George, its more complex than that You keep saying it Ralph, it’s the main cause for me, and even noted SS amp manufacturers like the highly regarded Solution amps deigner/owner ect. "Cyrill Hammer (Soultion Amps) "if you want to have your product performing at the cutting edge it is not possible with today's known switching technologies. In order to come close to the performance of the best linear design we would need high-current semiconductors that provide switching frequencies of several MHz or even GHz." I know your developing your own Class-D around present day technology. We all know hiend isn’t how it used to be, and we all have to do what we can to make ends meet. I wish you luck on your venture into Class-D, but to me and others like Cyrill it’s too soon yet to take the plunge. Cheers George |
If bias was a disqualifier, these forums would be dead quiet.
|
"
It's interesting how some defenders of Class D amps go to such lengths to classify the critics of these amplifiers as a minority, yet then go on to claim that the critics are prejudiced. Hmmm ... "
Hi cleeds,
Sorry, I'm not understanding your point.
I really didn't go to great lengths to classify the class D detractors I've read responses from since I became interested in this technology about 5 years ago. Just a few minutes recollecting, a few classifying those I recall from Audiogon and other forums and a few minutes detailing my thoughts.
In retrospectively considering and gauging the totality of posts I've read about class D in the past 5 years, I have little doubt that supporters of class D are in the majority and detractors in the minority.
I have no doubt that various forms of bias were evident in many of the class D detractors' posts. Here are some of the major forms of bias I recall:
1. Bias in the form of claiming class D was only good enough for subs even though they'd never auditioned a good recent class D amp in their system.
2. Bias in the form of claiming their current amp would outperform a class D amp even though they'd never actually auditioned one in their system.
3. Bias in the form of claiming the majority of class D amp's switching frequencies were too low and negatively affected sonics in the audible range even though they provided no scientific or even anecdotal evidence to support their claims.
4. Bias in the form of claiming class D amps were inferior because the Damps they auditioned in their systems failed in their opinion to outperform their much more expensive tube or class A existing amp.
There are more forms of bias I recall but I'm short on time right now.
Yes, I do consider class D detractors overall a minority and do consider many of their posts I've read over the past 5 years to be biased in some form.
Your stating this and adding a "Hmmm..." does not amount to a coherent statement. Please clarify.
Thanx,
Tim |
George, its more complex than that.
The reason Technics is switching so fast is to reduce distortion. The
filter has little to do with it. At their speeds, the inductance of the
speaker is sufficient. So their filters are mainly concerned with preventing RFI.
Keeping the switching speed high is important for resolution, and decreases distortion. The problem is that the faster you switch, the more time has to be alloted to allow the devices to turn off before its mate can be turned on.
This waiting time is called 'dead time' and increases distortion. so there's a bit of a catch-22: the more you try to decrease distortion by increasing switching speed, the more dead time you have to have and that increases distortion.
Technics' solution is by using Galluim Arsenide devices that no-one else can get, which are a lot faster (and can switch considerably faster than they are actually being switched in the amp). The reason they are doing this is to minimize dead time, and so have created one of the lowest distortion Class D amps made.
We're taking a different approach. We found a way to eliminate dead time altogether. This allows us to switch at a lower speed and still get lower distortion, or switch at a speed Technics is doing it, without having to use devices that are as fast.
|
It is the notion that Class D switching speeds are the cause, and that someday they’ll be fixed that irritates me. If you guys are going to point a finger, get the whole story right. It’s not the switching speed per se, but the output filter that has to try to get rid of it without any detrimental effects down into the audio band that’s the problem. That’s why Technics with their $20k SE-R1 class-d has striven for double the switching speed, so then that output filter can do it’s job properly without much detrimental effect down into the audio band. Cheers George |
I have had Class D amps from Classe (Sigma 2200i), Auralic (Merak Mono Blocks), PS Audio (HCA-2) and currently use a Lyngdorf TDAI-2170. The Lyngdorf and Classe amplifiers were designed in-house and didn't use off the shelf modules. Don't know if that is good or bad.
I don't know why people have to defend or overly praise Class D compared to other amplifier topologies when the end result is if you like it then keep listening.
