Purifi 1ET400A has no buffer, so it is expected to a manufacturer to add a custom buffer, and add more gain as needed. It also has a disappointedly low 2.2k input impedance, so the use of most capacitor coupled (unless >10uf) preamps, tubes, or solid state or passive preamps direct in are out of the question if no extra gain is needed, which with today’s sources giving so much higher output, no extra gain is needed, so then neither would be an opamp buffer. And if more gain is needed then a direct coupled opamp smd buffer is the only obvious option, again not capacitor coupled, solid state or tube buffer otherwise a massive 10uf coupling cap will be needed into that 2.2k input impedance. WHY!! they keep making low input impedance amps these days is beyond me, go back to 48k (the once recognized industry standard) or even 100k like it used to be with tubes, makes for a whole better range of preamps ,tubes SS or passive able to drive them properly. Cheers George |
Custom buffer adds gain and increases impedance to 47k ohms. As seen on current NC500 based amps such as Nord or Apollon. Just Google it before complaining... These modules are NOT finished products yet, manufacturer is supposed to add their buffers.
For all in one, buffer+power section+power supply, see Hypex nCore MP series or ICEpower. The bufferless modules are for manufacturers wanting to differentiate their implementations. |
Custom buffer adds gain and increases impedance to 47k ohms. There’s no need for it in many cases, as sources and preamp have enough gain these days. It’s just "another opamp in the signal path" that’s not needed in many cases if the input was high enough instead of 2.2k, who wants that in hi-end if it can be taken out and one less opamp yay!!! gotta be good for the sound, and the business. I think that’s a very legit observation or "complaint" as you would put it.. |
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WHY!! they keep making low input impedance amps these days is beyond me,
go back to 48k (the once recognized industry standard) or even 100k
like it used to be with tubes, makes for a whole better range of preamps
,tubes SS or passive able to drive them properly. The reason you see this has to do with the fact that a filter often has to be installed between the audio input and the encoder (comparitor or the like). The filter is there to remove high frequency noise that might otherwise get amplified and add to the noise floor of the amp. But good high speed comparitora have issues of their own and can be unstable with a high impedance inputs. Hence low input impedances if there is no input buffering. There’s no need for it in many cases, as sources and preamp have enough
gain these days. It’s just "another opamp in the signal path" that’s not
needed in many cases if the input was high enough instead of 2.2k, who
wants that in hi-end if it can be taken out and one less opamp yay!!!
gotta be good for the sound, and the business. This statement is incorrect. Of course there is a need for an input buffer in many cases- a lot depends on the encoding scheme of course (for example with PWM the gain is based on the difference between the amplitude of the triangle wave in the circuit and the input signal). Things might not work out in the design that you have enough gain- particularly if feedback is employed. So an opamp or instrumentation amplifier might be used to make up the needed gain. Quite often this isn't a lot of gain, maybe a gain of 2 to 10. You could do it with an input transformer which has certain advantages, but it should be obvious that an input transformer adds a whole set of problems of its own. Our preamps can drive such low input impedances- any preamp that supports the balanced standard can, but in high end audio such preamps are quite rare. |
Our preamps can drive such low input impedances-
Of course it can, how did I know that was coming, stick with tubes, your good at it, and built your rep on them. The fact is this amp without buffer it has around 15db of gain around the same as the Nelson Pass First Watt F5 and with today’s high output sources and preamps, in most cases you don’t need another soul destroying opamp buffer in the signal path with or without gain. Here is the comments from a manufacturer of these Purifi’s Class-D amps when I queried him on the unnecessary low 2.2k input impedance. I think it could be because of the use of bjt input stage instead of fet, I’ve yet to suss that one out. Yes you are absolutely correct that you can use a high output DAC directly into this module. "That would be the ultimate solution"
And I am considering a buffer bypass mode. However most power amps will have gain in the region of 26dB to account for sources down to 2 Vrms. A typical DAC straight in is a good solution with digital volume Most digital sources today have far more than 2v and owners preamps can certainly have enough for the Purifi without another buffer. As Nelson Pass with his F5 said " If you need to turn the gain up on your preamp, then do so." Cheers George |
Here is the comments from a manufacturer of these Purifi’s Class-D amps
when I queried him on the unnecessary low 2.2k input impedance. I think
it could be because of the use of bjt input stage instead of fet, I’ve
yet to suss that one out. Yes you are absolutely
correct that you can use a high output DAC directly into this module.
