Good Class D amps ??

[PorkChop]

On 3/29/2018 at 4:09 PM, mfsoa said:

Amps from the Digital Amplifier Company are not based on either NCore or ICE, but on a completely custom solution.

 

The Maraschinos get fabulous reviews from everyone that hears them. The least expensive version is less than $1K.

 

The newest Megaschino amp is better still. It uses a large transformer and 12 output devices per channel vs. the 4 used in the Maraschino. In my experience the highs on the DAC amps are superior to the ICE and NCore implementations I have heard. Designed and made in the USA.

 

A recent review:

http://www.jeremykipnis.com/MEGAschino_Review_-_03_18.html

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On 3/29/2018 at 4:09 PM, mfsoa said:

 

I've got their mini Cherry monoblocks hooked up to Gallo Strada II's in my nearfield system and am loving the sound. So clean!!  Not only is the treble now perfect to my ear, but they brought out a little more fullness to the upper base as well.  Still need the sub of course, but the extra meatiness was an unexpected benefit.

 

[John769]

23 hours ago, Matias said:

@John769 I went the opposite direction, ordering the more expensive PRO opamps to get even higher performance and higher price. But I agree, the NC502MP based stereo power amplifier has a great price.

 

Prices from Apollon website:

- NC800SL (NC500 based - 2 x 400W at 8 ohms) with standard SI opamp - 1575 euros.

- NC800SL (NC500 based - 2 x 400W at 8 ohms) with PRO opamps - 1875 euros.

- NCMP700 (NC502MP based - 2 x 350W at 8 ohms) - 825 euros.

 

Plus optionals.

 

What is the SQ difference between the SI 994 and 2x990 Enh Ticha?  Why do Nord only offer the SI 994?

 

Quote

That is half the price for the 502MP. Never listened to them though...

Shame nobody seems to have compared them to the higher model.  It's difficult to make a decision..!

[Matias]

Nord (and Apollon) offer both SI opamps. The 2 larger pro ones are said to be a little better sounding. But seems like the pro opamps are temporarily unavailable.

[mocenigo]

On 1/18/2019 at 1:45 PM, John769 said:

 

Looking forward to some more discussion. 

 

"The NCore MP modules have an on board PSU and twin channels providing 85-90% of the sound quality of the NC500 in a compact footprint. They easily outperform older UcD amplifiers. They retain all the bass control, dynamics and most of sound stage and resolution of our NC500 amplifiers out performing most commercial amplifiers found on the high street costing 3-4 times more."

 

Anyone listened to the MP variants?  They seem good value..

 

I haven't, not in a 1-1 comparison with the rest of the system being equal,, but one needs to be able to read between the lines to understand at least what the manufacturer believes. They would never say that mids are less transparent and highs a bit harsher 😞 So you can expect that NCore MP based amps will not have the delightful forwardness in the mids and the smoothness of the highs of a NCore NC based amp with a good buffer. To me, saying "90%" of the perceived sound quality cannot make sense at all since we do not know how to measure it, whereas classic measurements would in fact show the two types of amps to be quite similar.

 

 Roberto

 

[mocenigo]

On 1/19/2019 at 1:38 PM, John769 said:

 

What is the SQ difference between the SI 994 and 2x990 Enh Ticha?  Why do Nord only offer the SI 994?

 

I would expect the difference to be quite small, but if your speakers are sufficiently revealing you will probably notice it.  I expect a bit of less noise.  The 990 is essentially one half of the 994 - or a 992 - in a little shielded box, so there may be an even lower noise floor resulting in a even more relaxed and smooth presentation with very sensitive speakers. Also, note that the pins of the "pro" opamps are larger and better spaced, so at the interface they may conduct better than the little pins of the usual opamps. 

Note that Apollon's amplifiers have an astonishingly low noise floor because of the way the buffer is designed. Yes, they are all derived from the same designs by Richard Doporto of Sonic Imagery, with a few custom tweaks, but with these things the devil is in the details, such as proper separation of the grounds, crossing power and signal orthogonally and other details, which look less than perfect in the Bellissimo and Nord designs, and a close look at the buffers in my Apollons shows a lot of care.  That low noise floor means that you could use them with highly sensitive speakers - mine have 96Db/w/m - and hear nearly no noise at all even with your ear glued to the transducers. You can probably use 110Db speakers. Of course this means that either you have a listening room the size of a sports palace or you are using a few hundred mWs (in my case usually 1-2W), but then you are using the class D amp in a region of absurdly low distortion and near perfect linearity. And you still have that reserve in case your music contains some high transient energy loud bass!

 

In my humble opinion the SI opamps sound better than the Sparkos in the Apollon buffer - I have no idea how they behave in the Nord buffers. This with the REV B Apollon input buffer - I had them recently installed in place of the original REV A that I had, and boy they made a difference (also, with the REV A input buffer I was undecided between Sparkos and Sonic Imagery). So if one manufacturer judges that the larger Sparkos (or the larger SI) are not worth the extra expense, they will not include it to reduce confusion.

