Is D for Dry? Class D...


Class D sounds dry and lifeless... thats all, carry on
128x128b_limo

@deep_333 No I will pass on the Schiit stuff, found your post to be hypocritical. Panasonic, is not on my radar. Prefer products from the EU.

Sure, drop the 70k on Aavik, it sounds amazing/brilliant and has some European innovation on display....Oh wait, it is class A...lol (Michael Borresen knew better, good for him).

P.S Nothing hypocritical on the Technics, I told you why I have it dude and it certainly isn't the only amp I run. On those hot summer days, if the hvac keeps kicking on, the hvac noise makes your listening lofi....call it seasonal

Deep,

 

If you do not like Class D, that's fine. You have stated your distain now move along. I happen to like my Class D amps over my Class A ones. Different strokes for different folks I guess.

@deep_333 No I will pass on the Schiit stuff, found your post to be hypocritical. Panasonic, is not on my radar. Prefer products from the EU. 

 

@deep_333 Found this in your Equipment list....Amp 3: Technics SU-R1000, This is Class D no?

That amp is class D-ish no matter what the white paper claims, but, it is not a 1 trick pony (like the loads of class D-umb that’s being sold)... has a few other tricks up its sleeve to deal with certain speakers. But, I have to put it through Masterclass, PEQ, etc on the front end to make it work for my ears. It is also over-engineered/built from scratch in Japan where I gave it a pass on price (no mass purchased foolery there).

In any case, i wish all the guys with purist rigs great luck as the sterility of class D takes over to maximize manufacturer profit margins.

 

P.S. Try the Schiit Tyr class A-ish topology for a measly 3200 dollars and let me know which class D crap priced way higher sounded any better. Schiit shall set you free.

 

Just bought a pair of Merrill Veritas monos. They sound great on great recordings, but show flaws of not so great recordings. Had them about two weeks. Currently using generic power cords.

@deep_333 Found this in your Equipment list....Amp 3: Technics SU-R1000, This is Class D no? 

Class D = Dry, Processed, Lousy, Nauseating

A favorite indeed of lousy manufacturers (naked emperors) looking to maximize their profit margin, a.k.a buy the cheap boards en masse from China for pennies on the dollar, put it in a box, sell it to senior citizens for 20k a piece.

My hybrid class D PS Audio M1200 monoblocks sound great.

Stereophile rates them class A.

Even Michael Fremer liked them.

Pretty useless review. Everyone is entitled to their opinion. 
 

Class D rules.  Never going back again.

There is always new product hype - e.g., according to TAS, AGD has "unobtainium" GAN transistors that only Alberto Guerra has access to, and "everyone else in the industry is using GAN devices that were not specifically built for audio".  The audiophile trend embraces the latest as the greatest but, as usual, only time will tell if the hype is borne out in reality.

Strange - because I have read on this forum about some hardcore tube guys replace their tube amps with Class D - namely the AGD amplifiers.

And I generally check the profiles of folks posting. I mostly ignore reviews from folks who do not have a system posted - because I am not sure if they are just marketing or genuine. But the one person actually had his system posted and he had replaced tube amps with the AGD.

Well, "10Audio" just did a mini review of a pair of class D amps and...ouch!

I wonder if they were defective?

@grk No, its more likely that Jerry is behaving the same way he did 25 years ago. At that time he dissed our products (by changing previously published good reviews to bad after the fact) when I called him out after he reviewed a poorly built kit version of one of our amps as if it was factory built. Obviously that amp had some problems and he had bought it used.

We don't know how he got this set of amps either (if he even has a set), but IMO he is unreliable. That is how thoroughly he discredited himself back then. As I recall he didn't post on any audio forums for years after that. Apparently he is still carrying a grudge. Obviously he isn't a candidate for a review sample from us.

Here are reviews by more reputable reviewers to put this in perspective:

https://pmamagazine.org/is-class-d-amplification-now-better-than-class-a-b-and-class-a/

https://www.audiokeyreviews.com/akr-magazine-january-2024

https://hifiplus.com/articles/atma-sphere-music-systems-class-d-amplifier/

You can see that Jerry has done what he did at his own risk. I have to admit I'm a bit surprised that he would attempt something like this again.

