The Future of Audio Amplification

shad,

Only of your system is 100% true balanced, but then you won't need tubes anyway. True (differentially) balanced cures a lot of ills. Sadly, most reviewers have no clue

I don't doubt the NuPrime is great, but how many of us have 8K for amps? If the tech interests you, check out Nord from the EU. Very reasonably priced and high quality using latest IcePower

There are also some amps like the latest Technics SE-R1, which are true digital amplifiers in that they convert everything from Analog to Digital, allow for phase and amplitude correction in the digital domain, and then produce an output based on a PWM output stage.

Just for the record Eric, such an amplifier is a hybrid. Pulse Width Modulation is an analog technique. In any Class D amp, some form of encoding is needed, and PWM is probably the simplest means.Even if the amplifier is computer controlled to adjust its encoding scheme to accommodate various codecs (in effect a DAC that can drive a speaker), ultimately its still class D and thus also analog.

Strictly speaking, encoding is not used in Class D. There is no conversion of one type of data to another. Instead Class-D relies on feedback, and a great deal of it. It is a comparative technique.

That’s the nature of Class D and why it remains overall an analog process.
The Technics uses no feedback. It has at least 3 processing steps:

1 - Initial encoding from Analog to Digital
2 - Signal processing(alters the input signal to match the speaker behavior)
3 - PWM
Away with your nonsense, but I expect you will write four pages of barely related word salad to reply.

I don't understand why there isn't more discussion of Bel Canto, specifically in this thread and more generally on A'gon.  They seem to be doing a lot of things right, and at a number of different price points, unlike some manufacturers.

What evidence? You know, like 80,000 fancy fuses sold. Hel-loo! Wake up and smell the coffee, guys! ☕️

Mention mains fuses as "snake oil" and look who shows up, the king of directional mains fuse detection, really, and the rest of the fuse crew follows?

Strictly speaking, encoding is not used in Class D. There is no conversion of one type of data to another. Instead Class-D relies on feedback, and a great deal of it. It is a comparative technique.

That’s the nature of Class D and why it remains overall an analog process.
The Technics uses no feedback. It has at least 3 processing steps:

1 - Initial encoding from Analog to Digital
2 - Signal processing(alters the input signal to match the speaker behavior)
3 - PWM
Away with your nonsense, but I expect you will write four pages of barely related word salad to reply.

Thanks pretty funny!  :)

Feedback (self oscillating) is one of three methods of encoding. The others are PWM and sigma-delta (Pulse Density Modulation). PWM allows the designer to build a zero feedback circuit.

Some form of encoding/modulation is of course required to make a class D circuit. Strictly speaking :)
Since you think this is all hand waving, see:
https://www.analog.com/en/analog-dialogue/articles/class-d-audio-amplifiers.html
(a short introduction to class D amplifiers by a manufacturer of class D amplifier ICs)

The trolls have infiltrated this forum now.  Too bad.  It maybe shut down soon by moderators.  Happens all over audiogon forums.   

The trolls have infiltrated this forum now. Too bad. It maybe shut down soon by moderators. Happens all over audiogon forums.

They have always been here , just seem to be getting more vociferous of late.

This thread is under review and can possibly be closed if the subject does not remain on topic. 

My system retails for over $24,000.

 I have friends whose systems retail over $300,000.

I've been to CES and the Rocky Mountain Audio Fest numerous times.

That said, the only time in my life that I've ever actually been physically moved to tears while listening to music was through my iPod.

All this talk about amplifier technology is BS. Just shut up and listen to the music and enjoy it.

The title of the thread is The Future Of Audio Amplification.

The future is here now. It includes efficient toplogies that waste little energy as heat to drive loudspeakers. The future may improve from the current 85% to 95% or higher, but will certainly not incorporate far less-efficient designs such as Class A/AB.

