Can someone write an explanation of Power Factor?
In the case of power supplies, do you try to make the power supply look like a resistor to the power company OR the amp look like a resistor to the power supply? I don't know that a pure resistive speaker is possible. |
Spectron,
Switching power supply offers many advantages such as ripple that is easier to filter out, voltage that is line and load regulated and transformer that can deliver same power at high frequency at 1/10 of size. The problem here is that SMPS got bad rap from designs utilizing them for the size and cost and not for the quality. Looking from perspective of manufacturers - why to develop SMPS while 90% of people believe that it is no good. Only very brave that already established their name like Rowland or Linn are not afraid to use SMPS in class AB amplifier.
Claim that class D amp work better with linear supplies is in a sense illogical since SMPS is class D with fixed voltage (that's how class D was invented). Most likely implementation of given type of supply is the key. Icepowers in REF1000M benefit from extra capacitors, according to reviews, but my tiny Rowland 102 keeps composure (having regulated supply) even under long heavy orchestral peaks.
Question to you. I read some of the Karsten Nielsen doctoral work and understand a little nature of the beast. Modulator is a little similar to Sigma Delta converters what doesn't surprise me since this idea (using byproduct of sigma delta) was already used in things like SACD.
What is different in Spectron amps? I heard a lot of good things but wonder if they share the same principle. I'm not asking of course for any design details, just adantages in general. |
Timtim, I'll back you up. I had the McCormack DNA 500, the W4S ST 1000 (twice), and currently the Cary A306 Class D amp. The DNA 500 was the sweetest sounding solid state amp I've owned with the most outstanding upper end I heard with the speakers I owned at the time. Sonically, much more refined than the Wyred, and the Wyreds are good. But considering the price difference, the Wyred ought to be outclassed by the DNA 500. |
Foster_9 .... I appreciate the love LOL. Of course this is the world of high end audio we are discussing, and many are quick to get upset if their apple cart is tipped slightly.
Regardless of what anyone may think, I truly have NO adgenda to bash Class D ... and I will promise this : The day I hear a Class D amp that matches the sonics of the better Class A A/B amps ... I will buy it on the spot.
I would love to downsize, but I won't downgrade ;-) |
Tim,
If you want Class D to sound good to you bad enough, maybe try building your system around a Class D amp of choice.
That would give you a better chance than plugging one into what you have currently and like and expecting that it will sound the same or better.
I went Class D because it fit the bill perfectly for what I needed in my rig at the time, especially the big full range power hungry OHMs that mainly benefit from the juice. So I too have a basis to compare.
The amps sound great to me on the Dynaudio monitors as well (hard to fault in any way for their size), but for those alone there are many amps that can fit the bill.
Most speakers I have heard that use ribbon tweeters would probably benefit from an A/B amp like the McCormack or similar than most Class D amps I suspect.
My expectation is most Class A/B amps in this discussion will tend to have a hotter top end than CLass D, at least Icepower. That is one difference I notice between the two.
Of course, different people hear the top end differently and that also changes with age which can also be a factor in what kind of amp sounds best.
You are making a mistake by dissing all Class D amps categorically though just because you like the sound of others in your system.
As has been pointed out, all amps are different and will have different perceived strengths and weaknesses.
My ears tell me Class D amps can be in the same league as their older brethren already these days but YMMV. |
Kijanki,
I more or leass agree with you in your assessment of SMPS versus lienar power supplies and already noted that we use both, one type in audiophile products and another in pro audio projects (e.g. 8kw rms pro audio ampliifer with linear power supplies will need a truck to move from one place to another).
The only reason whyt we did not move SMPS to audiophule products is the cost. I think very few music lovers will be willing to pay additional , say $1k or $2k (I don;t remember exactly) for slight improvment in sound. Plus it would be bad for our reputation: to charge money and not deliver.
