Which Class D Amplifier? PS Audio, Ghent, Nord, Merrill or other???
One thing I should point out: I have no explanation but my Class Damps sound pretty mediocre unless warmed up for about 72 hours. If you are auditioning amps cold, or recently moved, and you don't like the sound, that could very well be why. Do use your own ears. Don't think that Class D means zero warmup time. |
My experience aligns with Eric's.... All class D amps I have had in my system require warm up.... Particularly older generation class D could sound rather dry at power up time.... To sound their best, 24 hours or more were a must.... More recent amps, such as Rowland M925 and M535 sound pretty good a few minutes after power up, but if you want them to give you their very best, warm up is definitely necessary. Don't want to warm them up? No problem... Do what I do.... Leave them on at idele 24/7.... Being some 95% to 97% efficient, you will never notice their existance on your monthly AC bill, nor will they ever heat up your house..... Just remember to unplug your entire system when thunderstorms are around. G.
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byington711, If you're still following this thread I have a question: From your 1/4/19 post on this thread, I'm not sure if you own the stereo PS Audio BHK 250 or the mono block 300 amps in your system. Regardless, it's my understanding that the PS Audio BHK 250 stereo and 300 monos are class AB amps, not class D amps. Therefore, neither have the usual class D benefits of compact size, low weight, low operating temperature and low electricity consumption, Both of these amps are quite large (at least 17.1"W x 8.7"H x 14"D), quite heavy (83-100lbs), have high operating temperatures and consume considerable electricity (at least 175w @ idle and 850/1.600w @ full power at 8/4 ohms). By listing and suggesting these amps on a thread titled :Which class D amp?....", my concern is that some might mistakenly believe that the PS Audio BHK amps actually are class D. Can you please clarify and definitively confirm the PS Audio BHK areps are both class AB? Thanks, Tim |
As far as warm up is concerned, other than Bourbon has taken over and everything in the room is just better. +1 and more!! Amps are adjusted and calibrated at the factory for peak performance after a short 1/2-1hr warm when they've reached operating temperature, even tubes, to say they sound better after hours and hours is a furphy. Yes electrolytic capacitors like to be formed/polarized with a little time from new, this again is only a short time, and not every time it's turned on. Cheers George |
As far as warm up is concerned, I cannot hear any differences in a cold start up vs. the amp having been on for 4 hours... other than Bourbon has taken over and everything in the room is just better. Me neither. I can only hear it after at least 24 hours. I suspect this is very amp specific however. But mine are stock ICEpower modules. YMMV. |
georgehifi stated: " Amps are adjusted and calibrated at the factory for peak performance after a short 1/2-1 hr warm when they've reached operating temperature, even tubes, to say they sound better after hours and hours is a furphy." furphy? Please take our official multiple choice quiz on this weird word's meaning: A. furphy: An Australian English slang word meaning an erroneous or improbable story that is claimed to be true. B. furphy: An Australian English slang word describing the sound a down-under cat makes when attempting to cough up a fur ball. C. furphy: An Australian slang word, only permitted to be utilized in emails but forbidden to be ever spoken aloud and exclusively used by members of a certain Australian political fan club, that members claim translates to American English as 'covfefe'. D. furphy: How an Australian pronounces the word 'thirsty' after downing 2 gallons of Foster's beer. Correct entries may or may not be eligible to win an official Aussie Georgehifi Furry Fluffy Furphy Action Figure that performs Frequent Forward Flips, unofficially but commonly also known down-under as an OAGFFFAFFF just for fun. Batteries not included, Tim |
I can tell you why my amps are Always turned off after each use: Lightning strikes! I turn them off by unplugging from the wall. At $7K its not worth risking damage. I lost my entire sound system/ TV/ Digital readout on my Bridgeport mill, and more due to a strike which came in via the main power supply from the street. This is the second time I have been hit. The first came in from the grounding system and took out my well pump. |
Hello slimpikins5, if your amps do not require warm up, go with what your ears tell you.... Eric's report of very long warm up time for ICEpower amps is similar to mine.... Although with my old ROland M312 I started to hear better sound after one hour or so.... Very good sound after 24 hours of power up and crunching some signal, and best performance after one more day or two. NCore 1200 devices seem to have a faster warmup curve. As for George... Perhaps he and I are not talking to the same manufacturers *Grins!* Or perhaps his ears are dramatically different from mine and Eric's. About 24/7 power up.... I confess that my wintertime 24/7 practice will come to a schreeching halt by may, when the thunderstorm season starts around.... At that time I will change to a "turn off after music" policy. ... Even now, if I hear any distance thunder in the middle of the night, I get up, power down, and then disconnect the entire system from the AC outlets. G.
