What I’ve learned lately on this thread is to avoid using speakers that present loads to the amp of less than 2 ohms.What can be the case, is these speakers can be the best measured/sounding ones, why drive them with amps that can’t do them justice. As for flipping the bird to amp manufacturers, only when it’s warranted because of not saying how it is, or recommenders of them that have no idea what they’re on about. Because they the manufacturers/recommenders would have "you" believe if an amp with 800w can drive a speaker that’s "inefficient" and with a "average impedance loading". Then that same amp can also drive a speakers that are "even more efficient" but with a "very hard impedance loading". |
What I've learned lately on this thread is to avoid using speakers that present loads to the amp of less than 2 ohms. I believe if speaker designers and manufacturers decide to rule out the use of the majority of amps working well with their speakers, then we can certainly decide to rule out the purchase and use of their speakers. Flipping the proverbial bird at reasonable and responsible amp designers and manufacturers, as well as reasonable and responsible potential customers, should rightly have consequences, not be rewarded and not be considered a recipe for success in a high sound quality speaker product. Tim |
FYI. The Merrill 114 is a single chassis, stereo, power amplifier. It has been mentioned a few times here, stating the 114 amps are mono blocks. Talk about 5th grade reading levels...lol.....why can't discussions of audio stuff, hifi stuff and music listening stuff, be non confrontational ? Power cords, and fuses / fuse direction, have been the tops so far.... |
tell us which proven amps specifically you are recommending dsper consider buying? As I posted just ones that can almost double their clipping wattage from 8 to 4 to 2ohms. Even the ML2 monoblocks at only 25w into 8ohms will do it, but not at party levels, because they can double down to 200w at 1ohm. All we have here are a few manufacturers spruiking their new or yet to be released Class-D amps without any shame, saying they "can handle" the 2ohm load, making out they can drive this speaker to it’s best in the bass. Without presenting any measured proof of their claims, that they can almost double their clipping wattage from 8 to 4 to 2ohms. |
Nothings been put to rest, let’s see the independant test or even his own, that show the rms wattage doubling just before clipping (same distortion) with all three 8, 4, and 2ohm loads, then I’ll eat my words, and congratulate you on doing something that other Class-D’s can’t. I’ve asked the same from Merrill twice now and got no answer. That would be cool. But what non-Class D amps exactly are we comparing these to that have been proven to do the trick? George sounds like you are convinced accordingly that some existing non-Class D amps are proven to do the deed so tell us which proven amps specifically you are recommending dsper consider buying? Thanks. |
Nothings been put to rest, let’s see the independant test or even his own, that show the rms wattage doubling just before clipping (same distortion) with all three 8, 4, and 2ohm loads, then I’ll eat my words, and congratulate you on doing something that other Class-D’s can’t. I’ve asked the same from Merrill twice now and got no answer.Its put to rest everywhere but (by your admission above) in your own mind. Although we just got news this week that the USPTO is granting our class D patent with all 20 claims supported, that isn't the same as saying we're ready with a production product that is going to independent review. The power supplies that we are using for testing won't support the current of 2 ohms at full power even though the circuit boards we designed will. But the amp behaves as a pretty good voltage source so as long as you stay within the limits of the power supplies we're using, doubling power into 2 ohms is no worries. I am well aware you didn't make that claim about GaNFETs but if you apply United States 5th grade reading comprehension skills (which these days isn't saying much) you will see that I suggested that this was something you might not have been aware of and by your admission above that surmise was correct. Again, what I said is that the output impedance of an GaNFET-based class D amp is so low that it will easily double its power into 2 ohms from 4 ohms- provided that the power supplies and heatsinks will allow it. These latter qualifications BTW are the same ones that limit any traditional solid state amps as well, so none of this is any surprise to anyone anywhere, except perhaps you. |
