Atma-Sphere Class D… Amazing

@holmz 

Ralph seems to have an amp that measures well and sounds great.
It seems like a lucky outcome to achieve both at once

Since he hasn't to my knowledge published the measurements I couldn't say it measures well or not. It seems to sound great to some, but every amp on the market sounds great in the minds of some people.

I don't think it is luck to have an amp that measures well and sounds good. I think it is the goal of many skilled engineers/designers. There are plenty of amps that measure very well and are very successful in the marketplace. There are also many that measure poorly in comparison, and yet they too find their supporters. If one didn't know better one might be tempted to believe that people's tastes vary quite significantly and that "good" and "not good" perceptions are relative to the individual, not the gear.

Thanks for your review. The Frankie’s are a great amp. And as you said excel in certain areas. I figured your review would be as such. As the AS Class D aren’t as good as my MA-1’s in the same areas. But your findings are basically mirror mine when comparing my MA-1’s.

No surprises, and experienced listeners know that no amplifier/audio component is flawless. You listen and choose what suits you best and provides the higher degree of joy and pleasure, accepting inevitable compromises.

If the desire is for more emotion ,soul, humanity, breathe of life type of sound, a high quality SET or OTL is very difficult to match. It just always depends on what you want. Other topologies will excel in other specific sonic parameters/areas.

Charles

 

 

 

@tinear123 you mentioned these Atma-sphere's class D being in the realm of PS Audio m700. I've been considering the M1200's with a tube input. Have you heard these? Would you care to explain how the same or different the Atma-sphere may be vs the PS Audio monoblocks? 

@tinear123,

When you listed your system, it looked to me that the Atma-Sphere amps would be the best fit to replace your Crown-XLi-1500 bass amp. The Reference Compact cabinets in my experience respond well to the best amplification possible.

(I have a pair of BD-Design Reference Compact bass cabinets I built years ago -- they are in storage).

Although perhaps your configuration is such that it would be hard to replace the Crown for some reason? If not, you may want to try a swap.

Cheers.

 

 

@j-wall

Unfortunately, no I have not tried the PS M-1200 it would be severe overkill for my horn application as was the M-700. That being said I did hear it back to back with the PS-BHK300 on Wilson Sasha DAW and my preference was the M-1200. If you need the power might be a solution especially with the tube rollable input stage.

@williamdc

Funny you mentioned this as it was on my mind for this morning... I will say the cheapo Crown did spank the PS M-700 previously leaving me shocked. I was so sure the PS would crush the Crown that I dug out the Crown box from the attic before installing the M-700s... then 3 days later took the Crown box back to the attic and sold the M-700s.

 

 

I don't think it is luck to have an amp that measures well and sounds good. I think it is the goal of many skilled engineers/designers. There are plenty of amps that measure very well and are very successful in the marketplace. There are also many that measure poorly in comparison, and yet they too find their supporters. If one didn't know better one might be tempted to believe that people's tastes vary quite significantly and that "good" and "not good" perceptions are relative to the individual, not the gear.

@kuribo my attempt at sarcasm or sardonicism may have been too well disguised.

 

One last comment then I’ll sign off. I have not been on AGON for about a year and since I was interested in the new Atma-Sphere Class-D I thought I would check to see what others were saying and stumbled on to this thread at page-2. When I secured a home demo opportunity, I thought I would give input to add to the community. That being said, the fiasco that this thread has become with the measurement vs perception "comments / pissing match" has reaffirmed my worst fears of what AGON has devolved into. Worse that small children. I just cannot understand why stating your position and one possible retort with civility is not possible by some. You may be having fun being the bully of the playground, and smarter than everyone else, and while you may think you are teaching others, you are in fact disenfranchising those that are starting their audio journey and corrupting the social space this platform can enable and frankly killing the hobby.

Done & out for another 6 to 9 months.

the fiasco that this thread has become with the measurement vs perception "comments / pissing match" has reaffirmed my worst fears of what AGON has devolved into. Worse that small children.

Agreed @tinear123 . But I think the regulars have stopped feeding the trolls. Good to read about your experience. Thanks for sharing.

@tinear123 your posts were refreshing change, so hate to see an adult leave the thread.

Since I am considering these amps, it would also be nice to read more, should you have further comparisons of this amp with any others.