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Eric’s report of very long warm up time for ICEpower amps is similar to mine.... Glad to hear I am not alone. Although with my old ROland M312 I started to hear better sound after one hour or so.... Ahhh! This reminds me of a JR Class D amp I heard years ago, cold. It was painful to listen to. It was only many years later that I went with all Class D and didn’t put the two together. Thanks! E |
I'd like to answer George (above): Amps are adjusted and calibrated at the factory for peak performance after a short 1/2-1hr warm when they've reached operating temperature, even tubes, to say they sound better after hours and hours is a furphy. With another quote of his from another thread:
Best, E |
I had a Parasound Zone Master Class D amp on loan to give an evaluation of. It uses the ICE Power modules and in that particular case, it did sound better after a long warm up period or as Parasound told me at least a 200 hour break in period. And although it did sound better, to me it still had a high frequency range harshness which I didn't like. I removed it from service and put the A51 back in which of course is the Class A/AB amp and it was more pleasing to me. The zone master did have a noticeable boost in low/mid range and it was a 600 watt per channel vs. 400 watt as in the A51 at 4 ohms. However, when I installed my Class D Anthem M1 mono blocks, it was hands down no comparison in performance upgrade I heard immediately. The M1's blew away everything, no harshness at all, better sound stage/imaging and monstrous immense power. And no warm up needed, they just plain old sound fabulous. Hey, who could ask for anything more than 2000 watts per channel? |
I had a Parasound Zone Master Class D amp on loan to give an evaluation of. It uses the ICE Power modules and in that particular case, it did sound better after a long warm up period or as Parasound told me at least a 200 hour break in period. That's interesting. Also, here's the manufacturer, not George, telling you how long a warm up to expect. :) Poor George, found wrong again. I should point out it this is also interesting for me as I replaced Parasound A21s with IcePower. I could not hear a difference even knowing which was which. Best, E |
Concerning whether class D amp performance improves by leaving them constantly on 24/7, I tend to agree with erik_squires that there are sonic benefits. I initially turned all of my class D amps(2 stereo and a pair of monos all with linear toroidal power supplies) off each night, with amp off/down times varying between about 6 to 20 hrs/each. It was fairly obvious to me that my class D amps required some warm-up span of time to reach their optimum performance levels once they had been turned off for 6-20 hrs. How long did they take to warm-up? I didn't record time trials but I subjectively recall a time range between about 15 minutes and an hour. After a few weeks, I then began just leaving them on 24/7 and I could clearly hear my amps remained at a optimally warmed-up performance level.right from the get-go. For accuracy sake, it should be noted that my perceptions of when my class D amps are optimally warmed-up is a subjective measurement based on my ears and amps so YMMV. I should also state that, even if this warm-up period of my amps was proven to me to be a 'placebo affect', I would continue to leave them on 24/7 simply due to the impressive simplicity and convenience factors. The main point I want to make, however, is concerning the statements from slimpikins and georgehifi of " As far as warm up is concerned, I cannot hear any differences in a cold start up vs. the amp having been on for 4 hours... other than Bourbon has taken over and everything in the room is just better." Besides this statement being mildly humorous, I'm not sure these gentlemen understand that their agreed upon confession logically leads to only one conclusion of leaving class D amps on 24/7. Since turning class D amps off would result in insignificant electricity and monetary savings, and since both of these individuals are admittedly unable to discern the sonic differences between cold and optimally warmed-up class D amps, why would they not just leave these amps on 24/7 and gain/enjoy the dual benefits of simplicity and convenience? Do they have a phobia of a highly unlikely fire? Are they overly sensitive to the minute levels of heat produced by idling class D amps? Are they adverse to the simplicity and convenience of having their amps perpetually and immediately operating at the first inputted source signals? Are they being overly argumentative due to personal biases against the current large crop of good class D amps because they're not yet perfected? I really don't understand. Tim |
