High end Class D amps?

I see a slight problem in Michael Fremer’s review of the PSA amps...he and Paul McGowan happen to be very good friends...so..for reality’s sake...I would take that review with a grain of salt.

It's Fremer. If a dog looked like a turntable, he would claim its bark sounded like Pavarotti. I take anything he says with a bottle of salt.

noble,


as an X maggie 3.5R owner, I wish I was aware of this back then. Consider posting this in magnepan threads too

OMG

'Now excuse me I’m going back to the workshop to finish off my 1973 Ducati 750 sport (round-case) engine main bearing replacement.'

so there is something to like about Gfi

Ha! Photos or it didn't happen. If he wants a classy Italian early 70s motorbike that he can actually ride without fear of it stranding him, maybe a Laverda instead of a Ducati. A Laverda from that period is far more reliable, far more likely to still be running this whole time, whereas a Duck has probably spent most of its time in boxes, moving from garage to garage.


I sold off my motorbikes except for my Moto Guzzi LeMans (which will probably go on the chopping block this spring). I was getting too fat so I switched to bicycles.

Ha! Photos or it didn’t happen.

Really more digs? You are the pits Ralph.

None of the 750 Sport as yet all it’s in bits in my workshop, but here are two shots of my Desmo 900 Super Sport I also restored slightly modded, and sold 10 years ago.
https://ibb.co/sw59hSw
https://ibb.co/vmR8gbH

As for Moto Guzzi, they’re ok, had one of them also, a 1000 sport, same as this but black
https://mcn-images.bauersecure.com/upload/967/images/1440x960/166690@Moto-Guzzi-1100-Spor.jpg?mode=m...
nice looking built like a tank, but they ride like a tractor with their odd vibration, not being naturally balanced. The Ducati’s are superior in all departments that matter to a rider.

The rogue sphinx is a nicely designed class D/tube hybrid integrated. A very tastefully done design and no nonsense looks. The top of the line Marantz integrated is of a class D design. Not certain but I think it’s the PM 10. Also, the well reviewed Ruby integrated by Marants, designed by the late Ken ishiwata, you guessed it, class D.

Really more digs?

Ducatis like the 900 you had look fabulous; there's a few of those here in town. Apparently every single one of them emerged from boxes, and as you pointed out, your 750 Sport (also a fabulous looking bit of Italian dreamwork) is in boxes as I write this. That's where most of them are.


OTOH most of the older Laverdas you see in town have been in service (not boxes) since they were built (to be clear, there aren't nearly so many around). Ducati certainly is one of the few to make the Desmo drive work, but if its about riding across the country (here in the US that can be 1000s of miles) I'd prefer to do it on a Laverda even though some of their parts are harder to find (they vibrate more too), simply because it will hold together (I had both the 750SF2 and a Jarama 1000 triple). Ducatis and Moto Guzzi as you know share the same top end angles between their cylinders so vibration harmonically cancels; i.e. 'naturally balanced'.

 'naturally balanced'.

This statement is not correct!
And as far as Laverda's go your lucky to keep your fillings in your teeth after a ride.

Moto Guzzi's  feel very similar to the BMW horizontal flat twin vibrations, both are no-where near as smooth as he V Twin Ducati.
 

Ducatis and Moto Guzzi as you know share the same top end angles between their cylinders so vibration harmonically cancels; i.e. 'naturally balanced'.

This statement is not correct either. Ducati's V-twins are perfect balanced because of the counter weighting that can be done (my mistake saying they were "naturally balanced")

Ducati:
The first thing is that Ducati V twins have or 90 degrees. This uniquely makes it possible to balance a 90-degree twin with counterweights of 100 percent of one piston's shaking force.

Moto Guzzi: 
"There are two aspects to our Moto Guzzi engines. One is that they are "fairly" vibration free compare to some other twins (like HD and old British twins) but "they still have secondary vibrations". But that is also separate from the side to side torqueing vibration of the motor that is more noticeable when you get on or off the gas but is always there." "Guzzi parts are not well balanced and the transverse layout also contributes...the late, great Gordon Jennings felt that transverse engines seem to vibrate more.."

