Time to buy a class D amp?

No.

Has anyone had AM/FM reception problems when using Class D amplifiers?

Hi,

This is in response to the original post of Niodari.  I have the same setup but for power amplification I use M700 monoblocs.  For my digital front I have the DirectStream with Bridge II, and for my analogue front I use two turntables with PS Audio's Stellar Phono Preamp. I enjoy listening to Jazz and Classical.

Before considering a new amp, may I suggest looking at interconnects, and speaker cables as well as the incoming power line for interference from any transformers / adapters that are connected in parallel. I would start with the power conditioner and the devices that share it with the pre - power combo.  

One of the options you may want to test-drive is Van Den Hul The Second in XLR format. Linear Carbon has unique audio characteristics. Once you have exhausted the possibility of improvement with interconnects, you may wish to test-drive your speaker cables. There reasonably priced very good cables from AudioQuest, Tellurium Q, QED, Black Rhodium, and Chord Co.  

Hey Ziggy,

     Agreed.  My 1st class D amp I bought about 6 years ago, a Class D Audio SDS-440-CS, came with a 28 day in-home free trial.  It sounded very good straight out of the box but it kept improving in sound quality well past the trial period.  I think its important that prospective class D amp purchasers are aware of this 'break-in period' which may last up to several months.  
     I'm still not even sure if the class D amps require a break-in period or the listener/buyer actually needs an adjustment period to get use to the sound of the amp.  From my perspective, I noticed immediately that the amp was a big improvement over the good quality class AB amps I had previously used for decades (Adcom, Aragon and McCormack) that was pleasantly surprising in its quality but I also sensed it was a fundamentally different listening experience that I thoroughly enjoyed.
     It was initially hard to describe what specifically the sound qualities were that gave me a sense of being fundamentally different but the more I listened to the new class D amp, the more it became apparent exactly what these qualities were.  The major sound differences I identified were an extremely low noise floor that gave the impression the music was emerging from an inky black and dead-quiet background, improved bass impact and dynamics, a more neutral overall presentation that also was more detailed from top to bottom and a smoothness to the midrange and treble response without brightness or harshness and the ability to portray a solid 3D soundstage that's at least the equal of my previous class AB amps. 

     All of the above just further supports our advice for auditioning any amp one's considering in their home and system prior to buying when possible.  I just wanted to let prospective class D amp buyers about what to expect.


Later,
Tim

Yes for sure, that's what I was trying to say.  At the end it's all about what is sounds good to you in your own system.  Pretty much it!

A few days really doesn't do it justice either, to your point, an extended trial is important.

eziggy:"Last I checked this is about listening to music not about technical specifications.  All components will sound different paired with other components.  As with anything high end it is best to demo it, preferably at home and see how you like it."

  Hello eziggy,

     I agree, auditioning a class D amp, and really auditioning any prospective amp, is best done in your room with your own other system components.  I also agree with Erik that using a dowsing rod would likely be an ineffective method for choosing a system amplifier.  Critical listening to an amp prospect, preferably during a multi-week in-home trial period if you're able,  is probably the better method.

Tim

Last I checked this is about listening to music not about technical
specifications.

When you keep using specs which are unproven to related to listening experience one way or another, you might as well be using dowsing rods.

Last I checked this is about listening to music not about technical specifications.  All components will sound different paired with other components.  As with anything high end it is best to demo it, preferably at home and see how you like it.

Many people love the sound of class D.  Just look at Bel Canto’s Black line.  Many people absolutely love their unique approach to combining DAC, preamp, and amps in one system.  I have been eyeing their Black EX Integrated, just haven’t gotten around to demo it.

    Hah!  Words of sardonic wisdom.  Well said, teo_audio.


Tim

The class D landscape will quite possibly change in the next 12-24 months....  
All these issues of contention may be going bye bye.... (and then we can bitch about something else, as we will do that regardless)

If it has a switching carrier frequency of about 1.5 MHz, perhaps georgehifi may even be interested.

