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.
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.
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"!
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."
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
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...
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:
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.
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.
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. " The best one I heard was the Krell KSA-250 (their latest product—though by the time you read this there will be a KMA-600), followed not too far in second place by the older Krell KSA-200. The newly arrived Threshold SA/12 monos had plenty of overall power, but lacked the drive at the low end possessed in such quantity by both Krells, and had a refined, neutral upper range that seemed to leave the Thiels lacking in sparkle. Until now, my favorite overall amplifier has been the Mark Levinson No.20.5, but it simply didn’t have the low-end punch necessary to bring the CS5 to life"
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.
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.
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?
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.
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....
And still, no one commented, as likely, did not read, the two reviews I mentioned were worth reading, having to do with the Merrill 118s ), on page one of this thread.
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.
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".
Spectron Musician III mk2 mono blocks - I believe they will provide around 300 watts at 1 ohm - or it might be at 0.5 ohm - I used a pair with ML CLX for many years with fantastic results - but these are only avail used - they will drive just about any speaker
Spectron Musician III mk2 mono blocks - I believe they will provide around 300 watts at 1 ohm - or it might be at 0.5 ohm -
Once again this means nothing, give us the clipped wattage at 8ohm 4ohm and 2ohm and 1ohm, only then will you know if it's being current starved (sagging).
600 at 8ohms. 800 at 4 and 1300 at 2 ohms - it does not double the power when halving the impedance - but it is apparently stable at 2 ohm
I’m not an electronics engineer - but the specs are in the link - I just know that these sounded great - but I never cranked the volume - as the room is too small - they deliver lots of current
it does not double the power when halving the impedance - but it is apparently stable at 2 ohm
No it’s "not bad" for a class-D, nowhere near doubling still, at least it goes up as the impedance goes down, too many either don’t go up at all at 2ohms or go backwards. "Could" be ok for the OP’s speakers if it's to be believed, and "may" get the best out of the low impedance bass they have. 600 Watts at 8 Ohms 800 Watts at 4 Ohms 1400 Watts at 2 Ohms
It will be interesting to see with independent tests if they give it to someone like Stereophile, if they have "underquoted the 8ohm and 4ohm" to make the 2ohm look as good as it is. As many manufacturers are doing that now, that you can see that on Stereophiles bench tests, it one way of making the amp look to be doubling, and it’s wrong (lying) and should be stamped out.
Sorry - the specs above are for stereo single amp - the power is considerably more in mono block configuration
If these are bridged stereo’s into mono’s? (probably as they give no specs) if so they won’t even do as good as the stereo amp in doubling down.
I have driven my 1 ohm Scintilla's with the NC400 mono blocks from hypex.I use them sometimes in the summer months when it gets to warm for my Krell KRS100 mono blocks consuming 700watts each.
I have driven my 1 ohm Scintilla’s with the NC400 mono blocks from hypex.I use them sometimes in the summer months when it gets to warm for my Krell KRS100 mono blocks
1st post, bet you can’t wait for winter, otherwise you wouldn’t still own the Krells. It must be because they sound and drive the Apogee’s better by quite a margin, otherwise you would get rid of them? Also there are cooler running Krells, that would sound almost as good as the 100 mono’s, and still blow away the NC’s on these great speakers..
That when the vinyl warp frequency will tax an amp, or even a bit of dc servo flutter when the mains chucks a slight wobbly.
It's been reported that Jim Thiel ended up using Krell 600 Watt'ers.
Correct type of amp, that will almost double down to 2ohms without breaking a sweat, though the 250 or even 150 watt'ers would do, they all can do the Krell doubling act. There are many other brands that do the Krell doubling act also, all use Bi-Polar (bjt) output transistors, just like the Krells.
And you maybe happy with that, because you don't know better.
Cheers George
This is an unfortunate reality from those of us attempting to make a helpful suggestion with very little actual in home comparative experience.
After owning four makes and in home auditions of three other switching amplifiers I've been using a pair of Hypex nCore 400s to drive my studios monitors that dip down to 3.6 ohms, an Acoustic Image Focus 2R driving a menu of Bass cabinets, and various Velodyne subwoofers. My only suggestion is to listen for yourself.
