What Class D amps will drive a 2 ohm load


Just asking.

I see specs into 4 ohms but nothing into difficult speaker loads (like Thiel CS5's).

Thanks for listening, 

Dsper


dsper
I believe PS Audio Stellar M700 monoblocks
are rated to be stable down to 2 ohms.
Class D 350 watts at 8 ohms, 700 watts at 4 ohms
Dsper - hopefully you have checked out the Thiel users group thread, lots of good discussion on amp pairing, lots of good discussion on how to get the most out of the CS5s, more focus on what listeners are hearing rather than technical debates.  Personally I always enjoy comments linking specific listening experiences with hypotheses on the connection to equipment design, rather than starting with design and the associated engineering factors to reach a hypothetical listening experience.  Also fyi Jim Thiel, as he is working on crossover updates fo some Thiel models, uses the Benchmark AHB2 as a modern reference (along with other older amps) as he fine tunes his mods. Not trying to put words in his mouth, but Ibelieve in this case reference meaning a neutral clean sounding amp with enough power to drive some challenging loads, but also at a reasonable price, in other words one many many users could consider as an excellent starting point for some Thiels, honestly not sure about the CS5, if i remember correctly those are some beastly beasts.  

Btw, despite wading through a fair amount of bs, I did learn a bunch about amps on this thread, so thanks.
why not just start a new thread about the theoretical disadvantages of Class D?
No sorry, I don’t start threads asking for others to post negatives for me, I prefer to debate and show tech proof, on the pro’s and con’s of anything I feel need to be shown.

That would then emulate Eric Squires on what he’s trying to do to Pass amps. https://forum.audiogon.com/discussions/the-imperfect-amp-pass-or-ayre/post?postid=1815745#1815745

BTW:  Bryston 14BSST (15 amp version)  beating this is nothing to crow over into the Thiel CS7's. If and amp had 60-100amp capability down into 2ohms and your Class-D better it then you'd have something. 

Cheers George
All I try to offer in any particular thread (and as noted per my last post I have lots of experience setting up systems and among the speakers that the store carried where my friend worked were Thiels and Maggies), and this will be my last word (regardless of how many more insults someone wants to hurl my way whether that is not be able to hear or not knowing what an impedance curve is, and an impedance curve I've already previously referenced here if someone actually read my comments which apparently some have not), is actual experience intended to provide additional relevant information to a question posed by the thread originator.  It is not intended to made judgments about other peoples tastes, listening habits, etc.

With forum like this one, I've already noted and quoted the Wikipedia definition of an internet troll in these threads.  It is just the way it is and nothing to get all excited about, it is the norm that there will always be a few.  For example, if someone asked a question about Magico speakers, which by the way I think are wonderful and have heard in a store more than once and at audio shows more than once, and I started making theoretical comments about something that they don't do well, there are probably some people after the first comment who might consider me a troll (it might be a bit judgmental for one comment).  If I continued making many comments over and over with no relevant experience to offer to the original poster's question, I'm sure there would be more and more people who would think that I'm a troll (and I'm not sure how I would argue that I'm not).

