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Good Class D amps ??


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2 hours ago, Ralf11 said:

Which are the best Class D amps?

 

Has anyone compared them with other designs, Class A or AB, etc.?

Well, yes, but not enough comparisons to make any decisions - i.e. too small a sample set for any meaningful conclusions. In my case both my analog amps sound better than the Behringer NU1000 that I own. Not that the Class D amp sounds bad, it just lacks that subtle sophistication of reproduction that says "high-end amps playing here", if you get my drift. 

George

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Mola Mola's Kaluga monoblock amplifier ($16,500 USD per pair),which  had their measurements shown on P.1 of the other thread, are from Bruno Putzeys company Mola Mola, and  are using the latest generation nCore amplification technology..

 Many other amplifiers use these higher powered NC1200 versions.The Bel Canto  REF600M monoblocks have similar shaped output measurements, but not as good as the enhanced higher output power Mola Mola.

The Kaluga circuit is designed around modules that are apparently enhanced versions of the NC1200 created for OEMs., also shown on the same page has similar looking measurements, although the tweaked flagship model from Mola Mola has achieved lower distortion figures .

 

More info about the Bel Canto REF600M (Price: $4990/pair)

Quote
 
Bel Canto  REF600M monoblocks :
Inside are three circuit boards: a Hypex NC500 amplifier, a Hypex SMPS1200 power supply, and Bel Canto's input conditioning board with their Impedance Optimized Input Stage, for balanced, high common-mode rejection and to provide a low output impedance to the input of the amplifier board. The active element on the board is an LME49720 Dual High-Performance Audio op-amp in what appears to be a low-pass filter configuration.
Read more at https://www.stereophile.com/content/bel-canto-eone-ref600m-power-amplifier#QlxKMqg0heVxdC91.99

 

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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9 minutes ago, Ralf11 said:

Technics has a Class D using GaN devices

 

and the nad M series?  are they Class D?

 I don't know about the rest of the Technics Master range, but The Masters Series M22 is based on a version of Hypex Electronics' model NC400 NCore amplifier module that has been customized for NAD.
Read more at https://www.stereophile.com/content/nad-masters-series-m22-power-amplifier#Hjkw5oqW1daEkfmi.99

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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I would and plan to checkout the NCore amp built by ATI.

They make their own linear power supply and come in a ton of configurations,

although MCH music seems to be a low interest aspect on this forum.

Uniformly excellent reviews. Kal Rubinson reviewed them in his column.

Pretty sure he uses the Bel Canto monos.

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There is a lot of chatter about the new Icepower 1200AS2 based board over at Mivera Audio Forum at Audiocircle. One of the threads there lists a couple of other manufacturers incorporating this board into a case. The board has onboard power supply so other than connectors, cables, switches, etc. there's not much for a manufacturer to do. 

 

https://www.miveraaudio.com/shop

 

YMMV.  There's a listening impression thread but not much in the way of listening impressions.

 

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For starters performance matters more than class of operation.  Each class of operation has its own areas of difficulty.  It really is a poor way to pick what equipment to use. 

 

Below are the graphs at moderate power from Stereophile testing of three well known brands of very powerful amps of class D, A and AB operation.  Which is which? The drive level is at 8 ohms, 4 ohms and 2 ohms with lower impedance giving higher distortion in each case.  We are looking at roughly 20 watts into the 8 ohm load and all amps are capable of well over 200 watts.  This graph is THD+N vs frequency. 

 

 

image.thumb.png.185b393241ae53c7492821e16e12ec52.png

image.thumb.png.4169b85c1689366acdbb8b673d47f1db.png

image.thumb.png.56b51b03c67371fbf1e12882254236e7.png

 

 

 

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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11 minutes ago, esldude said:

For starters performance matters more than class of operation.  Each class of operation has its own areas of difficulty.  It really is a poor way to pick what equipment to use. 

 

Below are the graphs at moderate power from Stereophile testing of three well known brands of very powerful amps of class D, A and AB operation.  Which is which? The drive level is at 8 ohms, 4 ohms and 2 ohms with lower impedance giving higher distortion in each case.  We are looking at roughly 20 watts into the 8 ohm load and all amps are capable of well over 200 watts.  This graph is THD+N vs frequency. 

 

 

image.thumb.png.eb78efccfed412fd18741973df9fd411.png

image.thumb.png.4169b85c1689366acdbb8b673d47f1db.png

image.thumb.png.56b51b03c67371fbf1e12882254236e7.png

 

 

 

 

My wild guess is that the 1st is the class D...or maybe the 3rd...