If you like Class D, great, but perhaps some of you fanboys can tone it down. Many of us are tired of hearing your opinions, and it is pretty obvious you are biased so your opinion doesn't mean a lot to the community at large. |
"
IMHO I find class D amps to be less musical then Class A amps. I tried several class D amps and to my ears they lack the midrange, rhythmic
space, texture, air and less involving compared to good Class A amps.Something just seems to be missing musically to my ears. But to each his own. I'm not a audiophile snob I just know what makes my finger snap, head nod and foot tap."
Hi bluesy1,
I understand. I think it's a good and healthy thing that there's such a wide variety of amps currently available that individuals can tailor their system sound by choosing an amp that matches their sound preference.
Sound preferences are as unique like fingerprints and snowflakes.
Your snowflake, bluesy1, seems to fall into group#3 from my last post.
I'm glad you found a system sound you prefer with your class A amp.
Enjoy,
Tim
|
Different strokes for different folks, as is always the case. I owned many amps over the years and my newest Class D amps are the best. Saved me from going the tube amp route. Benefits are greatest for those that favor smaller speakers with extended bass, or similar power and current hungry speakers which is the norm today for most affordable high quality speakers. If you run a tube amp with the right speakers to match and are happy probably no need to consider Class D. Otherwise you may be missing out big time! Beside the top top notch performance and sound you save space with both amps and speakers and your power bill and overall TCO is minimized.
|
noble100 'A type of
prejudice not born in evidence' is a very accurate and succinct way of
describing how some class D detractors have a knee-jerk response ... there seems to be a small
group of class D detractors .. there are so many class D amp
listeners and owners ... class D detractors and naysayers are best not
considered as a single group but as a collection of smaller groups ... their
comments being more biased ... group#3 is definitely the
most frustrating since they offer no scientific evidence ... I'm not aware of a single experienced class D
user/owner, including myself, who has ever heard any sonic anomalies
that they claim exist. I think it's safe to state that any logical person would consider their theory as being thoroughly and completely debunked ... Just the fact that the
majority of humans are incapable of perceiving these sonic anomalies
but a small minority of the population can indicates an allergic
reaction to class D by this minority ... individuals
in group#3 can be extremely frustrating and annoying. But perhaps we
should be more sympathetic to these poor afflicted souls. It's interesting how some defenders of Class D amps go to such lengths to classify the critics of these amplifiers as a minority, yet then go on to claim that the critics are prejudiced. Hmmm ...
|
IMHO I find class D amps to be less musical then Class A amps. I tried several class D amps and to my ears they lack the midrange, rhythmic
space, texture, air and less involving compared to good Class A amps.Something just seems to be missing musically to my ears. But to each his own. I'm not a audiophile snob I just know what makes my finger snap, head nod and foot tap. Cheers |
"
It is the notion that Class D switching speeds are the cause, and that someday they'll be fixed that irritates me. It's a type of prejudice not born in evidence. It's the equivalent of "all feedback is bad" sales pitch for some amplifier designs."
Hi Erik,
'A type of prejudice not born in evidence' is a very accurate and succinct way of describing how some class D detractors have a knee-jerk response, whenever class D is mentioned, of proclaiming a completely unproven theory that current class D switching frequencies are too low and negatively affect frequencies in the audible range.
Nevermind that the current leading expert on class D, UcD and Hypex NCore inventor Bruno Putzeys, has stated the current switching frequencies are not too low. Nevermind that there is absolutely no scientific evidence supporting the claim that current switching frequencies are too low and cause audible sonic anomalies. Regardless, there seems to be a small group of class D detractors that still claim that current switching frequencies are too low and negatively affect sonics that they're able to detect.
I've spent more time contemplating this subject than it likely deserves as well as why there are so many class D amp listeners and owners, just like you and I, who perceive no sonic anomalies at all while an apparently smaller group claims to hear some and dismiss class D technology as a result.
My current thinking, based on multiple threads discussing the amps and technology over the past 5 years, is that class D detractors and naysayers are best not considered as a single group but as a collection of smaller groups such as these:
1. Those that have never actually listened to a good D amp in their system but simply parrot other critical comments they've read previously. This group can typically be identified by their comments being more biased toward whatever amp type they own and use than biased against class D.