While I have a dedicated listening room I built 25 years ago, I made some major errors in construction.  It is good that it has a 6" rebar reinforced slab, 8" plates with staggered 6" studs every 8".  Survived a 6.9 earthquake with no damage (or to the rest of house).  However, I also made it vaulted from 8' to 11'6", have large multi-pane wood casement windows along both long walls and behind the speakers and dual layers of screw attached, non-staggered jointed 5/8X drywall on walls and single layer on ceiling.  Also, the room designed to have 25,000 records now has 42,000 records.  I was able to tweak the acoustics to sound very good.  Without treatment, slap echo galore but definitely no problem with sound in or out of the room.

In 2 months, I'm moving to another home and will convert 2 of 4 oversized garages dedicated as a sound room.  No windows, flat high ceiling, superior insulation   Sure, it's 40% smaller space but at least it will be dedicated to sound only and built better for it than in 1993.  The records/cds will be stored in the adjacent room.  We will have a large family room for video and a small audio system in the large living room.  I would have built a dedicated larger listening room but for the 2017 City of LA law cutting in half the floor area ratio. 

That small living room system has a small high end CD player, really small sub-miniature tube pre-amp and a voltage regulated (non-ultralinear) redesigned Dynaco ST70.  Fits on a small rack.  Almost like a streaming setup size.  Only the speakers are medium size Legacy Signature IIIs.

IMHO, the underlying question to the future of class D is:

Who is going to buy super exotic (expensive) USED amplifiers? Recalling the TAS March 2016 review of my Audio Alchemy stereo amp and dac/pre @ was $1995 each. The reviewer, Robert Harley (gave them Editors Choice Award)  compared their sound to the Soulution amp/pre which I think was priced near $60,000: the reviewer  noted that both were designed by Peter Madnik, and that the AA components were not sonically that far off of the uber expensive, and highly praised Soulution components 

Here's a great quote from erik in his AudioGon class D thread:  "Sighted or blind, I cannot hear a difference between them an Parasound A23s. None. Zero. Nada."

Now I owned Parasound A 23, several W4S stereo/mono/ multi channel amps, Emerald Physics 100.2 SE monos and now my Audio Alchemy stereo amp, and I can definitely hear the generational improvements, and the AA (apparently with HypeX modules) stands way above those that I owed. The AA amp had considerably more wallop than the 4xs as expensive (MSRP) EPs, which can often be ha for ~$2000 the pair these days 

Snippet from Stereophile August 2016 (according to review the stereo amp is essentially the same topology as the monos):

"Madnick told me that, inside the DPA-1M, the signal is fed to a differential pair of JFETs feeding a low-power MOSFET driver stage. The circuit is servo-controlled to cancel any offset and to avoid having to use coupling capacitors in the signal path. This input circuit is powered by a dedicated power supply with ultra-low-noise voltage regulators. The class-D Hypex output module is powered from a switching power supply. The DPA-1M is a bridged design, which Madnick considers "the best-sounding way to do it." Of course, the sonic characteristics of the DPA-1M depend not only on its circuit topologies, but on the choice of specific components, PCB layout, and fabrication materials, as well as the selection of internal wiring and, one assumes, various proprietary factors. 

There was certainly nothing about the sound that screamed "class-D." In fact, had I been told that I was listening to a high-power class-AB amplifier—the kind that would require the help of a friend to lift it—I would have had no reason to doubt the truth of that statement.

Theta comparison;  And so, in a more modest way dictated by its price, is the DPA-1M. Like the Prometheus, it produced no artifacts, and added none of the "clinical" sound for which class-D amplifiers are often criticized. (FURTHER >80% OF THE SONIC GOODNESS AT 1/3 THE PRICE!)"

So, whereas the older class D left many of us wanting, the current and near future of class D is such (IMHO) that people who own uber expensive A/AB amps will already have a hard time getting pennies on the dollar

Read more at https://www.stereophile.com/content/audio-alchemy-dpa-1m-monoblock-power-amplifier-page-2#X4UzH1ZEC5...
Read more at https://www.stereophile.com/content/audio-alchemy-dpa-1m-monoblock-power-amplifier#DaPTJ23tBl4br8kO....