You want to talk smooth motorcycles? My 1996 Yamaha Royal Star Classic Cruiser (purchased new out the crate)  is 4 cylinder

Moto Guzzi's feel very similar to the BMW horizontal flat twin vibrations, both are no-where near as smooth as he V Twin Ducati.
 

For along time the 916 was my dream bike. Then a friend let me ride it and I never wanted to ride one again. It vibrated more than my Guzzi, the seat was hot and I nearly threw the thing on the ground trying to turn into an entrance ramp at slow speed; I was unprepared for its limited turn radius.


Actually you can get the Laverdas to be quite smooth (but not as smooth as a 90 degree or 180 degree twin). The trick on the triples is a computer controlled timing advance. It also helps to weight the ends of the handlebars. With the twins they are actually well-behaved on account of the pistons being 180 degrees apart when firing, and a well-weighted flywheel. Despite all that, they hold up extremely well.

Michael Fremer says it drives the Wilson’s very well? I have not read the review yet. OH NO, this cannot be. George will never talk to us again.

You believe Fremer on any PS audio product? good luck with that

I see a slight problem in Michael Fremer’s review of the PSA amps...he and Paul McGowan happen to be very good friends...so..for reality’s sake...I would take that review with a grain of salt.

You can say that again.

JA bench tests found this PS Audio amp’s distortion rises very quickly into 2ohms, about 3 x higher even only at 1/3rd it’s output power, would be nice to see what the distortion would be then with the Alexia’s 0.9ohm!!!

And as for wattage power tests into 8 and 4ohms yes it does well, just like any Class-D, but JA didn’t post up any test or mention into 2ohms, and you can only guess why, as he nearly always does with linear amps.

JA
Like he did with the smaller A-Class Gryphon Essence poweramp
8ohms 53w (all in Class-A)
4ohms 101w (said to be all Class-A as well)
2ohms 182w

Cheers George

Also the linear Soulution Amp
135W into 8 ohms
260W into 4 ohms 
490W into 2 ohms 

Not many Class-D's have I seen JA do 2ohm loading wattage figures on, in fact can't remember any.

Cheers George

aolmrd

I bought a pixie dust sprinkled EVS 1200 dual mono from tweakaudio roughly a year ago. Prior to buying it I had the PS Audio M700s which I liked quite a bit, but my quite large room needs even more umph which the EVS1200 delivered in spades- no tube input needed, or wanted. Best was it was a mere $2300 (~ the same price as the M700s). Since PS Audio went direct, IMO, they should reduce their prices to reflect the 40% dealer markup, so while Micky F was very impressed, they are not the bargain they should be, and I doubt they would rival tweakaudios version

Class D done right can sound very good.. I had the Bel Canto Ref 600M based on the hypex 400 modules.  cool running, silent and very dynamic. I replaced my BAT VK75SE with them..
I had them paired with some Focal 1028’s and found them to be too bright on top,  Just couldn’t listen for too long without turning it down or fatigue, Not a great match for my tastes.. 
I moved to a Pass Class A amp and now I have more heat, mass and cost.. but Now I have music I can listen to for hours on end.. 
Well worth the trade off I’m afraid.. 

@mikem

Class D done right can sound very good

this is of course the correct answer... like any technology/format it is in the implementation quality, skill of the designer, the care in the voicing

over 300 posts in this thread... much heat very little light

people bellyache why a sub 1000 dollar class d amps sounds like crap... well there are cheap class ab amps and tube amps that sound poor too...  true for more expensive ones too...