2. Those that acknowledge the strong points of class D but consistently mention the same perceived flaw of switching frequencies being too low This group can usually be identified by a lack of scientific support and a lack of even an anecdotal description of the claimed flaw's sonic affects.
3. Those that actually do try out class D amps in their system but claim that 'something is missing from the sound' and decide to just continue using their existing amps. This group can usually be identified by statements containing sentiments about how they really wanted to like class D but liked the sound of their existing amps better.
Their existing amps are often high quality and expensive tube and class A amps that are very large, electrically very inefficient, emit copious amounts of heat into their rooms and color or flavor the inputted signals in some preferred manner. This group is typically and understandably seeking a more electrically efficient amp that doesn't raise the temperature of their rooms but still performs at a high level.
The 'something missing in the sound' they have difficulty pinpointing is predictably the coloring and flavoring of the inputted signals that is avoided by design by most good class D amps in favor of a much more neutral approach that emphasises faithfully amplifying inputted signals more attuned to the audio ideal of an amp as 'a straight wire with gain'. I have no issue with this group preferring their more colored amps.
Of my 3 general groups above, I agree that group#3 is definitely the most frustrating since they offer no scientific evidence of support because none exists, are very vague about the sonic manifestations they theorize exist in the audible band due to the switching frequencies being too low and I'm not aware of a single experienced class D user/owner, including myself, who has ever heard any sonic anomalies that they claim exist.
I think it's safe to state that any logical person would consider their theory as being thoroughly and completely debunked.
Just for fun, however, let's assume they're correct and all the thousands (millions?) of very satisfied class D amp owners/users are wrong. Let's assume these sonic anomalies actually do exist in the audible range due to switching frequencies being too low.
If this was actually the case and the truth, I would expect medical experts, neurologists and hearing care specialists to inevitably classify the ability to hear sonic anomalies in class D amps as an auditory/cerebral affliction, malady or syndrome. Just the fact that the majority of humans are incapable of perceiving these sonic anomalies but a small minority of the population can indicates an allergic reaction to class D by this minority.
I agree that individuals in group#3 can be extremely frustrating and annoying. But perhaps we should be more sympathetic to these poor afflicted souls. Just as being lactose intolerant prevents those afflicted from enjoying a delicious glass of cold milk, being class D intolerant prevents those afflicted from enjoying the delicious sound of a good class D amp.
Love,
Tim |
This back-n-forth between class D and class A reminds me of the raging debate in the late 70's / early 80's over V8 engines and the up-and-coming 6s and 4s. Nobody, back then, could have imagined a 6 or lowly 4 producing the horsepower and torque of today's engines. IMO today's class D amps are the 4s and 6s of the audio world. Soon, and very soon, conventional amplifiers will go the way of the 426 hemi; the 427 corba jet; and the big block Chevy. Some will hang on to their Hemi 'Cudas, Gran Torinos, and Malibu Super Sports. And some of us will park our classics and embrace the Focus RS and the like. Regardless of which camp you're in, profits and competition drives innovation. Like it, or not, class D is here to stay. And one day class D will give-way to newer-tech. Personally I'm happy to be in the cusp of changing technology. I too am hanging onto my well-regarded, class A amp...but I'v also embraced class D and am happy. That said, if class D is not your cup 'o tea then so-be-it; being happy is the objective. But for those of you who are curious, take advantage of the plentiful home-trial offers...and ask those of us who gone before you about our experiences. |
erik_squires It
is the notion that Class D switching speeds are the cause, and that
someday they'll be fixed that irritates me. It's a type of prejudice not
born in evidence. That sounds more like an opinion than a prejudice to me. |
@cleeds
I’m perfectly OK with you not liking a class of products. That’s not what I’m talking about.
It is the notion that Class D switching speeds are the cause, and that someday they’ll be fixed that irritates me. It’s a type of prejudice not born in evidence. It’s the equivalent of "all feedback is bad" sales pitch for some amplifier designs. It is the boogie-man aspect of this particular line of reasoning that I am against, or that Class D still has anything left to prove to be among the best sounding amplifiers available.
Like what you like. Spend money to make yourself happy. But I'm done with arguments like "Bagostino amps are better because they have no feedback" or "Class D switching noise will never let it be as good as ..."
