Good Class D amps ??

[barrows]

Nord One Up is likely the very best amplifier available in the world in terms of cost/peformance.  I have heard it and it is outstanding.  It offers two options for the input stage which allows slight "tuning" of the sound as well.

 

Mola Mola Kaluga is likely the very best class d amplifier available period, and one of the best amplifiers available in the world regardless of topology.  I have never heard an amp which I could say was 'better" in any real way.  I have heard most of the heavy hitters (Solution, Audio Research ref series, VTL, Constellation, CH Precision, etc, etc).

[barrows]

10 hours ago, sandyk said:

Why should this be of concern for people who use say, 20W to 50W maximum Class A amplifiers, when Class D amplifiers used by many members at ear splitting levels into inefficient speakers STILL consume far more electricity overall ?

 Have you gone " Green"  and become a " Tree Hugger " too ? 

Because the idle dissipation is the problem.  Take my former Pass Labs amplifier, it required at least an hour of warm up to reach thermal equilibrium and its best operating condition.  It seemed to sound even better though when left on overnight.  In any case, I could not predict with an hours advance notice when I was going to be listening, so if I wanted the amp to sound its best it had to be left on 24/7.  Although it was not a high power model, it still idled at ~250 watts.  So that is a significant energy waste.

With my class d amplifier, which actually sounds a bit better, I leave it on 24/7 and it idles at ~10 watts.  Big difference.

 

But, I chose the class d amp because it sounds better, and the energy savings is just a bonus.

[barrows]

This one, Hypex NC-400 DIY build, direct soldered Cardas speaker output wiring, Cardas binding posts and XLRs, Cardas direct soldered AC input wiring, crystal AC power conditioning, optimized layout for shortest possible in/out wiring and best orientation of power supplies.  Since this picture was taken I have removed the standby toggle switch from the back panel and added a nice, lighted, touch switch for standby function on the underside of the chassis near the front panel.  I also find Herbies Tenderfoot soft/tall footers are a better match with this amp than the Stillpoint Minis I used to use.

[barrows]

1 minute ago, Ralf11 said:

kit components, or ??

DIY, using Hypex NC-400 modules and SMPS-600 modules.  See:

 

https://www.hypexshop.com

 

for details...  

[barrows]

1 hour ago, GUTB said:

 

Class D sounding better than a Pass is fake news.

Nope, it is entirely true in my system.  It took a bit of work to get the amp right, but once it was I sold the Pass.  It was not a night and day difference, but ultimately the Ncore had a lower noise floor, better detail retrieval, bigger dynamic contrasts and a deeper soundstage.  At first the Pass had a bit of an edge in terms of body and timbre, but the changes I made to the Ncore's wiring pulled it even in that department.

I did not make any spot decisions on this, and kept both amps around for over a year before selling the Pass, switching back and forth, etc, as I was a bit unwilling to believe it myself, but the listening does not lie.

 

Clearly you have not had enough experience with the best that class D has to offer in the right systems.

[barrows]

10 minutes ago, sandyk said:

There is no valid reason why the Pass should not have had a lower noise floor unless it was a much earlier design, or it's main filter electros had partially dried out due to heat related issues.

The nCore obviously would need a huge amount of work done to eliminate the extremely high RF/EMI generated by the switching action at a very high power level, partly due to FCC requirements, whereas the Pass would not need this.

 Could it be that the nCore has a noise gating action in the absence of a valid signal ?

If so, I suppose something like this could also be done with a Linear amplifier to further improve S/N to ridiculously low levels for specification boasting purposes ?

Hahaha, you are making me laugh:

 

1.  Look at the specs, the amp was the X150.5, and no it was not old or anything.  I was the first owner and purchased it new.  

     The Ncore amps are exceptionally low noise.  Anyway can see this in the specs.

 

2.  I did the listening tests of this right here in my own living room, it was easy enough to hear the differences.  And this was 

     was not short term listening alone, I tested over a year long period.

 

Please stop posting this nonsense when you clearly have no direct experience of it, and cannot even be bothered to look at the noise floors, or S/N ratios...  This info is not hard to find, and no i am not going to be bothered anymore to go and look it up for you.  Look at the noise floors with signal, in order to rule out your absurd theories...

[barrows]

Alex, these two amps were contemporaries at the time.  The Pass .5 series was current, as was the NC-400.  It was not some old design against a new one.  Now both makers have newer models, but neither amp is a slouch by current standards either.

 

My comparison was between these two amps, not some other linear SS design which might have a lower noise floor than the Pass, that is neither here nor there is this discussion.

 

I have never suggested that class D amps are the "best", all I have ever said is that the best class D amplifiers currently can equal the best amplifiers of any other topology.  There are lots of amplifiers I admire, some are class A/B, some are class A (predominantly), and some are class D.

