it allows for direct playback of a class D amp from a digital source,There's your hint Eric from Ralph , think about it.
Cheers George
Class D is just Dandy!
I thought it was time we had a pro- Class D thread. There's plenty of threads about comparisons, or detractors of Class D.
That's fine, you don't have to like Class D amps, and if you don't please go participate on one of those threads.
For those of us who are very happy and excited about having musical, capable amps that we can afford to keep on 24/7 and don't require large spaces to put them in, this thread is for you.
Please share your experiences with class D amps!
That's fine, you don't have to like Class D amps, and if you don't please go participate on one of those threads.
For those of us who are very happy and excited about having musical, capable amps that we can afford to keep on 24/7 and don't require large spaces to put them in, this thread is for you.
Please share your experiences with class D amps!
Showing 19 responses by georgehifi
shadorne6,590 posts01-28-2018 8:06amLittle known factoid. Stereophile do similar now testing Class-D as not to upset readers with the noise on the graphs and to keep the manufacturers happy in case they may advertise. They use a very low power handling Audio Precision's auxiliary AUX-0025 passive low-pass filter between the Class-D's speaker output and the test equipment, which eliminates noise above 200kHz. On figure 3 you can see the switching noise of the 1khz test sine wave, it will be far greater if they showed with a 10khz sine wave. https://www.stereophile.com/images/218PSM700fig03.jpg Fig.3 PS Audio Stellar M700, small-signal 1kHz waveform into 8 ohms without AP AUX-0025 low-pass filter. If this noise was on test waves of the audio band like this on a linear amplifier, any tech would say it's faulty. Cheers George |
erik_squires OP3,082 posts01-29-2018 4:20amSorry George, as always, you are going to have to pivot from one point to another by yourself. If you need a dance partner it is not me. That's a cop out Eric, your the one who said said: " Most Class D amps I know of do considerably better. I'm more than a little surprised PS Audio put that out there." I ask again, Eric. Please show JUST ONE Class-D, with a clean 1khz sine wave, without using the Audio Precision's auxiliary AUX-0025 passive low-pass low power filter. Cheers George |
So my question is with the main boards themselves being made by a third party, how does one go say from a $1400 D-Sonic amp to a $5000 Bel Canto (or other similar) amp (per pair) up to a Merrill Veritas at $11K plus (pair)? I realize a nicer chassis, etc. In the "hiend" Class-D's there must be a huge profit margin compared to linear amps, even with the glitzy cases, as what's inside is worth peanuts compared to similar dollar linear amps. EG: The $8k Rowland Continuum S2 http://www.theaudiobeat.com/equipment/pics/jeff_rowland_continuum_2_large_inside.jpg uses one of these Danish modules http://www.pascal-audio.com/amplifier-modules.html Which from what I found, are slightly modified Chinese $150 modules I believe from Class-D module manufacturer called Sangaway or something from memory. And these modules were also used in the far cheaper Red Dragon Class-D amps. https://www.reddragonaudio.com/products/s500 Cheers George |
I do though see some advantages regarding heat generated (if that is a concern.. for me it isn’t) and size/weight. They offer a ton of power in a small mass versus trying to heft around a 90 pound Class A/B amp or an even heavier (with less power) tube amp. I see my system as something I want to get the very best from, and if I have to compromise and pay for it in less efficiency so be it. I wouldn’t buy a Ferrari put low octane fuel in it, stick cross-ply tires on it and drive it like a granny just so I could say I’m being kinder to the environment. But Class-D amps with the promises of higher switching frequencies technology in the future, may become all they need for me to jump camp, then my current amps will become door stops or boat anchors. Cheers George |
It is the notion that Class D switching speeds are the cause, and that someday they’ll be fixed that irritates me. If you guys are going to point a finger, get the whole story right. It’s not the switching speed per se, but the output filter that has to try to get rid of it without any detrimental effects down into the audio band that’s the problem. That’s why Technics with their $20k SE-R1 class-d has striven for double the switching speed, so then that output filter can do it’s job properly without much detrimental effect down into the audio band. Cheers George |
George, its more complex than thatYou keep saying it Ralph, it’s the main cause for me, and even noted SS amp manufacturers like the highly regarded Solution amps deigner/owner ect. "Cyrill Hammer (Soultion Amps) "if you want to have your product performing at the cutting edge it is not possible with today's known switching technologies. In order to come close to the performance of the best linear design we would need high-current semiconductors that provide switching frequencies of several MHz or even GHz." I know your developing your own Class-D around present day technology. We all know hiend isn’t how it used to be, and we all have to do what we can to make ends meet. I wish you luck on your venture into Class-D, but to me and others like Cyrill it’s too soon yet to take the plunge. Cheers George |