Hello Eric, you might have been referring to the first class D generation ROwland M201 or M501 monos.... M 501 sounded to me powerful but uninspiring no matter break-in and/or warmup.... M201 tended to run out of steam.... I heard them at length at a dealer, and then again at RMAF, where I also heard the M312.... AT RMAF the three amps were powering a pair of VIenna Acoustics Mahler.... M201 and M501 sounded like interesting experiments, but they were rather uninvolving.... Then They connected the M312 stereo, and.... I fell in love! Soon M312 replaced my beloved golden toned Rowland 7M class A/B high bias monoblocks. The logical successor of M501 was the M525, which I have not heard.... Third party reports were that while it did deliver a more emotional presentation than M501, it still sounded a little "non-denominational"... M525 was recently replaced by the bridgeable M535, which I have in my system. As already mentioned a few times on this thread, it delivers the emotional goods in spades... is an extraordinary amp under all audible parameters that I can think of. G. |
Give it up Eric, be happy with yours, that you say you can’t hear any problems with it. Stop trying to convince yourself by trying to convert others that can hear problems with it at the moment.https://forum.audiogon.com/discussions/the-future-of-audio-amplification/post?postid=1682049#1682049 |
@rsf507 , I wish I could be more precise, but I was listening to a system with equipment I never listened to before, so I really can't give an opinion because it might have been one component that affected sound reproduction to lead me to 'sounded okay'. I can say that there was nothing harsh or class D'ish, like I have heard before. Did it wow me? no. But, it was respectable. As I said before, I am waiting for Ralph Karsten's amp. If he can build it, it will be a killer. bob |
I’ve never heard one wanting a Class D amp simply for no reason other than wanting one. So it’s an odd sort of thread. Having said that, here is one that might tweak your fancy: AGD Vivace Monoblock Class D amps. http://agdproduction.com/ |
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I know it's almost impossible to find a dealer who has the Anthem M1 mono blocks on hand for a demo, but if you were able to find this one in a thousand dealers, take a listen with your favorite known music... I think you'd buy these. They are really good and you get all of the benefits of the efficiency. |
Knowing Ralph, he is going to surprise us all. Maybe, if he’s got the new GaN technology Like Merrill Audio has, and he's keeping it quiet till it’s released, you never know. https://forum.audiogon.com/posts/1682049 Cheers George |
The need for higher switching frequencies in class D amps is usually based on the theory that current frequencies are too low and cause sound anomalies in the human audible range of 20- 20,000 Hz. Current class D switching frequencies are typically in the 400-600 KHz range with theory proponents claiming switching frequencies above about 1.5 MHz are required to ensure there are no sonic anomalies in the audible range. The human ear is capable of decoding intermixed harmonics and timing cues into the 200khz plus ---with zero jitter. Micro and macro signals intermixed. With two ears doing this as a combined spaced pair, with the micro and macro intermixed temporal cues. So 1.5mhz, with zero distortion in all parameters might finally be good enough. Who knows. Except the amps, as good as they might be, very likely won’t make that spec. Hearing has just about nothing to do with 20khz sine waves. consider not looking at engineering specs .. and start looking at the literal library of research of the human ear. After all... its about the ear, not the amplifier alone with just engineering weighting and engineering measurement considerations. :) |
Damn George, for some one who doesn’t like Class DDamn yourself sunshine. I’ve always said it’s the future and has always had better bass, just needed something like these GaN transistors to cure it’s ill’s in the upper mids and highs, which it’s always had from day one and never changed. Just went off on different tangents but never got down to the root of the problems, too much dead time and too low switching frequency with output filter effect getting down into the audio band, and these GaN’s address all these ill’s. |