Hello mikem,

     As I understand it, many class D power modules have traditionally had rising distortion levels as the frequency being reproduced increased.  This is what led to these amps sounding a bit overly bright or harsh in the upper treble region and listener fatigue.  I think this is what you were perceiving.
      I believe the new Purifi class D power modules, designed by Bruno Putzeys, have claimed to have solved this problem by significantly reducing distortion in the upper treble region through the use of global negative feedback levels in excess of 35%.  Figuring out how to successfully do this has proven to be a very difficult thing to do and is, therefore, considered a technology breakthrough.
     However, I'm not an expert on this subject and make no claims of having a complete understanding of it.  Actually,  I find this whole topic a bit perplexing based on my class D experiences.  For example, I use a pair of D-Sonic M3-600-M monoblocks in my system that are now over 6 yrs old and utilize Anaview/Abletec power modules that are at least as old technology wise.  Why do these amps provide upper treble frequency performance in my system and with my main speakers that is, according to my perceptions, very detailed and revealing without ever sounding harsh or bright?
     Do these amps or modules utilize some alternative method or technology to provide such high quality levels of performance?  Perhaps I'm boasting a bit about the high quality performance levels of these amps,  but the main factors influencing my inquiries are curiosity, a search for logical and reasonable explanations and the attainment of knowledge and understanding.
     My suggestions for you, mikem, are that you are likely to find very good class D amp options in a new Purifi module based amp, a new or used D-Sonic amp or amps or even other high quality class D amps.  As other experienced users have already mentioned, not all class D amps sound the same and I'm certain they all don't reproduce the upper treble frequencies in an overly bright, harsh or fatiguing manner.

Best wishes,
   Tim
      

@noble100  Thanks Tim.. Appreciate the response, but I’m not giving up my Inefficient, heavy Pass class A amp anytime soon..  It sounds too good and checks all the boxes that I find important in an amplifier, and it’s executed so very well. Appreciate the response and Happy Holidays !!

@jjss49  No doubt class D is getting better with each  iteration..  I’ve had several of them, Tripath, ICE, Hypex ..  Yet I will continue down the road of linear PS, inefficient Class A topology..  Experience has shown me that Class A gets the vocals,  textures, etc more Lifelike than other topologies..  Bruno Putnzey has really improved the Class D sound.. I’m sure it’s only going to keep improving too.. Each class type of amps have their strong and weak points.. like everything else.. I’ve moved on to different speaker/amp combination and I’m now enjoying music more and topologies less.
Happy Holidays !

If all you have heard is a stock Bel Canto Ref 600.....then you have no idea how good the latest class D is. The Ref 600s use a stock Hypex power supply, a stock Hypex NC500 module and an input buffer that is an integrated circuit powered by two three pin regulators.......and this is for $6K per pair. Now, Bel Canto has updated this amp (now called an e1x)) to make it a stereo amp using the same stock NC500 modules and a single Hypex power supply but finally they made their own discrete front end buffer for the amp......this amp is also $6K and you can read a review (that is completely worthless) on Stereophile. Let’s look at what VTV does....They will sell you a stereo amp with two Purifi modules (slightly better than the NC500s), a single Hypex power supply and their own discrete input buffer board with say Sparko Labs discrete buffers.........basically the same configuration as Bel Canto and the cost is $1500 delivered (including shipping) and 30 day money back. One quarter the price!!!! My modifications to the VTV amp cost $1050 bringing a totally tweaked Purifi based amp to $2600......less than half of Bel Cantos latest thang. The mods completely transform the amp. I actually mod the Purifi board (change the output coils to super OFC air core coils, use better caps on the output filter and bypass the power supply with modified Wima caps).

Bruno is just one of many people who are pushing class D further. The Merrill amps, the AGD amps, the new Technics amps ($10K pure digital integrated coming early next year...OMG!...check it out!), the Cherry amps, New Class D amps, etc. etc. are all fantastic sounding and completely designed by other people. The Purifi module is not "pure" sounding. My mods make it way more "pure". This game goes on and on. As these latest amps (and about to be released amps) get out for more people to hear then the reality of what class D is doing now will finally be known. I will be sending out one of my modded VTV/Purifi amps on tour......so get in line to see what is possible.

Class D is coming of age. Some are still too expensive for most (like the Merrill and AGD amps).......but my modded Purifi and soon others at $3K or less is what we need. The (to be released in Feb.) pure digital class D Technics integrated at $10K...is a preamp, amp, DAC and phono stage with wild distortion reducing stuff in it......so, it is really not that expensive (and you save space, have only one power cord, and no interconnects).

Class D is coming of age.