Regarding "What is different in Spectron amps? " - again from our web site:
"Uniqueness of the Spectron Design
====================================
Chief Designer John Ulrick is a control systems engineer (and an amplifier is a control system). Because of this, Spectron amplifiers are designed with an emphasis on very high speed control loops. These high speed control loops result in the amplifierÂ’s remarkable ability to reproduce detail that other amplifierÂ’s cannot reproduce. Moreover, due to this incredible control loop speed and stability, our amplifiers can drive the most difficult speakers in the world (down to a 0.1 Ohm load!) effortlessly. "
Simon |
I have a Jeff Rowland Continuum 500 integrated amp that sounds as good if not better than any other amp that I've owned. You should hear it with a pair of Wilson Sophia 2's. It sounds fantasic. I don't think that all Class D amps should be written off characterized as being all the same. Just my .02 cents. |
Simon, I checked Spectron website - very impressive. 100kHz bandwidth and 65A max current is not easy to do. I am especially impressed with bandwidth - less phase shift in audio band. Spectron will be possibly my next amp. |
Mapman was absolutely right saying,
"If you want Class D to sound good to you bad enough, maybe try building your system around a Class D amp of choice."
I have the same class D amps, the H2O for 7 years. My system now is clear through every frequency point. That was not so over the first 4 years. It was great in the 2 years between then and now, with now being spectacular.
I continued making changes in my system around my class D amps as Mapman suggests. |
I'm thinking on Kij's wavelength.
I'm a current 'd' owner....some ICE amps, but the Spectron would be on any short list of auditions....and it is a pretty short list.
With the black faceplate! |
Timtim, your interest for switching amplifier improvement and your appreciation for their obvious strong points is refreshing.
Not to devaluate system synergy I feel there are obvious similarities of the basic amplifier types that are distinguishable regardless of synergy. I still own a tube amp, linear solid state, and two switching amps. and I'm sorry none of them sound like the other contrary to all the, "sounds like a tube amp," statements one reads.
The weakest aspect of switching amplifiers is they are not plug and play. They may need a little effort to integrate them into a system and more importantly the systems electrical supply. If a class D design has any of the sonic generalities you read about, more than likely they can be tuned in or out. As Muralman describes it can be a substantial tuning process or as simple as a cable switch. Unfortunately, you seldom read of a major reviewer taking any special effort to integrate them.
Currently, I'm listening to a standard Asthetix Atlas (hybrid?) on loan. To my ears the Atlas comes very close to bridging the tube to solid state gap. At some point a direct comparison with an Acoustic Research VT would be interesting. The Sanders Magtech linear solid state with its unique regulating power supply and the Devialet integrated switching amp running in class A whatever that is are very interesting. As I understand it these amps have some unique design innovations and initial reports of both designs sound very promising. |
"I still own a tube amp, linear solid state, and two switching amps. and I'm sorry none of them sound like the other contrary to all the, "sounds like a tube amp," statements one reads."
Exactly.
Most all gear sounds different, especially when radically different technologies and design approaches are applied.
And that's why it is not a sound approach to swap in a piece of gear into a system you already think sounds right and then lament that it is not as good when it sounds different. If you want to get back to that original sound, there will be more changes required to do it.
My gut tells me that in general Icepower and ribbon tweeters may not be a good combo in that both tend to lean towards a non fatiguing (not "hot") top end. Too much of a good thing in combo perhaps? Whereas Class A A/B amps may deliver a relatively "hotter" top end in comparison and have a nice synergy with ribbon tweeters for many.
I can say I have found the BEl Canto ref1000m IcePower monoblocks do have a nice synergy with my Dynaudio monitors (isotar tweeter I think) which can tend to be a tad hot on the top end compared to some other monitors in general.
Same with the soft dome tweeters used in the OHM Series 3 CLS drivers used in the Walsh 100 and 5 series 3, more full range, speakers, which are a notch less hot on the top end relative to the Dyn monitors, I find.
My Dyns and OHMs can be both run concurrently in adjacent rooms of my system. I have had many opportunities to hear both with several radically different amps in my system over the last few years, so that is largely the basis for what I relate. |
class D amps with tube-like sound - I read and read. I think the best comment on it is on Spectron web site:
" The published measurements of many class D amplifiers reveal that while their THD is primarily second-harmonic in nature, there are also some higher-order harmonics present. This pattern of distortion is very similar to the pattern of distortion in poorly designed tube amplifiers. Thus, sonically, this euphonic coloration is confused by some with the warmth of tube amplifiers. In reality this deviation acts as both an annoyance and murky veil. In exchange for euphonic, overly rich harmonic texture (of absolutely artificial origin) the listener gets no transparency and a lower level of true detail."
