Volunteer sir sanders zingmore Posted December 20, 2018 Volunteer Posted December 20, 2018 45 minutes ago, georgehifi said: He wasn't a customer, he was a friend, the President of ASON audio club Richard Wong and the Wilson 8's or 7's in question he bought from Edgar Kramer at the time reviewer for Australian HiFi, ask them all about it if you don't believe it. Both had the same amps at the time. Yes I did the tweeter diaphragm work for Richard and there was no charge, I believe he kept the "blued voice coil"/diaphragms, so you may even have a look for your self if he still has them, damage was done with a "considered" perfectly healthy pair of class-D mono blocks, which both Richard and Edgar had for amps at the time they used those Wilson's. One single anecdotal experience and we should get rid of all class d amps because they fry tweeters.
aussievintage Posted December 20, 2018 Posted December 20, 2018 1 minute ago, Sir Sanders Zingmore said: One single anecdotal experience and we should get rid of all class d amps because they fry tweeters. Secondhand speakers as well.
georgehifi Posted December 20, 2018 Posted December 20, 2018 (edited) 1 hour ago, aussievintage said: I am impressed by how you rationalise that. Just need to look here, and think a little. https://www.stereo.net.au/forums/topic/256256-class-d-amplification/?do=findComment&comment=4024001 Edited December 20, 2018 by georgehifi
Buffle Posted December 20, 2018 Posted December 20, 2018 15 minutes ago, georgehifi said: Far from it water off a ducks back, that was for you and your lot. Owners of class-D amps or Kii D-power speakers, their defensive mechanisms set in when they're shown opinions of master electronic engineers like those of Cyrill Hammer and the others I've posted that have far more knowledge in their little toe than those have here. Cyrill Hammer (Souloution) : "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." https://soulution-audio.com/series7/soulution-701-mono-amplifier/ I've always said that Class-D will be the topology that takes the hiend mantle one day, when that day comes I'll be the first to off load my ME850's to get it. Technics have shown now that doubling the switching frequency to 1.5mhz is the way to go of what it is now and always has been, around 600khz. It's the way to get rid of most of the sound quality complaints of upper mids and highs that everyone who's heard say it has. But as Cyrill Hammer says several mhz would be even better. I would bet my life on it that doubters here that can't hear the problems with current Class-D will be the first to dump their present Class-D's for the higher switching frequency ones when they're available for the main stream, and call rubbish on the older ones they had, and so you should. Cyrill Hammer a master engineer? Is he an engineer at all? What research has he undertaken and what patents can be attributed to his (personally) designs (serious question - I don't know). And when did he make that statement? Was it prior to seeing solutions to the problems by those such as Bruno Putzeys? In any case, I'd be careful in forming my opinions based on the comments of those with little or no expertise in the technology, and especially of those with a stake in the industry and without the patents held by rivals receiving high praise with products far cheaper. Technics have shown that a product capable of receiving highly positive reviews can be designed using a switching frequency of 1.5 MHz. Hypex has shown how to do similar with lower switching frequencies. If a product obtains high praise by a reviewer does this somehow negate all products before it? From recollection, one reviewer said that he considered that the Technics product provided levels of detail he'd never heard before or similar: is your amplifier now a piece of junk? If we go down that path we'll be forever running in circles, as many products seem capable of receiving this claim by one reviewer or another. As for what products may exist in the future, how is this relevant? We are talking about performance available now. Can the best class D amplifiers compete with the very best class A and class AB amplifiers? Well, many people who have heard and used the products say "yes". Mola Mola amplifiers (Hypex nCore), Bel Canto Black (Hypex nCore), and Australia's own Kyron audio speakers (Hypex nCore) have all at some stage been called the best of the best. Personally, I think that if you took the best examples of class A, class AB, and class D and listened back-to-back you'd be hard pressed to pick them apart, if you could at all. 5