No it's only got 500khz similar to everyone else with the same associated phase shift problems, but they advertised it as "very fast 500,000hz switching" just to intimate it's even quicker, "but 500,000hz is 500khz", that was fixed in their ad once pointed out to them.
So you draw your own conclusion to what kind of manufacturer they are for tying one on.

Hello niodari,

     I believe most internet direct class D companies ship worldwide without too many exceptions but I'm not certain, you may want to call or email and ask.
     I agree the LSA amp looks very interesting. If it has a switching carrier frequency of about 1.5 MHz, perhaps georgehifi may even be interested.
     I'm currently very pleased with all my the class D amps I use in my system.  I strongly believe they have so many positive attributes it will be hard for them not to be the predominate amp technology in the near future.  
    At their current stage of development, I understand some preferring to use their beloved class A, top of the line class AB or tube amps.  Of course, class D has no current monopoly on high quality performance. 
    However, it's apparent that class D technology performance quality has been improving at a faster pace than the technology the more traditional amps are based on.  I envision this fast paced improvement in the performance quality of class D technology and amps to continue for the foreseeable future.  Eventually, even those afflicted with the worst cases of amp-type bias will relent in favor of improved audio quality.  Perhaps it may result from class D amps incorporating DSP circuitry that is able to mimic the sound qualities of state of the art class A and tube amps at the press of a button.


This should be fun,
        Tim

@niodari

As you can see, more and more people are making class d amplifiers...or about to make class d amplifiers.  Unless you plan to hold on to it forever...or don't care about massive depreciation when you resell, I'd suggest you buy one that is well reviewed (much easier to resell) and which you don't see being offered for resale very often (meaning people tend to like them and hold on to them).

As for a 30 day trial period for a product shipped to Mexico....maybe it won't be possible....meaning it is even more important to buy a product with a good reputation that will be easy to resell if and when the time comes.

Good Luck

niodari 
I am not sure about Red Dragon as they (S500) seem to be not so tolerate with low impedance speakers

Not just Red Dragon, look at any Stereophile lab test on class-D for 2ohm loading and they either. 
1:switch off and go into protection. 
2:or they don't even bother to test them because they go unstable. 
3: or their performance is very average and actually go down (have less) in total watts with 2ohms compared to 4ohms. When they should if strong with good current ability go higher by at least 1.5 x's compared to 4ohms wattage.

Cheers George

Guys, perhaps, "time to buy a class D amp" is closing up... :)

Interesting developments in class D, did not think there are so many (new) brands producing class D amps listed in this thread, e.g.,  the last one, Voyager GAN 200 power amplifier at $2500 looks interesting (I think they could have a better ratio performance/price than Merrill amps). Their serial production is planed to begin this December, as Walter Liederman has notified. 

Tim, I am keen to audition D-Sonic amps (unfortunately, they are not so flexible in sending their stuff to Mexico where I am currently living). I am not sure about Red Dragon as they (S500) seem to be not so  tolerate with low impedance speakers (one below 4 ohms, see an earlier post in this thread), don't know about their new series amps that will be released soon.  Let us keep each other informed. 

Cheers

Nodari

Hello niodari,

     Everything you said in your last post makes perfect sense to me.  Even though I've never heard the Merrill Veritas, I consider them one of the best examples of how well class D amps can perform because all of the numerous pro reviews I've read consistently state they are excellent amps regardless of amp type and price.  

     I wasn't willing to verify this at a price tag of $12K/pair but I'm seriously considering it at $5K/pair.  However, I can verify that other class D amps offer very good performance at a much lower price.  I went this route, initially buying a Class D Audio SDS-440-CS stereo amp for $630.  This was my first D amp and I was stunned by how well this amp performed with my Magnepan 2.7QR speakers, better in all aspects than the high current class AB McCormack and Aragon amps I'd previously used that I had paid over $2K each for.  It was also about 1/3rd the size and weight, ran much cooler and sipped, rather than gulped, electricity.
     For the past 5 years, I've been using D-Sonic M3-600-M monoblocks($2,100/pair new) on my Magnepans and have been very pleased.  They're very powerful (600w@ 8 ohms, 1,200w@ 4 ohms and, I believe, stable down to 2 ohms), have great bass, powerful dynamics and a detailed but very smooth midrange and treble that I never perceive as bright or harsh.  I bought these with a 28 day free in-home trial period, they sounded very good to me right out of the box and I never considered returning them.  I did notice an occasional brightness on the upper treble but this completely disappeared over during the first few months of usage.
     I believe the D-Sonic amps should be on your short list of class D amps to audition along with the Cherry models.  If you can wait a few months, Red Dragon has stated they'll be introducing an all new lineup of stereo and monoblock amps by the end of the year.  I haven't heard of any details about their new amp lineup yet but suspect these may be good candidates for you to audition, too.


