kdude661,200 posts05-02-2017 6:55amGeorge,
Were can a mate get a bi-aural Exostosis operation?
Can it be accomplished in the states or would I have to go down under.
Kenny. Sorry Kenny missed your post question, a while back. In Australia I had both done in one hit the first time when I was young and very fit. Mine took 6hrs the first time for both and 3.5hrs for the right again the second time many years later, should have kept that car window shut, dam it. But it also depends on the doctor, how bad it is and how much stamina the doctors/ anaesthetist/ nursing team have, as one ear can take up to 3-4hrs if really bad. But it’s worth it, you hear like a bat after it, because the doc said the ear drum and it’s bits are being protected while you have the exostosis, in other words not aging as fast. BTW of all the surfers I knew throughout my competition days, I was the only who was ever able to get both done in one go. Cheers George |
heaudio ,
Slope on the edged is not caused by phase shift, it is caused by bandwidth limiting. Oh dear! Which is caused by the output filter which and causes phase shift and yes if you must have that included, "bandwidth limiting" as that’s what the filter is there to do, without bandwidth limiting you have no phase shift!!!! please get it right.
heaudio
This is another ClassD no filter with a bit of overshoot likely due to underdamping also indicating from a frequency response peak.
You really need to do some more understanding, JA used his high order special testing output filters because he didn't yet have the
Audio Precision's auxiliary AUX-0025 passive low-pass testing filter, which eliminates noise
Stereophile
Audio Precision sells a precision passive low-pass filter to be used between the output of an amplifier with a class-D output stage and an Audio Precision analyzer. Unfortunately, I have not yet upgraded my test system with one of these filters, so to examine the MX-D1's performance at low signal levels, I used an active sixth-order low-pass filter with a 20kHz bandwidth and a floating input.
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rather than attacking the dissenter in your little circle, you might pay attention to what he is saying +1 Randy-11 It’s because they can see the forest through the trees, understandable as they’re protecting their investments, as it will make theirs very hard to sell once it becomes available and the word gets out. BTW can find anything on the Mytek, claim of new developments that address the problems of Class-D. Being a small company I doubt also that they have access to the new higher switching frequency components from GaN. I think for now maybe Technics has a strangle hold on supplies. Cheers George |
EPC (small company) Alex Lidow is the inventor of this new GaN-FET transistor Technics uses, and he happens to be the inventor of the Mosfet/Hexfet all those years ago I believe.
Cheers George
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im thinking of the Peachtree Nova 150 I remember the Peachtree importer a friend of mine here in Australia demo’ing me a pair of midrange floor standing Focals to be our Audio Clubs "house" speaker, which he also imports, as well as Krell amps. He was using the Peachtree at the time because he had no Krell’s handy, and quietly said to me the Peachtree isn’t very good, you should hear these Focal’s with the small integrated Krell feeding them. Cheers George |
georgehifi happens. Oh dear, you never did forgive me for exposing the JR Continuum 2 re $100 Class-D module con. |
Nothing was addressed to you at all, I was addressing listening99 post.
You can’t let it go sunshine, you really are a cretin
As for heaudio123 and your comment about me having 2 accounts, that could almost be slanderous, put up or shutup!!
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I heartily recommend the NuForce STA 200 to anyone looking for bargain solid state audiophile amplification, but it does not do well when pushed to 4ohms and below.
Nuforce went back to linear amps, but this is STA200 is just a reincarnation of the budget Job225 from Goldmund. Good little amp but built to a performance level that really doesn't suit down to 2ohms or even below 4ohms, just like Class-D. But probably sounds better to where it can be loaded down to within it's comfort zone. Cheers George |
maplegrovemusic
They are active with class d amps inside . These are in no way bright or fatiguing , things I have associated with older class d amps . Looking to find out how and why this could be ?
This 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-measurementsCheers George |
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To both of you.
The Parasound Halo JC1’s in high bias class-a (which is no more than around 20w of A) sounds magnificent, and will blow away any Class-D full stop!!
Cheers George
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tweakjunky
I struggle to understand why this tech isn’t more prevalent today. 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
Am curious to open my amps and check the components but given the heatsinks present I suspect it’s not based on GaN tech.
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.aspxCheers 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 |
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
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Very understandable, as your Maggie 2.7's like most Maggie's has a very benign 4ohm load that doesn't need that much current, just watts.
You should use the 4ohm tap for best control, penalty is you'll loose wattage compared to the 8ohm tap.
Cheers George
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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 |
George, its more complex than that You 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 |
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 |
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 |
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.jpguses one of these Danish modules http://www.pascal-audio.com/amplifier-modules.htmlWhich 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 |
Poor George...he wants evidence from measurements vs. using his ears...