As I understand, Spectron goal is ulta low distortion levels particularly of odd-order harmonics. |
Dob, I'm confused. I thought that warmth of tubes IS euphonic coloration since tubes enhance even harmonics (artificially added warmth).
What is "absolutely artificial origin" and why it is attributed to class D only. Why details are supposedly lost in class D but not in tube amp that also enhances even harmonics? Claim that class D has no transparency and low levels detail is unfounded, in my opinion, and is just opposite to opinion of many, that class D is too transparent/revealing and bright sounding.
When some people believe that class D has "murky veil" being too warm and the same time others claim that they couldn't stand it because it is way too bright - then perhaps it is just right where it should be, neutral, transparent liquid and very clean. It is also very dynamic sounding. |
Listening to my Bel Canto ref1000m Icepower monoblocs, I have no idea what that comment on the Spectron website quoted above is talking about or what the basis for the negative description of the sound of other Class D amps is based on.
Must have been put together by the marketing guys...... |
I agree with others, I can't hear any second order harmonics distortion on my system. I do know what that term means. I have heard all tube systems where their coloration is quite noticeable. Spectron is just tooting it's own horn IMO. |
"Dob, I'm confused. I thought that warmth of tubes IS euphonic coloration since tubes enhance even harmonics (artificially added warmth). "
I don't think that BEST tube amplifiers shows artificially added warmth but life-like presentation. What role of even harmonics there I don;t know. I believe that their THD are very, very low and even may be near zero. I repeat, I don;t know why Joule-Electra and Athmasphere, for example, show very realistic sound.... I may not undertsand "why" but I know "what" I hear. Sorry, this is beyond my knowledge.
"Must have been put together by the marketing guys...... "
It could be posted by Satan himself but what its said is "BASED ON PUBLISHED MEASURMENTS...". For more facts, check John Atkinson measurments in Stereophile of different class D amplifiers. If its marketing lie then its marketing lie.
If one likes what one hears then it should be good enough and no defense needed. |
Dob,
Gotta disagree.
"In reality this deviation acts as both an annoyance and murky veil. In exchange for euphonic, overly rich harmonic texture (of absolutely artificial origin) the listener gets no transparency and a lower level of true detail"
I hear none of this with my Class D, regardless of whetehr or not the technical details regarding the distortion related apply categorically to all Class Ds or not ( I do not know the answer to this).
Prior to Class D, I had various class A and a/b amps. The Class D is the best transparency and detail and least amount of murkiness of any I have heard and compares to teh best I have heard elsewhere, so that subjective and unsubstantiated statement is not true based on my experiences. |
Mapman, if a tube amplifier is fully-differential from input to output, it will not have even-ordered harmonics- they will be canceled at every stage throughout the amplifier. The even orders show up when part of the tube amp is single-ended. With most tube amps, that is the input voltage amplifier.
So when Dob was wondering why our amps don't seem to have any 2nd order coloration, that is why. IOW, its not a universal thing that tubes inherently have that coloration! You can get transistors to do that too if you run them single-ended.
|
Atmas,
Thanks for that clarification on tube amps.
Class D amps are not tube amps though so I am not sure why Spectron groups tube and other Class D amps together in any technical discussion other than to assert that their products are superior to both for similar reasons, which does not seem like a viable argument. There are many factors that go into end sound quality as has been discussed ad infinitum here and elsewhere. So pointing out a single technical characteristic and attributing good sound or not to that alone does not carry much weight for me, especially when I ears tell me I should not care.
It is a typical marketing ploy though, so Spectron is not uniquely guilty of anything new there. It is what it is. |
Athmasphere,
Thank you, thank, thank you for explanation !!!
This is EXACTLY the same philosophy of use Spectron in fully balanced configuration: cancelation of all distortions: even, odd, blue and read !!!
