I still have a pair of pre-production Beolab 1 speakers incorporating first generation ICEPower from 1999 for the bass drivers (450 Watts per speaker), and two 150 Watts class AB amps for mid and treble (700 Watts per speaker with analog active cross-over). After 25 years of continuous running, they still work flawlessly today as my home theatre left and right speakers in a 5.1 system. I’m also having a couple of upgraded/tweaked Velodyne servo subwoofers running class D very well. For bass, class D is best.
@@AllboroLCD Yes, I also had a pair of the Pentas in the 90s. They were way ahead of their time in cabinet design (no standing waves), active speaker design, configurability, elegant display showing status and esthetics. Their sound was also quite impressive although they needed a subwoofer for getting the deepest bass to match overall performance, but so many speakers are similar on that. You are right. In many ways, nothing has ever beat it and now you make me regret I sold them ages ago.
In the late 70's we started to work with switchmode poer supplies.. We did it by using dual 555's with a comparitor/opamp control, it was rough but much more efficient. Then the 3524 control chip came out and everything just worked.It was stable had great overload contol and just made everything easier. Time just marches on and what you thought impossible becomes commonplace.
Maybe look at Purifi modules .... Yup. What about talking about how the Input stage and filters help the over all performance beside the amp " module " itself.
Switchmode power supplies have been perfectly suitable for the last 30+ years. The problem is that they can sometimes be a royal pain in the butt to get right. These days we have a lot of neat IC packages to make the design process a lot easier. That's the only thing that has changed.
You can't expect a sound system made with high quality components to be cheap. But even if we get the best hi-fi result with a reasonable sound system combination, some people don't use it just because it's cheap or not expensive enough. You can't explain this to someone who listens to an MP3 128 quality record on vinyl or through a tube amplifier and expensive speakers and says "oh, that's it." But when they read this, they will say that quality and cheap can't go together. Nowadays, a few thousand dollars is all it takes to get a decent sound system, but of course there is no upper limit.
@mikebrookshire3464 I have seen people buy expensive systems to listen to bad music that was badly recorded and badly mixed. Such listeners could have listened to the same music on a regular boombox and still get the same results.
I own an S300 that I 've been using since they were first offered. I also have Pass xa-25 in another system. They are both really nice to listen to. The S300 can idle all day and generate very little heat. The Pass is like having a space heater on. The S300 is clean clear, neutral, and as non - fatiguing to listen to as the Pass. That's high praise for an amp that costs about half of the Pass. I'm using the S300 with a pair of Kef R-3 metas supplemented by a pair of REL T-5 i subs. .
One can maybe convince me of class D, but I can never have faith in switchmode power. I do not have any issue issue with my power amp weighing in at 90lb, and the power rails output is only 60% efficient. It sounds fantastic, and that is all I want from it.
The old problem of switchmode power supplies was noise . The best of them now are quieter than linear supplies . Benchmark's DAC/Preamp changed from linear to switchmode PS when they evolved from Model 1 to Model 2 . If noise will be heard it will be in a preamp sooner than a power amp . You can't imagine how black the background can be .
@@MasterofPlay7Class D sounds in no particular way. Class D has been excellent for bass and subwoofer amps for many years already. Class D for higher audio frequencies can also sound excellent when well designed. There is no “dry” to class D as general perceived audio attribute.
@@ThinkingBetter Exactly. Just look at Pioneer's AV receivers of 2010-2014 age - they had a multichannel Class D amp and has had an Air Studios certification. Which means that these devices complied to high-end standarts of music recording industry.
Audio and its conservative views, Bruno released the first production ready UcD 15 years ago, they didn't, want it now they singing from the class-d him sheet.
That was the slogan of the Acoustical Manufacturing Company, aka Quad. (Actually, it was '...a straight wire with gain'. If it was bent it would have inductance!)
Uh. Robert zeff invented class a-d.. you are discussing class a drive and class d output stage..there are 2 designs ignored..class bd and class ad..my friends invented both.
I retract my stolen statement. Ill say..his totem pole idea without optocouplers .. They agreed with and decided on .. its comon to agree with someones unprotected style and go that direction..so ill kinda calm from the stolen extreme statement.haha Paul do i get an interview yet?
all is done for %20 efficiency gain . it cant outperform class ab in sound quality . so the gain is to pay less for electricity basicly . and ppl pay tens of thousands of dollars for their systems . this is a clown world .