Yes when you have this sort of GaN technology with Class-D amps like the flagship Technics SE-R1 with it’s 3 x higher 1.5mhz switching speed, to fix the Achilles Heel of all class-d’s, in the upper mids/highs that many complain about after living with them.
And hopefully they’ve carried this switching speed onto their new integrated flagship, yet to be released (Feb-2021) SU-R1000 Integrated.
https://forum.audiogon.com/discussions/technics-su-r1000-a-new-class-d-gan-technology-integrated

mikem:"  Thanks Tim.. Appreciate the response, but I’m not giving up my Inefficient, heavy Pass class A amp anytime soon..  It sounds too good and checks all the boxes that I find important in an amplifier, and it’s executed so very well. Appreciate the response and Happy Holidays !!"

Hello mikem,

     No problem, I was never trying to talk you out of your excellent Pass amp or the very good performance of the class A topology in general.  I was more thinking you may want a much cooler running amp, also with very good sound qualities, as an alternative for the warmer months.

Enjoy and Happy Holidays to you, too!
Tim

Ricevs, I believe Millercarbon has already claimed the title of Master of self Promotion. Perhaps you can choose a new title?

There is nothing wrong with a 3 terminal regulator if followed with adequate filtering. It will be sonically transparent especially if driving a stage with feedback.

I am sure you have measurements that justify your claim of "purer"?

It's problematic for class D when Bruno P. himself in an interview states that if you don't care about efficiency there's no reason to get anything but class A.

There is no perfect "Class".  All amps sound different....no matter what the class of amplification is.  All classes are imperfect.  All need tweaking. If this were not true then we would be all using 1977 Pioneer receivers.  Everything has gotten better.....all classes are improving.  A great class A is great......a great class D is great.  A not so good class A is not so good.  A not so good class D is not so good.  Every single thing needs to be done at a super level.  I have never seen an amp that I could not improve.  Just the binding post bypass system will improve any amp.  There is no end.  We have only just begun....enjoy the ride!

He also says audiophiles are wasting time playing with preamps, amps, cables, etc, while ignoring room acoustics and speakers. The real audiophiles keep saying it's all about room acoustics and speakers. The ones that start threads and blather on about cables, fuses, cable risers, etc., Etc. .... We'll make your own conclusions.

https://www.soundandvision.com/content/bruno-putzeys-head-class-d-page-2

"Real Audiophiles?"  Who is to judge that?  Audio is every man for himself.  There is no criteria for who has the best sound, or how to achieve it.....as it is all subjective.......the opposite of drag racing.....where most everything is known by everyone and tested by clocks.  Best to not rely on ANY one persons opinion.......but base your truth on your own direct experience.  All amps that measure the same sound different....all speakers that measure the same sound different......which do YOU prefer?  That is what matters.......

No all regulators do not have "a sound". Circuit implementations have a sound. Even a properly implemented low cost 3 terminal regulator implemented properly will be sonically transparent.

So what you are saying is NO you don’t have measurements. So pure is just your personal taste, not an accurate unbiased assessment. Thank you for clearing that up.

At an electronic level pure can be measured. Given you have no measurements your claim of pure is only that, a claim. You feel it is. I may think it sounds more colored.

I am judging. Too many audiophiles claim to be seeking sonic accuracy because they tweak this or tweak that, meanwhile their listening space is a disaster and they have more money into cables than their speakers.

There are so many highly experienced audio pros in this thread that I still get a little overwhelmed by the technical talk, specs, etc. So after reading all the responses, here's what I'm thinking---so I have a pre-out on my Luxman 505uxii integrated and I have a pair of power hungry Dynaudio Special 40s. I am thinking of adding a class D to help the little Dyns and this is why I started the thread. Between looking at the Dynaudio S40 specs and the class D specs, I'm not sure which one would be better (or all of them). Let me know what you think. Also, I've never tried monos so that sounds interesting (budget is < $3k)
1. D-Sonic M3a-800 s (stereo or mono)
2. Wyred 4 sound ST500 Mii (stereo or mono)
3. Nuprime ST-10 or ST10M (really looks interesting)**
4. Bel canto REF500s
5. Red Dragon S500 (all sold out for now but Ryan at RD emailed me and said the Mk3 will be coming out in Q1 of next year---COVID has slowed everything down)

All have great reviews. I think all of them have 3-5 year warranties and pretty good customer service. I appreciate your thoughts and suggestions. 