George, Weren't you the person who advised me to let those who like a technology go and enjoy it? Because every time an A'gonner says they are buying or like Class D you are right there telling them how wrong they are, bringing up 40 year old complaints and claiming, without evidence, that there are technical hurdles that must be overcome before Class D becomes listenable? Based on reading so many of your threads, I would say your biggest problem isn't technology, it's users. You just don't want people to like Class D. Best, E |
The human ear is capable of decoding intermixed harmonics and timing cues into the 200khz plus ---with zero jitter. Micro and macro signals intermixed. With two ears doing this as a combined spaced pair, with the micro and macro intermixed temporal cues. So what, specifically, does this mean for what specific class D amplifier? I could pull out a dozen measurements of your favorite Class A amp that show it is imperfect, and none of them may have anything to do with the perception of sound. Best, E |
Eric, I’d love to pull all the lore out of my pocket and then, as I give to to all, it turns into money in their pockets (for builders and buyers), and better hifi for all as a final outcomes. As that is how this works, the reality we are dealing with ..when it comes to talking on forums. Since I worked hard, very hard, over decades, pretty well 7 days a week...in order to know this stuff inside out.... I’m reasonably reluctant to just give that away. I need to be able to put food on the table in order to have the hard work be of use to me personally. So, I’ll do the thing where I will make the self aware and willing to work at it, make them aware of the problem’s realities, aware of the fallacies of their argument..and then they can work it out for themselves. Which is all an intelligent thinking person actually needs--if not knowing where the mistake was made, but just to know the mistake exists, at all. That's more than enough. If I was purely business minded and had zero empathy for my fellow man, I’d keep my damned mouth shut and let ignorance flounder, for as long as humanly possible. Some of us say as much as we can in that spirit, but we still get beaten up by the remorselessly ignorant, no matter what good we try to do. |
teo_audio stated: " The human ear is capable of decoding intermixed harmonics and timing cues into the 200khz plus ---with zero jitter. Micro and macro signals intermixed. With two ears doing this as a combined spaced pair, with the micro and macro intermixed temporal cues." Hello teo, Are you certain this is true? I've never heard or read this claim before and I'm very interested in reading about any research you know of on this subject. Contrary to your apparent opinion, I am very interested in the subject of human hearing and how the brain processes the signals from our ears and determines how we perceive these inputted signals. I believe the understanding of the ear-brain relationship, along with the understanding of room acoustics, are critically important in explaining how a solid, stable and 3-dimensional sound-stage illusion is able to be created in a room utilizing just 2 properly position speakers. My understanding is that humans cannot detect frequencies above approximately 20,000 Hz, which I believe is mainly based on early 20th century empirical research. In fact, audio recording and playback equipment since this time has been designed and built based on this upper frequency limit. Before I go any further, however, I'll wait for your reply just in case I'm misunderstanding something in your statement: " The human ear is capable of decoding intermixed harmonics and timing cues into the 200khz plus ---with zero jitter." Thanx, Tim |
You just don’t want people to like Class D.Really!!!! I’m pushing Class-D with this newer technology, because the old technology that’s basically been the same since it started (save for some input detours) is flawed. Reason why all detractors ALWAYS find the mid/highs are not right. You are the one every time I bring it up that is putting **** on this new GaN technology, possibly maybe hoping it won’t advance every time I’ve talked about it, what is it, do you have monitory interest in present day Class-D, because you sure do push the old, never the new. I want it to advance so the mids and highs get the same respect the bass has, then I’ll get 2 pairs to take the place of my inefficient boat anchors. We now have GaN users Merrill, Technics and AGD Production. And as GaN in an email said " We are unable to reveal due to the Non-Disclosure Agreement (NDA) with our customers. https://positive-feedback.com/reviews/hardware-reviews/agd-production-vivace-gantube-monoblock-ampli... Cheers George |
This guy knew what was coming a couple of years ago, even though not one amp was yet built using EPC's GaN technology. https://audiophilereview.com/cd-dac-digital/why-well-soon-be-living-in-a-class-d-world.html Cheers George |