But again that’s preference. I was mislead by dealer and the internet that led me to believe that Maggie’s required brut power it wasn’t until I decided to let my ears be the judge and bought a class A amp that puts out a whopping 95wpc. I’m not saying class D is bad I’m just saying that for my system and listening preference I went class A.What was this 95w linear Class-A amp?? Cheers George |
Nelson Pass's statement on Class-D in an interview yesterday. "JS:There has been an explosion in high-end Class D amps in recent years. Some companies now market some fairly sophisticated – and expensive – Class D models. Pass currently manufactures Class A and AB lines only. What are your thoughts on Class D? NP: Personally I think it’s a miracle that they work at all, but then I think that about my phone, too. I have great respect for people who can make Class D amplifiers sound pretty good, and for delivering low cost, high power, and efficiency. They have earned their place in the industry. That said, I am not tempted to go in that direction." https://parttimeaudiophile.com/2018/02/21/an-interview-with-hifi-legend-nelson-pass/ Cheers George |
Wake up and smell the roses sunshine, Class-D is not as Dandy as you try to make out it is YET. I can quote many more just as esteemed as Nelson Pass if you like. In the future with higher switching frequencies that look to be promised by the semiconductor tech-heads, it very well maybe the amp of choice, then our heavy, gas guzzling linear amps will become door stops or boat anchors. Class-D today certainly has it's niche in audio, but it can't mix it with the real top of hiend yet. Cheers George |
tweakjunky Because mainstream semiconductor manufacturers like Motorola, Hitachi, Sanken ect, haven’t tooled up for it yet, probably because the inventors of the GaN devices EPC (a small company in comparison) I would say have a provisional patent on it, who were if you dig deeper from what I’ve found maybe also the inventors of the Power Mosfet transistor as well way back. And are now maybe waiting for the best offers from the big boys above. Till then they are probably happily supplying in small numbers to Technics for their SE-R1 poweramps. tweakjunky Only the $20k Technics SE-R1 has them so far, and you need connections to get one. PS: Just dug up the link to EPC being the co-inventors of the HEXFET power MOSFET back in the day. https://epc-co.com/epc/AboutEPC/Team.aspx Cheers George |
celander https://www.stereo.net.au/forums/topic/49395-why-are-some-speakers-suited-to-valve-amps/?do=findComm... " I’ve set up Duntech Sovereigns, it is abundantly clear that John Dunlavy designed them to be used with the very lowest output impedance amplifiers available. They don’t even wake up when connected to even quite prodigious valve amplfiers. Even highly capable amplifiers like the ME850 barely get them under control. It takes something like the big Krell monos, or an ME1400/1500 to make them sing." https://ibb.co/iY7oE9 https://ibb.co/bWWyE9 ME is what I use, in a bi-amped setup Cheers George |
Krell KSA-300 used here http://www.highendnews.info/reviews/DuntechSovereign-eng.htm Sounds like Hypex N-Core Class-D can’t cut it with them here. https://www.gearslutz.com/board/showpost.php?p=11771281&postcount=5 Cheers George |
Oh, I don't mind that. I'm not hear to convert anyone. Why then interject with personal backlash, when celander and I, were just talking about amps that are most capable of driving the Duntech Sovereigns, and I just happen to see and post a link to amps that can and couldn't, and it just happens that Hypex N-Core Class-D couldn't drive them. Here it is again as it's lost now on the other page. Duntech Sovereign's suitable amps that drive them. Krell KSA-300 used here http://www.highendnews.info/reviews/DuntechSovereign-eng.htm Sounds like Hypex N-Core Class-D can’t cut it with them here. https://www.gearslutz.com/board/showpost.php?p=11771281&postcount=5 Cheers George |
maplegrovemusicThis may help, but the reviewer found it a bit dry and lacking in harmonic complexity and bloom in the upper midrange, a bit dry in the mids, and maybe even somewhat aggressive on top. It's one of the first, commercial Class-D that came after the original Class-T (Google these also as they only used N channel fets which allowed in some cases a higher switching frequency) The 18 year old Sharp SM-SX100 Class-D, if you look at the 4 ohm frequency response it's already starting to roll off the high frequencies at 2khz, and the simulated speaker load is not much better. https://www.stereophile.com/content/sharp-sm-sx100-digital-integrated-amplifier-measurements Cheers George |