Good luck,
  Tim

Has anyone posted this yet $2500  https://thelsagroup.com/products/lsa-amplifiers

I have been very happy with a Wyre4sound St 750le. You can check it out on 10 Audio's review site. He favorably compares it to a single ended tube amp sound and gives it a 9.5  rating.

Hey Tim. An important attractive side of class D amps is their low price 
and high ratio performance/price. I am not sure if for Merrill class D amps this is also true. Neither you nor me have auditioned it, given their price, they should sound almost magical to have a high ratio. Buying   Merrill amp would be similar to buying a very expensive electric car. I have a hybrid one which did not cost much more than similar non-hybrid onces, this made a sense. Demo Cherry amplifiers are on sale, some of them cost nearly the half of their normal price. If their sound quality is somewhat close to  Merrill class D amps (at least, not too far), ratio performance(Cherry)/price(Cherry) >> performance( Merrill)/price( Merrill)
even considering used price. And, perhaps,  older Veritas series amps are not magic sounding (if not, why they have changed the profile of their class D amps?). I am curious to compare SQ of Cherry,  ATI, Veritas and Element amps

Hey niodari,

     If you're looking for the highest performance/price class D amp and don'[t mind buying used, I think the Merrill Audio Veritas monoblocks are a great option to consider.  Reviews on these amps claim they're among the best performing amps available regardless of amp type or price. They sold new a few years ago for $12,000/pair but I've recently seen numerous ads from owners with an average asking price of about $5,000/pair.
     Merrill audio recently came out with a new lineup of Element amps utilizing extremely fast switching GaN transistors that virtually eliminate 'dead-time' which significantly reduces distortion and improves sound quality. These include the Element 114 which is a stereo amp priced at $15,000 and 2 monoblocks,  the Element 116 and Element 118 priced at $23,000 and $36,000/pair respectively. 
      I'm thinking  the reason numerous ads are appearing for used pairs of Veritas amps is due to current owners of Veritas monoblocks planning on buying one of the Element amps and are selling their Veritas monoblocks in preparation. I strongly believe you'll prefer the sound quality performance of the Veritas amps over the Cherry amps but I can't know this with certainty.  Here's one of many good reviews on th Veritas:

https://positive-feedback.com/reviews/hardware-reviews/merrill-audio-veritas-monoblock-amplifiers-are-all-class-d-amplifiers-the-same/


Tim

Thanks indeed, Tim and @snapsc for your comments! 

I did not know, Tim, that all these brands produce Class D amps.
It would be virtually impossible to verify all of them (but will make a search for some of them) and given that i live in Mexico, buying and returning would not be really feasible. 

Although I am not yet completely convinced that it is already time to buy (another)  class D amp, i am still desperate to try one more because i like class D concept. I listen to 2-channel systems (no home theater!)  and could take an option of a stereo amp or monoblocks. Naturally, i would only consider a candidate with a high coefficient *performance/price* according to my vision of class D concept. 

@snapsc, your impressions on 2-Cherry after trying two other (known for me) class D amps are important for me. I was also inclined to a Cherry amp. The biggest and supposedly best one is Megaschino  (should be very good at $6900 in class D), then comes Gold Cherry with the same price i think and Cherry 2 with a much more accessible price. My question is, which of these three models maximize ratio  *performance/price* ?
Did someone compare these three? 

snapsc:
"My advice...since amps DO sound different....and since class d amps are generally lighter in weight and less expensive to return....try 2 or 3 of them at the same time and send those back that don't give you the sound you are looking for....$50+- if return freight is nothing compared to getting to hear them in your home, on your system with your music."


