I will add that my class D Mytek Brooklyn amp is very neutral, revealing and smooth in the HF. It briefly shuts down at 300 watts into my inefficient electrostatic + parallel Enigmacoustics tweeter combination whose impedance is about 2 ohms in HF. SO WHAT--it plays music beautifully over 99% of the time. I am not complaining about its technical deficiencies. I am looking forward to ricevs' more powerful amp.
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find out whether the phase shift has any relevance in your listening. If you believe there nothing to hear when you have 70 degrees phase shift at 5khz and still 50 degrees at 2khz!! then there’s no hope for you. https://ibb.co/JdrgGBH I have heard class D amps that sound euphonic/rolled off in HF, and others that sound harsh. All because of the setting of the switching frequency output filter and where it acts, either "too high" or "too low" "rolled off in HF" (too low) , and "others that sound harsh" (too high), with today’s 500khz switching frequency. Raise that switching frequency 3 x to 1.5mhz as you can with GaN, and you’ve got rid of the problem because the output filter can then also be raised 3 x higher, and then you don’t get that phase shift so low down into the audio band or the problem of as you say ("rolled off in HF, and others that sound harsh"), because the filter then can be set to do it’s job fully and rid the switching frequency completely and not effect the audio band with phase shift. It’s that simple, even the most technically inept should be able to understand, maybe! Or you can believe the ones that are trying to tell you it doesn’t matter. From day one Class-D has had this problem, because of it’s low switching frequency/filter. |
There is indeed no hope for you. All your pseudoscience data is nothing more than pseudoscience because without listening correlation it is irrelevant to the pursuit of audio excellence. Accuracy in sound doesn't necessarily correlate with specs. It is obvious that you don't do any serious listening to confirm what you claim. To prove me wrong, present to this community your listening experiences that corroborate what your measurements say. Without your honest descriptions of your listening, your comments can be ignored. And your simplistic explanations of rolled off or extended HF based on setting of the switching freq output filter are ignorant until you personally measure a product and correlate with the listening. My credentials are many decades of having played solo violin in major concertos with orchestra, chamber music playing, and listening up close and further away in the hall. I have played examples of most of the great violin masterpieces of the 17th through 19th Century. It doesn't appear that your musical credentials are in my league. I am also an integrative medicine physician who knows that clinical observation must be correlated with objective lab, electro- and neurologic physiologic and radiological data. Just as it takes decades of clinical experience to know how to combine clinical and objective data in a useful perspective, it also takes informed listening and musical experience and competence to know how to integrate subjective and objective audio data. Even the leading electronics designers are still learning. They change parts and do their tweaks based on listening. If you claim to know more than anybody, design your own amp, send it to me, and I will tell everyone the truth about it. If it really is great sounding, I am in the market for SOTA and would happily pay you for it as well as proclaim that you really know what you are talking about. I will wait patiently. |
design your own amp, send it to me You just need to search buddy, I’ve built some of the biggest pure class-A solid state that were water cooled, one that was a three man lift, explained in great detail in Audiogon and other forum pages if you could be bothered looking.!! This is what I use at present https://ibb.co/zNMMnpT https://ibb.co/8XqKvJd |
Wait, so George is Peter? It all started in 1976 when Peter Stein of “ME Sound” started manufacturing high-quality audio amplifiers in Australia. Sadly in October of 2003 circumstances led to the close-down of manufacturing operations. Since that time they have not left their loyal customers totally in the cold, but have been provided advice and repairs wherever possible, within the resources and time frames available. Many models and units were built during those 26 years and the advice I’ve heard is that they are extremely reliable and serviceable for many years to come. Notice he says manufactures. George has never designed a thing in life. Just resurrected a company from the dead, but it doesn’t appear any have actually been made and sold. http://www.meamplifiers.com.au/me-history-news.html Ironic that George calls others shills. Just part of his classic psychological projecting. |
Well you have just made yourself look like a total ? Read again and take it in, I didn’t say I built Peter’s amps who is a long time mate, and not at all in a good way. I said it’s what I’m using at the moment, mcreyn get a life, really!!! |