Those arguments are tired as can be.
Best,
E
|
erik_squires
I still here the same fear obfuscation and doubt thrown at Class D amplifiers, without meaningful research behind it ... With
zero objective evidence of such a thing. This is a vague, moving goal
post. I've heard a number of Class D designs that equaled or better
very expensive Class A designs.
I'm not asking you to like any
particular class D design, nor am I saying all Class D amps are going to
sound as good as any linear amp with particular speaker. I am
suggesting this is thin techno-fear without research or experience
behind it.
That you disagree with what some say here doesn't mean that they are guilty of obfuscation or are fearful. And while you claim otherwise, you are indeed asking us to like Class D because, as you state, "
I've heard a number of Class D designs that equaled or better
very expensive Class A designs." It's not because of "thin techno-fear" that I don't like Class D amps. I just haven't met one that I like. To be fair, I'm not looking real hard, either. I just don't see any reason to replace the amplifiers that I have and which work very well in my system. As Paul McG says in the video - we're just talking about stereo here. So why such a need to "vent?" Why should the preference of others disturb you so? |
I still here the same fear obfuscation and doubt thrown at Class D amplifiers, without meaningful research behind it.
One of the biggest: Class D can't be as good as (blah blah) until the switching frequencies are above x Hz.
With zero objective evidence of such a thing. This is a vague, moving goal post. I've heard a number of Class D designs that equaled or better very expensive Class A designs.
I'm not asking you to like any particular class D design, nor am I saying all Class D amps are going to sound as good as any linear amp with particular speaker. I am suggesting this is thin techno-fear without research or experience behind it.
Yes, there is ultrasonic noise. So what? All amplifiers have noise. I have seen and heard zero evidence of this being audible. Yes, there will be amplifiers that will move the switching frequency from 450kHz to higher. So what? At what point, exactly, will it be high enough? What measurements, exactly, and what threshold of those measurements, will satisfy you that they have reached audio nirvana?
You do not have to like Class D. That's fine if you do not, but I've read encyclopedia's worth of hogwash on this particular subject here and elsewhere on the net. It's like a scam diet, which proclaims that x protein is the root of all evil. Buy my new book and I'll show you how to avoid and heal your gut... blah blah blah.
I also want to point out, I've been listening to Class D amplifiers since the 1980s. They were horrible, despite overall reasonably good specifications. So I'm not saying you should listen with specs, but rather, find the specs that correlate to audible effects. 400mV of 500kHz noise is measurable, but not audible, and my amps sound a lot better or as good as several Class A amps with all the speakers I've heard. I would gladly trade the size, cost and efficiency in exchange for a measurement that has zero bearing on my experience.
Sorry. had to vent.
Best,
E
|
|
I'm using a PS Audio HCA 2 with the Cullen mods and I love it.
I auditioned a variety of amps in my home - a high powered ARC tube amp and a Pass Class A amp at the same time I had the PS Audio. I think I may have liked the Pass amp about as much as the PS Audio, but I'm inclined to keep my gear turned on all the time I didn't think I'd like the extra heat and energy usage.
Time and innovation march forward so I'm sure there are others that are better, but I'm not feeling any urge to upgrade at this point. |
I haven't seen much discussion of the NAD M22 outside of general discussion of the Hypex nCore modules, but I've had this amp for the better part of a year. It replaced an Ayre V-5xe which put out too much heat for the hot southern summers I have to endure. While perhaps it doesn't have quite as much depth as the Ayre, it has incredible bass definition and control, a wide soundstage, and a sense of liquidity, propulsion and flow that the Ayre definitely didn't have. It has a pristine clarity and neutrality without seeming anywhere near harsh, dry or boring, and the dynamics are thunderous. I really couldn't ask more from an amp. Considering I see the M22 going for roughly 55% off the MSRP around these parts, I don't think there's a better performance bargain for power amps on the used market. |
There isn't time to read all of this thread, so my apologies if it's already covered the Red Dragon S500, but I've had that for almost two years and am really pleased with it. Sound is detailed, balanced across the frequency range, bass is deep and articulated, mid-range is clear, treble is also clear and realistic though I sometimes think it might show a little more sparkle. Certainly it's well ahead of the Class AB monos I had previously, and they'd been well recommended.