The problem with class-d is that the changes and improvements only happen with EXPENSIVE EXPENSIVE class-d amplifiers and almost never with cheap ones that are still not that good!
No, Karsten Nielsen was inventing ICEPower at B&O in the late 90s right across where I was sitting in the engineering department. It was legitimate R&D incl. university thesis and patents filed. Due to a much bigger business potential, ICEPower was created as a spinoff company. Lots of products use ICEPower with or without making the brand visible.
That's a bit misleading you didn't make the first or one of the first class D Amplifier you bought a module from ice and put a power supply to it, that's not making an amplifier it's assembly what you did man you're losing credibility
Paul specifically stated that their first class D product didn't use an off the shelf module. Meaning that he was not talking about their current products, whatever you may think of them. Your animosity is hardly justified.
@@jonathanvanier there's no animosity I don't know how you get that from that statement? You can't criticize now is what you're saying? Well give me the code engineering patent number for this amplifier then we can have a look who made it if you're so convinced he made it?
@@jedi-mic You're the one making the accusation, therefore it's on you to back your statement with evidence. And attacking his character by implying he's a liar (without evidence) is indeed displaying animosity, not criticism. Try your basic trolling tactics elsewhere.
The writer specifically mentions GAN technology.......Paul does not address that specific at all in his response. Just talks about class D in general. Swing and a miss.
@@paulstubbs7678 after his remarkably detailed response that never really responded to the viewer’s question was “if someone else makes one, we’ll try it out” The answer to the actual question was “no”
The writer talks about new technology and mentions gan as an example. Gan is more or less a meaningless discussion. In theory it can switch faster, with less switching losses. In reality Gan is only slightly better or on par with modern mosfets. It's also a LOT more expensive. And if you really want to get crazy, you can put in the effort to drive the various capaticane pathways in the mosfet which would allow the fet to switch STUPID fast with EXTREMELY sharp and clean square waves. Gan is not actually all that useful unless you are trying to make very small form factor devices. Paul didn't talk about gan because there is nothing to talk about.
Most everyone is using the Hypex power supply Two of the best technologies are Purfi and Nilai but The GaN technology may have the most upside Hypex/class d keeps evolving I would probably go with two mono-blocked Nilai amplifiers if I wanted and need higher power levels I prefer SE tube amplifiers
I think that viewers prefer to think that technology (like GaN FET) is the silver bullet when it is actually the attention to detail. I appreciate that at PS Audio R&D engineering is stronger than the marketing department.
Nerds here (present company included) noticed he didn't respond to the GaN question - which may have been intentional but personally I feel it's just a marketing gimmick. GaN has it's merits esp with efficiency and space (makes USB chargers smaller) but in the audio world I think it's just something for a company to glom onto preying on someones ignorance. It doesn't necessarily make something sound better. If you feel your GaN-equipped amp sounds better, good for you. Probably 5% of the reason it sounds better :)
I suggest you go test Daniel Hertz Maria integrated amplifier at your local dealer and compare it to their most expensive separates they have on hand. Expect to be shocked.
Making a class D amp isn't that difficult. Classe and Atma-Sphere have already done that. Classe no longer uses their design and so far, there have been no other companies releasing product that utilizes the Atma-Sphere efforts. Every company is going to make decisions based on the availability, unit cost, and reliability of the modules on the market versus something made by the home team. Then comes the question of how much demand is there for a proposed product. It's hard to survive on efforts to re-invent the wheel. PS Audio is doing alright presently utilizing the ICE modules as exemplified by the evaluations in the audiophile press and customer satisfaction. Other manufacturers that have engineering staff have also been successful by using off the shelf modules. Over the past few years, new modules have been released, promoted, and there's little doubt that they are fine. That may not be enough for a manufacturer to take on the expense of introducing a new model or line when the audiophile market is as small as it is.
Because of their cost effectiveness, compactness, low weight. I suspect we will see more and more class D. Sad news for a luddite like me, I can see the choices for good old class A and AB SS designs to only be offered by esoteric boutique brands at a premium cost. I have heard and enjoyed many fine designs. Nonetheless I just cannot warm up to the sound, and always purchase the amps that are modern day equivalents to the A and AB amplification I grew up with. I still like the sound of a good old McIntosh, Pass Labs, or Accuphase over the marvelous class D amps from the likes of Bel Canto, AGD, and Jeff Roland. For me, bring back the Bel Canto SET 80 Monoblock, despite the hassle of a tube amps care and feeding.