and can handle speaker impedance loads under 2 ohms,dsper That statement it’s should tell you something, they "can handle" a 2ohm load. My car "can handle" being reved to 8,000 rpm. My hands "can handle" 60c on a Class-A heat sink for a few seconds! Your speakers are at 1-2ohms for nearly 3 octaves in the bass "JA which means that the amplifier with which it is used must have ample—to say the least—current capability if the sound is not to become anemic." Like I said above " find yourself a Krell type ect linear amp/s with BJT (bi-polar) output stage, with high bias Class-A used somewhere to get the best from your highly regarded speakers." Read these amps that were tried and you’ll get an idea of what’s needed to get the best from your speakers. . JA Stereophile. Cheers George |
Our prototypes can double power into 2 ohms and we’re not even trying to make it do that. It comes with the territory. +10 atmasphere for putting that one to rest. Nothings been put to rest, let’s see the independant test or even his own, that show the rms wattage doubling just before clipping (same distortion) with all three 8, 4, and 2ohm loads, then I’ll eat my words, and congratulate you on doing something that other Class-D’s can’t. I’ve asked the same from Merrill twice now and got no answer. And btw, I’ve never claimed the new GaN Technoglogy could drive these speakers properly and double at all 8 to 4 to 2ohms loads either, they just sound better than the old technology, but I wouldn’t recommend them here either. So dsper find yourself a brute linear amp/s with BJT (bi-polar) output stage, with high bias Class-A used somewhere to get the best from your highly regarded speakers. Do not get sucked into by these Class-D spruikers because you won’t get the best from your speakers. Or (I wouldn’t) sell your speakers and get something easier to drive that doesn’t reach down to sub 2ohm loads in the frequency range, then you can by a GaN based Class-D which will sound very good. Cheers George |
Hello George, For class D amps that double their output as impedance is halved down to 2 ohms, it looks like all the new Merrill Element amps, also using the new GaN fast switching transistors, all are capable but they're expensive, starting at $15K/pair for the Element 114 mono-block amps: https://merrillaudio.net/products/ However, Merrill's previous Veritas monoblocks, came close to doubling power down to 2 ohms at low rated distortion levels: https://merrillaudio.net/veritas-mono-block-power-amplifier/#1519988773686-7ab00bcd-5607 I don't know dsper's budget, but I've been considering buying a used pair of these and most are listed at about $5K/pair. I consider a pair of these in good condition the likely best bargain solution. New, the Veritas were priced at $12K/pair. The OP, dsper, was inquiring about a class D amp that could handle his speaker's crazy low impedance loads of less than 2 ohms without freaking out. Since this new amp from Purifi Audio was born out of the research work of Class-D pioneers Bruno Putzeys (of Philips, Hypex and Kii Audio fame) and Lars Risbo (Toccata Technology and Texas Instruments) and can handle speaker impedance loads under 2 ohms, even if it does so at less than ideal wattage and distortion levels, I thought dsper still might want to give it a try, anyway. If Purifi offers the typical internet-direct free in-home trial period, there's literally no risk to dsper from giving it a whirl. Tim |
Looks like there’s still no takers willing to put it on the line, and post up the 8ohm, 4ohm, 2ohm wattage measurements just before clipping, to see if they are "almost" doubling the wattage for each halving of load, so to prove if their amp/s are going to drive these types of speakers close to their best, not just "satisfactorily"!George, you like to promote GaNFETs as a thing in class D amps. But from this post is seems that you are unaware of something that GaNFETs bring to the table: very low 'on' resistance, often less than 100 milliohms. The devices we are using have an 'on' resistance of 60 milliohms. That's lower than most linear output transistors! So a class D amp has no worries behaving as a voltage source provided the power supply can provide the current required into lower impedances. IOW less technical terms this simply means that doubling power into 2 ohms is no worries as far as GanFETs are concerned (and for a lot of other switching transistors as well). Our prototypes can double power into 2 ohms and we're not even trying to make it do that. It comes with the territory. Whether its worth it or not is an entirely different subject as all amplifiers regardless of technology have higher distortion into 2 ohms which is audible as increased brightness and harshness. You can see this in the specs (if 2 ohms distortion