The main partnering equipment is an Esoteric X05 SACD player, Townshend Allegri preamp, and B&W 804S speakers.
I don't doubt that there may be better Class D power amps. Some will be better because of their design and the quality of their components. It's also possible that some Class D modules are better than others. Living in Britain I don't get much opportunity to compare the sound of different systems. I did hear one of the first NORD NC500 power amps (it's only an hour's drive to where they are made), but the demo wasn't very successful from my point of view - mainly to do with the circumstances and not necessarily a criticism of the amp itself. Buying the Red Dragon was something of a risk because although I could return it within 45 days, I wouldn't get the import duty back and there's be expensive carriage costs. But it's been highly successful and I'd probably have to pay a lot more to get something that performs significantly better; though in five years' time, perhaps, when things have moved on a lot, better quality may be available more cheaply.
|
Nearly forgot about my second system.
Linn Classik all in one which uses a 70wx2 class d amp and sounds pretty darn good for what it is and I have no desire to replace it with anything |
I did try a pair of bel canto ref 500m monos a couple of years ago but for reasons I think mostly associated with the other gear I quickly moved on!
However in my ht rig the move to class d amp was a massive step forward in every way.
Replaced my Emotiva amps with a tiny single nuforce power amp making a claimed 150w x8, only using 7 channels for my 7.1 system.
The emotivas claimed 300w x2 and 250 x5, not quite sure where they were hiding those horses as the nuforce creamed them in every aspect.
dynamics, action, dialogue, sheer volume were vastly increased with the nuforce.
and now I have one tiny little box which has replaced two behemoth amps that were sucking juice and pumping heat.
I will at some stage give a pair of mono class d amps a whirl in my main rig again I am very sure! |
MDE.. I'm not an audiogon regular so PMng seems to be escaping my abilities! Feel free to send from your end :) |
Thanks MDE.. gives me something else to read about. His approach seems a little different and his units carry a bit of weight to them (Makes class A/B people like me feel more comfortable!). I'll PM you fo rthe other info! |
@jdavis37 Not all Class D manufacturers use third-party amplifier modules. Check of Digital Amplifier Company. He designs his own Class D amps, or at least that's what he says (see website.) I own a pair on his Maraschinos and I love 'em. I also have some experience with other brands you mentioned. But I'd rather not speak of that here. PM me if you want more information. And I am not affiliated with, nor compensated by, Digital Amplifier Company...just wanted to get that said. |
Heat and weight are not a concern for me, either. But I can see where those 2 things might be appealing for some. I won't lie in that I am struggling some to be really attracted to Class D for now. The technology seems to be changing rapidly whereas Class A/B at the least is mature. Same reason why in general I do not prefer paying for a DAC built in to the preamp unless the maker has a way for future upgrades. Dropping $5K or $11K for a pair of monoblock Class D amps only to see a much improved amp board emerge in 2 years would hurt my financial feelings. My spousal unit is very good with accepting my expensive hobbies to a point. Course if that $5K Class D amp already produces sound quality I find superior to every Class A/B amp I can find in the same price category then it may well work. But am giving consideration to some SST equipment (Son of Ampzilla 2 and Theobe II) as well which will not cost as much as some of the Class D options I am looking into! Course maybe I should just stay with my current setup... it is good and is now free :) |
I do though see some advantages regarding heat generated (if that is a concern.. for me it isn’t) and size/weight. They offer a ton of power in a small mass versus trying to heft around a 90 pound Class A/B amp or an even heavier (with less power) tube amp. I see my system as something I want to get the very best from, and if I have to compromise and pay for it in less efficiency so be it. I wouldn’t buy a Ferrari put low octane fuel in it, stick cross-ply tires on it and drive it like a granny just so I could say I’m being kinder to the environment. But Class-D amps with the promises of higher switching frequencies technology in the future, may become all they need for me to jump camp, then my current amps will become door stops or boat anchors. Cheers George |
I do though see some advantages regarding heat generated (if that is a concern.. for me it isn't) and size/weight. They offer a ton of power in a small mass versus trying to heft around a 90 pound Class A/B amp or an even heavier (with less power) tube amp. |
Thx George.My only experiences are with Class A/B mostly and some Class A. I have heard tube amps but never owned one, and in past thought of Class D as mostly sub type amps (my ignorance). I started reading about the newer Class D amps and the price range is fairly broad. I also recognize pricing is not always linear with cost (whatever market will bring). But it is hard to see how 2 amps using the same identical amp board can vary in price so much which of course begs my question of why.