@@connorduke4619 That is true now. Think 10 years from today. Will it still be true, or will products be primarily class D? Especially as production cost for class AB product increase. All mass consumer companies are looking to increase profit margins and do not marry themselves to any particular typology. A decade from now you may find that their Michi integrated amps are class AB, but an affordable Rotel can only be found as class D.
@@ridirefain6606 Marantz have curiously done the opposite: their top models are Class D and base models Class AB. I think it was a poor decision as their top Class AB models were world beating. More generally just as there is still vinyl playback I am sure there will always be Class AB amps. Rotel as the kings of budget to mid-priced Class AB would be very foolish to give that all away, but stranger things have indeed happened as we saw with Marantz.
@@ridirefain6606 Yamaha is pretty good. I am still using a classic Marantz PM-11S2 from 2009 which easily stands up to most modern amps and has incredible bass dynamics.
There is not such a big advantage switching to GaN FET's in class D amp's. GaN FET's are good at high voltages, over 100V because they switch very fast and have lower on resistance (better efficiency) than regular high voltage MOS FET's. They will find their way in as they evolve and get cheaper and will allow for higher switching frequencies. They can also be operated with less "dead time" in the switching cycle which helps with distortion.
Big fan of class G. Love my class g parasound. First ten watts class A. Class D is fine for non audiophile uses, but not audiophile. And sorry but I'll go to my grave thinking that "pulse width" is renamed "pulse code"
Putzeys and company first identified objectional elements that accompanied the class D platforms, then addressed them. These advanced architectures and SMPS continue to proliferate, but there will always be big iron, class A offerings.
I think class D is more forgiving! You can't get it so wrong when playing class D. They are not chossy on fat power cable, multiple strends speaker cables, or special cables. They get along with most speakers and other equipment ( synergy). Don't find class D has had problem of not pumping out enough for good bass, puncy bass; don't find them deliver sound that is below average ... not like the fussy class AB, good amp + good speaker may ≠ good result! Expensive amp + Expensive Speaker, can be = Disappointment Sound.
I think the viewer was asking if PS Audio was planning on switching from MOSFET to GaN FET in any upcoming PS Audio products.
Exactly.
Paul McGowan, PS Audio, Subscribed because your videos are always awesome!
Don't buy the hype 😮
I still have a pair of pre-production Beolab 1 speakers incorporating first generation ICEPower from 1999 for the bass drivers (450 Watts per speaker), and two 150 Watts class AB amps for mid and treble (700 Watts per speaker with analog active cross-over). After 25 years of continuous running, they still work flawlessly today as my home theatre left and right speakers in a 5.1 system. I’m also having a couple of upgraded/tweaked Velodyne servo subwoofers running class D very well. For bass, class D is best.
Youre gonna give someone a heart attack talking about active speakers around here, lol
@@AllboroLCDPerhaps, but my comments are never BS.
@@ThinkingBetter The older Beolab active speakers are amazing! Particularly love the Penta's
@@AllboroLCD Yes, I also had a pair of the Pentas in the 90s. They were way ahead of their time in cabinet design (no standing waves), active speaker design, configurability, elegant display showing status and esthetics. Their sound was also quite impressive although they needed a subwoofer for getting the deepest bass to match overall performance, but so many speakers are similar on that. You are right. In many ways, nothing has ever beat it and now you make me regret I sold them ages ago.
In the late 70's we started to work with switchmode poer supplies.. We did it by using dual 555's with a comparitor/opamp control, it was rough but much more efficient. Then the 3524 control chip came out and everything just worked.It was stable had great overload contol and just made everything easier.
Time just marches on and what you thought impossible becomes commonplace.
Maybe look at Purifi modules .... Yup. What about talking about how the Input stage and filters help the over all performance beside the amp " module " itself.
I just saw Manley's new phono preamp is using a switching power supply. That is 2 ringing endorsements for that technology in my eyes.