Typical George, nothing to show, so attempts to distract. Here is your chance George, show us your designs and products. Wait, weren’t you going to stop replying to this thread a few days ago? I would still appreciate a response showing my calculations which refute your unfounded claims that a ML2 will outdrive a Ncore 400 amp into low impedance loads are somehow flawed. It should be easy for you given your expertise. |
Thanks for posting the info about the ME amps. They may sound excellent, but that is not the central issue discussed here. The issue is that you have not shown you understand the correlation of technical measurements with tonal qualities. Worse is that you keep dodging this issue as if you don't care about it. I'm not saying that I do understand the correlations, and most good designers admit that they don't fully understand either. That's why they design according to their technical concepts, but change and tweak based on listening. Bruno Putzeys has written that he works this way. I assume you respect Bruno, so why don't you follow his lead? |
And you believe all he says, I believe my own findings and an Electronic Institute before any manufacture spruiking and trying to make a buck. Once again here is one main difference why a Class-D with Mosfet will not drive into a hard speakers load like the OP’s Thiel CS5’s like a good linear amp like the ones I have suggested with BJT (bi-polar) output stage. And Class-D’s don’t come in BJT From Electronics Foundations: Semiconductor Devices [Lecturer] BJTs tend to have better, more linear gain characteristics…and can give you a lot higher voltage gain than MOSFETs.…They’re also able to handle higher output currents…and have a lower output impedance.…That gives BJTs a huge advantage over MOSFETs…for building amplifier circuits…that need to provide a significant amount of output power…and or drive loads that have low input impedance.…MOSFETs are going to have a harder time…driving a low impedance load…because they have a higher output impedance.… |
George, I read what anybody has to say, but the only thing I trust is my own EARS. Do you believe the Electronic Institute rather than your ears? If so, then you believe your ears don't matter and therefore you have lost credibility. I bet that few or none of the Electronic Institute writers have commented about the audibility of any of their claims either. Many audiophiles like me are interested in accuracy of sound from listening, not in writing a postdoc thesis about circuitry/devices/etc. Bruno seems to have expertise in technical theory, but also does the listening. That doesn't mean that I totally agree with what he likes or thinks is accurate sound, but I respect him or anyone else who do both theory and listening. |
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Viber6, I believe most equipment designers/engineers are pretty clear that there are two aspects of designing a new piece of equipment, the engineering side of designing, then the black art of voicing. I believe both Jason Stoddard of Schiit and Paul McOwen of PS Audio have been clear that there is an aspect of equipment engineering where the science says changes shouldn’t make a difference in the sound, but yet they do. |
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Give up Ralph, a good BJT amp will always drive into these sub 2ohm low impedance’s and do the wattage doubling act better than a Mosfet Class-D even GaN based one The best linear amps that can do it are all BJT M.S Electrical Engineering, University of Southern California (2017) Pros for BJT:And there’s plenty more, I’ll posting them till the cows come home. Please show just one from any great known amplifier designer (beside you) that says the opposite! |
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Like I said. Please show just one post from any great known amplifier designer (beside you) that says the opposite! I my view your just shilling with suspect claims of class-d being able to drive these OP's speakers to their max potential that I'm responding to, for your products yet again, in an indirect way, but always in threads that have a potential sale, whether it be your OTL, Preamps, Zero, Class-D now |
George, So what that "a good BJT amp will always drive into these sub 2ohm low impedance’s and do the wattage doubling act better than a Mosfet Class-D even GaN based one The best linear amps that can do it are all BJ" blah blah. The musical resolution at a fraction of 1 watt could be mediocre. But you don't know this because you don't listen or you don't know what to listen for. Don't attempt to refute me unless you can prove that your musical credentials are on par with mine. |
mcreyn
You are treading on thin ice, publicly questioning moderators decisions, I've seen one other removed from these forums for this. All submissions, whether they be questions or answers, are subject to moderation. Any designated moderator will have to the right to remove content that he or she deems inappropriate. As for your other question, go listen to a pair of 25w ML2 monoblocks, doubling is your key to which sounds better at the 2ohms "to a given level". Not which sounds louder, a PA amp at 3000watts will do this, such as the Behringer NX3000 will do it for just $299 go buy one!!!. https://www.parts-express.com/behringer-nx3000-ultra-lightweight-class-d-3000w-power-amplifier--248-7012 |