As long as you have high end manufacturers(that regularly post here) supporting this technology,and subconsciously influencing users,you will have rubes like the ones on A’gon making laughable statements like "buy a Fosi V3 with the best power supply for $140.00,it "WILL SOUND BETTER THAN MOST TUBE AMPS"(that’s a quote from a current thread)...
I have a $200.00 Chinese made PURE Class A integrated amplifier I bought WAYYY back when I wanted to transition away from tubes due to re tubing costs..
I CHALLENGE ANYONE on Audiogon,who says Class D is as organic,tonally lit & musically natural as a decent tube or Class A SS amp, to set up a listening test against ANY Class D amp up to 5x the value of my amp($200.00 vs $1000.00),matched levels & blind, with members from this community!Live stream it on Utube...
I will gladly provide the little Class A amp I have,based on the Sugden 21A & I will even pay the shipping to where ever the test is held!!!
WELLLLLLLL???

Audiophiles really, really want Class D amplifiers to sonically rival Class A and AB designs. What’s not to like, small size, low power consumption, low heat generation, and relatively high power output with low distortion. The same 10 Audio reviewer praised the Acoustic Imagery Atsah amplifiers (Putzey’s NC1200 modules) and rated them 10 LPs, yet they no longer appear in his system.

It seems audiophiles want the Class D amplifier technology to succeed so badly, they convince themselves that each new technology or new offering is going to be "the one."  This has been going on since ICEpower, B&O, and Spectron amps hit the mainstream in the mid-1990’s. While Class D has become the de rigueur choice for cell phones, car audio, and subwoofers, and despite having a few vocal fans and successful manufacturers (think Rowland), Class D still hasn’t become quite mainstream in the audiophile world.

It has been almost 10 years now since I took the plunge with those same NC1200 Acoustic Imagery Atsah monoblocks that 10 Audio raved about and it took me almost a year to figure out the Emperor wasn’t wearing any clothes. What I heard sounded like separate musicians each playing their part in separate sound booths, and not a band playing together. The ambient cues were somehow off, but it took me a while to sense that. Music through those amplifiers just didn’t sound real. You can still purchase Mola Mola’s Kalugas but the other manufacturers using NC1200 modules seem to be either gone, like Acoustic Imagery, or to have dropped the line, like Merrill Audio.

IMO, the most accurate review of NC1200 amplifiers was the review of the Mola Mola Kalugas by Matej Isak at Mono & Stereo who said,

"The familiar music didn`t sound much familiar through the MOLA MOLAs; in the midrange the voices did not posses enough dose of “human touch” to sound real. All notes were there but the illusion of musicians standing in front of me wasn`t convincing at all. The music didn`t sound inviting and involving, it was just… there. The emotional content was missing and the tonal colours were somewhat bleached...with the KALUGAs the sound was far from involving and believable..."

 

 

Well, "10Audio" just did a mini review of a pair of class D amps and...ouch!

I wonder if they were defective?

https://10audio.com/atma-sphere_class-d/

 

I guess I have had pretty good luck with my Class D amps. I had a Peachtree Nova 300 running ICEPower modules, and it sounded pretty good. I now use a NAD C298 with Purifi modules (using a ProJect PreBox RS2 Digital preamp) and it sounds great. I also have a Peachtree Carina 300 (Hypex modules) and a Peachtree Carina GaN and they each sound excellent, not "dry." The ProJect has a selectable preamp tube stage for a little of that warmer tube-distortion sound. I would say the Class D amps I have tried deliver what I expect, lots of low distortion clean power and a dead silent background. I have other tube amps, a modded and tube rolled Willsenton R8, which as a push-pull tube amp is as different to the class D amps as might be possible but still with a dead silent background and excellent sound. I think class D offers tremendous utility in space-constrained applications (like car audio and plate amps for powered speakers and subs) while offering much of the performance of AB designs without the energy and weight penalties.