     I think this is a good idea once you narrow your list down to amps you'd like to audition.  Most class D amps are sold internet direct and offer free in-home trial periods for a certain number of weeks stipulating you can return it for a full refund with no questions asked, and sometimes with free return shipping.  But I agree with snapsc that even paying a reasonable charge is worth it to hear it in your system and room.
     You could even add a column for "Trial Period" that lists the offered in-home trial period in days or weeks.  The only downside is that, in my experience, class D amps take a while to properly 'break-in' and perform optimally which could be longer than the trial period.  However, the three class D amps I own sounded very good right out of the box but still kept improving in sound quality over a number of weeks after until the sound quality stabilized at each amp's optimum quality level.  The danger being that the ultimately best sounding amp just happens to have the longest 'break-in' time and the in-home trial period was too short for you to discover this.
    All of my class D amps have been on 24/7 for over 5 years now and are still operating flawlessly (knock on my head).  I suspect their low internal operating temps likely only increases their lifespans but this currently lacks scientific, objective and independent validation.  If longevity concerns you, you could also add a column on your list for warranty length and terms.

Good luck,
    Tim

I've owned 3 class d amps over the past five years.  The Crown XLS 2000 at $500 did some things right and some things wrong: good low end, ok midrange, bright top end, huge soundstage but two dimensional, and somewhat blurred detail...but for $500....kept this amp for several years.


I also owned a Nuprime STA-9...their class a/class d hybrid said to emulate the tube sound; $700, better low end...better detail...slightly more three dimensional but somewhat bright (in my system at least) in the upper midrange and top end....kept this amp for a couple months.

Now I own the Digital Amplifier Company 2Cherry...$2400 (for the past 6 months)...and for that increase in price, you would hope/expect that things would be a lot better...and they are, the best amp (including tube amps and class a/ab amps) that I have ever owned (so far?).  Great detail, great clarity, great soundstage, life like realism (in my system with Salk loudspeakers with RAAL tweeters).  No weaknesses...not a hint of brightness.

My advice...since amps DO sound different....and since class d amps are generally lighter in weight and less expensive to return....try 2 or 3 of them at the same time and send those back that don't give you the sound you are looking for....$50+- if return freight is nothing compared to getting to hear them in your home, on your system with your music.

Hello niodari,

     I've never listened to any Cherry, Nuprime or ATI amps, but I've read good reviews on all of them.  I don't currently have any knowledge or experience that would lead me to think any one of them is the best.
     I know there are a lot of good quality class D amps, such as the ones you mentioned, as well as many others.
    My suggestion is to do as much research as you can on class D amps by reading audio forum discussions on class D amps as well as owner and professional reviews online.  Start a list or spreadsheet of all possible candidates that lists Company, Model Number, Type(monoblock or stereo), Condition (new or used),Price and a Notes section for important related info.  You can also do Google searches on particular brands/models to obtain more specific and even comparison info.
     I'll get you started by listing some good quality class D companies to consider and other thread readers, hopefully, will chime in with others to consider.  Since I don't know your budget, I can't currently limit my suggestions by price but it's very useful if you could post your budget as well as primary usage (music, HT or both), number of desired channels (monoblock single channel, stereo 2-ch or multi-ch with ? channels).
     Here's my starter list:

ATI
Acoustic Imagery
Anthem
Arcam
Atmasphere (first class D amp from this tube amp company.  Release date TBD.)
Bel Canto
B&K Audio
Cherry
Channel Islands
Class D Audio
Classe
Devialet
D-Sonic
Hypex (class D power module and power supply manufacturer for DIY amp kits) 
James Romeyn (Hypex NCore400 amp kit builder)
Kii Audio
Linn
Lyndorf
Marantz
Merrill Audio
Mola Mola
NAD
Nord 
Red Dragon (all new upgraded models coming late 2019.)
Outlaw
Peachtree
Primare
Purifi
Rogue Audio
Sunfire
Theta
Wyred 4 Sound


Have fun,
 Tim





    
     
 
 

Tim, did you audition Cherry amps (Gold Cherry, Megaschino etc) orNuPrime class D amps? Do you suggest that ATI class D amps could be better?  Thanks

As for ecological concerns, at low power levels, where most amps operate during most listening, even class D amps are inefficient.