But I think the regulars have stopped feeding the trolls

Name calling when one doesn't agree with an idea or opinion is in fact the immature behavior being complained about. Too bad insecurity and ignorance ruined the thread.

Classic move: accuse others of what you're doing yourself.

@tinear123

I just cannot understand why stating your position and one possible retort with civility is not possible by some. You may be having fun being the bully of the playground, and smarter than everyone else, and while you may think you are teaching others, you are in fact disenfranchising those that are starting their audio journey and corrupting the social space this platform can enable and frankly killing the hobby.

Nice summation and sign off. Continue to enjoy the Atma-Sphere and Frankenstein amplifiers.

Charles

 

 

Name calling when one doesn't agree with an idea or opinion is in fact the immature behavior being complained about.

I did not call out to anyone. Wonder why you were the only one to respond. Take it easy and make positive contributions, if possible.

@tinear123  Don’t give up now!  It is pretty easy to just ignore and not respond when there is no value to the posts. There are plenty of folks left who would value your perspectives.

Testing has indicated correlations between certain distortion spectra and "averaged" or group perceptions but there has been no perfect correlation established between measurements and human response on an individual basis because at the end of the day, you just can’t account for taste.

@kuribo

There are the rules of human hearing perception (such as Fletcher Munson or the masking principle) and there is taste. They are two very different things and the two get conflated quite often! All humans use the same hearing perceptual rules- otherwise audio as an art would be impossible. What people do with that is different, which is why there is disco, rap, classical, tone controls and the like. Human physiology responds the same way to distortion, so it is something that is predictable and reliable within certain limits (there is individual variance on how the 3rd is perceived, depending on its phase for example).

I wasn’t aware that class D amplification was doable without the utilization of negative feedback

@charles1dad It is. Our first prototypes were all zero feedback and demonstrated to us that the idea of class D was worth pursuit. You also don’t need opamps- again we drove early prototypes directly using our preamps, which have no trouble driving lower impedances like 2000 Ohms. These prototypes didn’t use any opamps.

You can’t seem to get beyond the simple truth that your experienced subjective reality and beliefs are nothing but opinions and are no more valid than anyone else’s. The guru complex.

+1 AGS, Audiophile Guru Syndrome, is an ugly thing :)

His high feedback Op-amps amplifier versus a near polar /opposite approach is something that I find compelling with regard to respective sonic presentation. All that concerns me with audio products is how do they sound? That’s why we buy them.

The reason for both approaches is the same. IMO/IME the amp must not have any increase in distortion as the test frequency is increased. Most amps using feedback suffer this problem- and they sound brighter and harsher than they should partially on that account. In a tube amp, getting it to run enough feedback to get around this problem is impossible regardless of the topology. This is because they lack the Gain Bandwidth Product to support the feedback at higher frequencies- as you increase frequency, the amp requires a lot of GBP; if its not there the feedback will fall off, causing distortion to rise. We avoided that in our OTLs by running them zero feedback.

This is a problem in solid state too- and is part of why traditional solid state amps are known to sound bright and harsh (especially at higher volume). Class D offers a way around this because you can get the loop gain you need to really support a high GBP value- and thus also support high feedback at all audio frequencies.

The reason feedback can be problematic is that the feedback node always has a non-linearity associated with it. This might be the base of a transistor, or the cathode of a tube; whatever it is means the feedback signal is distorted by that non-linearity and so when mixed with the incoming signal doesn’t quite do what its supposed to do (one effect of this is additional distortion is created...). But if you run enough feedback you start to get around this problem. That needs to be at a minimum 30dB and must be 30dB at all audio frequencies. We’re at about 37dB.

Probably more information than you were expecting, and actually IMO this explanation is really the nutshell version so those of you technically-minded I am aware this explanation is incomplete.

If the desire is for more emotion ,soul, humanity, breathe of life type of sound, a high quality SET or OTL is very difficult to match. It just always depends on what you want. Other topologies will excel in other specific sonic parameters/areas.

I think one of the issues you run into when making this comparison is that the zero feedback tube amps (whether SET or OTL) will have a frequency response variation depending on the load impedance (the speaker). I’ve found that anyone using such equipment, including myself, has made accommodations for that issue if they have spent any time trying to make their system sound neutral and musical at the same time. In my case this is mostly to do with the level settings for the drivers, found on the rear of my speakers. I use pink noise to set them up correctly. Whatever those accommodations are though, you have to back them out of your system if you really want to do a proper comparison, which is probably tricky. This is just a personal observation, but once I corrected my system for the voltage response of the class D I found it every bit as involving.

