amplifier is capable of, but it doesn't really describe the real world potential of an amplifier.

I pretty much agree with this for home use. I'd personally like to see ratings for SINAD/THD+N at 5 watts from 20Hz-15kHz (I can't hear any higher and this is what I would like to see) plus maximum peak power at 0.1%THD+N, although the current 1% is OK with me, as well since peaks tend to be outside the range where we can hear the best. However, now that Amir has started publishing the Power vs. Distortion charts at multiple frequencies, I can get a pretty good idea of these values, plus some additional interesting information. In fact, for this amp, it gives me info a single number never would have, which is the fact that at 1 to about 1.7 or 1.8 watts, where most of my listening will most likely take place, this amp's performance is really well optimized.

 

[joshfreeman]

Quite helpful thread.

 

[Matias]

I pretty much agree with this for home use. I'd personally like to see ratings for SINAD/THD+N at 5 watts from 20Hz-15kHz (I can't hear any higher and this is what I would like to see) plus maximum peak power at 0.1%THD+N, although the current 1% is OK with me, as well since peaks tend to be outside the range where we can hear the best. However, now that Amir has started publishing the Power vs. Distortion charts at multiple frequencies, I can get a pretty good idea of these values, plus some additional interesting information.

These measurements were already published in the other PA5 thread.

 

[Walter]

These measurements were already published in the other PA5 thread.

Yes, thanks. I meant in general--and I added a bit more info to my post apply to this specific amp.

Edit: When I first saw that THD+N vs. Frequency chart, I thought, "wow." Then I noticed the scale!

 

[pma]

These measurements were already published in the other PA5 thread.

Do you have an idea at which power it was measured? Otherwise it is a useless plot. BTW these measurements come directly from Topping PA5 page.

 

[restorer-john]

I'd argue that peak output at some low distortion level (less than 1% for sure) is more important. You will never run an amplifier at its RMS level with music because it wont be able to handle the peaks. It wont even come close to handling the peaks. RMS gives some indication of what an amplifier is capable of, but it doesn't really describe the real world potential of an amplifier.

There's plenty of amplifiers specifically designed to run at full rated average power and still handle any peak you'd like to throw at them. A large number of commutating rail amplifiers built through the 80s, 90s and into the noughties.

Continuous average power is the standard. Everyone had their opportunity to argue for, and prosecute for a different standard when the FTC asked for comments. Did you put forward an alternative and more representative testing regime for them to consider?

 

[Holmz]

E= i (R+r) =iR+ir where R is akin to load and r is akin to output impedance. If r is more it eats the available output. Even if we assume that you compensate by cranking up the volume even then high 'r' causes shortage of current during the frequency passages for which the impedance of speaker dips very low. …

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?

… for which the impedance of speaker dips very low. …

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?)

 

[Matias]

Do you have an idea at which power it was measured? Otherwise it is a useless plot. BTW these measurements come directly from Topping PA5 page.

They do not state which power was used for the frequency x THD+N graph. But very likely it is 5W as it is the power where we got the 1 kHz at 0.0005% THD+N.

 

[pma]

They do not state which power was used for the frequency x THD+N graph. But very likely it is 5W as it is the power where we got the 1 kHz at 0.0005% THD+N.

No, we have nothing to support this opinion. Look at post #1 and THD+N vs. level measurements at different frequencies. To me it is a marketing bla plot.

 

[Matias]

They do not state which power was used for the frequency x THD+N graph. But very likely it is 5W as it is the power where we got the 1 kHz at 0.0005% THD+N.

@JohnYang1997 could you please confirm this? Thanks.

 

[seaninbrisbane]

I'm trying to work out if this amp would be suitable to power a pair of 4 ohm, 90 dB SPL (2.83 V/1m) sensitivity speakers. I would be using it with an RME ADI-2 DAC.

 

[restorer-john]

I'm trying to work out if this amp would be suitable to power a pair of 4 ohm, 90 dB SPL (2.83 V/1m) sensitivity speakers. I would be using it with an RME ADI-2 DAC.

It will be fine.

A bit tiny, boring and limited in functionality, but fine. It's not the amp you want to impress someone, that's for sure. Hide it in a cupboard and pretend it's a McIntosh.