Both sunshine both, as it should be, can't have one without the other. 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.
Erik
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
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shadorne6,590 posts01-28-2018 8:06amLittle known factoid.
AES17 brick wall filters allow Class D Amps to report specifications IGNORING all the switching noise above 20KHz!!!! And there is a LOT of noise....
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 |
Most Class D amps I know of do considerably better. I'm more than a little surprised PS Audio put that out there.
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 |
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Yes most techs will not repair Class-D down to component level, too time consuming and difficult to trace faults with these surface mount, multi-layer boards class-D amps have in them. Because everything is is so tightly packed, so they can squeeze them into mini chassis.
They just want to install complete "expensive" new board/s.
Trouble is many of the manufacturers don't have old model boards in stock.
Cheers George |
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 |
You should get your facts right. It’s not N-Force, it’s NCore Really!! I stand corrected. And there is no modification to NC-500 module itself. We were told different by the importer/demonstrator, unless he had it wrong.
Why should various amps based on circuit boards of the same technology (NCore) and made by the same company (Hypex) sound different?
I wonder, could it have to do with what the demonstrator told us??? Cheers George |
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And stop with the ten-year old stories. Get in the now. The only current crop of D’s I’ve heard that have semi impressed, were the new Belcanto Ref 600M Monoblocks, yes they use the the newest "best" N-force NC500 modules that aren’t available to anyone but to Belcanto and other manufacturers. But Belcanto modifies them from what I’ve we were told by the importer/demonstrator, that was to either cascade/parallel or series a couple of the low order switching noise output filters to give a sharper filtering effect of the switching noise. But any speaker manufacturer worth his salt will tell you that doubling up on low order high power filters at or around the same area has it own set of problems with ringing ect. This is similar to what Mark Levinson tried with their $50k ML No.53 monoblocks, if you look inside at the series/paralleled?? massive red inductors in the pics. https://www.stereophile.com/content/mark-levinson-no53-reference-monoblock-power-amplifier Cheers George |
stfoth
it’s been awhile since I knowingly gave any class D amp a good listen, maybe a decade. so, some folks absolutely love these things. others can hear the flaws.
my impression from a decade or so ago was that I hated them (at least the few I heard), but really couldn’t put a finger on why--lots or power, ridiculous detail, etc. just something missing, and, inexplicably, my ears felt funny afterwards--almost like a ringing that shouldn’t have been triggered by the volume or duration. difficult to explain. +1 stfoth, others hear it too, and if they can’t good for them. This is why there are for and against post, from both sides of the camp, so potential purchasers can make up their own minds, and be happy with it or disappointed. These forums are not a marketing exercises to create a push to sell more Class-D. As the opening post says " Please share your experiences with class D amps!" Cheers George |
No I didn’t say that Techinics"finally fixes the Class-D problems.
I said:
" they (Technics) seem to address to a certain extent the problems that they all have still"
Cheers George |
Really? Just because it uses a linear rather than a crap SMP power supply, doesn't mean it's not Class-D
From Stereophile:
" Although the SE-R1’s huge twin output meters and beautiful anodized-aluminum finish were visually distracting, the marketing of a Class-D amplifier as a separate high-end component was important. This amplifier delivered some of the best reproduced sound at CES 2017. I persuaded Bill Voss to rip the contents of my copy of Rutter’s Requiem to his media server’s solid-state drive. The broad and deep soundstage, imaging, upper midrange detail, and bass extension were thrilling during the system’s rendition of "Lord, make me an instrument of thy peace" and "Pie Jesu." I appreciated the work done by the Technics staff to prepare their exhibit suite with recessed sound-absorbing panels. I left wanting to hear more."
From Audioholics:
" On the amplifier side, the SU-C700 and SE-R1 are utilizing advanced Class D topologies, featuring a couple new acronyms, JENO and LAPC. JENO (Jitter elimination and noise shaping optimization) provides clock regeneration for low jitter switching in the amplifier stage, sample rate converter, as well as a pulse width modulator that feeds the output stage. LAPC (Load Adaptive Phase Calibration) on the other hand is designed to maintain frequency and phase response regardless of loudspeaker impedance, which is a weakness in some Class D implementations. Finally, the output stage utilizes gallium arsenide FETs (field effect transistors) with a claimed switching speed of 1.5MHz."
