Digital, Low Mass, ClassD, Less expensive, Let it happen!

Well here we are! Not that you can't go back and buy boat anchors, but now we know sound is better with low mass designs. Digital source? Yep, the tide has turned. ClassD amplification is also here to stay. Lower mass speakers, on their way back too. The audiophile hobby is getting less expensive and better sounding.

I guess we can debate this, but it's happening anyway. The hobby is simply growing up and becoming more aware of how to get great sound, and get it smart. There has been a lot of myths passed down when we only had paperback magazines, mostly for marketing, but the internet has finally caught up with audio reality. Instead of $20,000.00 components we have $20,000.00 whole systems (including all the trimming). Shoot, there are $5,000.00 systems that excel. The Trade Shows are changing, the market is changing and we are changing. Want to stay old school? No problem, there will always be old school and plenty of used gear (at least for our lifetimes). There will also be smaller niche companies that spring up to tempt us.

The hobby is entering a new era for the extreme listener. It will be a hobby of doing and exploring Electrical, Mechanical and Acoustical as equals. Components will be much smaller and more flexible, and more time will be spent on playing our whole music collection, and not just a few recordings. Many HEA debates will be making their way to the archives as the hobby grows closer to mainstream. Mainstream as in higher quality audiophile mainstream.

Are you ready? I sure am!

Michael Green

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I’ve always been a fan of simple well made $1000 systems.

It takes effort on the part of the user of such, though.

Most throw money at it trying to get it to work, when effort is the part that makes it work. Throwing money at the problem can be ineffective and take far longer to get the same spot that could have been reached years earlier via effort.

Learn. Grow. think. Logic. All in the service of the emotions we attempt to invoke, when hearing great reproduction.

Most folks who are here, though, are enthusiasts and tend to put in some to more effort.



Buy the right speakers. Upgrade them.

Buy the right amplifier. Upgrade it.

Buy the right source device. Upgrade it.

Buy the right cables.. Of course, upgrading here can be a problem.

Sites that cater to the DIY audio enthusiast have fairly large followings. Such groups probably outnumber the percentage of people on audiophile forums. There is a reason for that.

Not a fan of class D, though. The sound they produce is mostly noise/hash, misheard as detail, due to how the ear processes signal. Most audio equipment (pretty well 100%, actually) is guilty of this sort of sin. A little of each, darker and noise/hash as detail a a pair of sonic bookends. It is literally the nature of electronics. Class D pushes this too far in the one direction. It can take time to discern this point.

Class D will probably take the same path as Digital. Where it (digital) was a step backward at first, and felt by some to be superior and pushed as superior. This (digital) was uniquely a industry wide corporate push, though. Then over the next 20-30 years, it (class D and digital) approaches the quality of what was available before in the prior technology, and then it is realized, openly, at that time...that it was a degradation, not an advance. But we’re much better now! Really! (will be the admission in 20 years, re Class D......)

But hey, if folks like it and it makes for them having fun with tunes, who am I to argue.

Yep, I think we’ll all have enough fun. The guys who probably won’t be having fun are the ones left behind arguing about what they think distortion is.

As far as digital, I loved it in the beginning and I love it now. A lot of folks who don't like digital for the most part haven't learned how to play it.


I am definitely on board the whole free wheelin’ low mass train 🚂 Toot! Toot! Not counting my elaborate seismic iso stand, which is quite massive and tricked out, the system itself is only 24 ounces, including Grado headphones and Panasonic portable CD player, made in Japan. Obviously when you go very low mass as I have you not only shed a lot of pounds but a lot of things that produce noise and distortion.
I am all in! Loving my digital powered dac with room correction as well as DSP options in Roon.  All lightweight, can stay on 24/7, produces no heat and sounds fantastic! 
Good luck. I am going in the opposite direction.
I've heard some digital amps that left me cold and wanting and I've heard some (Genesis and Audio Alchemy) that sounded really nice.

What I have heard is very, very limited but the potential its there. When all the bugs are ironed out and they get better as they get smaller I'll be all ears and maybe open wallet as well. 😄

All the best,
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I just love sweeping generalizations. Low mass speakers are "coming back"? ESL's never left. The vacuum inside a tube exhibits very low mass (zero), but the transformers of the amp it is installed in shouldn't (ask Roger Modjeski or Tim de Paravicini). More grandiose proclamations please!
One wonders if low mass speakers refer to the total mass or just the diaphragm. The flagship Martin Logan’s come in at 280 lb per pair. The big Sound Labs A-1s tip the scales at 370 lb per pair. Is that really considered low mass? Hmmmmm...
Yeah, they better get brain implants with music -upgradeable - and be done with it.