The Tad Evolution class D amps specs quote 1% distortion. I believe most amp designers look to minimize distortion, and I’m sure TAD does as well. I use Spectral and am happy with the lack of distortion,incredible dynamics,nuance,faithfulness to the waveform(read music) and emotional connection this allows. I’m surprised that some argue Class D is equivalent; but we all hear differently and have different sensitivity to distortion. As I listen to live music often; my ear is sensitive to sounds that don’t reflect live. One poster mentioned he found “live” music flat and boring. Obviously there are positions for everyone. If one grows up listening to mp3 perhaps they’ll gravitate to that for a lifetime? I can’t imagine it though. 

John Atkinson measured PS Audio's M700 monoblocks ability to produce 700 watts at 1%, and over 100 watts at 0.005%, both figures into 4 Ohms at 1K. At 30 watts into 4 Ohms, which many of us never exceed at normal listening levels, that number fell to 0.002%. From 20 to 20K at 20V, that number never rose above 0.2% into 4 Ohms; the figures were better into 8 Ohms. Not that distortion tells but a part of the story, is something not to worry about with well-designed Class D amplification.

Class D amps sound cold and analytical to me. Maybe its all the feedback or the output filter. Meat is ultimately taken off the bones somehow.

Having said that, Class D is the future for better or worse. There is quite a bit of cost savings involved for amp makers. They can be pretty good with a tube pre amp as a bandaid.

I still have never seen a LED TV that can come close to my plasma. Plenty of people will say that LED has gotten better and surpassed plasma.

I guess it comes down to what we value and what properties are important to us. Class D and LED both win in efficiency and that is extended to form factor.

So 0.02% distortion is an "ungodly" amount huh?

Talk about dumpster fires...

Nelson Pass once said

"The first watt is the most important watt"


Cheers George

Not at any rock concert I ever attended...8)

Class D manufacturers, big and boutique, have years of experience / dollars tied-up in this technology. They are 'here' to make money. They won't chase a doomed topology this deep into the proverbial rabbit-hole. For now Class D makes dollars and cents, until something else comes along. And when it does, I'll be checking it out too.

Plasma TV has a tube like sensitivity in warmth, color and engaging the viewer. I’ve moved on to top of the line LCD TVs with higher resolution and brightness, a solid state like sensitivity. OLED TV is similar to a combination of the two prior technologies.   

Each type has its own limitations (LCD-picture uniformity, viewing angle, OLED-brightness in white scenes, motion judder Plasma-heat , resolution).

kosst,
Yeah. Look at some of the tube amps that have been recently reviewed with claimed output of 60 to 100 watts per channel and deliver 2 or three watts at best at 10% distortion!!!! And you crap all over class D amps. Give us a break, PLEASE!

Having said that, Class D is the future for better or worse. There is quite a bit of cost savings involved for amp makers. They can be pretty good with a tube pre amp as a bandaid.

The main reason class D is the future is simple- the semiconductor industry really doesn't want to make linear devices so much anymore- not like they did in the 70s and 80s! Very many non-audio applications are better handled by switching or digital circuits that were handled by linear circuits just a few years ago- and now audio can be done that way too.

And even the linear solid state devices back then - really weren’t all that linear....and still aren’t....

Sort of a false intellectual enterprise to call them linear. Nice try, semiconductor industry.....

Luckily the tube amp industry is alive and well, and should be thriving for many years to come...If I'm fooling myself by enjoying a tube preamp, a single ended tube power amp, and efficient horn speakers, regardless of the specs (I honestly don't have a clue what the actual specs are for my Dennid Had power amp), it makes absolutely no difference to me what anybody else claims about how this stuff sounds in my home. That said, my Class D bass amp is fine...I just patted its little head and told it to not be intimidated by all the tube amps around it.