From Audio Aficionado:
" .I read a blip in The Absolute Sound that the Technics SE-R1 power amp ($18,000.00) is Class D. It uses a linear power supply rather than a switch mode power supply to produce 100 watts per channel. That’s a lot of money for a 100 w/p/c Class D amp. Along with the Technics SE-R1 Class D amplifier they also introduced the SU-R1 Network Audio Control Player preamp ($9000.00) and new SB-R1 Reference Speaker ($27,000.00). Technics calls this system the R1 Reference System."
Cheers George |
I have not heard the new Technics that use these new transistors, so I do not know how they would compare to the current crop of the better class D amps.... But sure am curious.
Have you heard these new Technics SE-R1 amps yet? If you have, please let us know your first hand impressions. Saluti, G.
No I haven’t yet as the Technics SE-R1 is unobtainium here in Australia, and you need to order them and have deep pockets in counties that do retail them. But from the number of Class-D’s I had here listened to and measured, they (Technics) seem to address to a certain extent the problems that they all have still, which is the filtering that has to get of the switching frequency noise, without it effecting the audio band in any way, and the only way to do this is to raise the switching frequency by at least triple, Technics have done double with the SE-R1 so were on the way. But these are typical of reviews (below) of the sound they give out from those that have heard it, and there are more from others on the web. " Listening to tracks that we’ve heard 100s of times — and on excellent systems at that — is now a revelation of once hidden nuance and detail. Not only are we hearing things we’d never heard before, we’re hearing it in a way we’ve never heard it before. A music system that sounds like a live performance is a tough goal to attain, but Technics’ flagship nails it." Cheers George |
asvjerry
Well said, as I've also stated, even I will ditch my boat anchors when the technology allows that dreaded switching frequency (Class-D's Achilles heel) to be 2-3 times higher than what it is. Then it will be an amp to contend with. Cheers George |
Like I said once before, to the ones that have blinkers on, they will be the first to change to the higher switching frequencies when they become available, that's almost a given.
As for now maybe just trying to protect their investments, with ignoring that the higher switching frequencies will give them what many hear is a problem with Class-D, which effects the upper mid/highs.
Cheers George |
This is an open forum, I believe that Class-d should be seen from both sides of the camp, not censored to just the pro-camp, this way members can make up their own minds whether or not to get one, because all do not see "Class-D as being just dandy".
Maybe soon in the future when the switching frequency can be raised double or tripple with advancement in semi conductor technology, so then it’s output filter can do it’s job properly without negative effect to the upper mids and highs.
Cheers George |
erik_squires OP2,223 posts06-24-2017 12:24pmFremer's 2013 review was riddled with bias. He's no neutral observer.
Well John Atkinson also backed his "bias" after doing the measurements. "
The sound was initially very impressive. It had tremendous dynamic sweep, with superb control of the Wilsons' woofers, tremendous clarity, and nothing identifiably wrong. However, the more I listened, the more the overall sonic picture seemed flat and uninvolving. An enigma.—John Atkinson" Read more at https://www.stereophile.com/content/mark-levinson-no53-reference-monoblock-power-amplifier-measureme...Cheers George
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But the general issues with Class D amps of the 1980’s were long solved by 2013, Please tell us all the issues they (who) solved? Cheers George |
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randy-11982 posts05-19-2017 9:50amI also saw news on a new Class D amp from Constellation with very high switching freq. - dunno if it uses GaN devices... Just checked, just the same as everyone else 600-800khz if they used the new GaN semiconductors it would be 1.5mHz, I wish they did, then that would mean supply to the little folk is available. Technics probably have a monopoly on them for now. " Its Class D amplifiers use a special topology with ultra-high-frequency 600 kHz switching" Cheers George |
randy-11982 posts05-19-2017 9:50amI also saw news on a new Class D amp from Constellation with very high switching freq. - dunno if it uses GaN devices...
Very interesting if it does, I thought Technics had a monopoly on them, if so they’d be the first one to start using them, since the Technics SE-R1 started thing off. Have you a link you can post to this? Cheers George |
I can only hope that the you can contribute as much for others in your life.
Yeah you do, but you kinda attacked him personally. Cheers George |
It's an open forum Erik, he's just at 180' to your "Dandy" propaganda.
I'm sure in time he will give he reason/experiences for his comment, as he had 4k posts.
Cheers George
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Our Kangaroo some say in plague proportions in Australia is very efficient, a bit like the Class-D, of the distance v speed travelled in the animal world. But is very one dimensional in it's movement and that straight ahead, easily picked off by a Mick Taylor (Wolf Creek) https://www.youtube.com/watch?v=uTUp4IJ_xqQ Cheers George |
For that matter, Bolt can also "compete" against a cheetah. I think we all know Al, that’s a far fairer race. Than Ralph’s V the Class-D given the ideal speaker for each. Cheers George |
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