Grant Slack Posted December 21, 2018 Posted December 21, 2018 23 hours ago, Buffle said: Cyrill Hammer a master engineer? Is he an engineer at all? What research has he undertaken and what patents can be attributed to his (personally) designs (serious question - I don't know). And when did he make that statement? Was it prior to seeing solutions to the problems by those such as Bruno Putzeys? In any case, I'd be careful in forming my opinions based on the comments of those with little or no expertise in the technology, and especially of those with a stake in the industry and without the patents held by rivals receiving high praise with products far cheaper. Technics have shown that a product capable of receiving highly positive reviews can be designed using a switching frequency of 1.5 MHz. Hypex has shown how to do similar with lower switching frequencies. If a product obtains high praise by a reviewer does this somehow negate all products before it? From recollection, one reviewer said that he considered that the Technics product provided levels of detail he'd never heard before or similar: is your amplifier now a piece of junk? If we go down that path we'll be forever running in circles, as many products seem capable of receiving this claim by one reviewer or another. As for what products may exist in the future, how is this relevant? We are talking about performance available now. Can the best class D amplifiers compete with the very best class A and class AB amplifiers? Well, many people who have heard and used the products say "yes". Mola Mola amplifiers (Hypex nCore), Bel Canto Black (Hypex nCore), and Australia's own Kyron audio speakers (Hypex nCore) have all at some stage been called the best of the best. Personally, I think that if you took the best examples of class A, class AB, and class D and listened back-to-back you'd be hard pressed to pick them apart, if you could at all. Hello, these are excellent points, all. I have looked at the basic arguments against class D amplification, and they appear to be entirely without foundation in fact and evidence, if the arguments put forth are meant to be an overall critique of all class D amplifiers available for the past 5 or so years. Evidence, that an expensive class D amp has very poor measurements and performance, means nothing at all if other class D amplifiers, at better price points too, don't share those measurements. Evidence, that switching frequencies of below 100 Khz are easily audibly deficient, is not an adequate argument that multiple-MHz switching is the minimum audiophile requirement, if class D amps exist with 200-400 kHz switching that would easily pass any blind test as being audibly without fault. Evidence and opinions trawled from the pre-UcD era: seriously, they mean nothing today, and might as well be talking about germanium transistors c. 1955. And, as you wisely pointed out, industry interviews and white papers completely fail any serious test, and the sensibly sceptical response is to treat them as biased, prejudiced, jealous, egotistical, and self-interested, to varying, but invariably disqualifying, degrees. Regards Grant 5
crisis Posted December 21, 2018 Posted December 21, 2018 On 20/12/2018 at 12:52 PM, georgehifi said: And why nearly every detractor of Class-D says it's the upper mids and highs that are the problem with it, (what a coincidence?) just because you cant' hear it doesn't mean others can't. Cheers George A lot of "others" cant. http://www.theabsolutesound.com/articles/primare-i32-integrated-amp/ " I customarily associate the retrieval of these low-level harmonies with classic Class AB designs, not Class D—a result that further supports my belief that, next to cone-driver box-loudspeaker technology, the components that have made the greatest leaps in sound quality are Class D amps. " " The shaded top end and the glaze that often smeared transparency were not part of the I32 personality. What I did hear in spades were pristinely clean backgrounds and an atmosphere devoid of any suggestion of electronic hash or grain. " https://6moons.com/audioreviews/primare/1.html The bass is lean and quick rather than massive, reaches deep and never wants for control. The mids continue seamlessly and any kind of music sounds fast and dynamic. Here the machine pulls no favorites. In direct comparison to amps with superior midband resolution one realizes how more remains possible. The treble is crisp to contribute to the amp’s signature of being agile and open. Not hyper present the highs aren’t recessed either and mostly just right. The dimensional perspective is flawless, realistically sorted and comfortably distanced. Localization focus is believable, i.e. neither artificially sharp nor diffuse. https://hifipig.com/primare-i32-integrated-amplifier-dac-media-board/ "The I32 will take all your musical tastes and run wild with them. It’s not coloured or warm, it’s rich and vibrant, it’s not sterile or analytical, it’s clean and accurate. The I32 is fast, controlled and utterly poised, it won’t bite you if you give it some volume or listen to Spotify Premium with the High Quality button turned on and it won’t feel limp or lifeless when you want t listen to something more beautiful. With dynamics that match the music and an effortlessness that is just so noticeably true, the I32 will remain a favourite for some time to come!" https://www.hifinews.co.uk/news/article/primare-i32-pound;2200/9376/ There was no softening of the piano here, yet neither was the edgy sound of the dense production uncomfortable. The sound was open, the pristine clarity allowing one to hear individual layers of the recording.