I would like to hear the designer’s take on how his class d design differs from those of Hypex and Purifi and at 3 to 4 times the price, what they offer over the Hypex and Purifi products that makes them worth the considerable difference. I would like to know why he decided to design his own class d modules, especially in light of the fact that it is no trivial matter and a completely different task than designing a tube amp....I would like to know why the designer choose GaNfets over standard fets and what advantages he believes they offer at his operating frequency over standard fets....

We chose to design our own module because it sends the wrong message to the marketplace by using someone else’s- it suggests that maybe you don’t don’t have the engineering talent in-house. Plus we can make it the way we want to. FWIW our modules seem to be lower noise than Bruno’s.

The reason we’ve not used SMPSs yet is we found that if you really want the amp to perform properly, especially at high volume, the SMPS really needs to be designed specifically for the application. Most of our prototypes ran SMPSs and we ran into this limitation quite frequently.

A good portion of our cost is the chassis, which is custom-built and designed to look decent, not man-cave and also be durable in shipment. It seems its a bit over-built! For the last 40 years we’ve gotten dinged on cosmetics a lot; you put in the cosmetics and then you get dinged on price...

GaNFETs are a little faster, but the main reason for using them is to create a lower noise layout due to less strays and lower drive requirements which are for the most part an order of magnitude lower than MOSFETs. In this regard the noise our amps put out on the AC line is lower than many tube amps and most of that comes from the power rectifiers rather than anything to do with the module.

 

 

 

 

 

@atmasphere 

 

A nice, "high-road" explanation. Thank you.

@atmasphere Thank you for your post.

Hi Ralph,

Would you mind reiterating your past comment of how Class D (yours and perhaps others) have finally made the leap to outperform tubes (yours and others)?
thx

@atmasphere (Ralph) 

As always your explanations and insight are most appreciated and welcome. I agree with your “no accounting for taste “ as this is true. Be it audio components/music genre/food or automobiles etc. as human beings, We like what we like. 😊

Thus the multitude of choices available in our lives,

 Charles

Would you mind reiterating your past comment of how Class D (yours and perhaps others) have finally made the leap to outperform tubes (yours and others)?

I find the class D to be more transparent in my system compared to my tube amps; less coloration also due to lower distortion. At the same time I don't find them harsh, a classic sin of solid state amps in general. I can play them all day and not get tired of them.

Now let's say you are a tube amp producer. You face a variety of problems. Right now a major one is availability. If you're not going to get in trouble with the law (due to sanctions against Russia), you're probably using Chinese or JJ tubes if you're using new tubes. Another one is the industry is tending towards 4 Ohms as the default speaker impedance rather than 8; I see this as a bad thing since all amps make greater distortion into lower impedances, and with many its enough to be heard (audiophiles use 'fat' 'muddy' and other similar expressions for this). But 4 Ohms is a thing regardless of what I think.

Its now possible to build a solid state amp that is as relaxed as a good tube amp, not lacking detail or depth (and maybe more). Since brightness and harshness of solid state is what has kept tube amp producers in business for the last 60 years, and also because tube amplifier power is more expensive, how long will tubes be a viable option in audio? IMO while it will still be a while (owing largely to highly variable results designers got out of class D over the last 20 years having poisoned the well at first) tubes will continue for a while, but even chip-based class D amps that might only be $75.00 are now giving serious tube amps a run for the money!

If I were an amplifier manufacturer that had not got the class D thing figured out, right now I would be worried. The market will be shrinking for tube power products- even in the guitar world. I know a lot of cheap class D guitar amps are so much junk but they aren't all that way, and most guitarists these days rely on their effect pedals for their 'sound'. The guitar market is a lot larger than the high end audio market for tube use- they drive a lot of what is available for high end as a result. If you lose the guitar market, that will be very nearly the end of tubes.

 

 

@atmasphere

Really appreciate your insightful experience and comments.

I am thankful that you brought Class D to the market and that it has been so well received. I run Class D myself, though it is not the typical Class D amp - it is the TAD M2500. In the process of choosing an amp, I listened to Luxman, Pass, Burmester (very good), and maybe one or two others, I forget, and the TAD was the best that fell into my budget - only the Burmester 909 with matching 077 preamp was better, but at $$ multiples of the M2500 + C2000 pre. This pairing makes my TAD E-1s sing and I’m sure part of that is system/manufacturer synergy, but if Class D were not good, the system would not be sublime like it is.