The point is that now we have class D amplifiers which are on a level playing field with any other topology for sound quality, and that those who do not  believe this need to open their ears, and get out and listen to some of them while putting their pre-conceived notions to rest.

 

I am still a great admirer of the Pass Labs amps, and if I ever got some much more efficient speakers, I could imagine the current Pass Labs XA 30.8 in my system as well, given that the capitol was available.

 

Actually, at this moment, if someone gifted me a Constellation Inspiration, I would be very tempted to run it in "direct" mode by adjusting my DAC's output stage to suite and be very happy with an A/B amp of very high sound quality (my sub would make up for the slight lack it has in deep bass energy).

[barrows]

23 minutes ago, sandyk said:

Unfortunately, you chose to offer a comparison of the very latest nCore technology against what is a basic Nelson Pass affordable design with a very limited power in the Class A region of 10W.

The Pass Labs X150.5 was, as I recall about $6K when i purchased it, and it was a current contemporary of the NC-400 modules.  The XA version of this amp, with the higher class A bias achieves about 30 watts of purely class A output before transitioning to class A/B and costs the same, it ultimately lately has bit less total current output though.

The NC-400 modules and power supplies are much cheaper, although of course one must source a chassis.  this is apples to apples except that the Ncore amp is less than half the cost even if you have to pay someone to build it for you.

 

BTW, the Merrill Audio Veritas has about 130 dB S/N, this is the equal of anything out there.  The much acclaimed Benchmark amp achieves good performance, but its specified S/N ratio is a trick as its gain is very, very low.  If it has normal gain of 26 dB the noise would be much higher.  See Stereophile measurements for confirmation.  Still it does have some interesting engineering.  Never heard one myself.

 

Stop making excuses.  I presented my actual experience.  Pass Labs produces both the X series and the XA series amps because they know that some customers want one kind of sound and some customers want another.  the amps are virtually identical except for bias levels and ultimate output power power.  They two flavors of the same thing: vanilla or chocolate.

[barrows]

2 hours ago, sandyk said:

 I'm not the one making excuses.The facts remain about the huge increase in distortion figures to 20KHZ with the nCore amplifiers that you refuse to accept can affect transparency.

 I tried to be conciliatory and meet you half way in my recent post, but then you just had to come back with this comment, didn't you ?

 

 I am  out of this fanboi thread. I will leave you to GUTB.

 

OK Alex, I am done as well.  You praIsed the subjective listening experience of Pass XA Series amps, see figure 7 of these measurements of the XA 60.8:

 

https://www.stereophile.com/content/pass-laboratories-xa608-monoblock-power-amplifier-measurements

 

Hmm, I see a large rise in distortion at high frequencies to levels much more than those of any of the good class D amps out there.  Now take a look below at the performance of the current SOTA amp module from Hypex/Ncore.

Everytme I give evidence your seem to shift the discussion to something else.  I would suggest you listen to Mola Mola Kaluga in a good system/room, with a nice pair of speakers which are a good match, my choice would be Vivid Audio Giyas.  Your bias is so strong you cannot see the forest for the trees.

 

NC500-OEM-datasheet-R4.pdf

[barrows]

45 minutes ago, Forehaven said:

Can you build one of these NCore amps and use a linear PS instead of SMPS?  JC

Sure, but the performance would be no better...  The SMPS 600 is designed specifically for this amp module and is essentially "perfect" already.

 

SMPS are not inherently "bad" as long as they are well engineered and implemented.  Chord uses them in their amps/DACs, and Meitner/EMM in their DACs.  They just get a bad rep from all the cheap wall warts around.  Like any circuit design they can be done well by good engineers.

[barrows]

7 minutes ago, GUTB said:

 

SMPSs are inherently bad.

Incorrect.  Like any circuit design they have their strengths and weaknesses.  Well implemented SMPS are low in noise, and low in impedance, and do not require the large transformers which generate strong magnetic fields inside component chassis which have to be dealt with.

Either way, linear or switched power supplies can work very well, as long as the engineering is good and appropriate to the design.  You are stuck in the past inside your head.

Linear power supplies have lots of noise at 60 Hz and 120 Hz, directly in the audible frequency band, which has to be carefully filtered out.  SMPS have much higher, out of band noise, which has to be filtered only enough that is not so strong it causes IM problems.  Both of these problems are solved by good engineering practices.

Chord and Linn both use very well engineered SMPS in their products, and their products exhibit no problems from the use of SMPS.  Most traditional, old school audio companies do not have the engineering chops to design good SMPS, as an old school analog taught engineer does not have the high speed/RF design chops to solve the problems.  But more recently schooled engineers know how to deal with this as they have studied high speed design/RF engineering.