This is not to pick on a particular person.  It is just to make my point that it is probably best to start a new thread vs. make comments without actual hands on experience relevant to the topic.  As an example, at one point I bought a lightly used Bryston 14BSST (15 amp version) when I originally had Thiel 7.2s (and I've already posted this information within the Class D threads if anyone bothered to read). I used them in a huge room (probably almost 7,000 cu. ft. that opened into other spaces).  I listen to a wide variety of music, some of which is very dynamic.  The impedance of the 7.2s caused the amp to shut down a bunch of times.  I called the guy I bought it from who had Thiel 6s (which I heard many times and help deliver more than one pair) and only listened to small jazz combos in a small or average sized room and did not play things at the levels I might.  If I posted a blanket statement that the 14BSST can't drive or get the best out of any Thiel speaker, I don't think that would be either a factual statement or one that would probably be useful to someone posting a question.  An example would be the question posed here which deals with what Class D amps can drive certain things.  The original poster is entitled to seek information from others about their experiences and determine if there is something he or she would like to try in their system.  That does not mean that if they tried it, they would like it better than another amp or might find faults with how it sounds.  It is just more helpful when someone provides feedback about their experiences so that the person posing the question can come to a conclusion as to whether something is possible to use in their system.  That's all from me.
Yes - definitely getting the best from the 3.7s vs. other more expensive amps (and not just my opinion as others have heard it in my system with Class D and I'm not talking about non-audiophiles but people who have gone to shows and heard really expensive high end systems).  Now I'm not saying that there aren't products out there (as there are many products consisting of different amp classes) that might sound better (I can only offer actual experience, vs. theories which are just that and not particularly useful vs. actual in home listening and including the reaction of others who have heard it in my system in my room and no need to insult others who can hear vs. someone who has not heard the system in the room).  That does not mean that it is the last word in amplification. Upon my first listen (after breaking in a Class D amp), I was shocked how well it drove the 3.7s and how much better it sounded than two highly regarded non-class D amps with list prices of around $9k.

George, with all your comments on various threads, why not just start a new thread about the theoretical disadvantages of Class D?  Would not that be better to have all that discussion organized in one thread?  Once would think (at least I would, others can disagree of course)  that it would be far more productive than insulting other peoples (and a bunch of people who have had separates for 30- 40 years) hearing.  Personally, I just don't see the point of regurgitating the same comments with a complete lack of actual experience with the room and the components and speakers. When I had a friend who worked at a high end shop many moons ago and did virtually all his set-ups in deliveries with him (and I'm talking some two channel systems with around $150k in costs going back more than a dozen years), I learned very quickly not to say that for example a particular speaker is always wonderful sounding (I heard pairs of speakers I previously owned that sounded like complete crap in another room).  I don't take any of your comments personally (or those by anyone else btw).  I can't take anyone all that seriously who makes comments without actually hearing things (and I would have no problem if you heard it and posted all over here that my system actually sucked in your opinion).  Not trying to start anything.  Just think it would be best to get all points of view concentrated in appropriate threads (and would be fine if this thread was linked in a new thread - much betting than making comments that really are not that relevant - if you think they are, then why don't post your actual experience using Class D vs. other classes of amps driving Thiel 3.7s or 5s and if you don't have any that is basically what I'm saying - theories are fine and at one point the earth was flat according to one as well)
Post removed 
I’ve already noted how easily the AS1200 can drive my Thiel 3.7
https://www.stereophile.com/images/archivesart/1208T37fig1.jpg

Yes they can drive them, but I’m 100% sure your not hearing the very best from them.
As your the one who asked " Can a class D amplifier do justice and get the best or close to the best from the speakers?"

Cheers George
gillatgh
speakers in user are rated at 90db efficiency with nominal impedance of 8 ohms 3ohms minimum. Can a class D amplifier (let’s use 300w per channel)do justice and get the best or close to the best from the speakers?

You ask to get close to or the best from these speakers

Show a impedance graph with -phase angle overlay, as what you asked for can’t be answered properly, even using the 3000w!!! Behringer Class-D.

You say that speaker has a minimum load of 3ohms, if that’s in the bass and you have it in conjunction with a -phase angle of 50 degrees the amp could be seeing even 1ohm as a load, and I know of no class-D that can take that.

That’s why you never see Stereophile tests on Class-D’s that go down into the 2ohm testing, because they mostly **** themselves when it’s done.

Cheers George





" Having read this very interesting discussion in its entirety several times I have to ask the commentators a question since neither the pros or cons truly answered the original Inquiry.
Let's say I want to take a plunge into class D but do not want to revamp my entire system and the speakers in user are rated at 90db efficiency with nominal impedance of 8 ohms 3ohms minimum. Can a class D amplifier (let's use 300w per channel)do justice and get the best or close to the best from the speakers?
Let's hear your opinions."