Well, like I've been saying (as well as others here), it's happening whether there's a debate here or not. Simple passive acoustics, room correction (DSP), low mass amps and entry level speakers, inexpensive enough to make the audio cheapskate blush, are making their way into the audiophile mainstream way of thinking.

None of this needs Agon membership approval. It's just a fact that simpler, happier audiophile days are here that is far more practical then what was preached years past.

Many of you are putting together, past and now, systems that rival the big buck systems and that's good. The cool thing that I'm talking about is, your sharing your findings and that's what is needed. And, that's what's going to balance out this hobby and introduce new blood to the magic of in-room listening. Headphone and car listening are already there, more or less, but HEA has struggled to get to that comfort level it deserves.

Room correction is now the norm, passive and electronic, that's a big step. Low mass is taking place, that's the most needed next step taking place. Low mass more gain.

Michael Green

In 1974 the FMI 80 was a very good low-priced speaker, better than many much more expensive models from other companies. The same was true of the NAD 3020 integrated amp in the 1980's. I guess they could be described as "low mass", but that's not why they sounded good. Good design is not a bumper sticker slogan.

Hi bdp24

"In 1974 the FMI 80 was a very good low-priced speaker, better than many much more expensive models from other companies. The same was true of the NAD 3020 integrated amp in the 1980's."

I agree, 2 wonderful products.

"but that's not why they sounded good"

That statement is where you and I would disagree. Double the weight of either the 80 or 3020 and the soundstage will shrink, shift up and run into the speakers' locations.

Michael Green

My fav all-around system by a considerable amount, if I have to choose one, is my Ultra Light portable Sony Walkman cassette player with Grado SR-60 headphones (which I made even lighter by removing the really horrid sounding ear pads, whose brilliant idea were those? ). Dynamic, engaging, musical! Total mass 14 ounces. I’m not hot doggin ya. 🌭
MG... On the wrong side of the know as usual. 

There's no shortage of boat anchors. Nobody building heavy class A is feeling any pinch or worry about class D. Nelson Pass cited adding mass to his amps with bigger heat sinks and beefier power supplies was the secret to getting better sound from his designs. Stereophile agrees they sound better. Their amp of the year last year wasn't class D amp. It was a single ended class A amp. 
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Yeah, Class D sounds like poop.
"Nobody building heavy class A is feeling any pinch or worry about class D."

What a dodo egg-drop that was. Keep the dream alive.
In 1974 the FMI 80 was a very good low-priced speaker, better than many much more expensive models from other companies.
I went from Altec horns to FMI 80s (Fulton was here in Minnesota). Eventually I had a set of Js and then Premiers, before going in a different direction.

But that set of 80s I had are still alive- doing background music duty at a coffee shop in NE Minneapolis.

In the 90s we sought out some SET amps, since they were a sort of rising star back then, to see if there was anything we needed to be worried about. There wasn't. Class D- same thing, until just very recently. I've been of the opinion that class D was the rising star in amplification for some time, but that they just weren't fully realized.
All technologies follow a price/performance curve, with lots of investment initially with little performance gain. As the technology gets sorted out, big gains are made with little money so the tech improves rapidly during that time. When its mature, only small gains are made and with significant investment.

IMO only, we are somewhere in the middle to top of that curve; I don't think that class D technology is all that mature yet. The reason is that relatively small players like Merrill are able to make contributions that advance the art. Heck, we've even been able to do that. So I have to assume its still got a ways to go. At any rate, recent Class D amps are sounding a lot better than even just 5 years ago.

Everybody though big class AB amps would just own the whole world in the 60's and 70's. And there are plenty of them to be sure. And if you try really hard and employ enough tricks you can get a class AB amp to sound as good as a simple class A amp, but even high bias class AB amps make more low level distortion than a good old fashioned class A amp. And class D has really only proven itself as good as a typical class AB amp. 

Kosst, I have a question for you.

How many of Nelson's amps have you owned? Many of us here are Nelson Pass fans (me included). I've owned quite a few of his designs and when reading your responses I ask myself how much experience does Kosst actually have with the equipment he makes comments about, like others here have questioned you.

I have had success with A AB and D, mainly because I've learned what they do through listening.



teo_audio said it all for me. I don't listen with my conscious mind, it's too easily deceived; I listen with my "subconscious inner mind" that hears into the depths of the music, it can discern which reproduction is the best.

As an example; way back when people listened to the radio for music, it sounded good because they were listening to fine tube amps; especially on floor models; music lovers knew the newer SS radios didn't sound as good, but almost overnight, that's all that was available.

I put SS and Class D in the same category, although to be honest, I've never heard Class D.