 

Do not confuse a cheap wall wart with a well engineered SMPS. 

[barrows]

Indeed the Crown amps are not bad at all.  President of Sonore has one in occasional backup use, but he much prefers the sound of his new mbl Corona integrated which uses Hypex class D modules.  

[barrows]

22 minutes ago, R1200CL said:

 

How about the Theta Prometheus ? ?

Or any other Ncore based amp...

[barrows]

13 minutes ago, GUTB said:

I auditioned a Crown XLS2. It was hideously bad — in many ways it was okay but it’s ability to render inner detail was very lacking, a completely lo-fi experience. Burn-in won’t transform something that bad. Anyone who tells you it’s wonderful isn’t an audiophile.

I would not argue with that point of view.  As with any amplifier topology, there are a few very, very good amps, and plenty of ordinary ones.

[barrows]

3 hours ago, skatbelt said:

 

@barrows I value your contributions very much. I am interested in which amps you consider very, very good. Can you list (or PM) them?

I am assuming you mean class D amplifiers specifically?  I can only comment on those which i have heard extensively, and this leaves out a few which could be very good.  For example, I have not heard anything using the new ICEPower 1200 AS1 or AS2 modules, which some have said "blow away" Hypex DIY NC-400 builds...

Of what I have heard:

 

The Hypex NC-400 with SMPS 600 (DIY only, but it is so easy, anyone can do it) is very good.  We (Sonore) ran mine (pictured earlier in this thread) at RMAF three years ago with expensive Raidho C 1.1 speakers and the combo sounded great.

 

The Merrill Audio Veritas amps, which use the Hypex NC-1200 modules and SMPS 1200 are better than the NC-400s, I am not sure why, it could just be the result of the extra headroom.  We used the mono blocks of these at RMAF last year with Focal Ultima Diablo speakers and again achieved excellent sound.  Even tube lover Lukasz Fikus (The LampIZator) loved the sound in our room.

 

I have a friend who has the Nord One Up amps.  These use Hypex NC-500 modules and an input buffer/driver stage of their own design.  I heard it with the Sonic Imagery 994 discrete opamps installed.  This is a friend's amp and I listened in my system, with about an hour of warm up (not ideal).  It is also better than my NC-400 amp, where it stands in relation to the Veritas I could not say without direct comparisons.  The Nord does not appear to have the best internal layout/wiring, so it likely could be improved upon as well.  Even so, it produces superb sound as is a fantastic value. 

 

The Mola Mole Kaluga, which uses a custom version of the NC-1200 module with a custom discrete input buffer/driver stage is the best class D amplifier I have heard, and the equal of any amplifier I have heard.  I have only heard this one at RMAF, but I kept going back to the room over and over to listen more and I could find no fault on any kind of music.  It was playing with Vivid Audio Giya speakers (I think G2, but they could have been G3) which are also tremendously good and very revealing.  If I had that kind of cash, I would put the G3 and Kaluga combo in my system and live happily ever after.

 

Of course, any amplifier with this level of resolution, has to be carefully matched to speakers and the system, suffice it to say, not every amplifier is going to sound its best when just dropped into any system.  This applies to all topologies of course.

 

And I am not suggesting that these class D amplifiers are better than the best class A and class A/B models, I am saying that the best of the class D amps are on a level playing field with the best of class A and class A/B amps though.  I have heard all the usual suspects, like Pass X.8 and XA.8 series, Constellation, Soulution, ARC, VTL, Lamm, etc, etc...  I really like Constellation.

[barrows]

13 minutes ago, Ralf11 said:

 

They have a stereo amp under $1,000 USD, correct?

Not with Ncore modules....

[barrows]

1 hour ago, monteverdi said:

GUTB opinions are not news. Fake opinions?

I heard an early version of the Kaluga and was quite impressed as I was with some Constellation, CH Precision etc. but I never heard them in the same setup and room. Any statement which is better needs to come from comparisons with only one variable but one can have an opinion if one hears various components in various systems.

I am happy with my hybrid A/D amp!

 

Agreed.  I have not made direct comparisons, but have heard Constellation and various Ncore amps enough times to know that they are comparable, which is better, IDK, but I know I would be happy with either and the right speaker match.  I have heard both amps enough times to know that in the right set up the are not flawed in any way, there are likely small differences.  I have not really ever heard Soulution at their best, I guess, because they always seemed a bit too tipped up, and uptight (bleached out, nervous, whatever one might like to call it) to me-but again I suspect in the right system they would be excellent.

[barrows]

1 minute ago, GUTB said:

I’ve owned or auditioned Drive Core 2, early IcePower, latest gen Pascal, Toshiba’s GaN FET and various consumer-grade implementations (ie Pioneer, Sony, etc). Of these, the GaN FET and the Pascal are the best, the IcePower being the worst and the Drive Core not being far ahead. How many class D implementations do I have to cycle through before I’m allowed to say that they suck? If I listen to an nCore and it ends up sucking as per expectations will I be allowed to say that class D sucks?