I've already noted how easily the AS1200 can drive my Thiel 3.7s.  These -  https://www.muraudio.com/sp1  (and it indicates 2 ohm minimum and they are not super efficient) were used by Merrill Audio at the 2019 Florida Audio Expo and sounded great.  I've seen a bunch of other examples at shows in big rooms (e.g. 2017 RMAF with a Wyred4Sound Class D driving Acoustic Zen Maestro speakers (87 db and rated 6 ohms nominal).  I think will any product, it is too general to just say Class D as if they are all identical (same is true of any other type of amp).
Having read this very interesting discussion in its entirety several times I have to ask the commentators a question since neither the pros or cons truly answered the original Inquiry. 
Let's say I want to take a plunge into class D but do not want to revamp my entire system  and  the speakers in user are rated at 90db efficiency with nominal impedance of 8 ohms 3ohms minimum.  Can a class D amplifier (let's use 300w per channel)do justice and get the best or close to the best from the speakers? 
Let's hear your opinions.

Wow!
The Wilson Alexia’s get into areas of the Kappa 9’s for difficult to drive?
Did not know that, thought all Wilson’s were very efficient speakers.
Yes efficient 90db like many Wilson’s, but a right b***h of a load like most them also, EPDR (impedance + phase angle) down to 0.9ohm!!! in the bass.
OTL’s will drive them, and pigs might fly!! What was that Supertramp track? oh yes "Dreamer"

Absolute Sounds Alexia measurements for HiFi Review https://ibb.co/YWSSXPX
Stereophile measurments on the Wilson WP8’s https://ibb.co/LpTPmXt
" " " " Wilson Alexx https://ibb.co/nbGFGtB
" " " Wilson Sabrina https://ibb.co/8Kg5hJv

Cheers George
Bel Canto digital amps most often the Ref 1000, I tried those amps with my own speakers and they worked really really well for my classical and jazz listening but not quite so well as the Pass products.
I said pages back the "better" Class-D’s like the BC Ref-1000 will work, and probably to the owner sound fine with the op’s Thiel CS-5’s.
But "he" hasn’t heard the CS5’s at their best yet until he’s heard an amp that can do <2ohms without breaking a sweat far better, like the Pass X150.8, then he’ll know that Class-D was doing it hard.

Cheers George
I’ve had Thiels for 12 years but have since moved onto to Magnepan 20.7’s. The best amp I ever found for my Thiel 2.7s was the Pass X series and a Pass x150.8 would probably work but an x250.8 would be better. As far as "digital" amps goe, if you poke around the Thiel users groups you’ll find that ALOT and I do mean ALOT of Thiel owners were using Bel Canto digital amps most often the Ref 1000 to drive them. I tried those amps with my own speakers and they worked really really well for my classical and jazz listening but not quite so well as the Pass products.
Wow!
The Wilson Alexia's get into areas of the Kappa 9's for difficult to drive?
Did not know that, thought all Wilson's were very efficient speakers.

We're gonna need a bigger boat...
Post removed 
With the stat speaker, impedances can be as high as 30-100 ohms in the upper/lower bass, and 1 ohm or less in HF.  This is more than the 10:1 ratio you cite, but still nowhere near as much as the inverse RIAA curve.  Still, according to your theory, the stat speaker should sound like a less drastic inverted RIAA curve, which I didn't find in the listening.  Also, all dynamic speakers have marked variations in their impedances, and your theory would predict that a SS amp would produce markedly different sound from different speakers in relation to each speaker's impedance curve.

@viber6  this isn't correct. (BTW what I'm talking about here isn't theory, its more like audio history. The Power Paradigm is what was around before MacIntosh and ElectroVoice developed the Voltage rules in the late 1950s.) With most dynamic speakers (there are exceptions in high end audio) the speaker is meant to be 'voltage driven' so variable power output is what you're looking for in the amplifier in order to get flat frequency response. The idea is plug and play, no need to adjust any midrange or treble controls (like you see on older speakers, stuff from the 50s and 60s). Of course like anything else, this approach solves one problem while introducing others.