I'm a class D fan but I'm not fooling myself either. Their plate glass transparency along with switching amplifiers general lack of congestion make them a tool in my studio. In the living room they're simply no match for the relaxed musicality of my tube amps. All the best with that Ralph, you've got the ears for it.
m-db: "I’m a class D fan but I’m not fooling myself either. Their plate glass transparency along with switching amplifiers general lack of congestion make them a tool in my studio. In the living room they’re simply no match for the relaxed musicality of my tube amps. All the best with that Ralph, you’ve got the ears for it. "
Hello m-db,
’Plate glass transparency and a general lack of congestion’ is a very good description of good class D sound characteristics. I’m a big class D fan, too, using a pair of D-Sonic M3-600-M monos for my main speakers for music and two additional stereo class D amps for HT, one in bridged mono for the center and one in stereo for the rear surrounds. They all function and sound great and they draw so little juice at idle, I’ve just left them on virtually 24/7 for the past 5 years. I usually describe their sound as very detailed, accurate, dynamic, smooth without ever sounding harsh or bright and so neutral they’re like ’the audio ideal of a straight wire with gain’. But ’plate glass transparency’ is very descriptive and really paints an accurate picture. I hope you don’t mind if I steal that phrase. I'm also really looking forward to auditioning the class D amp or amps Ralph is creating. He definitely does have the ears for what good amps should sound like. Hopefully, he's able to make them reasonably priced since I get the feeling I'm going to be a future customer.
Having a dig are we? well at least you’ve got that one right sunshine. I’ve never been against Class-D, just it’s two Achilles Heels I have a big problem with, switching frequency and dead time. Which gives it that " Plate glass transparency" that you call it, I call it "sterility" and missing harmonic decay. I’ve always said, ever since I started the the debate about the new GaN technology here way back, that when the GaN Class-D amp becomes affordable to me, with what Technics has done with the SE-R1 with using 1.5mhz switching speed, I’ll be the first in line to get one, and ditch my inefficient hot boat anchors, door stops if you don’t live by the sea.
he’s able to make them reasonably priced since I get the feeling I’m going to be a future customer.
I'm the guy Ric was referring to who previously had a Bryston 14BSST (15 amp version as that's all I could get with my circuit in the old house) and a Modwright KWA 150SE amp to drive my Thiel 3.7s Before the 3.7s I had Thiel 7.2s. The room in my old house was huge (19 foot ceiling and over 6,000 cu. ft. that opened into other spaces) and on certain things (both music and movies as I have an integrated system with a Modwright LS 36.5DM preamp) the Bryston 14BSST would go into protection mode from overheating due to the impedance. I had to build a custom amp stand with fans inside. The Modwright (amp) drove the 7.2s better but still would get so hot (and the heatsinks are inside the case). I ended up selling the 7.2s and getting the Thiel 3.7s (when they came out), which, although not as bad as the 7.2s are not an easy load (https://www.stereophile.com/content/thiel-cs37-loudspeaker-measurements).
Anyway the EVS 1200 dual mono amp not only sounds better than the Modwright
KWA 150SE (which was better than the Bryston) in my system, it doesn't even get warm to the touch when I crank it loud. My current room is not as huge as my old one but it is still a big room (over 3,000 cu. ft.) that opens up into other spaces that are probably a bit bigger than the room itself (system is in the living room which is completing open to the foyer, dining room and most of the kitchen).
The CS5 impedance (https://www.stereophile.com/content/thiel-cs5-loudspeaker-measurements-0) is tougher below around 70Hz but probably not quite as tough as the 3.7s over the rest of the band. After the EVS 1200 (which I've had for just over a month), I have no desire for anything else. I'm still tweaking things and had a friend over (he has a Pass Labs amp, XA25, but his room is smaller and his speakers are more efficient and an easier load, Reference 3A Taxims) and he was quite impressed with the sound he heard from my system.
the Bryston 14BSST would go into protection mode from overheating due to the impedance.
With these sorts of speakers like the CS5 ect it’s no wonder, these tested figures show it was definitely no current master into low impedances 8ohm load 690w 4ohm load a reasonable 1000w 2ohm load it barely got off the 8ohm mark at 720w, very sad.