davewantsmoore Posted December 21, 2018 Posted December 21, 2018 On 20/12/2018 at 1:22 PM, georgehifi said: You fail to mention the the effects of the output filter, they have to have to get rid of it, and how the effects of that filter reach right down into the audio band from 20khz down to 5khz sometimes 3 khz. The reality is that there are class-D amplifiers where the effect of the filter does not reach into the audio band. You are 100% right that phase and amplitude shifts in the audio band are a problem (and usually unacceptable). You are wrong that the only way to solve this issue is to raise the switching frequency. On 20/12/2018 at 1:22 PM, georgehifi said: just because you cant' hear it doesn't mean others can't. He didn't say he could or couldn't hear it ..... You specifically asked him about the switching noise (not the in-band response). Please stop "playing the man, instead of the ball"... You wouldn't do this in person, or if you did someone would give you a sore nose. On 20/12/2018 at 1:36 PM, aussievintage said: Bottom line George, if you were right, then those filters would be wrecking the sound from the digital amp I (and many many others) listen to every day. They don't, so you must be wrong. Well, to quote some wise words I once heard.... "If you can't hear it, doesn't mean others can't" What I mean by this is .... just because you can (or can't) hear something, doesn't mean it isn't happening. The output filter in your switching amplifier might very well be causing amplitude and phase errors in the audio band. You might just have "tin ears" .... Don't get me wrong, I know what you mean (If you can't hear it... then it doesn't matter ... is it's not "wrecking" the sound) What George is wrong about, is that this problem applies to all switching amps. So maybe you have one which doesn't suffer form the issue. George is quite right that some (many) switching amps have this (and other) problem(s) .... but would like to ignore all evidence which doesn't support his world-view.... and I think anyone following along would have lost count of the number of logical-fallacies employed.
aussievintage Posted December 21, 2018 Posted December 21, 2018 9 hours ago, davewantsmoore said: What I mean by this is .... just because you can (or can't) hear something, doesn't mean it isn't happening. The output filter in your switching amplifier might very well be causing amplitude and phase errors in the audio band. You might just have "tin ears" .... I don't know Dave, I've been listening to quality audio for a very long time. It would have to be bad to be heard above, for example, amplitude and phase problems from the speaker operating in a real world room. I do notice that as soon as critics of digital amps are questioned, they switch to discussing only the very high end stuff. The implication is that, for everything else, there's no problem.
davewantsmoore Posted December 21, 2018 Posted December 21, 2018 2 hours ago, aussievintage said: I don't know Dave, I've been listening to quality audio for a very long time. With your tin ears??!? ..... the possibility is there, right?! .... Like I said, audibility is often a bad way to judge whether a problem is actually present ..... as opposed to a way to judge whether you "care about it". ('cos if it's inaudible to you, then you obviously won't care) 2 hours ago, aussievintage said: It would have to be bad to be heard above, for example, amplitude and phase problems from the speaker operating in a real world room. I do notice that as soon as critics of digital amps are questioned, they switch to discussing only the very high end stuff. The implication is that, for everything else, there's no problem. *nods*
Peta Posted April 9, 2019 Posted April 9, 2019 Plenty of passionate statements here. As always when discussing Class D. I think the simplest way of describing my own experience is that for a cost of circa $5k for a biamped set of power amplifiers, the results are: Class D (Bel Canto Ref series) give me as good or better results than three alternative Class A/B options that cost more. I can accept that there may be a small difference in top end sound. Whether that difference is material is a subjective assessment, of course. I am not sure that the differences are better or worse - just different is the only thing I can be sure of. All three Class A/B amplifiers sounded different to each other too. Each of them was trialled in home due to two generous dealers. I offered to buy the amp if it sounded significantly better. What the Bel Canto amplifiers do better than the others is to have very tight and controlled bass, clear and precise positioning in stereo and whatever you call the impression of not being troubled by high dynamic range. I would have to pay over $10k to get significantly better and probably more than 18k to bi-amp from Class A/B. By contrast $7k spent on a DEQX to adjust for room, speaker and anything else in the system produced startlingly improved sound across the spectrum. $1,250 spent on room treatments in the bass and midrange produced a marked difference as well (before the DEQX). On top of that an upgrade from an Auralic Aries Mini to an Antipodes music server/endpoint at $6k produced a result about half the perceived improvement compared to the DEQX. Spending $12k on good bi-ampable speakers sets a kind of baseline for the old idea of 40% on speakers, 20% on source, 30% on amplification and 10% on cables etc. Lesson? There is more to this than just direct one-on one comparison. It is a matter of where you spend your money to get an optimal result. To my mind and judging from direct experience, spending a moderate amount on good Class D amplifiers and putting the "savings" into other areas that deliver more cost effective improvements. 4