"That would be the ultimate solution"
And I am considering a buffer
bypass mode. However most power amps will have gain in the region of
26dB to account for sources down to 2 Vrms. A typical DAC straight in is
a good solution with digital volume I explained why already. This is a common issue and why you see many Class D amps with some sort of buffer input. Many opamps can drive lower impedances like 600 ohms no worries and since so much feedback (+30dB) is being used, the assumption is that the distortion added by the feedback on the opamp will be quite minimal. But there are some class D amps where the designer opted to simply have a low impedance input for the very simple reason of having less circuitry- a purist approach. But you have to have a source that can drive it. Its nothing to do with FETs or BJTs. |
Whatever Ralph.
Seems like this could be the module your using, as you've turned up the force shields a notch higher on this one, if so just go with the buffer by-pass switch. |
I've mentioned before, we're not using anyone's modules.
It seems that what you aren't getting is that comparitors (a kind of chip or circuit used in many class D amps) can be unstable if used with high input impedances. To prevent oscillation, lower impedances are used at their inputs.
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Sorry but what you get is a good PA amp. Hypex suck in, they purposely put things backwards to confuse at glance. Look again, and that’s peak watts and amps, also the wattage go backwards as the impedance goes down, it gets severly current starved. Nowhere in this universe can this thing come close to doubling into 2ohms The NC400 of theirs is a far better module as far as current delivery into low impedances it actually goes up in watts instead of down. Data sheet download here https://www.stereo.net.au/forums/applications/core/interface/file/attachment.php?id=480207Cheers George |
This just gets more interesting.
I emailed, to both Nord and Appollon, the Stereophile measurements for the Thiel CS5's and both suppliers said that their amps would drive them.
For example, Appollon replied that their NC1200SL HYPEX NC1200 BASED AMPLIFIER "...is
a perfect choice for your speakers and probably the only class d amplifier that
will drive your speakers with ease at 2 ohm loads. The NC1200 module is
specially designed for such low impedance loads. Any other class d amplifier
will fall apart sound wise with your speakers but the NC1200 shines @ 2
ohms."
So what am I not being told?
Thanks for listening,
Dsper
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So what am I not being told? :) Apparently you're *not* being told that the amp won't work... And FWIW, if the amplifier has a low enough output impedance, it will act as a voltage source even with a 2 ohm load. It **does not** have to double power to do that. |
dsper OP
I emailed, to both Nord and Appollon, the Stereophile measurements for the Thiel CS5’s and both suppliers said that their amps would drive them. (Without seeing any independent tests) Of course they did, they want a sale. No one disputes that they can’t drive the Thiel CS5’s to a point, just if they don’t try to double from 8 to 4 to 2ohm, you won’t get the very best out of them, they will be compromised in the bass, if you don’t mind that that go ahead. But not if you drove them with amps like the ones I have described, that can come close to doubling wattage all the way, from 8, 4, and 2ohms, I believe the Thiel’s are worth the right amp to make them sing top to bottom, don’t you?? it’s up to you. Cheers George |
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just if they don’t try to double from 8 to 4 to 2ohm, you won’t get the
very best out of them, they will be compromised in the bass, if you
don’t mind that that go ahead. This statement is false. The ability to double power as load impedance is halved has nothing to do with how well the amp will play bass- even if the bass is where the load impedance is lowest. Quite simply, it doesn't work that way; a lot more has to do with the output impedance of the amp which is independent of its ability to double power. |
Not at all in your wheelhouse, just an FYI option I overlooked mentioning in my earlier response. https://www.bobcarvercorp.com/crimson-raven-features-specs I drive a pair of 3.6 ohm Avalon Acoustics Eidolons off the 4 ohm tap with the earlier less powerful 180s with aplomb. Compared to an MFA D75 which would run out of steam and the Hypex nCore 400s described in my previous response. Point-to-point wiring, low heat, group biasing, switchable feedback, and untypical low maintenance. Again, just an FYI. |
This statement is false. The ability to double power as load impedance is halved has nothing to do with how well the amp will play bass Of course it does when it demands current into low impedance to do it, get over it.! Ralph you’re so transparent. Stick to what your good at, super efficient easy to drive horns that you heavily promote and your OTL’s, that can’t drive these kind of sub 2ohm inefficient speakers that you have no love for. But then yet in the same breath, promote the use of your OTL’s with them, with expensive Zero autoformers, saying that their great and the perfect answer for your OTL amps to use on these hard to drive speakers, just to make some more dollars from the gullible. All your doing here, is to branch out into the Class-D gravy train $$$’s (so transparent) without any loyalty to where you came from, OTL’s and horns. But then they are both a dying breed. |