 

What I would really want to see/listen are the Weiss opamps. Hopefully some of these manufacturers will make them available.

 

 Roberto

 

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Shame nobody seems to have compared them to the higher model.  It's difficult to make a decision..!

 

[Matias]

@GeneZ what I meant about power x THD measurements are the graphs that both ICEpower and Hypex use on their datasheets.

 

They were done with Audio Precision equipment, using 4 ohms impedance (8 ohms too but I show 4 because it is more relevant IMO).

 

Blue line is bass (100 Hz), green line is mid range (1 kHz), red line are highs (6.67 kHz, sibilant area of the frequency spectrum).

 

All power graphs end up in a high rise until they reach 1%, which is normally the standard THD percentage that manufacturers rate their power in a given impedance.

 

The top graph is an older ICEpower 1000ASP. Notice how the bass line is descending, meaning the distortion is somewhat constant but in relation to the increasing power level, its percentage goes down. But the same does not happen to mids and highs: the distortion increases with more power. Specially highs are all over the place up to 0.2% mid power. Higher distortion in highs may be related to the bad reputation class D got until a few years ago (1000ASP was released about 2003?).

 

Next is the newer ICEpower 125ASX2 in stereo (SE mode),  not bridged (BTL mode). The mids green line is better behaved, low and closer to the bass blue line. The highs red line is also a lot lower, specially in low power, and always below 0.1%. All 3 lines reach 1% in a lot less power than 1000ASP, but that is not my point here. This module was released about 2011.

 

Next is the newest ICEpower 1200AS. Again all 3 lines are very well behaved with the highs red line reaching a maximum of 0.01% mid power, which is quite a big step in performance. This one was released in 2017.

 

And last in line is nCore NC500. All lines are very well behaved, reaching incredible 0.001% mid power, including the highs red line! This is seriously low THD, closer to DAC figures than regular power amplifier figures. Highs are 200 times less distorted mid power than 1000ASP! nCore NC500 was released about 2011.

 

Notice that this performance increase is NOT directly related to switching performance:

- ICEpower 1000ASP - 350 kHz idle

- ICEpower 125ASX2 - 450 kHz idle

- ICEpower 1200AS - 500 kHz idle

- nCore NC500 - 450 kHz idle

Even Hypex datasheet says: "Commonly expressed creeds that an amplifier’s suitability for high quality
audio can be read from these numbers (switching frequency in particular) are ill informed."

 

That is why I wanted to see the custom NuPrime amplifiers being measured this way, to see how they compare.

 

(I am not 100% sure about the release dates, correct me if I am wrong)

 

Then I see Stereophile's measurements of Bel Canto REF600M, and the THD 1kHz 8 ohms line (Fig. 4) is a lot higher and increasing gradually. This is deliberately designed and implemented on the buffer, because the power stage is lower as we saw on the raw NC500 graphs.

https://www.stereophile.com/content/bel-canto-eone-ref600m-power-amplifier-measurements

 

 

[GeneZ]

I think (within reason) that measurements are not the means.  That is, as long as everything measures fine within reason?  Nothing measuring horribly?

 

Back in the day when I was on the scent of tube equipment - at a time when tubes definitely sounded better to me than solid state.  I was told by someone in the audio world...  "Solid state does not sound as good because its too accurate."... (as he pulled out a sheet with some measurements to show me how they were superior.)

 

I then learned to take measurements (as long as they are decent) with a grain of salt.  

 

Its all really a matter of... "Well?  .. How does it sound?"

[Matias]

@GeneZ I agree, by no means I am 100% objectivist. Heck, my system has a lot of expensive power cords, fuses and tweaks. I totally agree with you that "how does it sound" is the golden rule. Still, those measurements are interesting and should tell part of the story.

 

And with NuPrime being so hyped lately, I wonder how much better their measurements could get than the already fantastic nCore NC500.

[GeneZ]

1 hour ago, Matias said:

@GeneZ I agree, by no means I am 100% objectivist. Heck, my system has a lot of expensive power cords, fuses and tweaks. I totally agree with you that "how does it sound" is the golden rule. Still, those measurements are interesting and should tell part of the story.

 

And with NuPrime being so hyped lately, I wonder how much better their measurements could get than the already fantastic nCore NC500.

  Give you an example....  The few who know me think I am too "detail oriented."

 

All my efforts to improve the sound... which does happened in small increments at a time... As of late, it came as a surprise.  Just one power cord to my DAC transforms the entire system.  I can place the same PC on the NuPrime amp and that too will change the sound.  But, on the DAC?  That changes everything.  Its like upgrading my amp and preamp.

 

We are sometimes looking in the wong place...

[fas42]

2 hours ago, GeneZ said:

 

All my efforts to improve the sound... which does happened in small increments at a time... As of late, it came as a surprise.  Just one power cord to my DAC transforms the entire system.  I can place the same PC on the NuPrime amp and that too will change the sound.  But, on the DAC?  That changes everything.  Its like upgrading my amp and preamp.

 

We are sometimes looking in the wong place...