I hope the more manufacturers will make high quality Class D amps, glad you’ve beat nearly all of them to the punch.

Thanks again for being the gentlemen and sharing your decades of experience with us all.

@atmasphere 

Thank you replying....

There are the rules of human hearing perception (such as Fletcher Munson or the masking principle) and there is taste. They are two very different things and the two get conflated quite often! All humans use the same hearing perceptual rules- otherwise audio as an art would be impossible. What people do with that is different, which is why there is disco, rap, classical, tone controls and the like. Human physiology responds the same way to distortion, so it is something that is predictable and reliable within certain limits (there is individual variance on how the 3rd is perceived, depending on its phase for example).

Strictly speaking, Fletcher-Munson and the like are not rules or laws, but rather experimentally derived models of human aural perception. They are built on averages and generalities- in the case of Fletcher-Munson the results are said to apply to "average young people without significant hearing impairment". I doubt that describes many of those reading this thread... They have also been revised numerous times. While these rules of thumb are helpful perhaps to people such as yourself designing amplifiers aimed at as broad a segment of the market as possible, they are not "laws" or universally applicable "truths" like the law of conservation of energy or the laws of thermodynamics. As a result, they can not be relied upon on to be an accurate predictor on an individual basis. Thus, the guy shelling out $5K for an amp would be best advised to trust his own perceptions and tastes and to listen to the amp in his system, in his room, to form his opinions rather than rely on the perceptions, tastes, and opinions of others. Of course there are always those who love to gamble.

I see that you haven't made any comments addressing the patent that you received related to this amp, nor related why you have yet to publish any measurement plots, etc. Having this on the market now for a while, I would have hoped that info would have been forthcoming. Perhaps the transparency of Hypex and Purifi has spoiled me.

Again, thanks for your time. And best wishes on the success of your product.

Strictly speaking, Fletcher-Munson and the like are not rules or laws, but rather experimentally derived models of human aural perception. They are built on averages and generalities- in the case of Fletcher-Munson the results are said to apply to "average young people without significant hearing impairment". I doubt that describes many of those reading this thread... They have also been revised numerous times. While these rules of thumb are helpful perhaps to people such as yourself designing amplifiers aimed at as broad a segment of the market as possible, they are not "laws" or universally applicable "truths" like …

In terms of universal truths and laws, one can pretty safely say that as the distortion products go to zero, that the fidelity improves. How well this happens with complex loads, etc. is where topologies matter. But if we assume that some amps were possible with a vanishingly low THD+N, then they would sound the same regales of topology

… the law of conservation of energy or the laws of thermodynamics. As a result, they can not be relied upon on to be an accurate predictor on an individual basis.

Statistics, stereotype and generalities are borne from things being similar.
Humans are tuned to those sorts of easy ways to categorise things.
And the statistics of a group, are indicative if the sum of the individual biases and likes/dislikes. 

 

Thus, the guy shelling out $5K for an amp would be best advised to trust his own perceptions and tastes and to listen to the amp in his system, in his room, to form his opinions rather than rely on the perceptions, tastes, and opinions of others. Of course there are always those who love to gamble.

And thus if one considers themselves similar to others in the group, then they would be more wise to gamble that what other people like, that they will also find that they the same stuff.
and likewise if they find that they are at odds with the group, then they would likely deviate from the group perspective.

An example would be cable deniers or believers.

1. If one identifies as a cable believer, then other cable believer perspectives likely have more bearing, and theuy find speaker cables, IC and power cables all matter.
2. And for the cable denier, they likely find similarity with other cable deniers, and value their similar group’s inputs.
3. and some probably find no difference in XLRs and power cords, but could believe that speaker cables make a difference, and identify with their brethren/sisters.

@holmz

But if we assume that some amps were possible with a vanishingly low THD+N, then they would sound the same regales of topology

There are indeed those who claim once a certain level of performance has been reached, then products would indeed be indistinguishable from one another. I believe there have been rather rigorous tests done which seem to bear this out.