I recently tried two class d amps in my own home, I do every five or so years.  One was made by a small Japanese company, and remarkably good, but as the week went on, I turned it on less an less.  The second was also interesting with more features but it didn't bring out the midrange magic that I love about my speakers and it sounded a bit hard and flat. 
For me, if I was limited to class d, I wouldn't listen to music as often.  Now what I would accomplish with that additional time is more interesting than if I should feel shame for liking one more than the other.

I think it's pretty safe to say that an amp that makes 10% distortion at 2 watts isn't even hi-fi by the definition of the term.

@kosst_amojan
That is true- do you know of such an amplifier?

To step back into shallower waters here:
So much of our world has become increasingly visual and on-demand. Screens proliferate and dominate.  I can say the under-25 generation, having taught them for 20 years, can be even more capricious visually-reliant than ever, and streaming files has long since replaced object permanence.

And yet music plays as large a part in their lives as it did in ours. In fact, I would say that many teens and 20-somethings have a larger musical palette in their playlists than most of the mixtapes we had.

But the idea of having a "listening room" is a superfluous concept to most Americans, especially the ones with too much month at the end of the money. The idea of assembling a system costing 4 and 5 and 6 figures just for listening to music, especially nowadays, is pretty alien and unsympathetic. And since music has become transient files; since much music is listened to through ear buds and in cars; since Alexa and Siri, Sonos and Spotify, are cropping up in kitchens and living rooms everywhere; and since glittering OLEDs and other screens, including tablets, phones, and laptops, now dominate consumer consciousness, I can understand the aging of the audiophile.
Audiophilia is a niche interest anyway, like any dedicated hobby. And if a soundbar and an Onkyo receiver from Crutchfield or Best Buy is enough for most people, I can't see amplification expanding like it did 30 years ago, especially in America which seems to favor the multi-chassis set-up.

Ah.

I thought we were talking about class D, not SETs. SETs FWIW don't (or shouldn't) get played much at full power; at normal listening levels the distortion can be near or at measurable.

This month's Stereophile has the Cary and the Cambridge integrated back to back reviewed.  The Cambridge received an outstanding Atkinson review and quite good listening review.  We know what the Cary received.

Who cares! I like class A and tubes. If class D can sound similar at a low price, low weight and save me money, I’d be a buyer. 
It will be the future. My kids will recycle my heavy old stuff to the scrap yard. 