Switchmode power supplies have been perfectly suitable for the last 30+ years. The problem is that they can sometimes be a royal pain in the butt to get right. These days we have a lot of neat IC packages to make the design process a lot easier. That's the only thing that has changed.
You can't expect a sound system made with high quality components to be cheap. But even if we get the best hi-fi result with a reasonable sound system combination, some people don't use it just because it's cheap or not expensive enough.
You can't explain this to someone who listens to an MP3 128 quality record on vinyl or through a tube amplifier and expensive speakers and says "oh, that's it." But when they read this, they will say that quality and cheap can't go together.
Nowadays, a few thousand dollars is all it takes to get a decent sound system, but of course there is no upper limit.
Mo money make mo betta sound.
@mikebrookshire3464 I have seen people buy expensive systems to listen to bad music that was badly recorded and badly mixed. Such listeners could have listened to the same music on a regular boombox and still get the same results.
How true.
Informative Paul, thank you, however, is the bench mallet for fine technical adjustments or perhaps, keeping employees in-order? ;)
Just received an S300. Class D sounds great, the low end, mid range is awesome
I own an S300 that I 've been using since they were first offered. I also have Pass xa-25 in another system. They are both really nice to listen to. The S300 can idle all day and generate very little heat. The Pass is like having a space heater on. The S300 is clean clear, neutral, and as non - fatiguing to listen to as the Pass. That's high praise for an amp that costs about half of the Pass. I'm using the S300 with a pair of Kef R-3 metas supplemented by a pair of REL T-5 i subs. .
Using Purifi power with Freya tube pre. Not going back to anything else .
Which Purify are you running?
@@aa5az423 Purifi 1ET400A module
Purifi 1ET400A
One can maybe convince me of class D, but I can never have faith in switchmode power.
I do not have any issue issue with my power amp weighing in at 90lb, and the power rails output is only 60% efficient. It sounds fantastic, and that is all I want from it.
The principle of SPMS is superior to linear power supplies. And we’re now at a a stage where implementations prove the superiority.
The old problem of switchmode power supplies was noise . The best of them now are quieter than linear supplies . Benchmark's DAC/Preamp changed from linear to switchmode PS when they evolved from Model 1 to Model 2 . If noise will be heard it will be in a preamp sooner than a power amp . You can't imagine how black the background can be .
HypexNcore if well implemented is already superior to most everything...TEAC does a great one.
Hey Paul. Thor called. He wants his hammer back if you guys are done with it.
The future of class D: Dominance!
They don't sound good, too dry
@@MasterofPlay7Class D sounds in no particular way. Class D has been excellent for bass and subwoofer amps for many years already. Class D for higher audio frequencies can also sound excellent when well designed. There is no “dry” to class D as general perceived audio attribute.
@@MasterofPlay7 Bad engineering is the answer.
@@Ashen2501 no, golden ears can hear the difference
@@ThinkingBetter Exactly. Just look at Pioneer's AV receivers of 2010-2014 age - they had a multichannel Class D amp and has had an Air Studios certification. Which means that these devices complied to high-end standarts of music recording industry.
Mallet for fine adjustments.
Audio and its conservative views, Bruno released the first production ready UcD 15 years ago, they didn't, want it now they singing from the class-d him sheet.
Cheap watts sonic cheap 😮
Doug Dale is a Super Genius
Absolutely, i have S5.5 which I would not exchange for any class D, GaN or gan. 😂
Thanks!
I read somewhere the perfect amplifier is a piece of wire with gain. Sadly not possible.
That was the slogan of the Acoustical Manufacturing Company, aka Quad. (Actually, it was '...a straight wire with gain'. If it was bent it would have inductance!)
@@PaulCroome Good point on the inductance.
Uh. Robert zeff invented class a-d.. you are discussing class a drive and class d output stage..there are 2 designs ignored..class bd and class ad..my friends invented both.
I retract my stolen statement.
Ill say..his totem pole idea without optocouplers ..
They agreed with and decided on .. its comon to agree with someones unprotected style and go that direction..so ill kinda calm from the stolen extreme statement.haha
Paul do i get an interview yet?
all is done for %20 efficiency gain . it cant outperform class ab in sound quality . so the gain is to pay less for electricity basicly . and ppl pay tens of thousands of dollars for their systems . this is a clown world .