The brightness of an unequalized RIAA curve would **not** have been compensated by the way the ESL and solid state amps work together.  I think you will find though that the 10:1 ratio I described is generally pretty close- that describes Quads, Martin Logans, Accoustats and Sound Labs which are the ESLs with which I have the most experience. If you can find one that is outside of that (for example: 100:1) I'd be very interested in knowing about it!

@ georgehifi

All the amplifiers in the world double when drop in ohm to half, but when you reach their current limit then you will not see the doubling when you drop in ohm
Atmasphere,
I follow what you are saying about how a voltage source SS amp invariant to impedance theoretically would sound bright driving an electrostatic speaker.  But in practice I don't find this to be the case.  Years ago, for fun, I put my tonearm leads into the line stage, bypassing the RIAA curve of the phone stage.  Of course, that produced very bright sound due to the 30 dB boost at HF compared to low freq.  With the stat speaker, impedances can be as high as 30-100 ohms in the upper/lower bass, and 1 ohm or less in HF.  This is more than the 10:1 ratio you cite, but still nowhere near as much as the inverse RIAA curve.  Still, according to your theory, the stat speaker should sound like a less drastic inverted RIAA curve, which I didn't find in the listening.  Also, all dynamic speakers have marked variations in their impedances, and your theory would predict that a SS amp would produce markedly different sound from different speakers in relation to each speaker's impedance curve.  But I have found similar tonal differences A/B'ing 2 amps on different speakers.  For example, SS amps generally sound brighter than tube amps, which I have found to be true regardless of whether I used dynamic or stat speakers.  I am puzzled by my different listening findings compared to your theory.

I wasn't saying that amps don't make much difference, because obviously I pursue finding amps that offer more clarity, etc.  But it is clear that whatever sonic differences there are among amps, the sonic differences among transducers like speakers are vastly greater.  This is also true of transducers like cartridges which are really inverse speakers.  
The more general point is that the sound character is largely determined by the speaker, closely followed by the recording.  Most good amps today have superb specs and sound fairly close to each other.  
@viber6  Actually this isn't true. It is true that speakers have a lot of sound character (as does the room) but amps don't sound the same at all, nor do all amps interface correctly with all speakers.


One example is how solid state generally doesn't work well with full range ESLs. Full range ESLs have about a 9 or 10:1 range of impedance from the bass to 20KHz. For example a Sound Lab is 30 ohms in the bass and between 1.5 to 3 ohms at 20KHz depending on the position of the Brilliance control (if the control were removed it would simply be 3 ohms). (BTW, Sound Lab solves this issue to some degree by having a bit of adjustability to their speakers- bass settings, midrange settings (IIRC) and the Brilliance control.)


Now most solid state amps are designed to work as a voltage source, which is to say they maintain the same voltage regardless of load. This is the idea of doubling power as impedance is halved or halving power as impedance is doubled. So If the solid state amp makes 100 watts into 8 ohms, On a Sound Lab ESL with 30 ohms in the bass it will make only about 26 watts but with the same level signal applied at 20KHz will make 300 watts- over a 10:1 difference! The problem here is that unlike a box speaker with a driver in it, the ESL's impedance curve is based on capacitance rather than a base impedance influenced by resonance. Put more simply, it **has the same efficiency regardless of impedance**. This causes solid state amps to be bright on top and unable to make power in the bass. Martin Logan gets around this by simply having a super low impedance at high frequencies and most solid state amps (tube amps to a greater degree) can't make power into that impedance and so they tone down the brightness. In a nutshell, ESLs are not Voltage driven; they are Power driven. For more on this see http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php

Conversely a B&W 802 is designed for a voltage source amp (solid state) and so tube amps have a very difficult time making bass on this speaker.


