Correct, if you want big Class-D wattage at 4ohms the get a Behringer 6000watter for just $599USD! for 6000watts! With DSP!!!!
https://www.parts-express.com/Behringer-NX6000D-Ultra-Lightweight-Class-D-6000W-Power-Amplifier-with...
Cheers George
Class D
Been thinking of trying a D amp to reduce clutter. Most that I see are not rated at 2 ohms. My PSB Stratus gold's will drop to 3 ohms or lower at some frequencies. So my question is will these types of amps handle this impedance ?
Thanks in advance. Chris
Thanks in advance. Chris
Showing 26 responses by georgehifi
If Class D was even 10% as bad as he makes it out to be it would be a non-issue.You are the rumour spreader, not once have I said Class-D is bad, if fact I’ve praised the Hypex NC500 with linear power supply monoblocks (given the right loading) that I own in my second system. Class-D has yet to reach the same sound quality as good linear amp in the upper mids and highs. What you need to get right, is that I say Class-D the way it’s used (except for the Techincs SE-R1) has problems that MANY hear in the upper mids/highs, the deaf may not hear it. And this is a long way being fixed in the Technics SE-R1 by having a 1.5mhz switching frequency/low order output filter instead of 400-600khz as all are today. And those that are, or going to use the GaN transistor technology have the chance "to use 1.5mhz", but don’t, probably because they don’t have the R&D knowledge skill of Technics behind them to do it. And btw Cyril Hammer was the first to say this, even before GaN transistors were released to the market. And has more solid state knowledge in his little toe than some "tuber" here saying anything else. Cyrill Hammer (Soulution) "if you want to have your Class-D product performing at the cutting edge it is not possible with todays 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." |
he needs extraordinary proof to support his claimsI know you don’t believe them, just look at the Technics SE-R1 at what it does and the press reviews it gets of it sound quality. Which rids the Class-D bugbear of many that say the uppermids/highs are the problem with Class-D. And what designers of higher standing than you quote. Just one of those quotes from Cyril Hammer probably one of the best solid state designers in our lifetime with Soulution Audio amps https://soulution-audio.com/ Cyrill Hammer (Soulution) "if you want to have your Class-D product performing at the cutting edge it is not possible with todays 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."Now we do have those devices in the GaN, but so far the only one using those 1.5mhz switching speeds is in the Technics SE-R1. All the rest, including you are not using the GaN technology to it fullest. You started with a clean design slate, you should have utilized the GaN to it fullest, but you state you didn't. maybe you just didn't have the ability to do it like Technics design brains trust team do. |
No I defiantly don’t sunshine, but as you said "Decades behind"!!!!Decades! Really! It is also not that either, again just furphy from someone in product protection mode. As you say you’ll get around that problem with "global feedback", you can throw all the "global feedback" you want at it, to fix the phase shift problem. Every one knows "global feedback" is not a good thing in any amp, it’s a "sound sterilizer" and should only be used very sparingly if possible, just to clean things up a little, and preferably use only "local feedback". Which won’t help your plight as you’ll need a stack of "global "feedback" that has to incorporate even the speaker output filter into it, to try to remedy this kind of phase shift problem down to 1khz 40 degrees out of phase, and 70 degrees!! at 10khz (in red). https://ibb.co/vvwzGV5 And to those many that complain about it, this is why you have this concern with Class-D sound in the upper/mids and highs. And a 1.5mhz switching frequency goes a long way to remedy it (without throwing stacks of feedback at it), like they used in the 55kg $KKKKK Technics SE-R1, and hopefully next month in the far more obtainable and affordable SU-R1000 integrated. Cheers George |
But don’t send that tired link about an amp that is obviously decades behind us.The 1200AS 2 is still the current Class-D module from ICEPower, what have you been sniffing. https://ibb.co/vvwzGV5 https://icepower.dk/products/amplifier-power-modules/as-series/ |
This is fake news.Once again, straight into product protection mode, just like someone else that abuses this tiresome saying. Hope independent tests from the likes of Stereophile will sort out your furphy’s. https://en.wikipedia.org/wiki/Furphy |
I believe you would have, if the one/s you heard used the GaN technology to it’s fullest, which is to be able to increase the switching frequency 3 fold to 1.5mhz like Technics did with the SE-R1 and maybe in Feb 2021 the SU-R1000. Then the "switching noise output filter" can also be set higher and so eliminates most of the switching frequency noise left at the speaker terminals. Without introducing phase shifts back down into the audio band, like what happens with lower 600-800khz switching frequencies/filters. EG: in red https://ibb.co/vvwzGV5 Cheers George |
These AGD amps have been very highly reviewed. Yeah they may well be. I was the first to bring them up on Audiogon, because of my obsession with GaN with it’s ability to have 1.5mhz switching speed the Achilles heel of Class-D But Audiogon don’t need dealers propaganda shilling to say how good they are. They need owners to do the personal reviews or mags like Stereophile . |