 

One other thing that just occured to me is that all my cars have class D amplifiers in them and I have been listening to them without complaint for years now, some of them not that new for sure. And while one can reasonably argue the environment in a car is not the quietest or perhaps the best for listening to music, still I find little room to complain about the sound I get in my cars. Why shouldn't we accept the validity of current class D designs and their very real benefits of vanishingly low distortion at moderate power levels, and an extremely low noise floor in the best designs currently offered, and keep in mind these are all contributors to an overall high quality sound. Never mind that some of these sound a bit harsh when pushed or perhaps a bit thin in certain parts of the audio spectrum or have other shortcomings. These issues are being addressed as the designs of these amplifiers  evolves and improves. The fact that Legacy Audio is rocking the ICE modules in their amps speaks to their fidelity and to maybe a lesser extent their reliability. I will say that most class D manufacturers do not offer very long warranties on class D amps, often only a year or two, where many class AB designs get 5 years and sometimes more. So there is that to consider.

I am leaning very strongly towards class D, not because I particularly am strongly musically influenced to do so, but from cost, convenience, and power consumption. I used to have a ton of class ab equipment, old hafler dh200s and the like that I built from kits and they sounded great. I started letting them run all the time so they didnt have to go thru the power cycle current inrush and I think its helped them last and be reliable, but holy mother they love electricity and my wallet didnt like the power bills. Then I realized that more power was a good thing and would save tweeters from premature death...So class D or H at a minimum is where I am going to have to go. That means upgrading the house wiring too...A single 15A circuit will never be enough with two high power subs, and 5 channels of high power audio. I think I am looking at needing 2 20amp circuits at a minimum and maybe 3

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given Alberto Guerra’s career in the industry

From an interview with him about using empty 6550 tubes to house the GaN amplifier boards in.
"Company founder Alberto Guerra admitted that he did it largely for the sake of visual aesthetics. Otherwise a class-D amp just looks like a box”
You don’t have to be too smart to see the tube pins are going to be a problem with a bit of age on them, especially if being used with a speaker that demands a bit of juice sucked through those tube pins. (like I said you may as well have spring clip speaker terminals)

OK, so at long last it appears that the LSA Voyager has finally dropped, so we will have another piece of equipment to squabble about.
https://www.underwoodhifi.com/products/lsa-electronics

Otherwise, all that I can say is that, given Alberto Guerra's career in the industry and that of his principal decrier, I know whose opinion I would heed more.
Ralph, don’t skew things around "to seem" to suit your next product.
I did not say "won’t handle", I said will not get "the best" out of the Alexia’s bass because of it loading.
We have the Alexia’s here in front of us and know what they like to get the best out of them in the bass, and it’s not Class-D yet. (Maybe in the future when they can come close to doubling from 8ohm to 4ohm to 2ohm wattages like big better linear amps can)
Again, according to Wilson themselves, the speaker does not suffer any performance loss strictly on account of class D. Some class D amps are not as good as others just as some class AB amps aren't as good as others.


And for the record I'm not skewing things. To be clear, if you want to get '  ' 'the best' out of the Alexia's bass', a class D amp can do that as well or better than a regular class AB amp. Here are the provisos:IF-
1) as long as it is designed with the same current in the power supply as the AB amp2) as long as it has adequate heatsinks3) as long as the output section as the same current ratings in its output devices-then it will make bass no worries, with 'the best'.

This is nothing about our upcoming product so much as its about Ohm's Law.


I was a bit astonished that in the face of advice from the speaker manufacturer in question that you were continuing to hang on to your position, which they regard as nonsense.


Now it may be that you are actually comparing some class AB amp against a particular class D amp on that speaker- and I'll totally give you that anecdote. But anecdote is not proof of your position (its a data point at best); if that is what you are experiencing then I advise you look for a different (probably newer) class D of more competent design. If you need tips on what to look for here are a few:1) avoid amps with SMPSs as most SMPSs will current limit if they are off the shelf units. Get one with a more traditional power supply.2) look for units that, if using feedback, are of the self-oscillating variety. The Hypex is a good example.2) The input circuit, if installed by the ultimate builder of the product, should use high quality opamps operating at low gain. Even though I like tubes, they are very difficult to use properly as the input circuit because the comparitor input impedance is so low. This will make it hard for the resulting amp to have good low frequency response.
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Jeff Rowland is reading...and taking notes
He doesn't have to take notes, as NO WAY you’d see JR doing high wattage/current signal transfer through those sorts of contacts, EVER!.