is even specified, but you can also see it in the 4 ohm spec as opposed to 8). Further complicating matters is the critical nature of the speaker cable, which must be kept very short and also must have a fairly heavy gauge. At that impedance its very easy for the cable to contribute to the overall source impedance seen by the loudspeaker! In a nutshell, 2 ohm loudspeakers are impractical and the ability to drive a load like that is over-rated. Sure, we like to play with muscle power and boast about it, but in the end it doesn't matter if you can weld with your amplifier; its intention is to sound like real music (not a hifi, unless its intention is simply to make money) and no amp is going to do that driving such a low impedance. Another way of putting this is if you want to get the most out of your amplifier dollar investment, that dollar is best served by a loudspeaker that is a higher impedance, assuming that high quality sound is your goal. Any loudspeaker manufacturer can cause their speaker to sound smoother and more detailed by raising the impedance because when the amp makes less distortion, it sounds smoother and more detailed... Funny thing is, everyone knows this, its not some sort of hidden inner sanctum secret. But we still see these silly low impedance arguments when the simple fact is that the low impedance doesn't benefit anyone. You'd think that in high end audio where sounding real as opposed to sounding like a hifi is well understood, but here we are in the 21st century and this nonsense is still going on... |
There's no mention of power doubling down all the way down to 2 ohms but an amp that is completely indifferent to actual speaker impedance variations seems promising, right? That's because it can't, here is the a snippet from the manufacturer's data sheet, which you can take with a grain of salt normally, independant would be even more revealing usually. As you can see at 1% distortion!! the 2ohm watts didn't double at all from 4ohm, the 8ohm to 4ohm came close to doubling though. And that little 1 next to 450w said went into current limiting on 2ohm. https://ibb.co/YcQ8xV7 Cheers George |
I just read this article about Purifi Audio, and their class D amp that is said to be "completely indifferent to frequency, level and impedance variations, with measured intermodulation distortion way below any other technology." There's no mention of power doubling down all the way down to 2 ohms but an amp that is completely indifferent to actual speaker impedance variations seems promising, right? Here's a direct quote from the article: "The first product to be unveiled by Purifi is the 1ET400A, a 400W Class D single-channel, analog-input, amplifier module. Effectively, this is the module used in the prototype Lyngdorf 8 x 400 Watt Class-D amplifier shown at the ISE 2019 show. The technology is said to be completely indifferent to frequency, level and impedance variations, with measured intermodulation distortion way below any other technology." Here's a link to the full article: https://www.audioxpress.com/news/purifi-audio-promises-to-reduce-distortion-in-speakers-and-amplifie... Tim |
They will drive 2 ohm speakers with ease and aplomb all with a very satisfying sound quality. Looks like there’s still no takers willing to put it on the line, and post up the 8ohm, 4ohm, 2ohm wattage measurements just before clipping, to see if they are "almost" doubling the wattage for each halving of load, so to prove if their amp/s are going to drive these types of speakers close to their best, not just "satisfactorily"! Cheers George |
We have sold many of our amps for the very reason they can drive very difficult loads with loads of current. They will drive 2 ohm speakers with ease and aplomb all with a very satisfying sound quality. You would have to spend considerably more £5-10K and choose a direct seller boutique manufacture to better. |
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Hi DSPer, There are a lot of linear amps which are also not great for low impedance loads. Like those, many Class D modules are designed for more normal loads. Some however, like Hypex, have been rated down to 2 and will do a very good job. Just kind of depends. Where Class D tends to have more of a problem with speaker loads is at the top end. Think ESL's with dropping impedances, but again, a lot of linear amps have the same issues. Above all, assuming they are rated for the speaker, you should listen. You never know what serendipity will bring you. Best, E |