Per Simon Thacher of Spectron the KEY lies in the part quality - pure and simple.
Simon also is saying, and I am not sure if you will agree with him, that if we cancel distortions or actually greatly diminish them then the SOURCE of distortion is immaterial: it could be tube amp or transistor amp or class A or class WYZ - whatever; distortions are gone and so specific sonic characteristics of these amps also greatly diminished... and indeed, balanced monoblock Spectrons sound almost as good as Joule-Electra, I am in love with..
Incidently, Joule-Electra pre- and power amps may or may not have balanced input and/or output but internal processing is balanced ALSO (they use phase splitter).
Thank you again - I saw different pieces but could not put them together.... |
Dob and Athmasphere, your amps sound clean. So do the others. I have used a number of AB amps, and though the builder of such amps will say they have canceled out all distortion, they don't hold a candle to the clarity my ICE amps have.
I found this interesting quote muttered by John Atkinson:
"It's not that they (class D) measure badly, it's because I have to be extremely careful to ensure that I don't end up measuring my test equipment's limitations."
Oh, now that is quite a telling confession. |
"... they don't hold a candle to the clarity my ICE amps have. "
I am sure you are absolutely correct. No one in his right mind would challange your assessment of your own amplifiers.
Athmasphere was just helping me understand why the best tube amps have near zero distortions level. The same philosophy (approach), he described is that of many other companies. I mentioned Spectron statement that based on PUBLISHED measurments distortions are...distortion are...distortions and bad for you...even pleasant for ears as even-order harmonics or ear-piercing odd-order ones.
It has nothing to do with fantastic qulaity of yours and everybody else amplifiers. Somebody mentioned above that sound quality is a function of many parameters and distortions (type and amount) is only one of them. Nothing more.
Peace. |
Dob, interesting. I thought Atmasphere was suggesting that balanced amps have near zero distortion levels. |
"I thought Atmasphere was suggesting that balanced amps have near zero distortion levels. "
yes, but in comparison to the same amplifier configured in the single ended mode...
Also Atmasphere, in other posts, postulated that good sounding amplifier should have no or minimum of odd order harmonics as compared that to the even order ones in the same amplifier, of course. |
I am way over my head here with the techincal issues but I have owned Sonic Fronteirs Power 3 amps with KT88s for years before I switched to Spectron monoblocks. I due love the midrange of the KT88s but I feel the transparency is better in the Spectron class D. The amps both have different sounds and I would never confuse one for the other. There is a certain sparkle with tubes which I feel like I miss with my old tube amps. |
People please stop using the phrase digital amplifier. There is NOTHING digital about class D. |
This from a person who has borrowed my source duo. He has the same amps and preamp as I.
"I have been listening all morning and YES!!! It is incredible. It is unreal how good the Flatfish and the Audio note sounds. It has the right amount of ambience, air, staging. Bass is beyond description. Very tuneful and meaty with right amount of pitch definition. Vocal is NIRVANA to listen to. Nothing is exaggerated. No wonder you have been screaming how good your system sounds, unfortunately mostly to unbelievers. Oh well, Too bad they missed out big time. Top end is so exxxxxquisite...." |
Ralph do you think that a digital amp will ever be able to capture what tubes can do;personally I do not;but it is fun to listen and compare. |
One thing to be careful about is reliance on simple measurements such as frequency response, or THD.
Ideally, a measurement such as EVM that is used in the wireless industry would be a more appropriate measure of the quality of the amplifier.
One example of the problem with measurements like THD is that its easy to crank up the amount of feedback to create good THD measurements. However that will smudge out the transients in a signal and cause a dull lifeless sound. That is why on Class A/AB designs the better sounding amps tend to be the ones with zero global feedback.
Going back to Class D designs, my experience with several ICE amplifiers has been they tend to distort the transients - particularly the quieter signal levels. Perhaps this is due to the deadband issue that is described on the Mark Levinson website - I don't know. Its a type of digital nonlinear effect and so can't be described by simple 2nd order/3rd order products.
I recently got a Spectron digital amp, and haven't noticed this issue at all so far, although I have been using it in balanced mode, which perhaps serves to reduce the effect to the point of not being noticeable.