Peachtree Audio Nova 220-SE ,300,500 wpc
used on big Maggi Speakers. |
@atmasphere Although we just got news this week that the USPTO is granting our class D patent with all 20 claims supported Congrats Ralph, finally |
@georgehifi super efficient easy to drive horns Hi George, been following these class D threads, what's wrong with efficient easy to drive horns? I'm a neophyte in these matters and trying to learn. Thank you |
Bel Canto 600M monoblocks. Powerful, 2 ohm stable, incredible detail, etc, etc. |
what’s wrong with efficient easy to drive horns? If you need to ask that, you should delve into the measurements of both a bit To have that efficiency and easy load ability. Measurement tests show they are always compromised when compared to a highly tuned speaker eg Wilsons ect ect, that will be far more inefficient and much harder load, that yes need far more serious drive characteristics from the amp/s Bit like comparing a high octane highly tuned multi cam/valve Ferrari V8 motor, to a low octane V8 Ford iron slug from the 60’s. Cheers George |
This
statement is false. The ability to double power as load impedance is
halved has nothing to do with how well the amp will play bass
Of course it does when it demands current into low impedance to do it, get over it.!
George, the quote above suggests that you do not understand how a voltage source works. In case you don't understand what a voltage source is, solid state amps that can double power as impedance is halved are behaving as a voltage source. Having a low enough output impedance is for the most part what makes for a voltage source. A voltage source is defined as a circuit that can make the same voltage (not power) output into whatever load it drives. Now no circuit can really do this perfectly; perfection does not exist. So constant voltage is considered load invariant under the Voltage Paradigm rules. Historically ElectroVolice and MacIntosh led the way to this concept back in the late 1950s. To be a voltage source, the circuit does not have to double power as impedance is halved. But it very much has to be able to cut power in half as impedance is doubled! This is why tube amplifiers can operate as voltage sources and its also why a solid state amp that can't double power into even 4 ohms can nevertheless still play bass correctly into a 2 ohm load. Whatever power it makes into 2 ohms, to act correctly without distortion it will be half of that into 4 and half again into 8 ohms. So for those amps that do not have the power supply capacity, or the current capacity to survive higher powers in the output section, or for tube amplifiers which are well-known to not double power as impedance is halved, the designer simply has to make sure that the amplifier has enough negative feedback so as to reduce the output impedance such that the circuit behaves as a voltage source into the expected loads. If the amplifier innately has a low enough output impedance it may not need the feedback to achieve constant voltage operation. An example of this are the Ayre amplifiers. But any class D amp (GaNFET or not, even sans feedback) has a low enough output impedance as well. So as long as they are operated in their linear region 2 ohms is no problem. Again, this is defined by output impedance. In the case of a class D amp, the output impedance formula is dominated by the 'on' resistance of the output devices. Even in an older MOSFET based class D amp, the output impedance is usually well below 0.1 ohm, meaning that they will have at least 20:1 damping factor into a 2 ohm load. If the amp runs feedback (and most of them do) the output impedance will be even lower than that. The real issue of a class D amplifier driving 2 ohms is actually the filter at the output. What I regard as a bit odd here is that while you have acknowledged numerous times in other discussion the issues of a filter at the output of the amp, in this particular discussion you've not brought out this salient fact even once! This leads me to think that you have no idea what you're talking about. (Please note that what I think you know and what you actually know are likely two different things.) BTW, the way to deal with the filter issue is to design the filter to operate at as high a frequency as possible- hence the advantage of GaNFETs as they allow a much higher filter frequency since the switching frequency is so much higher. This allows the filter to still be effective for hifi purposes when presented with a 2 ohm load. You like to routinely discount my comments out of hand and insult me at every turn, despite the fact that I went to school for this sort of thing and actually design amps (including GaNFET class D amps) for a living. You're a fan on Nelson Pass- why not ask him? |
My two cents:
1) George is an extremely rude individual. Would you honestly speak to people in person the way you do here? Why go out of your way to insult an engineer who designs and builds excellent products and is wiling to impart information? Are you willing to share your audio CV so we have an understanding of your expertise, as your comments do not suggest you do not have much of an understanding of even basic electrical concepts (i.e. ohm’s law)?