As I said, Fletcher-Munson and other such empirical studies have predictive power in a general sense but are weak on an individual basis. Additionally, personal preferences when it comes to audio gear is not based solely on sound, in any case. There are several other factors buyers consider when making a purchase which factor into a decision. It’s a complex decision that one needs to ultimately make for one’s self in the proper context.

Sure, a person could choose a proxy and take a chance. It all depends on risk tolerance and finding a suitable proxy. Me, I prefer to judge for myself as finding someone else with my tastes, the same gear and acoustical space, would be more difficult, time consuming, and risky than just trying the equipment myself. Besides, even if I associated myself with a "like minded group", the critical issues of component interaction and acoustical interaction in my space would make it impossible to find a realistically "safe" bet.

I don't believe your analogy is appropriate, either for those  "cable deniers" who base their argument primarily on an intellectual argument- it's a belief system, not a perception driven matter of taste, nor for those who simply claim that they hear no differences. That is more a pure perception argument rather than a matter of taste. In either case, it isn't a simple matter of taste at work, unlike the debates centered on amps, etc.

@kuribo generally agree, but what is your point?

• Is it that you want to see specs?
• Or listen to it?

Or what am I missing?

 

If a bunch of people with speaker-X say that they like electronics-A, B and C, then I think to myself, “I should see if I like them.”
If I do not like speaker-Y and a bunch of people say electronics-C, D, and E are great, then and not sure what I should with that… especially with D and E.
 

As there are more electronics that one can often stumble across we use other peoples observations and opinions on a forum to make some sense of it, and get exposed to things which we may not find, or otherwise know to look for.

@holmz


I would have thought by now my point had been made.

Yes to both your questions.

No harm in using forums to learn of new gear. One needs to read critically and take the subjective opinions with a grain of salt. When it is all subjective opinion there isn’t much sense that can be made of it if you are a rational actor. Too many don't understand the difference between their subjective opinions and objective fact.

While these rules of thumb are helpful perhaps to people such as yourself designing amplifiers aimed at as broad a segment of the market as possible, they are not "laws" or universally applicable "truths" like the law of conservation of energy or the laws of thermodynamics. As a result, they can not be relied upon on to be an accurate predictor on an individual basis. Thus, the guy shelling out $5K for an amp would be best advised to trust his own perceptions and tastes and to listen to the amp in his system, in his room, to form his opinions rather than rely on the perceptions, tastes, and opinions of others.

Fletcher Munson is a bit more variable, but the masking principle isn't. Its what made MP3s possible. Also, how humans sense sound pressure does not change from individual to individual; generally, the higher ordered harmonics are used. This is really easy to demonstrate using simple test equipment.  Imagine a world where every individual used entirely different hearing perceptual rules! It would be a good basis for a scifi novel 😉

The patent involves the use of a Circlotron to reduce deadtime. If you are using GaNFETs, the inductive kick of the output filter coil is what really turns the device off (assuming the gate is already off); to allow that to happen a certain amount of deadtime has to exist. As it is there is still less deadtime in a GaNFET design as opposed to a MOSFET design.

Too many don't understand the difference between their subjective opinions and objective fact.

Being objective is a worthy struggle despite it being impossible.

FWIW we've done lots of comparisons and we have a lot of feedback from the field at this point- from a variety of customers that know our prior work. The feedback is surprisingly consistent, in the face of not knowing about any other feedback we've received.

 

 

I disagree with Ralph about tube guitar amps...they're not going away anytime soon, if ever. Note that serious pro guitar players generally start with a great tube amp in pretty much every case (exceptions for those who run "into the board" with effects...rare and generally sounding sort of processed), and add their personal pedal choices to the tube amp. Duke Levine (local Boston area guitar genius) describes his current rig in Vintage Guitar...he's touring with Bonnie Raitt...VOX AC30...I've known Duke for 20 years and every time I've either worked a show with him or simply seen him play he shows up with some of the coolest tube guitar amps on earth. Same thing with the brilliant Julian Lage...tiny 50's Fender tweeds like a Tweed Champ or some other little tube amp like a Magic. Brilliant sound...and no overdrive pedals for Julian.

I considered Ralph's D monos when I bought my Pass XA-25 but the Ralph amps (that's what they're called, right?) weren't available yet so I had no idea what they were going to cost...now I'm so disturbingly enamored with the Pass amp I'm hard to nudge away from it...I'd still like to hear the Ralphs sometime...maybe a lower powered stereo amp? Loaned to me? heh heh...