 

[Koeitje]

There's plenty of amplifiers specifically designed to run at full rated average power and still handle any peak you'd like to throw at them. A large number of commutating rail amplifiers built through the 80s, 90s and into the noughties.

Continuous average power is the standard. Everyone had their opportunity to argue for, and prosecute for a different standard when the FTC asked for comments. Did you put forward an alternative and more representative testing regime for them to consider?

These amplifiers also won't hit the peaks. Lets say they run at 100W RMS and get hit with a 20dB peak in music (which can happen with classical), then it suddenly needs to supply 10000W. Or are you talking about PA amplification?

Lets take this:

McIntosh MC2KW Amplifier

The MC2KW monoblock amplifier is designed to exceed the demands of true lifelike playback levels, capable of delivering 2,000 watts of continuous power and 8,000 watts of peak power.

www.mcintoshlabs.com

2000W RMS 8000W peak. But running at 2000W RMS it would need 200000W peak power for 20dB peaks . So at RMS output it won't be able to properly reproduce a music signal.

RMS output can give an indication of quality, but it doesn't tell much about how it performs with non-test signals. All that matters for an amplifier is what kind of output it can provide with music content. May I suggest using one of those Tchaikovskys Overture 1812 recordings where they used real cannons?

Anyway, I'd take my 50W RMS NC400's over an amplifier that has double the RMS but cannot come close the peak output of the NC400. Because I won't ever hit the RMS load, but I can hit the peak load. The second amplifier will clip, my NC400 wont.

 

[PeteL]

I'd argue that peak output at some low distortion level (less than 1% for sure) is more important. You will never run an amplifier at its RMS level with music because it wont be able to handle the peaks. It wont even come close to handling the peaks. RMS gives some indication of what an amplifier is capable of, but it doesn't really describe the real world potential of an amplifier.

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.

 

[Jake Cushing]

n00b question, but could one connect a cd player directly to this amp?

 

[Doodski]

RMS output can give an indication of quality, but it doesn't tell much about how it performs with non-test signals. All that matters for an amplifier is what kind of output it can provide with music content. May I suggest using one of those Tchaikovskys Overture 1812 recordings where they used real cannons?

I'm board with this. We analyzed a Denon integrated the other day and it had +/- ~60V DC rails (225WRMS if possible) and when putting out peak wattage @ 8Ω the rails where at about 38V (90WRMS). I don't remember the exact numbers but the idea here is what matters. So the power supply is loosely regulated but the peak output power if required for a split second is there if the amp can manage it at say 55-60V DC. Peeps almost never take this into account when they talk power numbers.

 

[restorer-john]

These amplifiers also won't hit the peaks. Lets say they run at 100W RMS and get hit with a 20dB peak in music (which can happen with classical), then it suddenly needs to supply 10000W. Or are you talking about PA amplification?

Lets take this:

McIntosh MC2KW Amplifier

The MC2KW monoblock amplifier is designed to exceed the demands of true lifelike playback levels, capable of delivering 2,000 watts of continuous power and 8,000 watts of peak power.

www.mcintoshlabs.com

2000W RMS 8000W peak. But running at 2000W RMS it would need 200000W peak power for 20dB peaks . So at RMS output it won't be able to properly reproduce a music signal.

RMS output can give an indication of quality, but it doesn't tell much about how it performs with non-test signals. All that matters for an amplifier is what kind of output it can provide with music content. May I suggest using one of those Tchaikovskys Overture 1812 recordings where they used real cannons?

Anyway, I'd take my 50W RMS NC400's over an amplifier that has double the RMS but cannot come close the peak output of the NC400. Because I won't ever hit the RMS load, but I can hit the peak load. The second amplifier will clip, my NC400 wont.

You're making zero sense. But that's OK.

You haven't actually tested any amplifier on normal, dynamic content when reproducing its rated, dynamic or maximum power, be that musical content or test criteria. I know that, by your comments.

 

[Doodski]

Momentary headroom is still "RMS" if we are talking Watts, we shouldn't even have to called them Watts RMS, it confused people, it's just Watts.

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

 

[Papaya_X]

n00b question, but could one connect a cd player directly to this amp?

Yes, usually using the RCA I/O

 

[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.