andyr Posted April 9, 2019 Posted April 9, 2019 8 hours ago, Peta said: Plenty of passionate statements here. As always when discussing Class D. I think the simplest way of describing my own experience is that for a cost of circa $5k for a biamped set of power amplifiers, the results are: Class D (Bel Canto Ref series) give me as good or better results than three alternative Class A/B options that cost more. I can accept that there may be a small difference in top end sound. Whether that difference is material is a subjective assessment, of course. I am not sure that the differences are better or worse - just different is the only thing I can be sure of. All three Class A/B amplifiers sounded different to each other too. Each of them was trialled in home due to two generous dealers. I offered to buy the amp if it sounded significantly better. What the Bel Canto amplifiers do better than the others is to have very tight and controlled bass, clear and precise positioning in stereo and whatever you call the impression of not being troubled by high dynamic range. I would have to pay over $10k to get significantly better and probably more than 18k to bi-amp from Class A/B. By contrast $7k spent on a DEQX to adjust for room, speaker and anything else in the system produced startlingly improved sound across the spectrum. $1,250 spent on room treatments in the bass and midrange produced a marked difference as well (before the DEQX). On top of that an upgrade from an Auralic Aries Mini to an Antipodes music server/endpoint at $6k produced a result about half the perceived improvement compared to the DEQX. Spending $12k on good bi-ampable speakers sets a kind of baseline for the old idea of 40% on speakers, 20% on source, 30% on amplification and 10% on cables etc. Lesson? There is more to this than just direct one-on one comparison. It is a matter of where you spend your money to get an optimal result. To my mind and judging from direct experience, spending a moderate amount on good Class D amplifiers and putting the "savings" into other areas that deliver more cost effective improvements. Great post, Peta. But you sure have a heap of money to spend. Andy
georgehifi Posted April 9, 2019 Posted April 9, 2019 (edited) 17 hours ago, Peta said: Class D (Bel Canto Ref series) give me as good or better results than three alternative Class A/B options that cost more. Yes Peta, the best Class-D's I have heard so far have been the Belcanto Ref 600 monoblocks, so long as the speakers are a smooth benign impedance load that don't dip below 4ohms too much, Maggies come to mind. I could live with them with this type of speaker. "That dotted - phase line would help push the small impedance peak back down and make it seem to look like a flat impedance line to the amp." Cheers George Edited April 9, 2019 by georgehifi
Peta Posted April 10, 2019 Posted April 10, 2019 13 hours ago, andyr said: Great post, Peta. But you sure have a heap of money to spend. Andy Not anymore andy 1
Peta Posted April 10, 2019 Posted April 10, 2019 4 hours ago, georgehifi said: Yes Peta, the best Class-D's I have heard so far have been the Belcanto Ref 600 monoblocks, so long as the speakers are a smooth benign impedance load that don't dip below 4ohms too much, Maggies come to mind. I could live with them with this type of speaker. "That dotted - phase line would help push the small impedance peak back down and make it seem to look like a flat impedance line to the amp." Cheers George VAF Signature speakers are very tolerant. I worked with them to get what I wanted ... right through to the DEXQ
Buffle Posted April 15, 2019 Posted April 15, 2019 On 10/04/2019 at 4:34 AM, georgehifi said: Yes Peta, the best Class-D's I have heard so far have been the Belcanto Ref 600 monoblocks, so long as the speakers are a smooth benign impedance load that don't dip below 4ohms too much, Maggies come to mind. I could live with them with this type of speaker. "That dotted - phase line would help push the small impedance peak back down and make it seem to look like a flat impedance line to the amp." Cheers George Except that, as I’ve explained to you before, the nCore modules employed in this amplifier accomodate differences in impedance by including the output filter within the feedback loop. So even if the speakers’ impedance did go lower or higher the performance would be much the same. Another factor with the nCore modules is that the filter is a Bessel alignment, meaning that phase shift within the pass band produces only a uniform time delay. As you know, this is not the case with many other class D designs.