OKAY...... This is the OP again...it sounds like I am hearing Class D might not be the best for tough, low impedance load speakers. If that is indeed the case, why is this and what has to change in Class D design to achieve it? Please respond realizing I know that doubling down from 4 ohms to 2 ohms by an amp is a good thing; but I probably cannot explain why this is so. Trying to learn. Seriously. Thanks for listening, Dsper |
Hello georgehifi, FYI, You’ve been using the abbreviation "ect" rather than the proper "etc.’ to refer to the words of Latin origin "et cetera". Translated literally from Latin, et means ’and’, while cetera means ’the rest’. An easy method to remember the distinction is that etc. means et cetera, while ect is the typical involuntarily sound people make after reading one of your posts. You’re welcome, Tim |
That’s just adding series resistance to the perceived load to make it look higher to the amps output stage so it doesn’t complain, and what that does is lower the damping factor and raise the output impedance as seen by the amp @georgehifi - You literally have no idea what I was talking about, so your reply is wrong in the specific and wrong in the general. Best, E |
I’m not going to get further involved as, for me, hi-fi is about the music more than the equipment although the latter isn’t without interest.Now that reeks of a copout. I also don’t pretend to have the level of knowledge evidently demonstrated by numerous contributors to these forums.Yet your not willing to take it onboard when it's presented to you in simple terms that anyone can understand. |
George, I appreciate that you responded with a more constructive post. I’m not going to get further involved as, for me, hi-fi is about the music more than the equipment although the latter isn’t without interest. I also don’t pretend to have the level of knowledge evidently demonstrated by numerous contributors to these forums. As for the vexed issue of speaker loads and compatible amps, my kit (now and potential) is unlikely to engage that conundrum in the foreseeable future, although, part of my curiosity wishes I was able to arrange a real world listen to a heavy-load speaker pair with a quality Class D amp :-). Sadly, I’m not in a position to do so! For context, my own system is relatively lowly and even if a demo goes well later this week (a distinctly non-classic NAD C 658 - hence my own interest in adding a power amp), the new kit will hardly be mentioned in the same breath as much of the equipment discussed within the forums. In any case, I sincerely wish everyone happy listening and/or hi-fi hobbying. |
Then why did you say "useless" Of course it will work, class-D just won’t get the best from these speakers especially in the bass, and some maybe happy with that not knowing any better. But I think if anyone had a speaker that was regarded as Stereophile "Class A" in the "full range" category, and one of Thiel’s all time master pieces, you would like to get the best out of it. Stereophile JA " All in all, the CS5 is both the most thoroughly worked-out speaker design I have ever come across and perhaps the best-measuring loudspeaker I have yet experienced." " The Manley 500s, which I held off hooking up for a long time, were, as nearly as I could determine, simply unable to deal with the CS5's cruel 2 ohm impedance at the low end." The Manly 500 watt monoblocks https://images.reverb.com/image/upload/s--i_Cjxmnb--/f_auto,t_supersize/v1552409073/zucn7la3dmcwphn2... |
Now your twisting things by saying "useless". Of course it will "work" and he will say so, but will it get the very best out of the speakers?, DEFINITELY NOT! especially in the bass where they are a pig of a load. George, once again you post with a hostility that is uncalled for. There was nothing "twisted" about what I said. It was fair use of English language. The provocative language you use does not reflect well on you or your credibility. If you are so sure of the view you state, why don’t you let Nord (and others) know they are wrong? That’s a rhetorical question. |
what about jeff rowland’s class d amps ? all from the old stereo 102 through to the 201/501 monos and up to the current 825/925 etc can double their power into 4 ohms. i’ve heard the big ones behind speakers like magnepans, martin logans and apogees, so they should have no problem driving the thiels. |
Kudos to Joseph Audio for going the other way, and actually adding crossover components That’s just adding series resistance to the perceived load to make it look higher to the amps output stage so it doesn’t complain, and what that does is lower the damping factor and raise the output impedance as seen by the amp You get a similar effect by using a ZERO output transformer with amps that aren’t right, and we all know know that is just a band aid fix, better off having the right amp to start with. |