"
With these sorts of speakers like the CS5 ect it’s no wonder, these tested figures show it was definitely no current master into low impedances 8ohm load 690w 4ohm load a reasonable 1000w 2ohm load it barely got off the 8ohm mark at 720w, very sad."
That probably was the beginning of what turned me off to mainstream dealer sold companies (not that Bryston is anything but a good company). Before I bought the 14BSST, I was using a 6BSST on the front (3) channels. As noted the room in my old house was huge. I had a 4BST at one point and it was clear that was at its limit driving the (Thiel) 7.2s. I corresponded back and forth many times with Bryston about the 15 vs. 20 amp version of the 14BSST. When I had the old house built (basically in mostly in the first half of 1997), I specified I wanted an extra receptacle on its own circuit in addition to what would be behind the audio system. I found later they used a 20 amp breaker but just used 14 ga. wire.
Anyway, the purpose of many communications (with lots of detail) going back and forth is I wanted an upgrade to the 6BSST (and in my old room was probably around barely above its limit based on my old 4BST where I had situations where it would almost go into protection mode) and then just use the 6BSST on the center and surrounds. I guess they just didn't want to admit that the 15 amp version of the 14BBST wouldn't drive my 7.2s. Before I sold the 14BSST, I sent it back to Bryston to have a check-up to make sure it was OK and it tested fine. When I spoke to the technician and went into detail over the phone and told him my Modwright KWA150 SE drove the 7.2s better, he just told me that was (literally) impossible. I may not be a technician but can feel heat and the protection circuits certainly confirmed the heat felt. The guy I sold the 14BSST to had B&Ws so I didn't think he'll have an issue with it (and he didn't).
So that was the beginning (and in combination with the fact that there are fewer brick and mortar 2-channel dealers than there used to be vs. stuff like custom installers who don't have showrooms) about a dozen years back of what pushed me more in the direction to look at things that are sold consumer direct. When one considers the cost of materials/quality that one gets at the price point, it is just off the charts compared to what gets from going to a brick and mortar dealer. One may not be able to go to such a route for all purchases for various preferences and purposes but it is a strong consideration for me personally. I have multiple systems (including one with a Hegel H190 and one with another with a Class D amp using the IcePower AS1200 stereo module) in different rooms and I'm quite satisfied that if I were to walk into a store the EVS 1200 would compete favorably to amps between $10-15000 (my Modwright was $9k list and the Bryston 14BSST was not a cheapie either) and if I went to buy either the Modwright or Bryston today used, I'd likely be paying almost double what my EVS 1200 costs new and I already know which amp is easily much better in my system.
Cascadesphil, thanks for taking the time and sharing your experience. Especially pertanent to me was your description of the amounts of heat being emitted. Well done.
I’m by no means an expert and cannot speak to class d amps, but old school heavy duty class a amps are made for this sort of load. I drive my Apogees with a Balanced Audio Technology VK-600 with bat pack and couldn’t be happier. Yes, they run hotter than class d (and aren’t nearly as efficient), but everything is a compromise in one way or another. At the end of the day, the quality of the sound and the experience are most important to me.
I went to the Purifi Audio website and found many charts and specifications for their
1ET400A, most of which I did not understand so I could have very well missed something important about relationships between the stats they quoted.
I did see this: Output Power, Short Term 8ohm, 1% distortion = 227 watts 4ohm, 1% distortion = 450 watts 2ohm, 1% distortion = 450 watts with a footnote stating "Power is limited by overcurrent protection system (OCP) and highly dependent on thermal conditions."
Not sure what the footnote means.
I went to the Spectron website for the
Musician III Mk2
and they tell us "The current headroom is primarily limited by the amplifier’s ability to deliver high currents into low impedance loads. There are many well regarded speakers whose impedance dips down, some even lower than 1 ohm. When a musical note is played at frequencies where the impedance dips, the current demands skyrocket. When this happens with amplifiers that do not have large output current capability, they “current clip”. These transients will be both attenuated and quite distorted. Moreover, most other amplifiers only deliver their rated peak current for sometimes a fraction of the time called for by the music. Spectron amplifiers can deliver peak currents of 65 amps, with a staggering peak power of 3500 watts per channel for over 500 msec (!), which allows the amplifier to deliver the full transient (burst of music) without current or voltage “clipping”. ".