@mcreyn - "George, still waiting for you to demonstrate how an amp putting out 200 watts at 2 ohms is flowing more current than one putting out 400 watts at 2 ohms." I'm pretty sure this is George's point. This is from the Pass Labs website - https://www.passlabs.com/press/power-supplies-commentary-consumers: "If the stereo amplifier is rated 200 watts per channel pure Class A, it will draw about 1000 watts all the time, meaning that about 3000 watts of power transformer is called for, no less." Also from the same article on Switching Power Supplies: "This can be a deep subject, but suffice it to say that I believe that some of the same caveats apply to switching supplies as linear regulators. Again, they should be rated far beyond the nominal current requirements of the amplifier circuit, particularly as the switchers I have seen usually degrade badly beyond their ratings. Also, it helps if the power supply capacitors before and after the switcher are very substantial. This is typically not the case, since one of the primary motivations to use switchers is to save money." And here's an example from Stereophile for the Mytek Brooklyn Class-D amp that viper6 owns: Defining clipping as when the THD+noise in the output reaches 1%, Mytek specifies the Brooklyn Amp as clipping at 250Wpc into 8 ohms (24dBW), at 300Wpc into 4 ohms (21.7dBW), and at 400Wpc into 2 ohms (20dBW). I measured clipping powers of 245W into 8 ohms (23.9dBW, fig.4) and 315Wpc into 4 ohms (22dBW, fig.5), both with both channels driven. However, when I tried to measure the clipping power into 2 ohms, the Mytek went into protection mode at 310W (18.9dBW), with any further increase in the input voltage not resulting in a higher output power - https://www.stereophile.com/content/mytek-brooklyn-amp-power-amplifier-measurements I believe all George is saying is that regardless of manufactures specs, it's probably in the best interest of a potential buyer for any amp to have measurements done independently to support the specs. It seems to be more often than not that when Stereophile measures Class-D amps, there's a comment about careful matching to low impedance speakers. |
golfnutz, Thanks for quoting Stereophile on my Mytek Brooklyn amp. George would say it is a mediocre amp because it doesn't increase its output capability much as the impedance is lowered. SO WHAT? It is a budget amp which happens to have accurate/neutral sound within its power limitations. It sounds much more accurate/neutral than the pure class A Levinson ML2 which was a perfect voltage source with hefty power supply. We are here to find amps that reveal more music, not to debate specs. The latter is for academic societies. Specs are useful to rule out very low powered amps for very inefficient speakers, for example. |
M.S Electrical Engineering, University of Southern California (2017)Here is more of the text George didn't include which precedes the above text by Jacob VonWagoner: BJT's can give you a lot higher gain. Just take a bunch of components and compare them, and you'll find the BJT's give you better gain characteristics and therefore require fewer gain stages.The words 'gain', 'linearity' and 'bias voltage' tell you that this has nothing to do with class D amplifiers which do not operate their output devices in the linear region. Instead class D amps go from Off to On and spend as little time in the middle (linear region) as possible. This is the reason they are so efficient. Obviously while all this stuff is correct with regards to conventional amplifiers it has nothing to do whatsoever with class D amps. George's remonstrations notwithstanding. |
All I’m talking about is the OP’s Thiel CS5’ speakers and today’s similar speakers like nearly all Wilson Alexia ect ect and what will drive them the very best into those varying low impedance’s they have. And that would be one of the linear bjt output brutes, with a power supply big enough that can power Lower Manhattan, ( read that in Stereophile somewhere sounded good). And no Class-D I know could as do it as well not even the 3000w!!! Behringer. The old Mark Levinson ML2 (BJT monoblocks) at just 25w would slay it for sound quality and control "to a given volume". https://ibb.co/X5rfnXL Cheers George |
Our OTLs do a nice job on the Alexia, You’ve now got to be joking!!, out of courtesy I didn’t mention which OTL’s wouldn’t drive these 89db JBL’s 1400’s, but now you leave me no option, they were a pair of your M60’s!!!!! and now your saying they’ll do a nice job on Wilson Alexia!!! ???? Probably the hardest speaker know to man to drive. This is just getting too ridiculous for words https://forum.audiogon.com/posts/1803629 https://forum.audiogon.com/posts/1804702 |