Cheers George
OK Sunshine.

What’s the issue with tube pins? I own 70+ year old Western Electric Amps and 300B tubes and have never had issues with tube pins, sure sockets can get loose but that’s a one minute fix and tube pins are easy to clean.

What AGD has done is brilliant on more than one level.

No not brilliant, more inept, but guarantees return service work in the future (maybe not so stupid.$$)
There’s a HUGE!! difference in output wattage and current going through the tube pins, compared to a 10w SE 300B even a push/pull one . (do your homework) 
Especially if the AGD is "trying" to drive Wilson speakers with low bass impedances.
You may as well have those nasty spring clip speaker terminals on the back of the AGD, because that’s just as good as the tube pins and the speakers are hooked through those to the GaN output stage in the 6550 tube envelop.
What’s the issue with tube pins? I own 70+ year old Western Electric Amps and 300B
See that what I mean, absolutely no idea.
Your not pumping any where near 400w and the current you would with a 300b just 🤣

What AGD has done is brilliant on more than one level.
I said it before you have no idea, and whatever your getting for this shilling, he needs to take it all back because your hopeless at it..

And the above post means what? That he was thinking literally outside the box?

What's the issue with tube pins? I own 70+ year old Western Electric Amps and 300B tubes and have never had issues with tube pins, sure sockets can get loose but that's a one minute fix and tube pins are easy to clean.

What AGD has done is brilliant on more than one level.
Was going to check out the AGD gear, 14 day return privileges for $7k in unknown gear with zero dealers.

NOPE!
First sign of a shiller. Here some more for you to agonize over.

Interviewer: I ask Alberto Guerra , why put solid state components inside an old 6550 vacuum tube envelope, bet it’s not vacuum’ed back out and sealed again either.
"Company founder Alberto Guerra admitted that he did it largely for the sake of visual aesthetics. “Otherwise a class-D amp just looks like a box”

PS: OK he’s shown all his cards, with that statement.

AGD is just GaN based Class-D slid into a "bogus" empty 6550 tube envelope, which uses (horror) the base pins for all it’s contacts, everything has to go through them, input output power supply rails everything🤢 
Just the whole gutted tube thing, stuffed with solid state, and still using all the tube pins as power/current transmitting contacts, guess in time it ensures return service work when those pins start to corrode and arc over????




Butt out, please, I was talking to Ralph🙏 (you didn't start the thread  b_limo did.)
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Shows you do not know what your talking about, look at the AGD spec's. And the only Wilson speakers i own are the 5.1's and XLF's  and not the Alexia.

So from your posts you have the AGD's powering the Alexia? Otherwise your blowing hot air and you only have opinion.
I’m refuting the idea that a class D can’t handle this speaker

Ralph, don’t skew things around "to seem" to suit your next product.
I did not say "won’t handle", I said will not get "the best" out of the Alexia’s bass because of it loading.
We have the Alexia’s here in front of us and know what they like to get the best out of them in the bass, and it’s not Class-D yet. (Maybe in the future when they can come close to doubling from 8ohm to 4ohm to 2ohm wattages like big better linear amps can)

Keep going like this and it will look like your shilling again, because of your yet to be released GaN Class-D
From the Wilson website page for the Alexia 2:


Measurements Sensitivity 89 dB @ 1 watt @ 1 meter @ 1 kHz Nominal Impedance 4 ohms / minimum 2.54 ohms @ 85 Hz Minimum Amplifier Power 20 watts per channel Frequency Response 19 Hz – 32 kHz +/- 3 dB Room Average Response [RAR]


We can see that Wilson does not think this speaker hard to drive with a 20 watt minimum. Because the AGD has such a low output impedance I think it should be able to drive this speaker quite well, depending on the power of the amplifier and the size of the room. If you have a larger room all you would need is more power.