 

Very few people appreciate the significance of what you're saying - it's a man's hobby; and the bling factor is very, very important to many - that "tiny things" are so critical does not compute; they don't want to know that fussing with boring, cheap stuff can be the vital link to best sound.

[GeneZ]

Why not cut to the chase? 

 

Someone ought to manufacture an amplifier and call it...   "The .00001 THD."

 

It would eventually gain the nickname...   "Are you Happy Now?  Amp."

[fas42]

The circuit is already out there, if someone wants to build it ...http://www.data-odyssey.nl/Super_TIS.html

[esldude]

2 hours ago, GeneZ said:

Why not cut to the chase? 

 

Someone ought to manufacture an amplifier and call it...   "The .00001 THD."

 

It would eventually gain the nickname...   "Are you Happy Now?  Amp."

I think benchmark and mola mola are one decimal point or less from being there.

[crenca]

3 hours ago, GeneZ said:

Why not cut to the chase? 

 

Someone ought to manufacture an amplifier and call it...   "The .00001 THD."

 

It would eventually gain the nickname...   "Are you Happy Now?  Amp."

 

Why not cut to the chase:

 

"...Just one power cord to my DAC transforms the entire system..."

 

its nickname would be...Audiophile!  Or would that be Audiophool?

[Ralf11]

I have to say that the tests one often sees run on amps don't always correlate perfectly with the sound.

[audio.bill]

1 hour ago, esldude said:

I think benchmark and mola mola are one decimal point or less from being there.

Maybe this was mentioned previously, but to be clear (given the subject of this thread) the Benchmark AHB2 power amp is not a Class D design. To quote from their website: "The AHB2 has a bipolar class-AB output stage." It uses some unique error cancelling technology and "achieves a power efficiency that rivals that of a Class D (switching) power amplifier."

[GeneZ]

1 hour ago, crenca said:

 

Why not cut to the chase:

 

"...Just one power cord to my DAC transforms the entire system..."

 

its nickname would be...Audiophile!  Or would that be Audiophool?

 

I know you are just phooling. 

 

I know you have good ears and can hear such differences. Right? ... RIGHT? ....RIGHT?.....RIGHT!?  Hello? 

[GeneZ]

17 minutes ago, audio.bill said:

Maybe this was mentioned previously, but to be clear (given the subject of this thread) the Benchmark AHB2 power amp is not a Class D design. To quote from their website: "The AHB2 has a bipolar class-AB output stage." It uses some unique error cancelling technology and "achieves a power efficiency that rivals that of a Class D (switching) power amplifier."

  Yet ,Benchmark does use a very Class D type technology in its design!

 

https://benchmarkmedia.com/blogs/application_notes/152143111-audio-myth-switching-power-supplies-are-noisy

[Kal Rubinson]

6 minutes ago, GeneZ said:

Yet ,Benchmark does use a very Class D type technology in its design!

Nope.  A switching power supply is not always correlated with Class D amplifier technology.  There are Class D power amps with linear power suppllies and there are Class A-B amps, like the Benchmark, with switching power supplies. 

[esldude]

1 hour ago, audio.bill said:

Maybe this was mentioned previously, but to be clear (given the subject of this thread) the Benchmark AHB2 power amp is not a Class D design. To quote from their website: "The AHB2 has a bipolar class-AB output stage." It uses some unique error cancelling technology and "achieves a power efficiency that rivals that of a Class D (switching) power amplifier."

Yes, but I was replying to GeneZ's post which didn't seem concerned with class of operation.  

[GeneZ]

2 hours ago, Kal Rubinson said:

Nope.  A switching power supply is not always correlated with Class D amplifier technology.  There are Class D power amps with linear power suppllies and there are Class A-B amps, like the Benchmark, with switching power supplies. 

 

 

My Class D uses a linear power supply.  Yet, it seems that many out there associate Class D with switching power supplies.

[Kal Rubinson]

8 hours ago, GeneZ said:

My Class D uses a linear power supply.  Yet, it seems that many out there associate Class D with switching power supplies.

So what?  There is no necessary correlation.

[Matias]

To be fair, even though I am curious to see THD measurements, truth is that big names like Nelson Pass and Dan D'Agostino do not care much about lowest THD. Instead they just design their amplifiers just sound good.

[crenca]

23 minutes ago, Matias said:

To be fair, even though I am curious to see THD measurements, truth is that big names like Nelson Pass and Dan D'Agostino do not care much about lowest THD. Instead they just design their amplifiers just sound good.

 

I don't know about Dan, but yes Pass does investigate and "builds in" 2nd order distortion and the like because folks like it.  This "coloring" is known (if not well understood) and part of the Audiophile world.  Its relationship to fidelity is controversial.  GeneZ point is the common art and wine radical subjectivism with the strawmen "how does it sound", etc. and is the usual trope.

 

On topic, THD and the like are relevant, correlated to the sound, etc.  It's not the end of the story, but it is part of it...

[Matias]

1 minute ago, crenca said:

 

I don't know about Dan

 

Hear it for yourself: