Class D is just Dandy!

This is probably over simplifying or incorrect, but maybe their maker voiced the speaker to the internal amps? Or did the amps only power the bass drivers?

@erik squires
Eric , I purchased a used pair of Bang & Olufsen Penta 1 loudspeakers a few months ago on craigslist. They are circa 1989 . They are active with class d amps inside . These are in no way bright or fatiguing , things I have associated with older class d amps . Looking to find out how and why this could be ? 

I am really not a fan of silver over copper cables. 

However, solid silver interconnects are pretty good and inexpensive to build on your own. 

Best,

E

@tweak1
+1, my friend. I suspect some type of class A-class D hybrid will likely be the future for all class D topologies. 

I love my Audio Alchemy DPA 1, which is said to be a hybrid, due to an FET input stage, I guess. Last night I swapped out a silver over copper Surf XLR for an old PS Audio (mid model) and was floored at the much needed warmth that was hiding in the amp

georgehifi,

There’s a vast number of class D amp owners literally throughout the world that have absolutely no doubt about whether their amps are extraordinary performers in their systems. Yes, the great majority of them have switching frequencies in the vicinity of 500 KHz and may not possess the latest and fastest FET transistors in their output stages. Most of them are probably unaware of this but likely wouldn’t give a hoot if they were aware because they sound so incredibly good in their systems.
The owners of one of the many current or recent crop of extremely good class D amps just hear the obvious; their amps have very low distortion levels, dead-quiet background noise levels due to very high signal-to-noise ratios, excellent frequency response throughout the entire audible range, very good dynamic range, very good channel separation along with the ability to handle very low speaker impedance levels and deliver more than enough power to properly drive any speakers.
Additional class D amp benefits include small size, low weight, high electrical efficiency that results in low electricity consumption and very little excess heat and all at very affordable prices. What’s not to like, right?
Despite all the benefits of good class D amps described above, you continue to suggest avoidance of these amps until they utilize switching frequencies in the mega-Hz range and the latest and fastest generation of super-fast FET output stage transistors .
Will higher switching frequencies and faster FETs enable class D amp performance to get even better? As a user of several exceptionally good class D amps of recent vintage, I find it somewhat difficult to imagine how their performance could significantly be improved but I’ll keep an open mind until I give one a good listen in my system.
Until then, however, I. would advise anyone considering a class D amp that it makes little sense to wait for possible class D amp perfection.
Nobody needs to deprive themselves of high quality sound by making the same mistake that georgehifi consistently and inexplicably insists upon: making perfection the enemy of the extraordinarily good.

Tim

@georgehifi

I understood your input to me as not trashing class D designs, per se. They differ among themselves as much as designs within categories of other topologies do. Sometimes the output devices (in this case—for our discussion—Duntech and Dunlavy SC speakers can reveal and distinguish those designs as being better matched over others, whether class D or class AB (tubes, for example). 

Even folks here who rave about their preferred designs within the class D family would concede that point. Their raves are within a given reference context. 

Oh, I don't mind that. I'm not hear to convert anyone.

Why then interject with personal backlash, when  celander  and I, were just talking about amps that are most  capable of driving the Duntech Sovereigns, and I just happen to see and post a link to amps that can and couldn't, and it just happens that Hypex N-Core Class-D couldn't drive them. Here it is again as it's lost now on the other page. 

Duntech Sovereign's suitable amps that drive them.
  
Krell KSA-300 used here
http://www.highendnews.info/reviews/DuntechSovereign-eng.htm

Sounds like Hypex N-Core Class-D can’t cut it with them here.
https://www.gearslutz.com/board/showpost.php?p=11771281&postcount=5


Cheers George

@celander 

Oh, I don't mind that. I'm not hear to convert anyone. 

But I think it shows a great deal of class when you speak your peace and then leave the subject alone for those who are contributing in a positive fashion. 

Best,


Erik 

@erik_squires

As is the case with most of what we are taught as our understanding, we must be willing to surrender our understanding to gain insight into truth. There will always be those who refuse to surrender their understanding to learn truths. And that’s ok. We just need to acknowledge it for what it is. 

No matter how nicely you ask George to start his own nay-sayer’s thread, he’s always going to share his impressive collection of articles about how planes can’t fly.

No sir, they are too heavy and completely unreliable. Plus, you will fall off the edge of the world if you go too far.

God help those of us who want to talk about how much we like Class D, because there is George telling us we are wrong. George would skip his own chemotherapy treatment to come and tell us this. 

Krell KSA-300 used here
http://www.highendnews.info/reviews/DuntechSovereign-eng.htm

Sounds like Hypex N-Core Class-D can’t cut it with them here.
https://www.gearslutz.com/board/showpost.php?p=11771281&postcount=5


Cheers George

Pretty sure the Dunlavy SC’s didn’t vary much at all from the Duntech speakers. The SC’s have a nice impedance response (6-ohms). The Spectron Musician III amp has a fairly low output impedance (< 0.1-ohms) and a high damping factor (500:1). 

Nice amps, George.

celander
He later told me in ~2006 or thereabouts that John Dunlavy used the Spectron amps to voice his SC series of Dunlavy speakers.

https://www.stereo.net.au/forums/topic/49395-why-are-some-speakers-suited-to-valve-amps/?do=findComm...
" I’ve set up Duntech Sovereigns, it is abundantly clear that John Dunlavy designed them to be used with the very lowest output impedance amplifiers available. They don’t even wake up when connected to even quite prodigious valve amplfiers. Even highly capable amplifiers like the ME850 barely get them under control. It takes something like the big Krell monos, or an ME1400/1500 to make them sing."

https://ibb.co/iY7oE9

https://ibb.co/bWWyE9

ME is what I use, in a bi-amped setup

Cheers George

I just spent the last hour catching up on this entire thread.

@erik_squires
Well done, my friend! You’ve navigated a wonderfully positive thread.

@georgehifi
Great contributions throughout. I very much would like to have seen the YouTube videos from EPC regarding their new class D modules for audio applications. Alas, they were blackened out on my iPhone. But I did enjoy your shares about new Gn-based transistors having higher switching frequencies. And your Aussie round table thread from high-end designers was special. Erik might complain about your rain, but it’s welcomed by me, as it seeks to clarify where the class D tech needs to improve. The opinion of Nelson Pass is a good benchmark to base all future commentary. 😂

@atmasphere
And yes, the motivation for class D amplification was all about increasing dynamic headroom—avoiding clipping. Yet, as @atmasphere will point out, it’s the first Watt that matters the most and where the class D tech really needs to focus.

As a teenager, I auditioned an Infinity SWAMP, which was a class D amp the late John Ulrick designed and based upon tech that John and Infinity was awarded a US Patent for. I bought a Digital One amp from Spectron Audio (apparently now defunct) in 1997 or thereabouts. I spoke with John numerous times about his topologies over the years. He said the SWAMP design was ahead of its time because the high speed switching transistors really didn’t exist during the 1970’s to make the amp stable. That all improved later in the 1990’s. He later told me in ~2006 or thereabouts that John Dunlavy used the Spectron amps to voice his SC series of Dunlavy speakers. He said that my SCIVa’s mated with the Spectron amp was a magical combination. I only saw one post here from a contributor who had a Musician III amp.

So my question is: how do the Spectron amps stack up in the mix of present class D amp technology? Back in the day, it was a 300WPC 8-Ohm) stereo amp at $2500. I’d appreciate personal accounts rather than speculation.

—Dan

P.S. Here is a link that is a tribute to John:

https://www.stereophile.com/content/john-ulrick

jwincville22,

You’re likely getting no responses to your request for sound quality reports on the 2 newer 52X and 54X ATI class D amps because you’re only reaching members who own one of these specific amps AND happen to still be following this long running thread. You may get more responses by starting a new separate thread.

Sorry, I’ve never auditioned any ATI class D amps but I can verify that the D-Sonic M3-600-M class D mono-blocks I own are excellent amps.
However, I bought mine about 4 years ago when they utilized Anaview/Abletec ALC1000-1300 class D amp modules. Anaview discontinued the ALC100-1300 modules in 2014 and I believe the current D-Sonic M3-600-A monos utilize the newer Anaview AMS-1000-2600 modules. I think D-Sonic only uses Pascal modules in their top of the line M-1500 mono-blocks.
Both Anaview and Pascal are Scandinavian companies and their class D modules differ from most by combining the amp section and the switch mode power supply (SMPS) on the same board. Most other class D module design/manufacturing companies, such as Hypex-Ncore and B&O-Ice, offer the amp sections and SMPS as separate products on separate boards.

I asked D-Sonic’s owner, Dennis Deacon, back in 2014 about the sonic differences he noticed between the Anaview ALC-1000-1300 and AMS-1000-2600 modules and here was his response:

" Tim,

I have been shipping amplifiers with the new AMS1000-2600 modules. The sonic differences with the previous ALC1000-1300 are very subtle with most source material. They do have a more natural resolution of detail and a more natural impact in the upper bass to lower midrange area. This is where most big dynamics are heard such as percussion, cellos, baritone and bass horns."

Here’s the name of that thread that you might find useful and interesting:

D-SONIC SOA Class-D Core Amps. The best Class-D ?

Tim

So, with all of this Class D talk, where to the new ATI 52X and 54X rate in the scheme of sound quality?  How do they compare to the D-Sonic and their Pascal modules?

Well I bought a NAD D3020V2 and have to say pretty darn impressed for the money.

Great features include a built in MM phono stage, an additional analog input,a toslink input and a spdif input. Another nice touch is a subwoofer output. Add all that to its tiny form factor, if you cannot find room for this then there is something wrong!

Sure 30wpc is not going to rattle the roof beams but paired with Epos ELS3 speakers it plays louder than I need it to.
Oh headphone output as well so very hard to criticize for a bedroom unit or third system which is where it now resides.

$300 shipped as a factory NAD refurbished unit with full warranty.

I do not. I have the v1 which has a USB input instead. 

Best,

E

@eric_squires

Thinking of buying the d3020 for my daughter's room and pairing with a pair of epos els3.
Sources would be a tt as I see the v2 now has a mm phono input and a PS3 via toslink.

Do you have the v2?

So, with all of this Class D talk, where to the new ATI 52X and 54X rate in the scheme of sound quality? I have read great articles saying how wonderful they are but what about people who have actual experience with them who don’t work for a paid magazine?

In a home theater application will there really be much difference than say running an older parasound or anthem amp?

@atmasphere , thank you Ralph.

1 - Direct Digital

@erik_squires FWIW the phrase above is a marketing thing. It means that the amp has a DAC as its input, but the amp itself is actually analog, like all class D amps are. IMO/IME marketing terms like this tend to confuse the marketplace.

@tomcarr ’PWM’ stands for Pulse Width Modulation.
Such an amplifier usually has something like a triangle wave oscillator in it. The incoming audio is compared to the triangle wave and this determines how long the output devices are either on or off. The switching frequency (which is otherwise determined by the frequency of the oscillator) is then stripped from the resulting signal and what’s left is the audio.

Erik, please educate me. What is a "Poor White Male" amplifier?

Tom

Tom - Yeah, I’m using an NAD D 3020 in the bedroom. It’s a hybrid Class D designed by Hypex, so it runs a little warmer than you’d expect. It’s really quite nice.

One thing I’ve learned recently is NAD is using 3 different types of Class D:

1 - Direct Digital
2 - Hypex Ncore
3 - The Hybrid approach they used in the 3020.

It would be interesting to compare them side by side! I will say that while I am a fan of Class D in general, I’ve never heard a PWM amplifier I actually liked the sound of. I suspect they get the feedback (if any) quite right and can’t solve the output filter issues well.