So I guess I’m refuting the idea that a class D can’t handle this speaker (any more or less than any other class AB amp of the same power might). I really don’t see what the problem is.

I spoke to Jerron that works at Wilson (for the last 20 years) and he is in complete agreement. He says the older Alexia was a bit harder to drive but the class D amps handled it no worries at all.
So I'm going with a 'furphy' on this one.




Before long, he’ll be calling you sunshine
Trust fusers to back each other sunshine.(because your soooo bright) 
(not you Ralph, the other fuser here with the AGD)

Ironically its the GaNFETs that George has been so enamored of in the last couple of years
Yes I have, and still do, but never that GaN could drive .9ohm bass loads like the Alexia’s to their best. Refute that Ralph
As I said the AGD has no chance of driving the Wilson Alexia to sound their best in the bass because of their .9ohm impedance load. And refute that also Ralph.

Go and read any thread and you’ll have georgie calling anyone a shiller
Especially owners that claim these amps can drive those types of loads. Which gives out the wrong info on what they can drive, they do it because they are shilling.
Go and read any thread and you'll have georgie calling anyone a shiller who doesn't agree with him. It's his fallback accusation.

Before long, he'll be calling you sunshine, which in Australia, is a big insult due to it's effeminate connotations.

Next, he'll use **** notations in his spelling to use curse words to get around the mods.

Aside from that.....

All the best,
Nonoise
George goes on about this EPDR thing. But he's not clear on what the impact will be on a class D amplifier other than saying that they won't drive it.

Almost any class D amp made today has an output impedance that is often a good order of magnitude lower than traditional class AB designs. This is because the On resistance of the output devices is (especially if GaNFETs are used) literally only a few milliohms (our amp has an output impedance of 10 milliohms as an example). When you have an output impedance that low, if a speaker has an effective EPDR that causes it to be effectively slight less than 1 ohm the class D amp will still behave as a voltage source while driving it. This is for the simple fact that at 1 ohm the class D amp may well have a damping factor of over 100.


That's not the same thing as the amp falling flat on its face! However there is a chance that the class D amp will go into current limiting mode to protect the output devices. GaNFETs are tricky to heatsink and as a result the heatsinks you have to use are unlikely to move heat away from the output devices fast enough to prevent failure when driving such a load. So the prudent designer will have some sort of protection circuit even though the output devices can easily handle the current.

As I've pointed out a good number of times in the past, the limits of class D amps to drive a low impedance are the same as they are for a conventional class AB amp: current rating in the output devices, current available from the power supply and heatsinks enough to move heat away from the output devices.


Ironically its the GaNFETs that George has been so enamored of in the last couple of years where this heat problem is most likely to occur; conventional MOSFETs are often packaged in a TO220, TO240 or other package that can be easily heatsinked.


Now we should be clear about one other issue regarding EPDR. In most speakers the region where this might be a problem is often just a very narrow range of frequencies, IOW not the entire impedance curve of the speaker! If this is the case with a speaker that has such a low EPDR rating, it won't be much of an issue for a class D amp because there just isn't enough energy needed  over this narrow range to heat up the output devices. The Wilson Sasha and Sophias are good examples of speakers of this, and in practice mean almost nothing to any class D amp. At most clipping onset might occur slightly quicker, but frequency response is unaffected.

George accuses me of shilling nearly every time I explain anything about class D, so I reiterate that what I've said in this post has to do with most class D amps that are available today.  
I do not see claims being made, but people expressing what they experience hands on there is a difference.

The "correct speaker" applies to any amp regardless of class and not just class D.

It’s nice all the Class D detractors have a thread to dump in.


There are different types of Class-D detractors, some only "dump" on those ** claims made by shillers of certain brand Class-D’s, who have no idea what they claim, especially in regards to what types of loads they are capable of driving.
If they didn’t make these false ** claims, there would be no confrontation from those detractors.

I for one have heard certain Class-D amps sound great, "with the correct speaker", and have acknowledged it here on Audiogon.

Cheers George