Hey MQA, if it is not all $voodoo$, show us the math!

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Just now, crenca said:

 

My wild guess is that the 1st is the class D...or maybe the 3rd...

Come on now, guess which is A and AB also. 

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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1 minute ago, esldude said:

Come on now, guess which is A and AB also. 

 

Ok, ok, my guess is that the 1st is A, the 2nd, AB, and third D...

Hey MQA, if it is not all $voodoo$, show us the math!

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Anyone care to guess which class this amp operates in from some Soundstage.net measurements.  In this case the load is 8 ohms and each line represents power level.  The green line is 300 watts and the red line 1 watt.  This amps is rated for 350 watts.  

 

image.thumb.png.1ee956469d5e41b86c93b8285647bed7.png

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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4 minutes ago, Kal Rubinson said:

The first is labeled Krell KSA-250.  Not a mystery.

 

Ha, I did not notice that...but I got it right!  Do I have "golden eyes" when it comes to THD?!?  :P

Hey MQA, if it is not all $voodoo$, show us the math!

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@Kal Rubinson

Please edit your post. 

 

Also @crenca

I posted the wrong image, but it is fixed. 

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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38 minutes ago, esldude said:

Below are the graphs at moderate power from Stereophile testing of three well known brands of very powerful amps of class D, A and AB operation.  Which is which? The drive level is at 8 ohms, 4 ohms and 2 ohms with lower impedance giving higher distortion in each case.  We are looking at roughly 20 watts into the 8 ohm load and all amps are capable of well over 250 watts.  This graph is THD+N vs frequency. 

 

 Perhaps a case of selective choosing,(?)  as NONE of those amplifiers' specifications  are particularly impressive.

 There are many lower powered designs available as DIY kits at a fraction of the price that will easily outperform these amplifiers at 20W, and almost certainly at a much lower cost ! e.g. the Silicon Chip Ultra-LD Mk.3 200W Amplifier, which has since been superseded by the Mk.4 version

e.g. http://www.altronics.com.au/p/k5165-ultra-low-distortion-mk.3-135w-stereo-amplifier-kit/

 

SC ULD 3 p.1- Specifications.jpg

SC ULD 3 p.4a.jpg

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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16 minutes ago, esldude said:

 

Yes, definitely selective choice to get across the point class of operation isn't by itself a key parameter.   BTW your graphs in this post don't show THD vs Frequency.  All the amps in my earlier post show very low distortion at rated power at 1 khz. Actually a somewhat deceptive practice among class D amps as they do better than than at higher frequencies usually. 

 

I could have picked this Benchmark which I think JA said might be just measuring his AP rather than the amp.  This one near 30 watts rather than 20 watts btw.  

 

This Benchmark and the mystery amp I posted above are among the best such I have seen with this measurement.  

 

The other thing worth noting looking at Soundstage.net measures is nearly all amps actually have lower distortion at higher power until just before max power.  So the idea your smaller 20 or 30 watt amps would show better than the 20 watt results for 300+ plus watt amps isn't surprising.  Shows the importance of sizing amps and speakers for minimum distortion.  When is the last time someone discussed that.   

 

These 300 watt amps operating at 20 watts in the Stereophile graph of THD+N vs Frequency more than likely show lower distortion at higher power.   Such nuances are why amps might sound different with different speaker loads while all having similar measured performance.  A topic not discussed or investigated nearly enough. 

 

1115BAHB2fig07.jpg

 

 

 

 Attached is the SC ULD -Mk.3 which has since been superseded and improved on by the Mk.4 version which I don't have a copy of.

Note that the graph here shows THD + N at 100W into 8 ohms.

 The performance is substantially better at lower powers.

 

SC ULD 3 p.3a.jpg

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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2 minutes ago, sandyk said:

 

 Attached is the SC ULD -Mk.3 which has since been superseded and improved on by the Mk.4 version which I don't have a copy of.

Note that the graph here shows THD + N at 100W into 8 ohms.

 The performance is substantially better at lower powers.

 

SC ULD 3 p.3a.jpg

So that is very good, but not quite equal to the Benchmark measurements posted above or the other amp tested by Soundstage.net which btw is the large Bryston mono amp.  The only one to pass  the transparency listening test both sighted and blind by the Swedish AES. 

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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6 minutes ago, esldude said:

So that is very good, but not quite equal to the Benchmark measurements posted above or the other amp tested by Soundstage.net which btw is the large Bryston mono amp.  The only one to pass  the transparency listening test both sighted and blind by the Swedish AES. 

Damn.

 

 

 

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