2) Atmasphere is extremely patient. Thank you you for continued information. Your posts are always informative for those looking for more technical information without getting deep into the math. |
George, the quote above suggests that you do not understand how a voltage source works Yes you use this old chestnut everytime as it suits you to bring it out every time your OTL’s are brought into question doing the same thing. So it’s simple for all, instead of doing war and peace to confuse everyone as he usually does. dsper OP here’s is the proof, Thiels CS5 that have impedances that reach down to below 2ohms will get "driven" and sound far better "up to a given level" with the 25w!!! Mark Leveinson ML2 monoblocks, but certainly not louder than 1000w, 2000w or even 3000 watt Class-D amps, because the ML2’s can do the doubling act into lower impedances right down to 1ohm |
Yes you use this old chestnut everytime as it suits you to bring it out
every time your OTL’s are brought into question doing the same thing. This statement is false. Our OTLs don't double power and in fact are not intended to act as a voltage source. They are intended to act as a Power Source. So it’s simple for all, instead of doing war and peace to confuse everyone as he usually does.
dsper OP
here’s is the proof, Thiels CS5 that have impedances that reach down to
below 2ohms will get "driven" and sound far better "up to a given
level" with the 25w!!! Mark Leveinson ML2 monoblocks, but certainly not
louder than 1000w, 2000w or even 3000 watt Class-D amps, because the
ML2’s can do the doubling act into lower impedances right down to 1ohm While this comment is a bit of a word salad, if I make it out right its mostly correct and doesn't repudiate anything I've said. Just about any class D amp that can make 1000 watts won't have any troubles making as much power as the ML2 will do into 2 ohms (100 watts) so what this comes down to isn't whether the amp can do 2 ohms better, its simply if it sounds better at all. |
Put the shields up Scotty, we’re being attacked save the Enterprise at all costs.
On these OP’s speakers with the minuscule 25w ML2 monoblocks will do bass and everything better to a given level, than any Class-D can, and that’s because of the current it can keep supplying down to 1ohm
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George,
You seem to misunderstand how amplifiers work. Take your ML2 monoblocks. They put out 14.14 volts max to make their 25 watts at 8 ohms before clipping. At 8 ohms, they are flowing 1.76 amps of current. At 4 ohms, they are still at 14.14 volts, but 3.53 amps of current. 2 ohms, now up to 7.07 amps and 100 watts of output. We will ignore anything below that, as the CS5s don’t dip below 2 ohms until the subsonic range (and even trying to put 100 watts through the 8" woofers below 20hz will cause them to exceed their excursion limits).
Now lets take a Class D amp, say the Ncore NC400 for DIY. It is rated at 200 watts at 8 ohms, 400 at 4 ohms, and 580 at 2 ohms. It has a maximum current capability of 22 amps per the manufacture. Lets only run it at 100 watts into 8 ohms, where it will be 28.28 volts and 3.53 amps. 4 ohms, still 28.28 volts nets us 200 watts, and 7.07 amps. 2 ohms, still 28.28 volts, 400 watts output, now we are at 14.14 amps, or twice the current of the Levinson and still well under the manufacture's limit of 22 amps.