Their stats also state 0.3% THD up to 600 watts in 8 ohms. Could not find anything about distortion at 4 or 2 ohms.
Not sure what that does or does not tell us.
It appears the old adage about trying it in your listening room will tell the real story.
In the meantime, quit bashing my low impedance speakers as they sound wonderful to me in my listening room 😍!
I did see this: Output Power, Short Term 8ohm, 1% distortion = 227 watts 4ohm, 1% distortion = 450 watts 2ohm, 1% distortion = 450 watts with a footnote stating "Power is limited by overcurrent protection system (OCP) and highly dependent on thermal conditions."
Not sure what the footnote means.
Amps goes self into destruct mode if current limiting doesn’t work, no other reason for it to be limited, unless purposely done to sound bad into those low loads?
dsper, All amplifiers running 2 ohms continuously will get hot, independent of class. But I have seen that class D modules (Icepower, hypex, purifi) have current limit to protect the module from overcurrent.
As for thermal dissipation, musical signal has peaks, it never has the same power requirements as a full signal sine wave. So the manufacturers add dissipation to the modules in a coherent way for music listening.
If an amp was to be built to run full power sine wave at 2 ohms just for long term measurements, just add a lot of heat sinks and even a fan or two. It would do great on the benchmarks, but would make no sense for customers to pay and lift the extra weight.
As for distortion is simple: along with the Benchmark AHB2, the Purifi module is the lower distortion amplifier in the market, as far as we know (most manufacturers don't publish THD x power graphs, just single number specs).
The only caveat I'd have about the Purify 1ET400A as a separate power amp in the gain spec of 12.8dB. I'm sure that doesn't hurt the distortion specs but may not be good for many people depending on their associated equipment.
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.
With GaNFETs having 'on' resistances of only a few milliohms, its obvious that a class D amp using such devices will easily double power into 2 ohms (not that such is important for proper audio reproduction) as long as heatsinks and the associated power supplies can support the current. This has been stated before, its really not an issue of debate to one learned in the art.
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.
@noble100 +1 on this comment and post. This is exactly the issue- IMO/IME its irresponsible to create such low impedances where serious power is required for the simple reason that distortion will be higher, and increased distortion will make the presentation less musical.
why can't discussions of audio stuff, hifi stuff and music listening stuff, be non confrontational ?
really you have to ask this?? Because there's way too much BS and Voodoo in hi-end audio Mr D
Its not so much voodoo (although that is a problem); on this thread it really comes down to the posts of exactly one person.
Good quality sound? into hard speaker loads it’s all about current.
This statement is misleading. Its really all about distortion.
Spectron amplifiers can deliver peak currents of 65 amps, with a
staggering peak power of 3500 watts per channel for over 500 msec (!),
which allows the amplifier to deliver the full transient (burst of
music) without current or voltage “clipping”. "
this statement is also misleading- here's why:
Current cannot exist without voltage. When the two are together you have Power, and the relationship is thus: 1 Watt = 1 Volt times 1 Amp.
If you don't know the voltage, you can use algebra to sort out the power anyway, using Ohm's Law. That relationship is used here:
Doing the math and giving the amp the benefit of the doubt, lets assume that the speaker load is 1 ohm. You'll see why in a second. Power equals Resistance times Current squared. So if we have 65 amps, the square of that is 4,225 watts into 1 ohm (just multiply that number by the impedance of the load if you want to know what 65 amps into higher impedances is). You can see right away that 65amps has nothing to do with the output of the amp. It likely represents how much current flows when the power supply of the amp is shorted for 10 milliseconds. IOW its really a measure of the capacitance in the power supply. FWIW, our MA-2 power amplifier (Vacuum tube class A triode OTL) has about the same current by this measure.
FWIW this sort of current number being bandied about is a common myth with solid state amps.
You must have a verified phone number and physical address in order to post in the Audiogon Forums. Please return to Audiogon.com and complete this step. If you have any questions please contact Support.