I have a Classe Class D Sigma Amp 2 driving Wilson's which I am told dip down to 2 ohms. They sound GREAT.Not saying they don't, but if you have Wilsons that go to 2ohms (your not saying what ones) then your not hearing them at the their best. And you maybe happy with that, because you don't know better. Cheers George |
I have seen some commercial speakers from Focal introduce a 2 Ohm low deliberately in the crossover. Took quite a number of caps and resistors too. My guess is that amps with low impedance around 100-150 Hz sound more discerning, more snobbish of amplifiers. "Look at me, I can only be driven by high current amps, so I must be better." I have also seen designs from Infinity which were an utter part crap fest. My guess for them is that at the time they were designed good simulation and measurement tools were far too expensive, and they reached their sound empirically with no concern for the amps. You may think "well, nothing wrong with voicing by ear" but the designs I’m talking about could easily have achieved equivalent results with easier to drive impedances. Kudos to Joseph Audio for going the other way, and actually adding crossover components which make them easier to drive by a wider range of amps. Best, E |
I have a Classe Class D Sigma Amp 2 driving Wilson's which I am told dip down to 2 ohms. They sound GREAT. Here is what Classe states: All amplifiers except the CA/CT-5300 have a virtually linear doubling of output between 8 ohms and 4 ohms but since it can be a misleading figure, we do not supply details of their performance at 2 ohms. This by no means implies that our amplifiers cannot operate at 2 ohms, which they obviously can. Impedance varies with frequency and most high quality speakers have the capacity dip to 2 ohms. Since our amplifiers are specifically designed to drive the world’s best speakers, they will have no problem driving a 2 ohm load. Nevertheless, driving 2 ohms in the real world requires an enormous amount of power, which is sometimes technically unavailable from the AC mains power outlet. This means that these types of specifications are vulnerable to external conditions, and can therefore be misleading. Clearly, we do not want our customers to make decisions based on potentially misleading information. |
I'd say to the OP, contact Nord directly and run your thoughts by them. I'm pretty sure the last thing Colin will want to do is sell an amp that turns out to be useless! Now your twisting things by saying "useless". Of course it will "work" and he will say so, but will it get the very best out of the speakers?, DEFINITELY NOT! especially in the bass where they are a pig of a load. |
Anyone know why Thiel designed such hard to drive speakers Not just Thiel, there's many others that strive for perfection and they're usually the most expensive. Xovers/drivers ect, are complicated to get everything to operate in the most linear function and best specifications without having many compromises, that most efficient speakers tend to over look for the sake of efficiency. That's why you need great amps usually with great speakers otherwise you don't get what's the speakers capable of giving you, if not you compromise the speakers performance. Cheers George |
A few minutes ago (14:00ish hrs GMT), I spoke with Colin at Nord Acoustics primarily with my own system in mind. However, I remembered this thread and mentioned it to him. Colin is positive that even Nord's entry level "MP" amps will, in almost all cases, be able to drive speakers at 2ohms. I'd say to the OP, contact Nord directly and run your thoughts by them. I'm pretty sure the last thing Colin will want to do is sell an amp that turns out to be useless! It's disappointing that this thread descended into an echo of 99% of cable threads.... PS: For the avoidance of doubt, I have zero vested interest in any audio equipment manufacturer or supplier. |
You only need as much power as you need. The "rated" lowest manufacturer suggested impedance for the IceEdge is 2.7 ohms. But in "real life" it puts out 1000 watts at 2 ohms. What a manufacturer recommends and what is real are sometimes far off. Again, the person with the 3.7s can blast as loud as he wants and it sounds incredible. What more do you want? A spec that makes you happy? Reality makes the owner happy. You don’t need an amp to double its power as it halves its impedance at 2 ohm. You just need enough power at 2 ohm (or whatever ohm) to control the speaker (assuming you have a speaker that needs that) at the volume you listen...again, I feel such low impedance speakers are outdated and don’t make "sense". Almost all amps (no matter what class) make more distortion (measurable) and have less damping factor the lower the impedance. Hardly any amp measures good at 2 ohms. Again, why have such a speaker? No way an old Levinson sounds as good as this mono tweaked IceEdge. But George will just keep repeating the same old lines (he hates class d...unless it has GaNs and has 1.5 meg switching). 