Erik

Hi Erik, thanks for starting this thread. Another + for class D. Bought a NuForce integrated for a bedroom system. It sounds unbelievably good considering its cost. Without regard to cost, it sounds quite good. A little on the warm side, no sibilant hash, non-fatiguing, pleasant, musical. What more could a sane, rational person desire?

Tom

New opportunities for those with a little DIY skill! 

Parts Express is now selling ICEpower modules new, and cheap! 

https://www.parts-express.com/cat/audio-amplifier-boards-modules/3464?N=21147+4294967118+4294960619&...

You can put them together with cases from Ghent Audio for your own mono or stereo amplifiers! 

https://www.ghentaudio.com/kit/asp-mxr.html

Enjoy! 

Erik

Exactly like the A21 and A23, the the JC1 is high-bias Class A/AB.

(model names in sentence above are links)

Good amplifiers.

Have not heard the JC1, just the A23 and A21.

I have to agree, "class warfare" in this context is meaningless and with little to no supportable evidence. This is what showrooms are for though. Buy what you like listening to, which needs no justification. 

Best,

Erik

My Lyngdorf 2170 has replaced a BAT VK600SE.
Am I happy with what I hear?
Heck yes although I believe the room perfect system may have just as much impact on my listening as the amp itself.

Also looking at buying a small Bel Canto integrated for my daughter.

The class warfare should really just end. There are very good and very bad amps of all classes. Furthermore one man’s bust may be another’s bounty. That’s how the world tends to roll in general. Deal with specifics not generalized statements that cannot hold true in reality. For example if I designed an amp it would probably suck no matter what Class because I am not an amp designer. Many are very skilled amp designers however and make very good products using their own unique skills to master technology in different ways. Those people are entitled to think their design is best but not at the expense of others. Each buyer will decide for themselves which is "best" for them using all the unique senses God granted them.

Give it up already!

Personally, I’d say Bel Canto Class D amps are one of the best things that ever happened to home audio in my house! They are marvelous sounding modern masterpieces of technology and meet my needs perfectly!

Cheers!

It seems clear @bluesy41 doesn’t have a clue about Class A Amos.  You can’t make broad statements about any amp Class.  There are Class A amps on Amazon starting at $500.00 and some of them they sound pretty bad.

To both of you.
The Parasound Halo JC1’s in high bias class-a (which is no more than around 20w of A) sounds magnificent, and will blow away any Class-D full stop!!

Cheers George

Parasound Fatiguing?? Hahahaa. Some of the warmest A/B amps out there. Run Class A most of the time. And yeah, I've heard _some_ pure class A amps they beat hands down. 

Unless of course you measure sound quality by money spent. Then of course, only Class A will be pricey enough for your ears. 

Erik 

No offense Erik but I find it hard to believe you can compare Parasound to any highend class A amp for musicality. I get it you love it, but let’s try and be objective. Parasound is a step over Adcom and 20 minutes from extreme fatiguing.

Cheers 

Sorry bluesy41,

My experience does not match yours at all. 

I've heard many Class A which I liked less than the Parasound A/B amps, and those are the equal of the Class Ds I have now. I think the idea that all Class A is better than all class D is nonsense. 



Best,

E

@sfseay -

I owned Mark Levington, Krell and ARC and their class D amps did not move me the way class A tube amps does. In fairness it could have more to do with it being solid state vs my preference tubes, however the best amp I ever heard was the Ayre MXR 20. So yes an ignorant statement on my part in saying all. I will clarify and say the class D amps I have heard didn’t sound as musical.

Cheers

class D is not as musical as a class A amps.

You have not heard a good one with a pair of Ohm Walsh speakers perhaps?

@bluesy41 - since you haven’t heard all Class D amps I wonder how you can make a blanket statement. If your $12K Class D amp was the Esoteric I-03 and you didn’t think it was musical then I wonder what “musical” is? I own the Esoteric I-03 and the Mark Levinson No. 585 and I they both sound fantastic to me.