An amplifier doesn’t put out more current than a speaker needs to reach a set voltage. The Ncore will maintain twice the power output as the Levinson down to 2 ohms (and below even). These are the laws of physics and why amplifier designers speak in terms of voltage, not current capability, except to establish the minimum impedance a given amplifier maintain its voltage. Put another way, even a cheap receiver can drive 2 ohm speakers, but will do so at a far lower output than at 8 ohms.
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Wake up and smell the roses. This is it for me, as this thread has just become a hand full of manufactures/retailers trying to make some $$ from their new ventures into Class-D Just look at any of the many Class-D test in Stereophile, when they test bench a Class-D with 2ohm loads, they either crash and turn off, goes backwards in watts compared to 4ohm, or it just current limit and s***s themselves. BYE BYE https://www.sccpre.cat/mypng/detail/275-2758889_emoji-world-bye-bye-emoji.png |
George,
So I take it you have no response regarding your abhorrent manners and/or your inaccurate statements? Would you care to rebut my 8th grade math or perhaps my very rudimentary understanding or electronics design?
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I did unfollow, but I got this one before. definitely gone now.
Look at complimentary BJT’s with massive power supplies that I’ve been suggesting for these loads, then look at your Class-D Mosfets usually not complementary as the P channel stinks, then the 8th grade maths don’t mean ****.. |
George's arguments are irrational. For him doubling down power is more important that the absolute power and current the amplifier actually gives. Typical audiophile rule of thumb that has no backing on actual physics and basic math.
McIntosh MC2KW is class AB and has 2,000 W in 8, 4 or 2 ohms. In his book it is a bad amp with not enough current because it does not double down too... |
Look at complimentary BJT’s with massive power supplies that I’ve been suggesting for these loads, then look at your Class-D Mosfets usually not complementary as the P channel stinks, then the 8th grade maths don’t mean ****.. This statement is false. One of the advantages of a class D circuit is that since the output devices are only switched on and off, matching the devices is unimportant and the need for a complementary device eliminated. McIntosh MC2KW is class AB and has 2,000 W in 8, 4 or 2 ohms. In his
book it is a bad amp with not enough current because it does not double
down too... Yes- as long as it can behave as a voltage source, doubling power is unimportant. Our amps don't even act as voltage sources and they've been getting awards in the high end press for decades now. Its a common audiophile myth that doubling power is the most important thing about an amplifier when other aspects such as distortion or bandwidth are often far more important. A myopic viewpoint is often limited... |
I am so pleased that others with, apparently, endless patience and REAL knowledge, have taken the time to contribute positively to this thread.
For me, it doesn’t matter that some of the posts have been made by suppliers / manufacturers. What matters is the quality of information and the clearly stated reasoning behind their position that the right Class D amp, properly designed and built, will drive heavy-load speakers.
There is an obvious point to me: certainly for EU/UK law, products that don’t do what is claimed will very quickly mean suppliers / manufacturers will be brought to book in the context of trading / consumer legislation. Also, most suppliers presumably rely on reputation. If they supplied goods that didn’t do as claimed, that reputation would be damaged pretty quickly.
To those who have contributed constructively, retaining their cool in the face of substantial provocation, I for one appreciate it.