they are the real deal in rendering an authentic 3D soundstage of the correct timbre pace and dynamics. I believe it, it has the GaN technology. Probably could have been below $10k if he didn’t use that marketing "tube thing", may have been even better sounding without tube pins in the signal path. Bet there’s a cheaper MkII without the tube thing soon. Even he said "Company founder Alberto Guerra admitted that he did it largely for the sake of visual aesthetics. “Otherwise a class-D amp just looks like a box,” he said. The amp uses gallium nitride MOSFET output transistors, which Guerra says switch faster and allow the amp to have a noise floor in the -120 to -130dB range. Power is rated at 200W into 4 ohms." |
Here's another press release, this time from
Murata Manufacturing Co's (subsidiaries P-Semi) Murata is one of the larger semiconductor manufactures and suppliers. https://www.psemi.com/newsroom/press-releases/545048-peregrine-s-new-fet-driver-brings-industry-s-fa... Cheers George |
I’m pushing Class-D with this newer technology, because the old technology that’s basically been the same since it started (save for some input detours) is flawed. Reason why all detractors ALWAYS find the mid/highs are not right. Right, you've called all Class D except for something new and expensive "junkers." Further, you have disparaged everyone who likes Class D as not having good enough hearing, and you told me to leave those who want to enjoy what they like alone. Lastly, and most importantly, here like everywhere else, your ears refuse to accept the reality that a lot of modern class D is already excellent. A real charmer.. |
I know I am, and believe most class D amp proponents on this thread are, very open minded toward further potential advancements such as the newer GaN FETs, improvements in the filters used to remove the carrier frequency prior to amplification and even the as of yet unproven benefit of MHz-plus signal carrier frequencies. With the extremely high quality performance levels of such a large number of class D amps using just currently available technology, significant future improvements in class D amp performance levels is difficult for me to imagine. I honestly cannot identify any aspect of my good quality D-Sonic M3-600-M class D amps’ performance that I would characterize as deficient. As an experienced user and proponent of good class D amplification, I have no choice but to consider claims of class D harshness and sonic anomalies in the midrange and treble as illegitimate, view those claiming such with great skepticism and suspect them of having ulterior motives. I state this based on my own experiences using multiple class D amps in my system for about 4 yrs, the complete lack of evidence that current signal carrier frequencies in the 400-600 KHz range affect frequencies in the audible range, anecdotal claims of class D upper frequency harshness being based on early class D amps and very rarely on the newer good quality amps and my complete inability to detect any sonic anomalies or upper frequency harshness. If you can’t perceive any sonic issues then you have no sonic issues, right? To be fair and empathetic to those who honestly hear sonic anomalies in good quality class D amps that I and many others have never detected, perhaps future research will discover that these anomalies do actually exist but only some individuals are able to detect them. If this is the case, that is an affliction that I wouldn’t wish on georgehifi, because listening to music through good class D amps is really quite spectacular when you’re not afflicted with this horrific condition. Just really bad dumb luck. I hope the GaN FETs and/or higher switching frequencies will eliminate or at least ease the suffering of all those afflicted with this horrendous and inhumane potential explanatory condition. Best wishes, Tim |
I state this based on my own experiences using multiple class D amps in my system for about 4 yrs, the complete lack of evidence that current signal carrier frequencies in the 400-600 KHz range affect frequencies in the audible range, anecdotal claims of class D upper frequency harshness being based on early class D amps and very rarely on the newer good quality amps and my complete inability to detect any sonic anomalies or upper frequency harshness. If you can’t perceive any sonic issues then you have no sonic issues, right? Exactly. We can debate switching speeds forever, but the fact remains: No one has ever said to me "Geesh, those amps, they're awful, I can hear the switching." No one has EVER been able to tell whether my amps were linear or Class D unless told they were in advance. Best, E |