I am also intrigued by the idea of the Devialet amp - which combines class A with a class D to capture accurate transients - although I have yet to hear one. |
Dan92075, class D amps need patience to bring out their best. Or, you can copy my recipe. ;-)
I have found what you say is the opposite of truth. That is, A/AB amps, with zero global feedback, distort the transients, not the best class D amps. The well tuned ICE amps will have no audible distortion, and will dig deeper into the CD than ever thought possible. |
I think I have been more than patient with ICE amps, including changing around my interconnects, power cables, speaker cables, even preamps to get the ICE amps to sound better! And tried several ICE amps to boot!
Don't get me wrong - the detail was not poor by any means - it was fairly good overall - but somehow there was something missing on higher frequency transients that created an ever-so-slight digital, plasticky sound.
When I did a comparison between the state-of-the art latest Ice amp (Bel Canto 500m) and a 8 year old Sim Audio Class A/AB amp with zero global feed back - there was simply no contest. Especially at low volume levels I found the Bel Canto would compress and sound anything but audiophile, whereas the SimAudio operating in Class A mode managed to retain most of its nuances, just at quieter levels.
I honestly don't know what else I could have done to bring out the best in the ICE amps. . . if you have a special recipe I sure would be interested to know! :) |
Ok, Dan92075, what CD players did you try? On my system all oversamplers failed miserably, especially in their highs. I use a 47 Lab Flatfish transport and a much improved Audio Note DAC. I cannot stress how important that is.
All speaker cables that are not nearly bare will flood the signal with noise. All power cords must be fully insulated against EMI. Saying that, only my speaker cables made the ultimate difference for me. They are ultra thin metal ribbons. I use Speltz ICs because what he says on his site is right on.
None but one solid state preamp will do their best with class D. The rest will diminish the music. Tube preamps do much better. It is a mismatch thing. There is one solid state preamp made especially to match class D, and that is the H2O Fire preamp. That is what I use. It will kick ass the sound into a music that shows flow and big impact.
I can go into great detail, but not here. Drop me an email if you are still interested.
See my friend's comments above. |
>>02-20-11: Muralman1
None but one solid state preamp will do their best with class D.<<
That is so lame.
How would you know that only one solid state preamp will work best for everyone?
That is true only for you and you alone.
There are many more experienced and knowledgable listeners/manufacturers/audio engineers/retailers outside of the muralworld.
You need to get out more.
LOL |
Audiofeil, you know how low ICE impedance runs. Solid state preamps have great trouble with this. It is not just my opinion that most solid state preamps deteriorate the sound. That is why people use DAC volume, and others line level preamps. Tube preamps are fine. |
I had a Musical Fidelity A3CR (Class A Stereophile rated FWIW) prior to the Bel Canto ref1000m monoblocks.
When I first listened to the BC's, the sound was so different from prior that I thought something was wrong. My ears were totally disoriented. We're talking night and day difference in the sound, not just something slightly different.
So these two amps sounded totally different. If you are sold on the sound of one, you will not likely take to the other without adjusting your listening habits along with whatever else. I found I had to adjust my speaker location a bit as well with the BCs in order to best deliver the new, big and well defined soundstage.
After a while I was able to discern a few key differences in the sound.
1) the BC were less hot and quite non-fatiguing in comparison
2) the BCs had a more open and dimensional soundstage which was perhaps the one thing that made most everything else sound different.
3) at first, the bass seemed to be gone with the BCs, then once my ears adjusted to the new soundstageI was able to detect that it was really there in spades and with much improved impact and nuance but again now within a much more open and 3-d soundstage |
Wait a minute muralguy.
Let's go back to the "None but one solid state preamp will do their best with class D" assertion.
That statement implies you've evaluated all of them personally with your ho 2 ho amps. Now any rationale and clear thinking person knows you couldn't have done this. So why not be a bit more conciliatory and admit there is more than one preamp suitable for Class D amps. In fact, I've used a number of them (dealer disclaimer) with great results.