But put even more simply, we've been getting spec sheets from amplifier manufacturers for 60 years, but we can't tell what the amp sounds like. So we have to audition the amp on our speakers to see if it satisfies! This simple fact is common knowledge with all audiophiles.


Of course we have to examine what is considered 'superb specs'; the simple fact of low THD doesn't mean the amp will sound uncolored or musical to the human ear- in many cases quite the opposite! This is why tubes are still around 55 years after being declared 'obsolete'. Its complex, due to how the human hearing perceptual rules work; how we perceive sound pressure (the presence of higher ordered harmonics, FWIW), how the ear converts distortion into tonality and the masking principle all play a role.


Because some manufacturers want their amplifier to conform more closely to the human perceptual rules, they are willing also to have 'inferior' specs. Its a simple fact that as our current regime of test and measurement goes, we're not always measuring the right things.
How about plasma drivers crossed over to electrostatic panels for lower freq.

Funny you should bring them up.
Which is what I use, ACI SV12's in 5cuft IB enclosures xover at 130hz to big esl's, xover at 10khz to MP-02 plamsa's  https://www.ebay.com.au/itm/Magnat-Plasma-MP-02-ion-tweeter-massless-air-plasma-speaker-Plasmahochtoner/272894087984?hash=item3f89c15330:g:V5sAAOSwCJxZ6PXy&frcectupt=true

Cheers George
Atmasphere,
You said, "But I don't agree about the 'best speaker you can afford' thing! The reason is simple- you may find that you have a preference for an amplifier technology- tubes for example- and if that is the case buying an incompatible speaker will simply be money down the loo. So- if you know what kind of amp you prefer, then get the best **compatible** speaker you can for it."

I say that no speaker is "incompatible" with any amplifier.  A 5 watt tube amp may make great music up to 105 dB with an efficient horn speaker.  But driving a 75 dB efficient electrostatic with small panels, it can make beautiful chamber music at SPL of 75 dB, which is the natural level of a string quartet, for instance.  Suppose the listener wants to hear sweet mellow sound from the string quartet, then the more "compatible" higher powered neutral/accurate SS amp is not for him.  

The more general point is that the sound character is largely determined by the speaker, closely followed by the recording.  Most good amps today have superb specs and sound fairly close to each other.  Any of them are much closer to theoretical perfection than any speaker available today, all of which sound hopelessly veiled compared to the real thing, although I come much closer with my electrostatic and EQ.    The real advances in high fidelity should be in speaker design rather than amp design.  Produce better electrostatic designs, rather than inferior huge curved panels of Sound Lab and Martin Logan which smear HF and bloat images.  It is interesting how the new smaller Maggie LRS is creating a sensation.  I haven't heard it yet, but the size is right.  How about plasma drivers crossed over to electrostatic panels for lower freq.   I heard the Plasmatronics speaker by Dr. Alan Hill in the early 80's.  Too bad most of the market cares about big dynamics instead of accuracy and finesse, which is why these plasma and stat transducers are largely ignored.  

Hi George,

I’m glad you are branching out to opine on something besides Class D amplifiers, I think that shows real progress in you participating constructively with others on a broad range of topics.

In regards to your reply to me, please just imagine me rolling my eyes around and guffawing repeatedly, in a very very respectful manner.

Best,

Erik
I ask you to provide a list of amps that have guts. I request this,
Sorry, if you search I've already given many examples, and you should really know if your debating this in this thread.

Cheers George
Of these only the Thiel is really difficult to drive.
You are in a world of denial now.
Wilson, Thiel, ML esl’s, MBL, Sonus Faber JM labs
Of these only the Thiel is really difficult to drive. We have customers with Wilson, Martin Logan and JM Labs. And we make tube amps that don't double power or even act as a voltage source. The mbls aren't that hard to drive either; just have a bump (not dip) in the upper midrange driver that can make an amp with no feedback sound bright. But the mbls are easy to drive; most of their 'inefficiency comes from the simple fact that they are omni-directional.
Hey OP.