The problem with
class-d is that the changes and improvements only happen with EXPENSIVE EXPENSIVE class-d amplifiers and almost never with cheap ones that are still not that good!
Is it cheap to replace class AB amps that burn up everyday & pay the electric bill.
Peopele, PLEASE stop saying"Hi, Paul" in your questions.
There are many kinds of greetings, the best of which would be unique to You.
It’s a signature opening. Kind of defines the channel in my opinion.
Ice stole the design from john pleitz.
No, Karsten Nielsen was inventing ICEPower at B&O in the late 90s right across where I was sitting in the engineering department. It was legitimate R&D incl. university thesis and patents filed. Due to a much bigger business potential, ICEPower was created as a spinoff company. Lots of products use ICEPower with or without making the brand visible.
That's a bit misleading you didn't make the first or one of the first class D Amplifier you bought a module from ice and put a power supply to it, that's not making an amplifier it's assembly what you did man you're losing credibility
i am pretty sure Paul made a class d decades ago, and not talking about the current icepower modules.
Paul specifically stated that their first class D product didn't use an off the shelf module. Meaning that he was not talking about their current products, whatever you may think of them. Your animosity is hardly justified.
He likes to toot his own horn
@@jonathanvanier there's no animosity I don't know how you get that from that statement? You can't criticize now is what you're saying? Well give me the code engineering patent number for this amplifier then we can have a look who made it if you're so convinced he made it?
@@jedi-mic You're the one making the accusation, therefore it's on you to back your statement with evidence. And attacking his character by implying he's a liar (without evidence) is indeed displaying animosity, not criticism. Try your basic trolling tactics elsewhere.
The writer specifically mentions GAN technology.......Paul does not address that specific at all in his response. Just talks about class D in general. Swing and a miss.
Because they are not making the class D modules, if you don't make them then it severely limits what you can do, try someone else's....
Everything Paul does is a swing and a miss
@@paulstubbs7678 after his remarkably detailed response that never really responded to the viewer’s question was “if someone else makes one, we’ll try it out”
The answer to the actual question was “no”
The writer talks about new technology and mentions gan as an example. Gan is more or less a meaningless discussion. In theory it can switch faster, with less switching losses. In reality Gan is only slightly better or on par with modern mosfets. It's also a LOT more expensive. And if you really want to get crazy, you can put in the effort to drive the various capaticane pathways in the mosfet which would allow the fet to switch STUPID fast with EXTREMELY sharp and clean square waves. Gan is not actually all that useful unless you are trying to make very small form factor devices. Paul didn't talk about gan because there is nothing to talk about.
That was what my grandma would call “taking the long way around the barn”
... and never got to the front again.
Most everyone is using the Hypex power supply
Two of the best technologies are Purfi and Nilai but
The GaN technology may have the most upside
Hypex/class d keeps evolving
I would probably go with two mono-blocked Nilai amplifiers if I wanted and need higher power levels
I prefer SE tube amplifiers
Bruno is a legend ! Super happy with my Marantz Model 30 !
I think that viewers prefer to think that technology (like GaN FET) is the silver bullet when it is actually the attention to detail. I appreciate that at PS Audio R&D engineering is stronger than the marketing department.
Thanks for the video!
You had me at ameliorates.
Paul has such a nice lab.😊
Nerds here (present company included) noticed he didn't respond to the GaN question - which may have been intentional but personally I feel it's just a marketing gimmick. GaN has it's merits esp with efficiency and space (makes USB chargers smaller) but in the audio world I think it's just something for a company to glom onto preying on someones ignorance. It doesn't necessarily make something sound better. If you feel your GaN-equipped amp sounds better, good for you. Probably 5% of the reason it sounds better :)
I suggest you go test Daniel Hertz Maria integrated amplifier at your local dealer and compare it to their most expensive separates they have on hand. Expect to be shocked.
Nothing wrong with switch mode supplies. Wade stewarts design surpassed bob carvers.everyone learned from those 2 approaches to modulation
Reeves made a class D in 1955...according to google.
Kinda forgot to answer the technical part of the question about GaN switching.