cafe67 Posted April 16, 2019 Posted April 16, 2019 Along with politics, religion and power cables , perhaps class D should be put on the banned list for discussion
crisis Posted April 16, 2019 Posted April 16, 2019 3 hours ago, cafe67 said: Along with politics, religion and power cables , perhaps class D should be put on the banned list for discussion or perhaps people could get over themselves and engage in robust debate and disagreement without getting all badoozled up. 1
rantan Posted April 16, 2019 Posted April 16, 2019 2 minutes ago, crisis said: or perhaps people could get over themselves and engage in robust debate and disagreement without getting all badoozled up. 100% agree. I personally didn't enjoy any Class D amplfier that I have heard or used, but that is it. I am neither right or wrong and all experiences are purley anecdotal. Just my opinion based on experience. No crusades, no agenda. We should all be able to express a polite opinion about any hi fi gear without people losing their schit and having a tanty. It should be kept in mind that audio gear is not a person and therefore cannot be offended. If an owner of a device has issues with that, then they need to walk away for a while. 2
crisis Posted April 16, 2019 Posted April 16, 2019 5 minutes ago, rantan said: It should be kept in mind that audio gear is not a person and therefore cannot be offended. If an owner of a device has issues with that, then they need to walk away for a while. I think most of the offense derives from an over bloated ego. When the science of cables or any other competent is brought up to people who derive pleasure from such things there seems to be a fear they will be considered foolish or naive. For "stereo" hifi to work we all have to be "fooled" . Fooled into believing there is a sound-stage and separate instruments. We all embrace that and commend our systems for fooling us. Whats wrong with accepting you believe what you hear is better and accepting its all in your head? This **** is entirely about subjectivity. 1
Darren69 Posted April 16, 2019 Posted April 16, 2019 The only Class D amps I have heard were the Nords powering the Hulgich at the 2017 hi fi show and it all sounded fantastic.But that's the extent of my experience, unless my subs are Class D amp'd etc.
keinesorge Posted August 23, 2019 Posted August 23, 2019 On 16/04/2019 at 1:40 PM, cafe67 said: Along with politics, religion and power cables , perhaps class D should be put on the banned list for discussion The majority of the repeated push back to class D on these forums is from the same few individuals. Commercial interests are possibly at play. On the diyaudio sub forums where the enthusiasm for class d is more rampant, the same antagonists are silent. 1
cafe67 Posted August 23, 2019 Posted August 23, 2019 (edited) 3 minutes ago, keinesorge said: The majority of the repeated push back to class D on these forums is from the same few individuals. Commercial interests are possibly at play. On the diyaudio sub forums where the enthusiasm for class d is more rampant, the same antagonists are silent. Lol, like repairing and upgrading old amps or pushing their own designs Edited August 23, 2019 by cafe67 1
keinesorge Posted August 23, 2019 Posted August 23, 2019 8 minutes ago, cafe67 said: Lol, like repairing and upgrading old amps or pushing their own designs Posssibly So 1
davewantsmoore Posted August 25, 2019 Posted August 25, 2019 On 23/08/2019 at 10:54 PM, keinesorge said: The majority of the repeated push back to class D on these forums is from the same few individuals. Commercial interests are possibly at play. ... or it could be some strong "bias" other than commercial. --------------- Doesn't necessarily need to be a Class D amplifier.... but (you could use any amplifier design) Keeping a system very very simple is my manifesto..... I find it super duper (duper!) ironic, that many people say "DSP and digital" is .... "too complicated" .... "too much processing" .... "too much....xyz". ... when it is the sure fire way to have a very simple system. One single D to A stage (per channel for a multi-way system) No passive crossovers No resistors, capacitors, or (unnecessary) inductors between what I buy from the shop and my ear. CD player/source -> (digital cable) -> amplifier(s) -> (speaker cable) speaker driver(s) It is about as simple as you can get.... but also the most effective. You get free access to all the room and speaker tuning EQ that you need (which you do need) .... built into the amplifier (or into the speaker if the amplifier if built into the speaker). You conquer one of the biggest issues in designing a playback system. Gain structure. You sidestep one of the biggest quagmires of audiophilia.... the sound of passive components. Let's be REAL, if they all sound different, they're all distortion generators.... and they ALL should be avoided. (The best sounding capacitor is no capacitor). 2
keinesorge Posted August 25, 2019 Posted August 25, 2019 4 hours ago, davewantsmoore said: ... when it is the sure fire way to have a very simple system. I'm with you on this. Source (analog output) -> Passive Attenuator (shunt) -> Amplifier -> speakers A bit of time was spent on getting things dialed in (with passive componentry and selection of copper etc), the system with its class d amp is (to me) incredibly enjoyable. Comfortably replacing an audiolab unit that i once "had to have". In my current room, the setup is good enough for me to stop the chasing the audio dragon. Thankfully, these times allow for the DIY audio enthusiast to enjoy pretty good sounding amp boards for modest money.
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