Ideally, amplifiers are pure voltage sources. That is, the voltage at the speaker terminals is 100% determined by the input from your sources. Usually there's a multiplier, around 20.
So, 1 V in ---> 20V out.

But as the impedance of the amplifier rises, and the impedance of the speaker drops, this drops:
1 V in --> 18 V out.

And it can be frequency dependent, because the speaker's impedance is frequency dependent.

Take a look at the very first plot from this review:
https://www.stereophile.com/content/conrad-johnson-premier-twelve-monoblock-amplifier-measurements
and you'll see how this happens with tubes, with notoriously high impedance outputs. 

This is not the whole story though, as amplifier feedback matters, so it may be that the amps can keep up but only to a certain current limit.


That's why I was strongly encouraging you to listen. If your Class D amp is rated for 2 Ohms, go by your hearing, not spec or class. If it has an actual issue you'll hear it.
If you want a gutless amp then look for a speaker to suit, they in most cases won’t be designed like the ones above.

@georgehifi
 
 I ask you to provide a list of amps that have guts. I request this, despite it possibly being beneath your dignity.-But, only to provide those less knowledgeable valuable information.
B
I just saw the impedance curve. Wow, that’s pretty brutal.

They do do this for laughs do they?.
Put it this way, what advantage is there for a speaker manufacturer like Wilson, Thiel, ML esl’s, MBL, Sonus Faber JM labs ect ect ect ect to make their speakers so hard to drive, because complexity of design, complex xovers used, that you have to spend big bucks on an amp with enough current to be able drive them.

THE ANSWER IS NONE!! They do it to make them as close to perfect as possible, and reward is reaped when driven right with as little compromises as possible.
If you want a gutless amp then look for a speaker to suit, they in most cases won’t be designed like the ones above.
I just saw the impedance curve. Wow, that's pretty brutal. I would love to see the schematics for this beastie and see if it can be made more amplifier friendly.


On another note, one thing I've found about amps and low impedance in the bass:



- Amps can be more susceptible to sounding weak due to low impedance than you'd think.
- This is easily audible. Basically pick the amp that produces the deepest tightest bass. :)
- Sometimes speakers have horrible impedance issues for lack of better simulation tools (i.e. old speakers designed empirically) and sometimes they get there to make them seem more demanding. Audiophiles often equate a demanding speaker with a better speaker.



To the OP: Buy what you like, I think the impedance issue, so long as it meets the amps minimum impedance requirements, will be something you can 100% hear for yourself, either way.

Best,

E
As per bel canto - their Black Integrated ACI 600's output is stable into a 2 ohm minimum load.

As per Devialet - their Expert Pro Dual 1000's and 440's output are both stable into a 1 ohm minimum load.

I recently shopped / compared all 3 and found them to be excellent sounding and aesthetically pleasing Class D & Class A/D Integrateds.
Sez you, some of the very best are insanely hard to drive, and why class-d, OTL and you have a problem with that.
Sez the specs of all amps. Obviously this statement is misleading; George is cherry picking. On the one hand he likes to trot out Stereophile ratings to support his claims but when that same source doesn't support his claims then its ignored.