I would not consider any of those amps equal to the best class D has to offer.

Even if you listen to the best class D amp and do not like it, all you can say is that it "sucks in my system", as the system context will matter, as with any amplifier.  And, if you listen to any component without an open mind, rather than your admitted "expectation" that it will "suck", then your impressions will be invalid as far as I am concerned.

 

It took the Mola Mola Kalugas, in the right system, to convince me that class D amplifiers have fully arrived and deserve to be considered in the same company as the best in the world regardless of topology.

[barrows]

18 minutes ago, Ralf11 said:

PS Audio HCA-2 Solid State Digital Switching Two-Channel Power Amplifier is/was  ~~ $1,700 with > 200 W into 4 ohms...  reviews seem to date from 2002-2006

 

used they go for about $600 -  I wonder how they compare to designs today??

I used to work for PS Audio and have some direct experience with the HCA-2.  It was OK, but has little in common with the performance of the best class D amplifiers today.  Much more noise in the HCA-2 for example. 

[barrows]

46 minutes ago, R1200CL said:

 

These are better ?

Theta did not like SMPS. (Which Bruno use). 

https://www.stereophile.com/content/theta-digital-prometheus-monoblock-power-amplifier.  The best he ever had heard !

 

They have now played almost 24/7 one week here now. Getting better. 

 

They sound is almost like surround. 3D. Fantastic soundstage. Detailed. Full control in bass. 

 

Anyway, yes it would be fun to test the Mola Mola here as well, but I’m afraid that’s not going to happen. Not available AFAIK. 

 

Theta is owned by ATI. ATI’s Ncore amps, may be a very good alternative.

Or the “reasonable” priced Theta Dreadnaught lll 

 

What would make you think that?  Have you done a direct comparison in your system?  The measurements at stereophile show a fair amount of noise form the transformer coupling into the amps output.  The versions with the SMPS 1200 do not have this noise...

In any case, this amp uses the NC-1200 module in stock form, just like Merrill Audio, and if even stock form with the included IC opamp buffer it is very good.

But the Kulugas use a custom discrete circuit for the buffers... of the same design as that Mr. Putzeys uses int eh Makua preamp.  This circuit is almost certainly better than what the OEM NC-1200 modules use.

[barrows]

5 minutes ago, monteverdi said:

This discussion could be soon replaced by SMPS vs LPS. It depends on inplementation

Exactly one of my points:  The stereophile measurements show more power supply related noise int he Theta amplifiers output than I would like to see.  The NC-1200 implementations with the matching SMPS 1200 do not have this issue.

 

But the bigger difference between the Kaluga and Theta is much more likely to be the discrete input buffer circuit in the Kaluga vs. the standard IC based input buffer in the Theta...

[barrows]

4 hours ago, R1200CL said:

https://onahighernote.com/blog/productfaq/linear-versus-switching-psu-in-mola-mola-kaluga/

Thanks, that is some excellent information from Bruno Putzeys.

[barrows]

11 minutes ago, GUTB said:

 

He seems fond of lying and self-promotion. For example, lying about toroidal transformers causing buzz/hum through speakers — to support an attack on audiophile reviewers who are dumber than he is.

Watch your words my friend, you are talking about one of the smartest engineers in all of audio.  And he is a straight shooter as well.  Clearly you did not graduate from your EE program Magna Cum Laude did you?

Additionally, the measurements of the Theta amp are available at stereophile.com for all to see and the noise form the linear power supply in the amps output cannot be denied, that is a fact.

You are making yourself look really bad here.

[barrows]

10 hours ago, GUTB said:

But why tell a falsehood about how toroidal transformers cause speaker buzz? Everyone knows that is very uncommon, as is 60 Hz artifacts. He also suggests linear power supplies aren’t linear?

This is just in error.  Torroidal transformers can easily cause interference in circuits.  At one manufacturer I worked for, we fine tuned output noise in a phono stage for each unit by rotating the toroidal transformer until we achieved the lowest noise level int eh output (of 60 Hz fundamental noise).  We tuned the transformer mounting this way because there is substantial leakage of the magnetic field, especially around the area where etc leads enter and exit the transformer.

I am not suggesting that a linear power supply using a torroidal transformer is inherently worse than a SMPS, but just that both designs have their tendencies and if you do not pay attention to limiting problems of either approach, your product will suffer for it.  As clearly the Theta amp in this example does, as measured.

[barrows]

I have not heard the stellar amps, so I really could not say.  I suspect that PS Audio probably has some kind of reasonable return policy making it relatively easy to try them though.