You like your system. Great. However, your combination is not universal. If so, more audiophiles would do what you're doing. In fact you seem to be on an island. |
"Audiofeil, you know how low ICE impedance runs"
It is 10k - just a little low but many class D manufacturers use additional input circuit that increases impedance. My Rowland Icepower uses THAT1200 instrumentation amp to obtain 40k input impedance. Others use transformers.
Low input impedance is not related to class of the amplifier or modules used but to practical implementation. For instance the newest Rowland 625 class AB amp has 10k input impedance - by designer's choice.
My Benchmark DAC1 has 60ohm output impedance at 0dB XLR output jumper's setting (that I use) - no problem even with 10k input impedance. The worst case is at -10dB jumper's position making output impedance 1.6k. It might look to high for use with Rowland 625 but this impedance is resistive (output divider) and will only alter output level by -1.3dB |
I would think a low input impedance would better suit most ss pres than most tube pres? |
Unsound, I think he was talking about the input impedance, not the output impedance. I could be wrong, but that is the best I can make out of: you know how low ICE impedance runs. Solid state preamps have great trouble with this. But how could there be a solid state preamp that could not drive the low impedance that tubes or a passive can? That part does not make sense. Muralman1, I think you need to restate whatever it was that you were trying to say here. |
Atmasphere your question mirrors my thoughts, we're on the same page. :-) |
My theory, at least for the better icepower Class D amps out there, is that one may have to have a setup that is capable of doing imaging and soundstage really well in order to appreciate these amps fully.
I have several speakers set up in several rooms running off my system. The Class D amps differentiate themselves best from what I had before in my two better rooms in this regard. In the other two, the differences are nominal, and in my worst room in this regard, one used more for casual background listening with less power hungry speakers, I do not hear any clear improvement with the BCs. |
As far as the low input impedance I thought this was mainly true with older Class D amps? For example all the recent Bel Canto and Wyred amps advertise that they change the ICE input circuitry to accomodate a wider range of input impedances. Do you think this is still an issue?
I do agree with the power cable suggestion though. The Class D amps do seem to improve significantly when you clean up the EMI. I used a Signature Lessloss cord for this - it really brings the sound into focus. I found other components could make improvements - but similar in nature to how they would make improvements on a Class A/AB amp.
I still think the sound of the BC 500m seems lacking but perhaps its a question of power - I have low impedance speakers with a long run of speaker cable - so perhaps that was the issue. But then again I had tried them out on my older system that had high impedance speakers with very short cable runs and they definitely didn't sound as good as the Simaudio amp. At high volumes it was close, but at low volumes the Simaudio managed to stay very musical but the BC just compressed badly.
Since then I have switched to the Spectron - was not able to compare it against the older system/Simaudio, but so far from memory it provides a very similar sound to the Simaudio, but with more cleaneliness - so I am very satisfied so far.
|
DAn9,
What was the rest of the system you tried the Class D amps with? |
One true statement weaves it's way through these comments. Class D amps only sound as good as you make them sound. |
>>02-22-11: Muralman1
One true statement weaves it's way through these comments. Class D amps only sound as good as you make them sound<<
I hope you didn't stay up all night working on that. |
Audiofeil, I look at my gear and see there is not one item that can be bought in a brick store. Everything is direct ordered, or I made myself. Everything got better when I stopped listening to advice from audio medial. That includes you. |
Muralguy, so far you have not responded succinctly to the questions asked of who i.e. the impedance concerns (atmasphere's comments) and the ridiculous "none but one solid state preamp will do their best with class D" statement. I know for a fact there are quite a few.
How about addressing specific issues instead of the lightweight "one issue weaves true......." crap.
Thanks |
Might you suggest a preamp that can do better than I have? Perhaps I can get a dealer near here to bring one over for a listen.
I was asked for details of my system. On hindsight I should have directed the query to private messaging. |
Sure I can.
But components are system dependent and what is "best" in one system is just "good" in another. This is audio 101 but that's ok, you missed that class.
If there was one universal "best" for class d amps, everybody would be using what's in your system.
I can assure you from speaking to customers with systems far more sophisticated than yours, that is not the case.
Now about that impedance information atmasphere asked for........ |