You should really add these to your list.
https://www.cherryamp.com/
Also, take a look over at AudioCircle; there are a number of active forums from Class D manufacturers and a variety of other threads.

The Luxman is more than enough to drive those speakers.

djones51
The Luxman is more than enough to drive those speakers.

Ditto. bluorion OP
Just look at the impedance/phase curves, absolutely no problem for the Lux, and it will sound better that any class-D on them, to boot.
https://www.stereophile.com/images/918DS40fig01.jpg

Cheers George

I'll wait for Atmasphere's amps.
If he can do for Class D, what he does for tubes, then I know it will be so good that I don't have to bother looking at other amps.
B

bluorion OP gdnrbob
As I said your Lux is more than fine for that speakers load and probally better than any Class-D.

But if your insistent on getting a Class-D, I’d wait for mid February to see what this new all out Integrated is all about, and if it follows the design set by their Flagship poweramp, it will be something special.
https://forum.audiogon.com/discussions/technics-su-r1000-a-new-class-d-gan-technology-integrated

Cheers George

I'm an early adopter of Boenicke's new P1 class D amp.  It's basic, but it does it very well.  Pair w/Boenicke W8SE+ speakers on a swing base; you'll be blown away.  

https://boenicke-audio.ch/products/electronics/p1/
          300 W into 8 Ohms

• Mechanically tuned Powersoft amplifier module
• Chord Company Shawline AC power cord directly soldered in (10% silver solder), no screwed or plugged contacts!
• 3 LessLoss newest generation Firewall filters in AC input
• Custom – made AC softstart module on FR2 circuit board, trimmed to exact resonator length
• Bybee Small GOLD Slipstream Quantum Purifier filters in the audio input
• 3 proprietary resonators installed (16-cm parallel spiral resonator, 16-cm series spiral resonator, new 2 cm series resonator)
• ETI Research RCA input sockets
• LessLoss internal cotton-covered wiring
• Black Ravioli Small Pads feet
• High-End, orientation optimised Refine Audio fuse installed with unique contact enhancing agent
• Solid walnut backplate. No, aluminum does not sound the same.

@greenwichct How does it compare to linear amps? What's your frame of reference?

So basically, it's a fire hazard?

Solid walnut backplate. No, aluminum does not sound the same.

Usually statements like these are made by people who do not like tweaking.  So they make something silly up.  The power supply in that amp is way away from the back panel.  The power supply (a switching one) is completely self protecting......it shuts off if there is over current/over voltage, too high of temperature, DC offset, etc..  Also there is a fuse on the power supply.  There is no "fire hazard".....same with having cotton covered wires inside.  If you don't understand or like something....then attack it......the ego says.  The heart says....what does this do?  Maybe I don't know everything.  Maybe I should keep my mind open till I have tested this with my ears.

So, uh, why can't anyone ever describe what their mind-blowing revelatory class D amp sounds like vs what linear amps they own? I do that all the time.

I have first watt J2 and F6 and also have Theta Prometheus class D 400 watt monos.  About as polar opposite as you can go.  I have great thoughts of both he first watt and Theta.  For sure class D can sound good anyone who lays a blanket statement over class D amps sounding bad period just ignore them.  Find out for yourself.  There are many pluses to them namely that they don't heat the damn house up.  I don't care in the winter but in the summer hot amps are a drag.  Can't be a tree hugger and love class A can you? maybe you can do carbon offsets to make up for it!  Also all this stuff about Michael Fremer being a shill for PS Audio I'm sure these keyboard warriors on Audiogon Forums are so enlightened I'd put a lot of faith in what they say.  

....yup, devolved into a variant of the old 'IC/speaker/AC line type/taste squabble.....with random snipes...*sigh*

Try using a wooden j-box in your house and telling the electrical inspector he is an idiot because the wires inside it are insulated.

There is no "fire hazard".....same with having cotton covered wires inside.

... It won't work with the safety inspector nor UL, ENEC, etc.

All those protections on the supply are not definitive protections from catastrophic events. There is a reason why electrical products are encased in metal or fire retardant plasics.

