Topping PA5 measurements )

[Doodski]

There was an expensive preamp with some black epoxy potted "opamp" style gain stages, built around through hole components with flying leads embedded in the epoxy block. Can't remember the brand. A long time ago. Made reverse engineering impossible- until the schematic leaked...

Burmeister had some potted modules in their gear at one point.

I ran into some sort of in-house vertical PCB from Clarion in car audio head units. They failed regularly and where in this really hard green stuff that was impossible to scrape off in any quantity. Hated those things because Clarion was slow on parts delivery and would not let us stock them. We had to provide a serial number with orders for the part. PffT... The really stupid thing was that the Alpine, Sony, SoundStream and even the Coustic head units where better and did not use anything dumb like that. O' Clarion...sigh* When we explained to customers that waited ~6 weeks for the part to come in-stock they where not impressed.

 

[kipman725]

Infineon has done an excellent job with their latest MCMs, so I would give all the credit for low THD to INFINEON designers team. Still, Topping is a great integrator.

Unfortunately, their feedback loop is not covering filter inductors and cannot compete with Hypex/Purifi at high frequencies...

oh but it can be made to take feedback post filter it just isn't documented by the manufacturer: https://www.diyaudio.com/forums/class-d/379537-ma5332.html

 

[bravomail]

so, like it or not, I ordered mine on Amazon!

 

[Yevhen]

oh but it can be made to take feedback post filter it just isn't documented by the manufacturer: https://www.diyaudio.com/forums/class-d/379537-ma5332.html

Nice, but have you seen any functional schematic? Post filter feedback can be done in principle but then, probably, your stability is screwed. TI has some application notes on it but never dare to put it into the datasheet. To me, it seems like only Bruno could commercialize this idea in the Hypex and Purifi products.

 

[MatthewS]

Isn't this one 120W+ into 4ohm? A 200W+ one is also going to happen not too far into the future.

Any chance for an integrated power supply in the future models?

 

[Sami]

Any chance for an integrated power supply in the future models?

And conforming to standards EN55032 Level B and EN61000, EN60601, and safety approvals for UL, TUV, CB, and CE.

 

[nagster]

Same as other devices. All amps need to past power, distortion, noise tests on AP.

I ordered. Thank you for the exciting amp.

I would like to ask about your post.
Is my understanding correct that every number of PA5s shipped from the factory must pass the power, distortion, noise tests by AP individually?

 

[BoredErica]

@JohnYang1997 How about a SPL limiter function in the PA7, sort of like in the pre90? Does that feature request make any sense?
Sorry for the ping and once again, great job with the amp.

 

[Streamc]

What schematic PA5 use?

 

[antcollinet]

What schematic PA5 use?

Topping are going out of their way to prevent competitors from reverse engineering the amp. There is no way they are going to publish the schematic.

 

[AudioArchitech]

If only they would have included a Pre-Out or Sub Out on PA5.

 

[Toku]

If only they would have included a Pre-Out or Sub Out on PA5.

PA5 is a power amplifier with a volume pot at the input.
Those functions you desire are the role of the preamplifier or integrated amplifier.

 

[KSTR]

@JohnYang1997 How about a SPL limiter function in the PA7, sort of like in the pre90? Does that feature request make any sense?
Sorry for the ping and once again, great job with the amp.

With regard to that, I'd really like to see the clipping behavior... another thing that Amir does not measure but it is quite important for lower power amps as they will be driven in to clipping more often, typically.
In a run for best specs (max 1% THD power) clean soft clipping is usually avoided, which I consider a bad thing.

 

[antcollinet]

With regard to that, I'd really like to see the clipping behavior... another thing that Amir does not measure but it is quite important for lower power amps as they will be driven in to clipping more often, typically.
In a run for best specs (max 1% THD power) clean soft clipping is usually avoided, which I consider a bad thing.

Isn’t the clipping behaviour sort of given by the power/distortion chart.

My understanding is that the steeper the line when clipping starts, then the harder the clipping. Conversely a shallower slope shows distortion increases more gradually as the power increases beyond the start of clipping.

Or are you looking for something more specific.

 

[tmtomh]

Isn’t the clipping behaviour sort of given by the power/distortion chart.

My understanding is that the steeper the line when clipping starts, then the harder the clipping. Conversely a shallower slope means shows distortion increases more gradually as the power increases beyond the start of clipping.

Or are you looking for something more specific.

Yes, that's basically it. Clipping is clipping unless there's a built-in "soft-clipping" gradual limiter like NAD has used for many years.

 

[NTK]

Yes, that's basically it. Clipping is clipping unless there's a built-in "soft-clipping" gradual limiter like NAD has used for many years.

A moderate amount of hard, clean clipping actually doesn't deteriorate the sound too badly.
Source:

(PDF) Assessment of nonlinearity in transducers and sound systems - From THD to perceptual models

PDF | Research of the audibility of loudspeaker nonlinear distortion has not shown good correlation between traditionally used metrics (harmonics and... | Find, read and cite all the research you need on ResearchGate

www.researchgate.net

 

[bigjacko]

A moderate amount of hard, clean clipping actually doesn't deteriorate the sound too badly.
Source:

(PDF) Assessment of nonlinearity in transducers and sound systems - From THD to perceptual models

PDF | Research of the audibility of loudspeaker nonlinear distortion has not shown good correlation between traditionally used metrics (harmonics and... | Find, read and cite all the research you need on ResearchGate

www.researchgate.net

Isn't it the same thing as compression? Nowaday many music is mastered with lots of compression that crops the peaks of music and people never complain........ Maybe we can get further compression with low power amp and think it sounds good!

 

[pma]

Isn't it the same thing as compression? Nowaday many music is mastered with lots of compression that crops the peaks of music and people never complain........ Maybe we can get further compression with low power amp and think it sounds good!

I hate listening to nowadays compressed pop music and the new compressed re- masters. You seem to like it?

 

[KSTR]

Isn’t the clipping behaviour sort of given by the power/distortion chart

No, or only very crudely. You have to look at the time-domain for this, with a sine input signal.
In the THD+N vs Power one can see some indications there is any explicit soft-clipping present; no kink at the point the distortion starts to explode, rather a smoothed rounded transition (requires a high enough data point density).

 

[antcollinet]

Isn't it the same thing as compression? Nowaday many music is mastered with lots of compression that crops the peaks of music and people never complain........ Maybe we can get further compression with low power amp and think it sounds good!

No, clipping is distortion. Compression is different.

Clipping cuts the tops of peaks.
Compression reduces the dynamic range between low volume sounds and high volume sounds overall. But nothing is clipped.