K (definitely not a seller of hi-fi equipment) |
George’s arguments are irrational. For him doubling down power is more important that the absolute power and current the amplifier actually gives. Sorry but this is wrong, have you ever listened to a pair 25w Mark Levinson ML2’s on a pair of hard to drive speaker like the OP’s? "to a given level" (because they are only 25w after all) they will annihilate any 500w or 1000w Class-D. This proves that doubling down (current) to below 2ohms into this kind of speaker load is the most important factor for sound quality, not wattage!. ( otherwise we would all own $400 3000W! Behringer NX3000 Class-D’s )
https://www.storedj.com.au/behringer-nx3000-ultra-lightweight-3000w-class-d-power-amplifier
Although if you want to go louder then wattage becomes a factor also, so then the same kind of amp that can double with more watts is needed then. So you my friend are the irrational one not me. BTW You’ll never see a pair of ML2’s for sale used as owners die with them! |
George’s arguments are irrational. To which George replied: So you my friend are the irrational one not me. George's argument was both incorrect and irrational. This is different from saying that a person is irrational- the principle to use of course is 'attack the argument not the person'. Calling someone else irrational as we see here is a forum violation. In addition, it employed a logical fallacy known as a 'Strawman', since George was trying to say that he had been called irrational when that didn't happen. Logical fallacies are by definition false. |
Keep it up Ralph, your not doing your Class-D venture any good service, by trying to pull the wool over people's eyes.
There are far better linear BJT amps around than Class-D's for driving sub 2ohm impedances, all one has to do is look what happens to the Class-D's Stereophile tests when they do 2ohm load testing, some times they don't even try because they know it cant take it. |
@Dsper — the "doubling thing" we love as audiophiles means that the amp will maintain its output voltage constant despite the drop in load impedance, which in turn means its power supply can adequately provide the increase in current needed to achieve said constant voltage. As you probably remember, volt/ohm= amp which means that every time you halve the ohm, you double the amps, voltage remaining constant. As power (Watts) is the product of volt x amp, it follows that keeping the volt constant means the wattage doubles.
In the real world, however, only a perfect amp will do this and there are no "perfect" amps. Many manufacturers just under specify the 8ohm rating to allow their product to be in spec for the lower loads. Nothing wrong with that in my book, you still need a well-engineered product to achieve numbers close to doubling anyway.
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The OP asked a simple question...
"What Class D amps will drive a 2 ohm load"
Specs Shmecs,
Opinions Shmapinions.
My Brother’s Shmother’s Frother’s Caruther said.
Ba-Loney!
1. Get a Class D amp.
2. Find some Kappa 9’s.
3. Set the the switch in the rear to Extended.
4. Crank up the music.
5. The Class D amp that doesn’t shut down will drive a 2 ohm load.
I can say this after completion of the above five steps,
This is gonna be one very short list of Class D amps... Bahahahaaaaaaa!
My answer to the posted question,
Stay away from Class D amps to drive low impedance speakers.
By the way dsper...
Truly a great pair of speakers.
Enjoy them with whatever you pair them with. |
1. Get a Class D amp.
2. Find some Kappa 9’s.
3. Set the the switch in the rear to Extended.
4. Crank up the music.
5. The Class D amp that doesn’t shut down will drive a 2 ohm load.
I can say this after completion of the above five steps,
This is gonna be one very short list of Class D amps Crude way, but effective. Better to just see how they behave in tests not understated into 8,4, and 2ohm and see if they can do "close" to the doubling act for each halving of the impedance. My answer to the posted question,
Stay away from Class D amps to drive low impedance speakers. Excellent advice. Many manufacturers just under specify the 8ohm rating to allow their product to be in spec for the lower loads. Yes this must be observed, as many "cheat" by understanding the 8ohm or the 4ohm watts, just so the 2ohm look better. If all above is not taken on board, just buy a 3000!watt Class-D for just $400 and see how you go. https://www.storedj.com.au/behringer-nx3000-ultra-lightweight-3000w-class-d-power-amplifier Cheers George |
@georgehifi As a matter of fact, I have heard that Behringer, slightly modded to improve the sound, and it's not a bad device. Compared to the usual hi-end device, it sounds harsh and with a bit limited extension at both ends (or so it sounded), but it has driving power aplenty.
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Holy moly, 3000w for $299?
That amp blows away the puny watts in my stable.
What was I thinking!
Wait a second.................
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joysjane That’s right, it doesn’t matter how many watts you have, if you don’t have the current to back it up all the way down into 2ohms and less, with speakers like the OP has in the bass, you got s**t. Like I said the "puny" 25w Mark Levinson ML2 monoblocks will slay them "to a given volume level" Cheers George |
According to George’s standards, the Behringer is a great amp:
440 w/ch into 8 ohms
900 w/ch into 4 ohms
1500 w/ch into 2 ohms.