If the cost of the parts, including cases, connections, etc. as well as the actual amplifier modules is a lot cheaper than their Class A/B counterparts, and their sound quality is close but it results in an overall cost reduction for the buyer than I would be more encouraged. It is difficult for me to hear much of this stuff without buying it. Not many nearby sellers.
But I am probably missing something along the way. If the more expensive units are adding proprietary mods that would be one thing. Otherwise it starts sounding like a prettier case, etc. is adding a lot of cost! |
So my question is with the main boards themselves being made by a third party, how does one go say from a $1400 D-Sonic amp to a $5000 Bel Canto (or other similar) amp (per pair) up to a Merrill Veritas at $11K plus (pair)? I realize a nicer chassis, etc.
In the "hiend" Class-D's there must be a huge profit margin compared to linear amps, even with the glitzy cases, as what's inside is worth peanuts compared to similar dollar linear amps. EG: The $8k Rowland Continuum S2 http://www.theaudiobeat.com/equipment/pics/jeff_rowland_continuum_2_large_inside.jpguses one of these Danish modules http://www.pascal-audio.com/amplifier-modules.htmlWhich from what I found, are slightly modified Chinese $150 modules I believe from Class-D module manufacturer called Sangaway or something from memory. And these modules were also used in the far cheaper Red Dragon Class-D amps. https://www.reddragonaudio.com/products/s500 Cheers George |
Hi.. I have been a Class A or Class A/B amp owner my entire adult life and trying to get a firm grasp on Class D amps. I have read through several threads and like many subjects this one is similarly polarizing. I'm not biased either way. Just seeking information and if I decide to change amps, getting the sound I'll enjoy.
It seems there are about 3 major players in companies that actually manufacture the amp boards, and that most people selling Class D amps are buying the boards versus designing and building their own (probably some exceptions). If I am correct this is very unlike most Class A and A/B amp manufacturers.
While I have never truly understood the prices attached to esoteric items, I do understand basic marketing and getting for a product what the market will pay. This may or may not be attached to the cost to produce said item.
So my question is with the main boards themselves being made by a thrid party, how does one go say from a $1400 D-Sonic amp to a $5000 Bel Canto (or other similar) amp (per pair) up to a Merrill Veritas at $11K plus (pair)? I realize a nicer chassis, etc. will add cost, and same for internal wiring and external connectors but am trying to see what each make ris adding to their product to result in so many price variations when the main "guts" are so similar. Thx |
Poor George...he wants evidence from measurements vs. using his ears...
Both sunshine both, as it should be, can't have one without the other. Cheers George |
Darn.
I did like jowever the hupex? Nycore amplifier. That did sound better than others i have heard. Not my cup of tea, but that one sounded descent. |
Poor George...he wants evidence from measurements vs. using his ears... |
erik_squires OP3,082 posts01-29-2018 4:20amSorry George, as always, you are going to have to pivot from one point to another by yourself. If you need a dance partner it is not me.
Erik
That's a cop out Eric, your the one who said said: "
Most Class D amps I know of do considerably better. I'm more than a little surprised PS Audio put that out there." I ask again, Eric.
Please show JUST ONE Class-D, with a clean 1khz sine wave, without using the Audio Precision's auxiliary AUX-0025 passive low-pass low power filter. Cheers George
|
I have had a Nuprime class d amp for a few months now,and am very happy with it!The bass control is excellent!Im using it with a pair of 805 diamonds with great results!I tried it out with a pair of Thiel 3.7’s with great results also!I need a little more power for the Thiels I think?Im on the hunt for another class d amp for them.Im converted,class d rocks for sure!
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Sorry George, as always, you are going to have to pivot from one point to another by yourself. If you need a dance partner it is not me.
Erik
|
I have owned the Bel Canto Black EX DAC and amp for over a month now. Wonderful.
|
Heard it again, still don’t like it. Wyrd4sound and..