Class A biasing is the easiest to get the most linearity from a tube/transistor. The other classes are a result of minimizing heat generation, and related detrimental effects.Throw enough time and money at a problem and it can likely be solved.The biasing class does not resolve other technical issues, like sloppy power supplies, noise generation etc. It is possible to screw up any biasing class, alone it does not solve all the issues.Measurement equipment has gotten a lot better over the years, but the dB scale does not correlate to what is important in psycho-acoustics. In the early days harmonics was easily measured, and an important and fundamental measurement in RF circuits. Here decibels works fine.The human ear generates harmonics internally and may mask the harmonics from an amplifier. Much have been said on the issue of non-linearities of sound equipment, and measurement standards have sharpened over the years. As transistor amplifiers replaced tube amps way back when, measurements for tube amp were applied, and looked OK, but sounded worse. Early transistor circuits where copies of tube circuits, with inter-stage transformers and everything. Maybe a good thing as the weak frequency response of the magnetics components may have filtered out some nasties.Then the power wars started (70's?) and FTC declared that "music power" was wrong and RMS power was the way. This lead to many wrong design decisions, as music was not the way to judge music equipment. This was stupid, as these audio amps where not intended to power light bulbs, but reproduce signal with very high peak to average ratio.Since then this has been mostly corrected or ignored.The poor consumer has been told to trust the numbers more than his ears, which has lead to generations of people not being exposed to good sound.The convenience factor is more important than sound quality. Sound does not have a "look" like TV picture, where quality judgement is plain to see.The .mp3 revolution hit the whole sound world in the groin. We are still trying to recover from this, and it will be hard.
Adding insult to injury music forms have been developed that masks the poor quality of the storage formats. Synthesized music which lacks an acoustic reality is not exactly challenging to reproduce. The loudness wars have further compressed the dynamic range and will mask low resolution storage formats. Recording studios, with "impressive" looking mixer boards, will do their best to produce a "sound" (-signature) that likely is much different than a natural performance, to sell more units. Close-miking and overdubbing may be cool, but gets tiresome. Old recordings made with very simple gear may sound better than later generation equipment.Hence the trend towards retro equipment.
There is as far as I know not any objective parametric audiophile grading standard for equipment performance.
Hence too many words.Subjective evaluation is fraught with difficulties. Listening fatigue, emotions, stress, and the like makes it hard. Music is by nature emotional, which is a trap for objectivity. Equipment can sound different but still good, so what is the verdict, fidel or no fidel?
Sound buffs may want to have a nice sound coming out of their speakers, which is opposite to what fidelity is. If the source material is crap so should the sound out of the speaker be too.
There are tons of bad music compositions topped by bad performances and bad recording techniques served up in mediocre formats. These _should_ sound bad if accurately reproduced.
Good music, with good performance, recording technology and storage format, is exceedingly rare. When was the last time the hair on your arms raised up from listening a beautiful piece of music?Seemingly most people do not care, keep listening to the junk material.
Looking at high end equipment makes me think that most of the money is spent on what meets the eye.Good sound equipment should not be super expensive. If you cannot tell how it sounds unless it is big and shiny, it is not sound reproduction that is primary. 
Congratulations if you read all this, you must be very mad by now :-)

This entire thread is about perspective. Which throne do you sit upon? I am a former bicycle racer. Which bike is best or what is the bicycle of the future? It all depends upon your perspective. Michael Green would be all about e-bikes s'far as I can tell. Again, which throne are you sitting upon? At the end of the day, we have moved light years in medicine and IT and have moved millimeters in audio technology. I own Class D in my car. It sounds good. But in my home, in my dedicated listening room, I prefer tubes. Which throne do you sit upon and what is your perspective? I don't really care, mind you, I have found what works best for me by trial and error. This Board is the silliest extreme of democracy. I enjoy it but I will protest here and there that some posts are vague, non-determinative, and sometimes, downright silly. Unlike photography in which digital has taken over most die hard film based stalwarts, audio is not going to change anytime soon. There will be SE tubes, Class AB tubes, Class A solid state, A-B solid state, and Class D and maybe more. Unlike photography, there will be no paradigm shifts in the next ten or twenty years.

My goal is to own a great representation of all class of amps . Having owned a Bryston 14bsst2 , Krell 300cx , Hypex Ncore 400 , Audio Research ref 75 , Exogal Ion , I find certain amps mate well with certain speakers . I have gone through roughly 30 pairs of speakers in the last 5 years . Each speaker brings out the best in every class of amps . No one clear cut winner for each . Does there have to be a best amplifier topology ? Have enjoyed all types . Enjoy what you got !

The first time I got so excited that I danced to a music system was when I was about 5 listening to a six way mono really big box speaker through Heathkit tube gear in 1961 listening to Dvorak Slavonic Dances and Brahms Hungarian Dances on Capitol.

Since then, I have experienced many excitable recordings.  Even my wife claps after a really great recording/performance.  The most recent was In A Jazz Orbit by Bill Holman and Tchaikovsky Sym. No.1 with Michael Tilson Thomas and Boston Sym.   Toe tapping (former) and jumping up and down fun music (last movement latter).

Amp classes are like school grades. 

Closer to F the worse the sound.

a/ab still the best.

D is low level tripe

So you see, this type of thinking is the problem.

@fsonicsmith
If you get a chance, look into the Tour Divide Race, from Banff to Antelope Wells.
@vt4c
+1