This statement is incorrect. The efficiency of a class D amp is such that at higher power levels its power draw is similar to conventional amps. But at lower power levels a class D amp draws considerably less power!

darkstar on his ATI amp:" The sound is high end. Huge stage, precise images and natural timbre. The sound reflects the front end. Changes in upstream equipment are easily audible.
ATI uses a large linear power supply. No SMPS power. I listen about 12 hours a day. Every day. Jazz and classical primarily. No listener fatigue here."

     As an owner and user of D-Sonic M3-600-M monoblocks, I consider this a very good description of what to expect from the inclusion of a high quality class D amp or amps in one's system.
     I haven't yet had the opportunity to audition an ATI amp in my or any system, but darkstar's description of the ATI's performance characteristics closely resemble the performance characteristics that I've perceived in my amps over the past 4 plus years in my system on both 2-ch music and HT playback.
     I also read this Sound & Vision review on a couple of ATI amps that further supports their high quality:

https://www.soundandvision.com/content/ati-at527nc-and-at524nc-amplifiers-review
     I 've read that many of the ATI amps utilize the newer and highly respected Hypex NCore500 class D power modules.  These are likely an important contributor to the high quality sound performance.
     These ATI amps also utilize conventional toiroidal transformers as part of their power supplies.  It seems like some believe the use of conventional toroidal transformers in the power supplies of class D amps results in superior performance when compared to the newer switch mode power supplies (SMPS) used in other high quality class D amps.  All 3 of the class D amps I use in my system happen to have power supplies using conventional toroidal transformers but I've listened to many other class D amps utilizing SMPS.  In my listening experiences, I've never perceived any noticeable sound quality advantage of either power supply types.  
     Overall, I consider the ATI amps a very good high quality class D amp option that I also consider  a bit overpriced.

Tim

a bit bright and somehow dry, lacking warmness

That description applies to every class D amp I’ve heard, even those with tubes on the input stage.

As for ecological concerns, at low power levels, where most amps operate during most listening, even class D amps are inefficient.

Can someone please list the Top to Midrange Class-D options on the market at present and the relative MSRP?  The Merrill 118 is fantastic but tooooo expensive.  Give me some options <$10k and I'm not one that believes something is better just because it costs more so if you know of an outstanding $700 amp, bring it on.

The Amp will be used in a bi-amp system handling the frequencies below 200Hz so a high damping factor may be a positive... or not.

I'm interested in the views of this group.

Thanks @sumaato for sharing your experience with using different pres for PS audio Stellar S300 amp, and thanks @darstar for letting me know about ATI class D amp (yet unknown for me). Did you select an integrated one or otherwise which  preamp are you using? 

As to the use of preamplifiers,  I suggest that if the source signal is good (and it has volume control) then this signal does not need to be altered before it comes to a power amp. In general, why the source signal should be altered in case you have a good DAC?  I suppose that  a good pre should not alter the signal coming from the source. Its like if someone does not like a salted meal. You still give him a salted meal suggesting to add much sugar to it so that to compensate the excess of salt. As a result, you get much salt and much sugar (but you just wanted a meal without salt, that's all). 

Best, 

Nodari

 

Niodari, Check out ATI. They make ncore based amps from 2-8 channels. Come in 200 WPC and 500 WPC.
I needed 200 watts and 8 channels. Driving Linkwitz Orion speakers which use an active crossover. Each driver gets an amp channel.