That is 27 amps of current per channel at 2 ohms, far more than the 7 of the ML2.
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Are you serious! You buy it and drive the Op’s speakers then
You are really in a world of denial. if you think this Class-D can out drive the 25w ML2’s "to a given level into these OP’s speakers."
I’ll lay money on it also that those watts are not real or RMS, would be nice to see some independent test, at 8,4,and 2ohms
You buy it and live with it, because you obviously think 3000w can sound better than 25w into the OP’s extremely hard to drive speakers.
It’s like saying a 1/4mile dragster with 8000hp can get to the top of Pikes Peak hill climb faster than a 100hp rally car, delusional is the only word, even the most technically inept on these forums would think so.
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This is so weird. We have a guy here who thinks that one thing he makes up means something. No one else would make up such a story. You don't need double the wattage into 2 ohms to drive a 2 ohm load. All you need is an amp that is stable into 2 ohms and has enough power to drive the speakers. If your speakers are 87db at one meter....then lets say it is 83 db at your listening chair. That means 93 db will be reached with 10 watts and 103db with 100 watts. If that is as loud as you listen...I rarely listen this loud.... then a 1000 watt at 2 ohms amp will give you plenty of headroom. This is simple science.
If an amp can double its power from 4 to 2 ohms that means it has a very stiff power supply. However, it does not insure that it sounds good with any load. This is just a static test. It means very, very little by itself.
If you get 20 different amps that do 1000 watts into 2 ohms (with stability) then you will get 20 different sounds. Some will sound bad, some good and some great. The sound of an amp is dependent on hundreds of different things. One factor (a made up factor) does not make a good sounding amp. I made my amp sound way more dynamic and alive by doing various mods to it. The power did not increase, the amps it can draw did not increase......but the powerfulness and transparency of the sound increased.
Why oh why would anyone make a speaker with a 2 ohm load? It makes no sense. It is not more linear and/or lower distortion to have lower impedances. If you have a speaker with a 2 ohm load that means you cannot use moderately powerful amps (that may sound better and be cheaper), you have lower damping factor and it is known by almost everyone that the lower impedance an amp has to drive the more distortion the amp produces. Only those designers stuck in a paradigm from the past will make speakers that way today (Wilson, etc?.). Even Magico has raised the impedance of their latest and best MKII speakers so they do not dip below 3 ohms. These guys are smart.
The trend is for more sensitive speakers and/or powered woofers. This is a good idea. Look at the latest Spatial and GR Research open baffle speakers. In some models you only drive the mids and highs (92-96 db sensitivity at 8 ohms) and you have either servo woofs or powered woofs on the bottom. |
Why oh why would anyone make a speaker with a 2 ohm load? It makes no sense. Some of the best speaker ever, have loads like this and even worse, that’s why they are some of the best. EG: Wilson Alexia 0.9ohm in the bass and many others. I couldn’t even be bothered to tell someone like you any more because you’d be deaf to it, as all your interested is selling your own Class-D IcePower 1200AS2 modules that have a woeful phase massive shift of 70’ degrees!!! between 7 to 15khz!!!! No wonder Class-D detractors complain about the uppermids/highs so much. https://ibb.co/JdrgGBH |
george hifi,
Maybe you do much less listening than analyzing specs. The Levinson ML2 fully broken in which I owned years ago was syrupy euphonic and veiled at low/moderate volumes with my electrostatic speakers. Instead of claiming ricevs is a promoter for his amp, why don't you spend a little money, find out whether the phase shift has any relevance in your listening. No risk to you, and then you could have more credible comments. Alternatively, have someone gather a bunch of amps whose specs are unknown to you, do comparative listening, and see for yourself whether listening tests correlate with the specs. The truth is that there is a very small correlation, but not enough to differentiate among good or great amps. I have heard class D amps that sound euphonic/rolled off in HF, and others that sound harsh. |