I love all the comments but their is really no comparison, class D is not as musical as a class A amps. Not saying that anyone shouldn’t love their class D amps but let’s not fool ourselves into believing they’re on par with a good class A amp. Like I said earlier I paid 12k for a very reputable manufacturers class D amp and it made me want to trash the rest of my system and speakers. It drove me crazy for over a year and then I finally ended up buying a class A amp and now I can’t stop listening to music. It’s like I have my very own personal concert every night. 

Cheers

OR.....Ayre monoblocks for totally different reasons. 

The CJ8's are juicy as hell. The Ayre warm to dark. 

I just wanted to say I have been pure Class D for about 3 years and I have never, not once thought to myself "I'm listening to a switching amplifier." 

Now, are there things I want differently? Sometimes. Can I attribute that to Class D. Nope, not at all. 

Before this I was using a pair of Parasound linear amps to power my main speakers. I've never looked back nor gone "wow, I can really hear the slow switching speed distortion." 

Now, if I had tons of cash and space, I'd probably have a pair of CJ Premiere 8s (mono right?). Wow, what amazing amps. But that's because they are just amazing amps, not because I need to get off Class D. 

Best,


E

Agreed it might have been better to be able to tailor the eq manually instead of just having the option to change preset curves from neutral.
However so far in my room to my ears I am liking it.
I performed a 12 point calibration initially and now I cannot bear to listen to it without the roomperfect running as i have way too much bass colouration.
Additionally the built in dac suits my needs well, all I would wish for is a little more power but it seems you truly cannot have everything...lol

@uberwaltz - I would have liked to tone down the midrange a little from what RoomPerfect picked, but you can’t make manual adjustments unlike the Classe. It just didn’t work for me in my room.

Could not leave it 666 posts!

sfseay...
Just curious how you came to rank the Lyngdorf last?
For my needs the room correction may be a winner.
Thank you

@uberwaltzi used the Classe for all my video sources and my DAC.  It worked very well.  If I wouldn’t have tried the Esoteric I could have lived with the Classe for a long time.  I didn’t use the internal DAC or streaming capability though.

D-Class amps?

Commercial break:

https://www.audiogon.com/listings/lis8f7f8-ps-audio-stellar-m700-mono-block-power-amplifiers-pair-in...

@sfseay.

I am looking at the classe 2200I right now considering a purchase.
How did you find its performance on digital sources? Very interested in your thoughts on this

I have tried a several Class D amps over the past 18 months.  I have owned a PS Audio HCA-2, Classe Sigma 2200i, Lyngdorf TDAI 2170, and now have an Esoteric I-03 integrated.  

My ranking in in order of preference is:
Esoteric I-03
Classe Sigma 2200i
PS Audio HCA-2
Lyngdorf TDAI-2170

I can’t imagine ever imagine getting rid of the Esoteric!  Wonderful imaging, dead silent, and tons of power.  This 68 pound tank blew me away compared to the other three Class D amps I’ve owned, or any of the other amplifiers I have auditioned/owned for that matter.

tweakjunky
I struggle to understand why this tech isn’t more prevalent today.

Because mainstream semiconductor manufacturers like Motorola, Hitachi, Sanken ect, haven’t tooled up for it yet, probably because the inventors of the GaN devices EPC (a small company in comparison) I would say have a provisional patent on it, who were if you dig deeper from what I’ve found maybe also the inventors of the Power Mosfet transistor as well way back.
And are now maybe waiting for the best offers from the big boys above. Till then they are probably happily supplying in small numbers to Technics for their SE-R1 poweramps.

tweakjunky
Am curious to open my amps and check the components but given the heatsinks present I suspect it’s not based on GaN tech.

Only the $20k Technics SE-R1 has them so far, and you need connections to get one.

PS: Just dug up the link to EPC being the co-inventors of the HEXFET power MOSFET back in the day.
https://epc-co.com/epc/AboutEPC/Team.aspx


Cheers George