The sound is high end. Huge stage, precise images and natural timbre. The sound reflects the front end. Changes in upstream equipment are easily audible.
ATI uses a large linear power supply. No SMPS power. I listen about 12 hours a day. Every day. Jazz and classical primarily. No listener fatigue here.
Enjoy
Kevin

This is wholly, completely, and utterly false, speculative, and prejudiced not only have some of us "listened' we have also actually "measured" using reliable, repeatable, objective measurement techniques that are recognized by engineers, scientists, and industry as fitting, proper, and appropriate but of course if you are happy with Class D you should absolutely enjoy it but you're reasoning, arguments, and suspicions are unfounded and false.

Wow. Because of the unqualified way in which this is stated, it renders the statement false.

I have a little Topping class D amp that makes 30 watts per channel. It has a lower signal to noise ratio than a Realistic SA-175 amp (despite the fact that the Realistic only makes 10 watts) we have in the shop that is rebuilt (being nearly 50 years old). In case anyone is wondering why I have an old Realistic amplifier hanging around, I put myself through college working at the regional Radio Shack repair center in the Twin Cities, and I enjoy troubleshooting and rebuilding work as a hobby; this amp is definitely a bit of nostalgia and its cute.  I rebuilt the matching tuner too.

In our work the main thing that we've seen that contributes to noise in a class D has to do with the encoding scheme- in our case, Pulse Width Modulation (PWM). PWM relies on the use of a triangle wave generator and a comparitor that compares the incoming audio signal to the triangle wave and thus has an output that is either on or off. If the triangle wave generator is not perfectly steady in its frequency, or if there is a bit of DC offset at the input of the comparitor, the result can be a bit of white noise hiss in the loudspeaker. With fairly simple techniques this noise can be reduced to noise floors that are less than conventional amplifiers.

I too, would be interested in your evidence to back up this claim. Of course there are low end class-D amps, i.e. cell phones, low end car stereos, etc. that are "noisy", but in general, class-D and variants of it are very low noise, and if direct digital, very low noise. This is not surprising since it is inherent in their operation. They don't suffer from amplified flicker noise, amplified Schott noise, etc. in the same way that traditional amplifiers do.

I am curious as to what measurement devices you used. Can you provide the make / model and perhaps what firmware version you were using at the time?



clearthink914 posts10-21-2019 2:16pmnoble100"Anyone who claims class D amps are noisy has obviously never listened to one"

This is wholly, completely, and utterly false, speculative, and prejudiced not only have some of us "listened' we have also actually "measured" using reliable, repeatable, objective measurement techniques that are recognized by engineers, scientists, and industry as fitting, proper, and appropriate but of course if you are happy with Class D you should absolutely enjoy it but you're reasoning, arguments, and suspicions are unfounded and false.

Hello clearthink,

     I was expecting a list of amp types with their SNR specs ranked from highest SNR to lowest.
     But there's really no reason for you to respond,  I think everyone reading this thread understands by now that class D amps are the quietest amp type.

Thanks,
  Tim 

  noble100 "Oh, and just to guarantee fairness and honesty, it is stipulated that your failure to respond on this thread will be an admission that class D amps have the highest Signal to Noise Ratios of all the amp types and, therefore, can be scientifically declared as the quietest amp type. "

Well here you have my little response to you're "stipulation" of "facts" and demand that I share with you research again that I have already provided and that you have dismissed, ignored, or refuted based on your deeply held cherished beliefs.

Hello niodari,

     Amen, brother.  I don't believe any class D amp user or fan is claiming they absolutely are the best overall amp type, that they sound the best, reproduce a certain frequency range the best  or are the best amp for everyone. 
     Personally, I'm just claiming in absolute terms that class D amps are the quietest amp type, are the most electrically efficient amp type, are the coolest running amp type and are typically the smallest and lightest type.  In more subjective and relative terms, I personally claim that good quality class D amps offer very good overall sound quality from top to bottom, are generally and relatively more affordable than other amp types and, therefore, are generally better bargains than other amp types.
     Of course, I realize our choice of which amp to purchase is a subjective one based on more than just personal preference and budget.  The truth is I don't actually give a hoot which amp type individuals choose to purchase.  I'm absolutely certain that I get more pleasure listening to my class D amp than I would ever get from convincing anyone else to use a class D amp.
     My main intent, based on my personal experience, is usually just spreading the word that class D amps were a very good choice in my system with my inefficient Magnepan speakers.   My expectation is that some individuals will find my comments useful, some will be offended and most won't give a sh$t.