Some of the very best speakers are also very **easy** to drive.  The issue is simple: Do you want the sound of a good hifi or the sound of real music?? If the latter, then you will want a speaker that is both state of the art and easy to drive since distortion is what separates the men from the boys.
While you and Ric Schultz are technically correct that higher impedance speakers get better performance from amps than low impedance speakers, this ignores the overwhelming superiority of low impedance electrostatics for most musical criteria, except in large SPL dynamics where the conventional dynamic speaker excels.  If someone designed a higher impedance stat, that would be great, but the disadvantage of somewhat higher distortion (and it is still fairly low) into their very low impedance is vastly outweighed by their superior transient response, clarity, coherence, less coloration, etc.  The old dictum is still true--the speaker is the most important element in the chain, with the possible exception of source quality.  Get the best speaker you can afford, then get the best amp that will drive that speaker. 
Electrostats are a bit of an exception. Their low impedance derives from a capacitance and is at the upper frequency extreme where very little energy exists! So you don't need a powerhouse to drive them. Sound Labs are a great example and some of the very best ESLs ever made. We have lots of Sound Lab customers- about 80-85% of all our MA-2s go to Sound Lab owners. IMO, the Sound Lab is one of the top 5 speakers made price no object. Even Martin Logans don't need that much power- we've driven them with our M-60s (and a set of ZEROs) no worries.

But I don't agree about the 'best speaker you can afford' thing! The reason is simple- you may find that you have a preference for an amplifier technology- tubes for example- and if that is the case buying an incompatible speaker will simply be money down the loo. So- if you know what kind of amp you prefer, then get the best **compatible** speaker you can for it.



Atmasphere,
While you and Ric Schultz are technically correct that higher impedance speakers get better performance from amps than low impedance speakers, this ignores the overwhelming superiority of low impedance electrostatics for most musical criteria, except in large SPL dynamics where the conventional dynamic speaker excels.  If someone designed a higher impedance stat, that would be great, but the disadvantage of somewhat higher distortion (and it is still fairly low) into their very low impedance is vastly outweighed by their superior transient response, clarity, coherence, less coloration, etc.  The old dictum is still true--the speaker is the most important element in the chain, with the possible exception of source quality.  Get the best speaker you can afford, then get the best amp that will drive that speaker.  
Can you provide some examples?

If you don’t know that, you may as well give up, and apply for lawn bowls, just look at the OP's speaker for one.
@georgehifi 
Sez you, some of the very best are insanely hard to drive
Can you provide some examples?
b
Plain and simple low impedance speaker loads are a Bad Idea

Sez you, some of the very best are insanely hard to drive, and why class-d, OTL and you have a problem with that.

By all means please show the do’s in Class-D, hopefully independently tested, impedance v rms wattage all at just before clipping into 8, 4 and 2ohms, the same distortion figures.
Ha! That's pretty funny!


**No** amplifier will have the same distortion figures. All amps regardless of technology used have higher distortion into lower impedances. This has been seen over and over again in tests by JA at Stereophile, Bascomb King and others all over the world.

And right here might be the simple salient fact to the pointlessness of the inquiry: If you want the best results from your amplifier investment dollar, that dollar will be best served by a speaker load of higher impedance ***IF HIGH QUALITY SOUND IS YOUR GOAL***. (Sorry about the caps- I was looking for emphasis, not shouting). This is where that magical line in the sand occurs- the difference between the results sounding like real music or just a really good hifi.


Plain and simple low impedance speaker loads are a Bad Idea and it doesn't matter if you can weld with your amplifier- it simply will make more distortion into that lower impedance, and that distortion will be audible as less detail and harsher. Doesn't matter if the amp can double power or not- the higher distortion will be there nonetheless. Again- its easy to see in the specs and independent measurement.
The story of Sisyphus is there as a teaching moment and applies directly to the the task of driving lower impedances.
some do some don’t

By all means please show the do’s in Class-D, hopefully independently tested, impedance v rms wattage all at just before clipping into 8, 4 and 2ohms, the same distortion figures.
Of course you can take my word for anything I say I hear.  Also, because I am not in the business I tell things like it is without concern for politics.  
I didn't doubt you :)
This thread should have been finished after the 5th post. I think your response nailed it perfectly. Class-D and speakers < 2ohms just don't work, with maybe the exception of some of the latest offerings
With class D amps the older amps were limited by their output filters- not their current. With newer amps that can switch faster, the output filter can be set to a higher frequency and so 2 ohms isn't the concern it used to be.
2 ohms requires more current of course. Most output sections can handle the current; we're using devices rated at 30 amps each which is double the current capacity required for our prototype to make full power into 2 ohms. The problem isn't the class D so much as it is whether the heatsinks provide adequate cooling (important even for GaNFET-based output sections into that sort of impedance) and whether the power supplies have adequate current to support the power.
So like any other amp: some do some don't. Simply inquire with the manufacturer. Yes- just that simple... 5 pages later.