Veritas amps, looked cool, sound was blah to me.
I like class a, or ab, even a switching class h has more feeling to the music. Something about the d sound just don’t sit right with me.
It’s just.........like 1 dimensional, or no emotion to the music, a,ab,h just have a quality to them when I’m listening, I don’t get from d class sound.
H class I’m referring to is my Carver sunfire. |
Most Class D amps I know of do considerably better. I'm more than a little surprised PS Audio put that out there.
Please show just one Class-D, with a clean 1khz sine wave, without using the
Audio Precision's auxiliary AUX-0025 passive low-pass low power filter. Cheers George |
|
I must say that for any amplifier, the PS Audio Stellar's measure poorly.
Most Class D amps I know of do considerably better. I'm more than a little surprised PS Audio put that out there.
|
shadorne6,590 posts01-28-2018 8:06amLittle known factoid.
AES17 brick wall filters allow Class D Amps to report specifications IGNORING all the switching noise above 20KHz!!!! And there is a LOT of noise....
Stereophile do similar now testing Class-D as not to upset readers with the noise on the graphs and to keep the manufacturers happy in case they may advertise. They use a very low power handling Audio Precision's auxiliary AUX-0025 passive low-pass filter between the Class-D's speaker output and the test equipment, which eliminates noise above 200kHz. On figure 3 you can see the switching noise of the 1khz test sine wave, it will be far greater if they showed with a 10khz sine wave. https://www.stereophile.com/images/218PSM700fig03.jpg
Fig.3 PS Audio Stellar M700, small-signal 1kHz waveform into 8 ohms without AP AUX-0025 low-pass filter. If this noise was on test waves of the audio band like this on a linear amplifier, any tech would say it's faulty. Cheers George |
Shadorne,
That's not really a factoid so much as an operating principle.
You make it sound as if the specifications are illegitimate, they aren't. The filter removes the noise you are talking about, so that the noise is on the inside, but not the outside (mostly).
Sure, if you measure any random point inside the filter, you can find horrible looking signals with little resemblance to audio. True could be said of any DAC though. :)
Best,
E
|
Little known factoid.
AES17 brick wall filters allow Class D Amps to report specifications IGNORING all the switching noise above 20KHz!!!! And there is a LOT of noise....
|
Does anyone have compared the job 225 vs any class d amp? |
https://forum.audiogon.com/discussions/mola-mola-dac?highlight=Mola%2BMolaThis link is mainly about the Mola Mola pre/dac, but there are some comments about the Kaluga mono block class D amps. The Mola Mola Makua and Kaluga have just received an award from AV Tech Media as best high end pre and power amp. If you need to know any more about the Mola Mola let me know. UK Mola Mola dealer. |
Hi migueca,
Okay, 70W on the Zu Omen Defs is plenty of power; almost overkill. I don't think it's too much since it's such clean, low distortion power You're virtually guaranteed the amp will never clip and you'll have plenty of reserve power for transients. I think you're really going to like class D with your Zus and I'm certain there'll be much less heat in your room.
Sorry for the belated response, I just saw your post. Have you got the amp yet? I'd like to hear your thoughts on the combo.
Enjoy,
Tim
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Noble,
my speakers are the Zu Audio Omen Def. 100dB, very easy to drive - I am pairing them presently with a tubes SET pumping "only" 24W.
That review that you mention is for the old monoblocks. The new model is 70W with standard PSU and 100 with the improved PSU. I ordered the best one.
I'm expecting to get the amplifiers in 3 to 4 weeks. Then I can post a review. |
migueca, I just read a review on the Temple mono-blocks that was very positive: www.enjoythemusic.com/magazine/equipment/0514/temple_audio_monoblock_amplifiers.htmat I've never heard any of the Temple Audio amps so I'm unable to provide you with any useful feedback. I noticed the monos are rather low powered at 40 watts/ch (the review doesn't mention whether that's into 8 or 4 ohms). I believe you know how important it is to match an amplifier's power rating and sound characteristics to your speakers and therefore assume your speakers are very efficient. Please let us know your room dimensions and what speakers you'll be using so we can offer further guidance. Thanks, Tim |