 

@wolf_garcia The smaller guitar amps will hang around for a while because they are low enough power that its practical to overdrive them. But the bigger stuff like 100 Watt Marshals are likely threatened, if someone can put a class D amp out there that's worth listening to. The weight is a big variable here. 

 

 

The OP has not been very clear as to whether Ralph suggested that he post his impressions. Ralph has a new product and he needs to get some attention over it. Even if not, it is pretty abundantly clear that the OP is already a fan of Atma-Sphere and is far from neutral. It is exceedingly rare for someone to go nuts over the sound of an amp. Amps have a subtle affect on overall sound, and there has never been an amp and likely will never be an amp that "bowls one over" immediately with sound from the heavens. I believe that amps are critically important to overall SQ but it takes months of living with an amp to assess it's character and attributes. So despite the silliness in this thread over non-related matters the circumspection is not surprising. 

And then we come to digital amps as a category. They are insanely cheap to manufacture as has been pointed out elsewhere in this thread. To my mind, a digital amp is a switching power supply built to drive loudspeakers. If there is a simpler way to harness power from the wall directly to the pre-recorded sound signal it has not yet been invented. Ralph has acknowledged that the box-a plain vanilla box at that-is the major parts cost of this product. When the best switching power supplies sound better than the best linear power supplies I will likewise believe that the best digital amps sound better than the best conventional Class A/Class A/B ss and tubed amps. 

Ironically enough, the discussion is still about distortion-that this digital amp has less of it. Here we go again-the old fallacy that the lack of distortion means more faithful sound reproduction. Loudspeakers are the number one producer of distortion. Distortion needs to be embraced, not made the focus of elimination. Even the power in the wall contains distortion. Harnessing raw power from the wall is not the answer. I wish Charles Hansen and Tim De Paravicini were alive to lend their voices to this discussion. I wish Nelson Pass would join. 

In summary, I have no doubt this amp sounds fine. Very fine. Just the same, it is bound to have sonic virtues and faults like any other amp. It won't make your grass greener, your hair thicker, or give you greater stamina in the bedroom. 

Also, how humans sense sound pressure does not change from individual to individual; generally, the higher ordered harmonics are used. This is really easy to demonstrate using simple test equipment. Imagine a world where every individual used entirely different hearing perceptual rules! It would be a good basis for a scifi novel 😉

@atmasphere

thanks for the reply.

Of course I am not claiming that the "how" is different in every individual. What I am claiming is that there is enough natural variation among humans in reception, processing, and interpretation of external stimuli that one can not predict with certainty how any one individual will respond, all the more so when the amp is but a piece in a complex system full of external and internal variables. Clearly experimental results with a large enough sample can yield tendencies and generalities, but again, nothing that can predict with certainty on an individual basis. From your standpoint, that’s useful. From mine, not so much as I still need to listen for myself.

I am glad to hear that the feedback from your customers has been positive. It’s clear a lot of time, energy, and thought went into your product. I won’t hold my breath waiting for the measurements- you must have your reasons for not publishing them.

It might be interesting to consider that sound itself only exists in the head of the individual. It’s a back and forth from air pressure changes to electric signals. Our ears are transducers changing the air pressure pulses to electric impulses in our head. It is in our mind that these signals are perceived as sound. A lot of links in that chain that can cause differences in how the end result is perceived.

@fsonicsmith 

 

Here we go again-the old fallacy that the lack of distortion means more faithful sound reproduction.

How would you define/measure faithful sound reproduction?

If the output doesn't match the input, how can the result be called faithful?

And then we come to digital amps as a category. They are insanely cheap to manufacture as has been pointed out elsewhere in this thread. To my mind, a digital amp is a switching power supply built to drive loudspeakers. If there is a simpler way to harness power from the wall directly to the pre-recorded sound signal it has not yet been invented. Ralph has acknowledged that the box-a plain vanilla box at that-is the major parts cost of this product. When the best switching power supplies sound better than the best linear power supplies I will likewise believe that the best digital amps sound better than the best conventional Class A/Class A/B ss and tubed amps. 

@fsonicsmith Let's clear something up. Class D isn't digital. It's a coincidence that the D and digital use the same letter. Its called class D because at the time (late 1950s) class A, B and C were already taken. Its an analog process.