As good as I like to say Class-D gets with the Technics SE-R1, I still don’t think it’s a good amp for driving the Scintilla’s 2ohm load, compared to big linear bi-polar amps, that can really dump many more amps (current), especially when the Scintilla’s are in the better sounding 1ohm mode. I head them at the Apogee/Krell dealer 20 years back, Len Wallis Audio, driven by a pair of these Krells, and the sound was to die for, speakers disappeared and had a sound stage and depth you felt you could walk into and greet the artists. https://i1080.photobucket.com/albums/j329/ALE7575/stereogear3_zpsc311def0.jpg 475W into 8 ohms 850W was available into 4 ohms I measured 1060W into 2 ohms, the AC line in our Santa Fe office was sagging significantly for this measurement. Cheers George |
Isn’t Jeff Rowland (hardly a bargain basement brand) still using Pascal modules?Y Yes, which are just tweaked Chinese Sanway subwoofer module’s, and Red Dragon use them also at 1/5th the price. 1st pic is the $10k JR Contiuum S2, 2nd pic is the module in the Red Dragon, the rest are $100 Chinese Sanway Audio sub woofer/PA modules https://www.china-sanway.com/ https://www.reddragonaudio.com/products/s500?variant=969867425 https://ibb.co/TwL29tF https://ibb.co/m56rBry https://ibb.co/LZ2br14 https://ibb.co/CnDG1pr https://ibb.co/27HJ0v5 Cheers George |
I don’t know your DAC, but I hope it has very low output impedance. The NC500 without buffers needs a low impedance source or you will degrade its performance.Are you blind as well as deaf? You are free, of course, to argue, defend, your product as you see fit. :)I don’t have to it speaks for it’s self. Unless ****** like milpai bring for no reason it into a Class-D amplifier thread but to try to cause a fight and you following like a rat up a drain pipe, just like "fusers" do! |
I smell another fuser So what bothers George?People, shillers and manufactures saying Class-D already great and is better than the best linear amps, which it’s far from yet. So what is your agenda?That Class-D has trouble with low <2ohm impedances, and that it’s switching frequency is too low for it’s output filter to remove completely without introducing large phase shift down into the audio band. And if you accept it for what it is, nothing will be done to fix those inherent problems. The Technics SE-R1 and maybe the SU-R1000 has done something about the switching frequency, but still the 2ohm load capabilities are not yet fixed, if you check independent tests. can your attenuator drive Class D ampsyou are a **** why bring that up if you know the answer already. If they have >33kohm input impedance buffers it can But no need, I go direct into my Class-D’s from my dac I own and listen to a pair of direct dac signal feed Hypex NC500 modules (with no buffers) with very big linear supplies, into my second system, which speakers are a nice benign 6ohm load. |
A typical response from a snake oil "fuser" https://forum.audiogon.com/posts/1572264 |
Just like *****, into protection mode for his own interests, the new Class-D must be coming soon. It may not double power into 2 ohms though, but that’s not importantThat more fake than anything! Most Class-D’s, independent tests, can’t better the 4ohm wattage with the 2ohm load, if they don’t turn off first, let alone double it. That’s how "strangled" they are for current. With regards to that bit about ’oscillate’: most modern class D amps already oscillate as part of their modus operandi. You can’t somehow make them oscillate *more*; the idea is rubbish.No you are. You know exactly what was meant by that, don't play the arrogant card, just another ***** side step to protect an upcoming Class-D from you |
Like I said
zappas OP
don't trust anything the manufacturers or shillers say, independent test figures are much closer to the truth, they tell the real story. Cheers George |
zappas OP Just use your "common sense" when asking why? when ever Class-D is bench tested, why it is they never give the 2ohm wattage, or advertised and compared to the 8 or 4ohm wattage And sometimes even stated that they try 2ohms but the amp switches off, before they could turn up the test signal level, to get some current flowing into the 2ohm load. We heard an A/B of what the sound was like into Wilson Alexia with 0.9ohm EPDR bass loading, the 150w-8ohm Gryphon Antillion’s bass sounded absolutely magnificent, but with my 2 x more higher wattage 300w-8ohm Belcanto Ref 600Mono clones (NC500) with linear power supplies, were not anywhere near in the same league. And that can only be due to current delivery into the low impedance. Cheers George |
zappasAs said in my first post, they don’t give it as they either turn off going into protection mode, or they are current starved into 2ohms, or the worst oscillate. Your speakers present a very hard load especially the combined impedance together with - phase angle (EPDR) And for @justmetoo here’s a link to "try" and understand how speakers torture amps, especially EPDR. (page2) https://www.stereophile.com/reference/707heavy/index.html Cheers George |
zappas OP Some here have no idea, believe Stereophile’s tester JA and his measurements that I posted, he has more knowledge in his little toe, than most of the self proclaimed know all’s here. Cheers George |
zappasBecause there’s a reason for that they don’t fair well or shut down. Be careful with your choice Look for independent bench tests, like this Stereophile one. Your PSB Stratus gold need an amp that breeze through very low "EPDR" (combined impedance/-phase angle) in the bass 50hz-100hz, also low impedance in the mid bass. https://www.stereophile.com/images/archivesart/PSB97FIG1.jpg Look for amps that can come "close" to doubling their 4ohm wattage into 2ohms (eg: 4ohm-200w/2ohm-400w) this means they have no problems with current into 2ohms. Stereophile: Its impedance curve (fig.1) also suggested that it needs to be partnered by an amplifier capable of a healthy current delivery. Not only does the impedance drop to a low 2.72 ohms at 97Hz, but the -phase angle is quite severe through the midbass region.Cheers George |