Tim

I think Tim gave a very clear and justified response. Both, listening experience and scientific measurements prove that class D amps are the most quiet ones, not only with the highest signal to noise ratio, but also, with the highest ratio performance/price; i.e., take a class D amp and compare it with another amp of any other class with the same price, and you will have much better sound quality in class D amp, and it will be lighter, smaller and will consume much less energy than the other amp.

Other issue is the sound quality of class D amps, in absolute terms, regardless of the price and other parameters. This issue might be discutible but note that in this case you will be comparing a class D amp with an amp that costs much more. Its like  the two amps are not in the same weight category (so it would be unjustified to compete them). In this sense, class D has no completion. 

Hello clearthink,

     Can you please tell us, using your reliable, repeatable and objective measurement techniques, what your results were for class A, AB, D and tube amps in the standardized specification of Signal to Noise Ratio?
     As you’re certainly aware, your Signal to Noise Ratio measurements will settle definitively our little disagreement about whether class D amps are noisy or not. Signal-to-noise ratio (SNR) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. The higher the ratio the less noisy the amp.
     Once you enlighten us all with your SNR measurements for each amp type, it will be obvious whether or not class D amps are noisy and which of the amp types is the quietest, in other words, which amp type has the highest measured ratio.
     Thank goodness you’ve been doing all your scientific measuring, ranking the various amp types from noisiest to quietest should be a breeze with your handy and definitive measurements.
     Oh, and just to guarantee fairness and honesty, it is stipulated that your failure to respond on this thread will be an admission that class D amps have the highest Signal to Noise Ratios of all the amp types and, therefore, can be scientifically declared as the quietest amp type.
     Sorry clearthink, I already know class D tops the list for highest SNR.  However, I have a suspicion you’ll be reluctant to freely admit this for some reason and the stipulation will at least guarantee your tacit admission of this rather well known fact.

Tim

noble100"Anyone who claims class D amps are noisy has obviously never listened to one"

This is wholly, completely, and utterly false, speculative, and prejudiced not only have some of us "listened' we have also actually "measured" using reliable, repeatable, objective measurement techniques that are recognized by engineers, scientists, and industry as fitting, proper, and appropriate but of course if you are happy with Class D you should absolutely enjoy it but you're reasoning, arguments, and suspicions are unfounded and false.

they're all so noisy anybody who has had years of experience in audio file systems well tell you that class D amps are just for beginners

Noise is what the Class D amps have least of.

I suggest anyone considering a Class D amp to listen for themselves up against similarly priced gear. I've had linear and Class D amps at the same time, I've had a number of audiophiles listen to the Class D amps without knowing it. They never ever noticed.

dutchydog,

     Anyone who claims class D amps are noisy has obviously never listened to one, forfeits all credibility and any further claims they make on the subject are best ignored.


Tim 

First off I would never own a Class D amp I don't care how far they've come along they will never equal a Class a the only thing that I can say about them is their lightweight they're cheap but they're all so noisy anybody who has had years of experience in audio file systems well tell you that class D amps are just for beginners

I have already bought two Class D amps . . . Crown 1502, and couldn't be more pleased. In fact, I may be buying two more to change my speakers from passive to active combos. The sound is more detailed than the two hefty monoblocks I used on my main speakers. The background noise is non-existence, and the power these amps can output, depending on their ohm resistance . . . so these speakers cruise, they are light, take up little space, have so many features, and I thoroughly enjoy their addition to my stereo system.

     Ryan of Red Dragon told me he's going to have an all new and upgraded lineup of amps coming out later this year.  He's definitely not going out of business. Here's a copy of his email response:

"Ryan Tew <ryan@reddragonaudio.com>Mon, Jul 22, 3:17 PMto me
Hi Tim
We are working on an entirely new MkIII generation and hope to have them ready later this year.