In regard to interconnects, way back when people discovered they mattered, I bought good shielded wire in bulk and made my own. This was wire that was used for TV stations, so you know it was the highest of quality.

Word got around about my high quality interconnects, and what a difference they made. I only made them for my friends and whoever they sent my way; no, I was not interested in a new business, just doing favors for other audiophiles.

One day I went to place an order, and discovered that wire was no longer available for the public, you had to be commercial in order to purchase it. No wire, no more interconnects.

Hi Mikey!

Not really sure what Pass amps have to do with the general behavior of amps in general. Care to explain that? It's a widely accepted reality that if you want the lowest distortion at low power levels, you want class A. A well designed class AB amp gets you close, but when the output devices transition out of their bias region there's always a rise in distortion, and for most AB amps that a fraction of a watt. Distortion then tapers a little, flattens, then rises near clipping.

Class D amps do nothing of the sort. Because their constantly switching they generate the most distortion at low power levels. Go look at the measurements. And beyond that, the distortion is almost entirely higher order garbage. 

It's widely observed and understood that dynamics and high order distortion are virtually indistinguishable to the human ear. Amplifiers that are making .02% distortion at half a watt aren't intrinsically bad unless that distortion is high order. The ear is going to perceive that as a false sense of dynamics. It's unavoidable. That's the kind of distortion class D amps make at those low power levels and the measurements make it obvious. 

Let's contrast that with any single ended amp. Instead of this distortion peak at half a watt it's way out near the power limit. At half a watt it's as low as it gets and it's 2nd order. It stays low even order across the power band. It only gets ugly, odd, and higher order at clipping. And sonically that makes sense to do since dynamics should be pronounced at high volume. I can't think of any reason why you'd want exaggerated dynamics at low power levels. It's like using a loudness control. 

kosst says "Not really sure what Pass amps have to do with the general behavior of amps in general."

My answer to that is everything since kosst uses them as his point of reference.

So what he is saying is, he using Pass Labs as his reference yet he doesn't have any experience with Pass Labs past the one amp that he built? 

Speaking for myself, if I have a question for Nelson I'll speak with Nelson or use his products for my own evaluations. Saying .02% means nothing to me. For example, tonight I made sonic changes to a recording I'm playing. I spread out the stage more and gave more presence to the cymbals. As a result the bottom end became more real and in better pace with the midrange. Am I now suppose to describe this in distortion measurements, or claim that I can only do this with class AB or D or A?

Fact is I can make these desired changes with any type of amp class. I can do this because I understand how systems play music and I have learned to tune them. No magic and no measurements, simple applied physics.


Hi Mikey! 

Pretty much nothing I said had anything to do with any particular amp or manufacturer. It's very easy to speak in broad generalities about these things because the characteristics of class A, class AB, and class D are universal to some extent. Anybody with eyes can look at the measurements and arrive at the conclusions I made. I guess since you don't have any argument you're going to resort to jamming words in my mouth I never said so you can weakly assassinate my character. That's not very nice, Mikey. 
I abandoned tubes amps (HK CII and CV) some years ago, but having heard a very fine 65 wpc KT88 tube amp recently driving my OB speakers with a 12 ohm impedance, I am swinging back in that direction.  Of course a tube amp is de rigueur, in my opinion, but there is such magic in a powerful tube amp that my SS amp can't reproduce.  Flea watt tube amps make no sense to me.   I demo'd a couple of mid-fi Class D amps  a while back and they initially sounded quite good, but after a time, I felt that I was missing something, the something being found immediately when I swapped back my Class A/B amp into the system.  Maybe the higher-end Class D amps are as musical as other Class A, Class A/B and tube amps, but they are out of my price range. 

MG's point is well taken that Class D amps are the wave of the future and I think they will figure it out, but at the moment I am going back to a tube amp myself.  One reason I abandoned the HK Citation amps was the PITA of biasing them.  With modern tube amps, it is a simple process, indeed.  Plus, there are a sufficient number of new tubes available that pretty much give NOS tubes are run for their money.

For a point of reference

I have Audio Note, Jolida and a few others, but the tube designer I've enjoyed listening to this last couple of years for amps and preamps is....

Especially the A25-M and the AP-01. I mention these as a reference to what I use to ping pong back and forth with the Class D world. I also have  outstanding relationships for borrowing equipment. Nice to live a few blocks from the CES. So I'm not that far from anything I want.

One thing I will mention about class D is how one mates them with the rest of the system. I have heard class D sound thin with speakers that have more components in the crossover. Class D likes simple crossovers or in my case only one capacitor. As with any type of amp design using the best speaker type match is important. If folks put a class D amp into a system use to A or AB they might find themselves coming up short. Class D is a different animal and really cool design once you find the variables that fit, like with all things audio.