Thanks George.

This thread should have been finished after the 5th post. I think your response nailed it perfectly. Class-D and speakers < 2ohms just don't work, with maybe the exception of some of the latest offerings that cost just as much as a good quality Class A amp.

golfnutz25 posts Sorry Erik, I won't be engaging in any more of this discussion. You can find the quotes yourself if you need to see them.
gdnrbob And, the Angels shall weep
gdnrbob
@georgehifi ,
Can you just drop down the level of sarcasm and argumentativeness a couple of notches?

Bob

REALLY!! after saying that to me,  https://youtu.be/YTY26k0CA0I?t=6 


And the self appointed forum cop has spoken.
golfnutz from his very few posts (25) had more knowledge than either of you. Audiogon's loss if he leaves.
My brand new Mola Mola Kaluga amp and Makua Pre-Amp will.  Oh by the way, I just listed them for sale on Audiogon. 
Sorry Erik, I won't be engaging in any more of this discussion.
And, the Angels shall weep.😭

Now, back to our topic:
So, what amp WILL drive a 2 ohm load?
B
Post removed 
Sorry Erik, I won’t be engaging in any more of this discussion.

Whew, there’s a load off! But it is a real shame because I can't imagine anyone on earth as interested in digging through my old posts like you have. I'll miss the closeness.

I guess you’re the only person that’s allowed to look at other members threads/posts.


Something I’ve never ever intimated. Hahahahha.

And for the record, Golf’s last quote was from a thread about DSP crossovers where I strongly suggested the OP stop reading and start doing to build a level of personal experience he won’t get from mere reading, but as predicted, the OP just started 3 more threads about DSP crossovers.

Best,

Erik

Sorry Erik, I won't be engaging in any more of this discussion. You can find the quotes yourself if you need to see them.

I’ve kind of been looking at your threads. I’m going to give you advice I’m sure you won’t take.

I guess you're the only person that's allowed to look at other members threads/posts.


TBC: I’ve never claimed I have not said I prefer one amp /speaker/whatever over another.

Nothing wrong with having a personal preference, and expressing it when asked and appropriate. I mean, my god, if we didn’t have preferences, this entire web site would be 1 message long!!

My quote, above:

Wow, huge difference in my dislike for particular brands, and being on a crusade.

I’ve never disrespected anyone for liking Pass. I’ve never told them they were wrong.

And that is why I don’t see @golfnutz claims of my alleged hypocrisy valid.

The issue is not whether or not an A’goner likes a particular technology, it’s whether they respect the wishes of the OP or those who disagree with them.

So you seem to have quoted me, though I have not checked to be sure, lets go over the last two:

Spectral is a line I wanted to be impressed with, like Pass, and I just haven’t. They do not bring me joy.

On the opposite end of the spectrum is Pass. A sound I really don’t like.

First, @Golfnutz, I have to thank you. I’m pretty sure no one on earth has been paying attention to anything I write more than you, so as my biggest fan, I’m flattered.

Those comments and comments like them are fine.

Please point to a place where some one says "I love x" and I say they are wrong.

In fact, I make it clear, often but not perfectly, that I’m expressing my personal tastes, while not demeaning others for having different tastes. When George turns around and starts talking specific modern models, and characteristics he’s herard, instead of random statistics which may or may not have any correlation to a listening experience we’ll all be happy.

Also, while we are at it, can you please point us to the original threads? I'd love to show that my statements were in context, and contributing to a discussion.



Best,

Erik