Thanks,
Ryan Tew President - Red Dragon Audio
www.RedDragonAudio.com
801.361.7138801.810.8184
On Jul 21, 2019, at 1:07 AM, RED DRAGON AUDIO (Shopify) <mailer@shopify.com> wrote:"

Tim

I see that you are interested in the Red Dragon amplifiers, I’m sorry  to say it appears that Ryan at Red Dragon Audio has closed his company. The website has sold out of all equipment and I have tried contacting Ryan about a needed repair and he has not responded. If I am incorrect please let me know. If anybody knows where to get a Red Dragon mono block repaired please respond. 

I ran a pair of Red Dragon M1000 MkII’s for two years. I found them to be dead quiet, accurate, revealing , with solid imaging and they threw a wide soundstage, they did not however have a lot of depth of field. I agree with other owners of class D amps, they are a bargain particularly, if you need a lot of power.

I can only speak for my experience with the Red Dragon ICE technology. I listen to music between 15-20 hours a week on average in a dedicated listening room. I enjoyed the M1000’s for the first year or so immensely but gradually found that the initial intrigue of their positive sonic attributes was lacking something.  I finally concluded, that for me the music was not emotionally engaging.  It took a lot of listening to reach this conclusion, if I listened less frequently or was primarily interested in musical detail  or frequency response I may never of reached this conclusion. I recognize that many class D owners enjoy their amplifiers and this is only my opinion. The M1000’s will be going in to a home theater application. 

     I originally agreed with all that have suggested pairing a good quality tube preamp with their class D amps.  For a few years I used a VTL 2.5L preamp, with the four standard tubes swapped out for a set of four NOS (new old stock) Mullard tubes in my combo 2-channel music and 5.1 ch surround system for HT.  The HT portion of my system included an Oppo 105 Bluray player and a Parasound AV-2500 5.1 surround sound preamp/processor.  The VTL has a HT passthru switch and the Oppo is able to play CD, SACD and DVD-A discs and hi-res music files for 2-ch audio as well as  DVD and Bluray video discs  for HT. 
     This setup sounded great for music and HT and I never thought I'd sell the VTL tube preamp.  But I had an urge to streamline my system and I tried my system out without the Parasound surround processor and the VTL.   I just went direct from the Oppo's outputs to my amps; a pair of class D D-Sonic M3-600-M mono block amps for l+r stereo for music and front l+r channels for HT surround, a bridged stereo class D Emerald Physics EP-100-SE amp for the center ch and a stereo Class D Audio SDS-440-CS amp for the rear surround channels. 
     The Oppo's audio sections are very high quality with a detailed and neutral presentation just as all of my class D amps are.  I expected the combined overall sound to be too sterile, neutral and lacking in dimension, warmth, bloom and body.   However, I was surprised to discover that all my familiar music sounded just as sweet, warm, dimensional and full of natural body without the flavoring I had assumed the VTL and tubes were providing.  
     I think it's important to point out that these very good results were obtained on music that was well recorded.  Fortunately, most of my familiar music turned out to be well recorded but, unfortunately, not all of my music recordings survived such close scrutiny of quality.  There are some recordings I've removed from the rotation if I was unable to find a well recorded example of the same music.  
     These were unexpected results, somewhat proven by the fact that I had just bought and installed a complete four tube replacement set of $200 NOS Mullard tubes in the VTL.  But I felt I had to trust my ears, so I removed the VTL from my system and sold it to a buddy. 
     My new system configuration, combining an accurate, detailed and neutral preamp with amps that have the same characteristics, not surprisingly delivers an overall system sound that is very accurate, detailed and neutral.  I related my experience just for the benefit of those considering class D amps.  My main point being you can obtain very good overall system sound quality using class D amps by either pairing it with an accurate, detailed and neutral preamp (usually solid state) along with exclusively well recorded source material or pairing it with a more flavored preamp (usually tubed) that is more forgiving on poorly recorded source material.  A choice of two methods reflecting different personal preferences. 

Tim