It behaves a bit differently from a switching power supply. For one thing the switching frequency is a lot higher- often by an order of magnitude. Another thing to understand is that switching power supplies are often used in class D amps but class D amps can run off of conventional power supplies too. But even in SMPSs the noise floor is much lower now than it was 30 years ago. Like anything else people sort this stuff out over time. FWIW our class D is so quiet that most tube amps inject more noise on the AC line.  

@kuribo You do know we have published specs right?

There’s obviously much more to good sound than a lack of distortion.  Japanese companies tripped all over themselves in the 70s/80s to produce the lowest THD specs and by and large produced amps/receivers that sounded awful.  

@kuribo You do know we have published specs right?

If you mean a rather thorough and complete set along the lines of Hypex and Purifi, no. Please provide a link if you have time...Thanks.

@soix 

 

There’s obviously much more to good sound than a lack of distortion.

"good" sound is a subjective opinion that depending on the listener, may have something, everything, or nothing to do with distortion or the lack thereof.

I knew I’d regret saying something.  My bad. 

Guys continue to spend time endlessly arguing back and forth, go listen to some music

@facten  @soix 

i just think it is a shame that one turd can muddy up a nice thread supporting ralph’s new amplifer ...

Agree with Facten. 

@soix 

I knew I’d regret saying something.  My bad. 

You have keen instincts. Trust them.

Charles

Loudspeakers are the number one producer of distortion. Distortion needs to be embraced, not made the focus of elimination

^This^ is total BS.

Fat girls or guys also need to be embraced, but I am not embracing them.

Coincidentally the Purifi drivers are also the lowest distortion drivers.

It is fine if you like high distortion, but don’t claim that high distortion is high fidelity. That sort of BS double talk is a like it is from a character out of Ayn Rand.

Embrace the 2nd and 3rd harmonic distortion at low levels is the message. If you don’t like the message then move on. 

It’s ok to prefer no distortion… think acoustic guitar. 

Its ok to prefer some distortion… think electric guitar with tube amp and pedals.

Preferences are just those… no right or wrong  

Not worth disputing… not worth debating.

Thanks Ralph for making another great product.

 

 

I am starting to think class D is the bee’s knee’s man. Really enjoying the Rouge Pharaoh II and it is not even near broken in. Tube pre- Class D power section with the Hypex Ncore. Time will tell but I may be selling a couple of integrated amps I have in the tool shed. 

 

Embrace the 2nd and 3rd harmonic distortion at low levels is the message. If you don’t like the message then move on.

Certainly - the message seems to be that the 2nd and 3rd harmonics are better than the hash of 4th + .

I would like to see an example PSD of a 1kHz tone, and the harmonics.

Someday would love to try a set of these! But got to say, pretty solidly in love with my current GoldNote PA-10 (class A into GaN power stage). But truth and proof in class D from here on out. 

@riccitone the Goldnote PA-10 is simply A-D not GaN I had them at one point. 
not sure what Core they are using. I might be wrong.

The PA-10 is a 200x80x260mm (WHD) Class A/D hybrid power amplifier. In stereo mode, it’s specified at 75wpc into 8Ω (150wpc into 4Ω, 300wpc into 2Ω). Enough for average-to-high sensitivity loudspeakers.

Embrace the 2nd and 3rd harmonic distortion at low levels is the message. If you don’t like the message then move on.

Someone, please correct me:

I don't believe that the idea is to "want" 2nd and 3rd harmonic distortion, but rather our brains use the 2nd and 3rd harmonics that are produced by the musical instruments to perceive certain aspects from the sound. I don't believe any type of harmonic distortion from an amplifier is "desirable".

@jerryg123

I had been confused about it initially, as GoldNote does not clearly specify what’s actually going on with the PA10’s internals. But learned this from a HiFiPig review (as quoted):

‘I’m a massive advocate of Class D technology when it is done well and so I asked Gold Note directly “What Class of amplifier is the PA-10?”. Here is the response I got – “ The PA-10 features quite an interesting design. It is not a Class D amplifier but it leverages a new technology that uses MOSFETs for the output stage, in common with the Class D, featuring an output oscillator (GaN Mosfets with Gallium Nitride), a proprietary design that actually doubles the power of the amplifier when reducing the impedance – exactly as a pure Class A but with extremely high efficiency to deliver great amounts of energy.” So there you have it.‘

So “more like” GaN Fet in output.