100 watts into 2 ohms is not 1000 watts at 2 ohm. And my IceEdge modules beat my super simple super tweaked custom mono class A amps (also 25 watts a channel and will double/double all the way down to 100 watts into 2 ohms). The IceEdge module is current limited at 38 amps.....it is not unlimited. No one ever said it was. It will drive 95% of all speakers to whatever levels someone needs and sounds very, very good. Not state of the art...but very good. Again, here is what it actually does: (600 watts into 8 ohm, 1200 watts into 4 ohms, 1400 watts into 2.7 ohm and 1000 watts into 2 ohm). If you need more power than that then you must look elsewhere. |
OP is asking about Class D amps rated for 2ohms. One of the suggested amps (1200AS1/2) is rated at 2.7ohms. This module also has a clipping indicator built into the controller. It would make sense to me that the clipping indicator was active to see how well the amp is doing. I doubt B&O had something like the CS3.7's in mind when developing this module. Based on OP's last post, it seem the question is if there's a Class D amp that drops down to 2ohms without any issues, while maximizing the speaker to it's full potential. Not a Class D amp that only allows a speaker system 40-50% of it potential. Is there a Class D amp that will do this, if so which ones. According to OP, the 2 that were mentioned failed. |
+1 George "I know someone using the Icepower IceEdge modules on his Thiel CS3.7's and he can blast it all he wants. I have tested the IceEdge module to do 1000 watts at 2 ohms." It was posts like this that sucked me into thinking these amps (Icepower 1200AS1/2) practically had no limit. Hopefully, anyone with speakers lower than 4ohm minimum won't get burnt by the hype. |
You guys are just p***ing against the wind quoting big watts, and not quoting the wattage for each halving of impedance at 8, 4, and 2ohms It’s not about the big watts, Class-D P.A. amps like Crown ect can do that. It’s about the amp being able to come close to doubling it wattage for every halving of impeadance 8, 4, and 2ohms! The classic massive Mark Levinson ML2 mono blocks at only 25w into 8ohms will sound better into into these speakers than any 10,000w Class-D, because it can double it’s 8ohm wattage all the way down to 1ohm ( 25w 50w 100w 200w). Which means it can "DRIVE" these speakers Granted it won’t do party levels because after all it’s still only 25w at 8ohms , but it will p**s all over your ice power class-d for sound quality, into these types of speakers. Cheers George |
For about $3k you can get an nCore NC1200 based stereo amplifier from Nord/Apollon that drives 2 ohm speakers with 1200W. Plus your choice of Sparkos or Sonic Imagery discrete opamps to flavor to taste. IMO this is a huge value. I don't need that much power and settled on "only" 550W in 2 ohms of the NC500 for my Thiels. That is plenty of power, lowest distortion and non existing hiss and noise. |
George, no negative comments here, please, but my point I am about to make is very relevant to the discussion, and just another person’s perspective. As most here who know me, I go wayyyyyy back with PWK and his Klipsch Heritage products. I have owned, borrowed, installed for others, and listened to, so many other speakers, and the same goes for power amplification. As much as I enjoy, and own, Heritage, I am certain, part of my enjoyment, comes from the driving amplifiers, simply " coasting along ". You do not hear a speaker, without a driving amp, nor, do you hear an amp, without a driven speaker. It is always, imo, and ime, the combination. Some of us hear an immediate " compression "; some of us hear certain " distortions "; some of us hear a lack of " damping " ( woofer control ), etc. If there are any questions, that reliable measurements cannot tell you, you simply need to try it....On another thread, I recommended to the readers, to read a review of the Peak Consult Dragon Legends, from Mono Stereo, last year, by the same reviewer who just reviewed the Merrill 118s, from Part Time Audiophile. After reading the Merrill review, and realizing I had read the speaker review a year and 1/2 earlier, I needed to read the speaker review, again. Richard Mak, the reviewer, does an excellent job, in both reviews, but, really highlights, greatly, the importance of the speaker / amplifier interaction, and most important, the expectations of the listener. Please read them both. Enjoy ! MrD. |