@viber6 - no need to get defensive about your Mytek Brooklyn amp. No where did I mention anything about quality of sound from any amp. My comments were specific to mcreyn's question to George. I would also like to add, my post has everything to do with the question asked about Class-D amps for 2 ohm speakers (from the OP), as the Manufacture specs do not align with the measurements from Stereophile. And I'll repeat it again, 'this is George's point about Class-D amps not being suitable for low impedance speakers - make sure they measure as the specs suggest because more often than not, Stereophile mentions the amp will have a hard time with low impedance speakers." Please don't twist my words around again and make this into something it isn't. |
golfnutz, In my post, I was not defensive about my Mytek Brooklyn amp. I thanked you for quoting Stereophile measurements whose power capabilities are at odds with the excellent sound quality described in the review and confirmed by my listening. My "SO WHAT" comment was intended to refute George who holds up the Levinson ML2 as the paragon of excellence for technical specs. The truth is that it sounds like muddy molasses at any SPL despite its power specs. But George has never heard it, doesn't care to listen, and merely goes on and on about irrelevant technical subjects. As to your point about the usefulness of independent measurements, I agree. |
You’ve now got to be joking!!, out of courtesy I didn’t mention which OTL’s wouldn’t drive these 89db JBL’s 1400’s, but now you leave me no option, they were a pair of your M60’s!!!!! and now your saying they’ll do a nice job on Wilson Alexia!!!MA-1s. Not joking- Wilsons have always been fairly efficient despite their impedance. They seemed to sound just fine to me. They played loud enough too but it was a smaller room IME. We also noted that particular customer was going through power tubes faster, which is no surprise since a lower impedance will cause more of the power generated by the output section to be dissipated in the output section- and that's hard on tubes. We finally got him to install a pair of ZEROs and then the tubes stopped failing, plus he had more power. The Wilsons traditionally have been fairly efficient so none of this should come as any surprise. The national sales manager at Wilson (John Giolas) had our amps for several years. |
We finally got him to install a pair of ZERO This is just trying to save face. Of course you did, an expensive band-aid fix, that will never get the best from the Alexia, instead of pointing him in the right direction for the right amp even at the cost of maybe an OTL sale. This Wilson Alexia "customer", was sold totally wrong amp for these speakers that have a pig of a load. That with the right amp eg: Gryphon Antilion and similar current pushing demons, will make them sing at all levels. I know as my friend Edgar Kramer owner of Soundstage Australia, owns a pair, and we’ve tried many amps on them, believe me "NO OTL" will drive them anywhere near their full potential, even with a Zero autoformer. https://www.soundstageaustralia.com/index.php/reviews/84-wilson-audio-specialties-alexia-series-2-loudspeakers John Atkinson Stereophile Test HiFi News Lab Report Now back on topic to the OP’s problem of driving his Thiel CS5’s which maybe an even worse/similar load as these Wilson Alexia’s. "Here's a thought!! maybe the OP needs some OTL’s"??????????? |
George who holds up the Levinson ML2 as the paragon of excellence for technical specs. This Stereophile’s JA’s statement, is the typical case where a 25w amp like the ML2’s with doubling capable wattage current will drive a pig of a load like these Alexia’s and the OP’s speaker "to a given level" with perfection better than any 3000w class-d can. John Atkinson Stereophile Test |
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I would if it wasn't warranted, and usually do. |
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You are seriously deluded, and twisting words to make yourself look like you know what your talking about, which you clearly don’t. I don’t recall ever mentioning that the ML2 monoblocks are Class-A "in this thread", that’s just a bonus, it's that they are 25w at 8ohms!! and said they can double all the way to 1ohm It would do the same if the bias was wound back and they were just class-B, and would still able to double down to 1ohm, and that’s because it has heaps of current sunshine, and that’s what matters for driving low impedance’s like the OP or Alexia speakers to their best, to a given level as this amp is still only 25w after all. |
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I'm sorry George, let me restate that. I've never seen you pass an opportunity to tell some one who says they like class D why they should not. If there is anything you are passionate about here it seems to be correcting people who like Class D. Even when an OP specifically asks detractors of Class D to go elsewhere, becuase they wan to read about relative differences between Class D amps, well, in moments there you are, telling them why they need to wait for a tech no one has heard of, or consider a linear amp instead. And in terms of style, you have routinely characterized others and projected your own patterns onto posters, especially me. |