A catastrophic event ..he he... is when you win the super duper lotto.  That is about the same odds as a wooden backed amp has catching fire.  When have you heard of an amp that caught on fire? (I have read about 2 in over 50 years....and no bodies house burned down).. And if it did.......did it have wood on it?  The answer to the above is practically never and never.  We worry about silly things.  By the way, fuses do not help with lightning.....the fuse blows and so does your component.  Maybe you mean putting a bomb in the amp?  That certainly would be catastrophic.  Maybe we can get back to how various amps sound instead of worrying about a wooden back plate.  People have different philosophies about what is safe.......some would never do anything without someone else telling them it was safe.  Some rely on their own intelligence.  Some hide in caves.....some dance in the light.  Fear and ignorance is what keeps people from being happy.  Trust your self....and dance in joy!

So I'm confused about the little Nuprime ST10 amp (which has gotten rave reviews btw). Its output is rated at 150wpc at 8 Ohms and the same at 4 Ohms(??). Plus it has a toroidal transformer. Does that make it a hybrid of sorts? 

madavido
The problem with Putzy's quote is that many aspiring a'philes cannot afford class A $$$$$, not just the initial purchase, but also the cost of electricity to run it, and cool it, especially if the owner lives in a warm climate, as I do. Way back when (some 25 years ago) I owned a Kinergetics KBA 75 (all class A), which was amazing, and the only amp of many I tried that could grab a hold of my Genesis Vs and make them play properly. Sadly I blew it up changing power cords without letting the caps discharge


Next, consider most rooms are far from ideal as listening rooms, meaning playback is compromised from the get go. My most recent Ds were Audio Alchemy DPA-1, PS Audio M700s; both sounded quite good, but lacked the drive my large room requires. The back wall (behind me)  from my listening position is 3 sided floor to ceiling glass ~ 15ft away, so zero back wall reinforcement

My EVS1200 (~1200 wpc in 4 ohms) does a great job of conveying all the musical ques to my Emerald Physics 3.4s, though over the weekend I reinserted my 2 SVS powered subs which helped considerably to fill the space with a decent SPL

hth

greenwichct

I am envious of the Black Ravs. I heard them here. They were extraordinary, especially the doubles, but too rich for my blood

@bluorion  I recommend you google a few basics on Class D amps.  First of all, the D does not stand for digital; A, B, and C, were all already taken, so it was simply the next letter in the alphabet.  A class D amplification circuit has a different topology/operation from the others.
Simplifying a lot, you'll find that many of the amps for sale contain three basic elements, an input buffer, the amp proper, and a power supply.  There's a lot of mix and match with these three elements.  There are different kinds of input buffer, and even ones that incorporate a tube.  There are different amp modules, from Purifi, Hypex, IcePower and several others.  There are switching-mode power supplies and linear power supplies; a subset of linear power supplies is those that employ toroidal transformers.  Some makers allow you to "assemble" your own amp on their website selecting from the available alternatives.
From here it gets a lot more complicated.  There are some genuine digital amps (not that many), and the next big thing will likely be GaN amplification.  All of these terms are googleable.

My baseline was a six year old McIntosh MA-7900 which was lovely and warm, in addition to being easy on the eyes. My speakers were B&W 804Ds -- pretty mainstream... That said, I’m in a new home office and while generously proportioned, I need an amp with a much smaller footprint.

Engaging the folks at Boenicke in Basel for advice, Sven responded directly and suggested that, if patient, I could be an early adopter and trial the new P1 amp (Class D).  I’m running his W5SE+ speakers (ridiculously expensive) and sold on their standards of excellence, so I waited...

Now being a month into enjoying the setup, I’m enormously pleased. I’ll next upgrade my W5’s to Boenicke’s W8SE+ floor standers (on a swing base). The W8’s footprint in relation to the W5’s on stands is only modestly larger, but the added volume delivers what can only be heard to be believed.

https://boenicke-audio.ch/products/electronics/p1/
https://boenicke-audio.ch/products/loudspeakers/w5/
https://boenicke-audio.ch/products/loudspeakers/w8/

@twoleftears Thanks so much! I'm still trying to learn. :)