So when is PS Audio going to start making your own class D amps, rather than using off the shelf modules, that anyone else can do
Making a class D amp isn't that difficult. Classe and Atma-Sphere have already done that. Classe no longer uses their design and so far, there have been no other companies releasing product that utilizes the Atma-Sphere efforts. Every company is going to make decisions based on the availability, unit cost, and reliability of the modules on the market versus something made by the home team. Then comes the question of how much demand is there for a proposed product. It's hard to survive on efforts to re-invent the wheel. PS Audio is doing alright presently utilizing the ICE modules as exemplified by the evaluations in the audiophile press and customer satisfaction. Other manufacturers that have engineering staff have also been successful by using off the shelf modules. Over the past few years, new modules have been released, promoted, and there's little doubt that they are fine. That may not be enough for a manufacturer to take on the expense of introducing a new model or line when the audiophile market is as small as it is.
Because of their cost effectiveness, compactness, low weight. I suspect we will see more and more class D. Sad news for a luddite like me, I can see the choices for good old class A and AB SS designs to only be offered by esoteric boutique brands at a premium cost. I have heard and enjoyed many fine designs. Nonetheless I just cannot warm up to the sound, and always purchase the amps that are modern day equivalents to the A and AB amplification I grew up with. I still like the sound of a good old McIntosh, Pass Labs, or Accuphase over the marvelous class D amps from the likes of Bel Canto, AGD, and Jeff Roland. For me, bring back the Bel Canto SET 80 Monoblock, despite the hassle of a tube amps care and feeding.
Rotel is producing brilliant Class AB amps at very fair prices out of their Japanese supervised factory in China.
@@connorduke4619 That is true now. Think 10 years from today. Will it still be true, or will products be primarily class D? Especially as production cost for class AB product increase. All mass consumer companies are looking to increase profit margins and do not marry themselves to any particular typology. A decade from now you may find that their Michi integrated amps are class AB, but an affordable Rotel can only be found as class D.
@@ridirefain6606 Marantz have curiously done the opposite: their top models are Class D and base models Class AB. I think it was a poor decision as their top Class AB models were world beating.
More generally just as there is still vinyl playback I am sure there will always be Class AB amps. Rotel as the kings of budget to mid-priced Class AB would be very foolish to give that all away, but stranger things have indeed happened as we saw with Marantz.
@@connorduke4619 Yeah. It is sad. Which is why I moved away from Marantz and replaced my Marantz gear with Yamaha.
@@ridirefain6606 Yamaha is pretty good. I am still using a classic Marantz PM-11S2 from 2009 which easily stands up to most modern amps and has incredible bass dynamics.
Probably one of the first commercial ones is the Sony TA-88 (around 1980)
The English company Sinclair Radionics marketed a 10-watt class D amplifier, the X-10, in 1964. It was not without its problems.
There is not such a big advantage switching to GaN FET's in class D amp's. GaN FET's are good at high voltages, over 100V because they switch very fast and have lower on resistance (better efficiency) than regular high voltage MOS FET's. They will find their way in as they evolve and get cheaper and will allow for higher switching frequencies. They can also be operated with less "dead time" in the switching cycle which helps with distortion.
Very informative. Fast switching seems like a huge advantage.
Big fan of class G. Love my class g parasound. First ten watts class A.
Class D is fine for non audiophile uses, but not audiophile.
And sorry but I'll go to my grave thinking that "pulse width" is renamed "pulse code"
try listening to a bel canto black you may just change your mind i promise
Most A purists wouldn't pass a blind test comparing a well executed Purifi D to an A.
Class D is to AB, what ARM is to X86.
Putzeys and company first identified objectional elements that accompanied the class D platforms, then addressed them.
These advanced architectures and SMPS continue to proliferate, but there will always be big iron, class A offerings.
Keep on swooning......KOS gearheads!
Whether were talking about chips or transistors, its all silicon no matter how you slice it..... SAND!
I've yet to hear a commercially produced class D integrated amp that rivals the sound quality- and costs the same - as Audio Analogue Puccini.
Nor Marantz PM11-S2 for that matter, that slays nearly everything.
PS AUDIO ALWAYS FIRST
I think class D is more forgiving! You can't get it so wrong when playing class D. They are not chossy on fat power cable, multiple strends speaker cables, or special cables. They get along with most speakers and other equipment ( synergy). Don't find class D has had problem of not pumping out enough for good bass, puncy bass; don't find them deliver sound that is below average ... not like the fussy class AB, good amp + good speaker may ≠ good result!
Expensive amp + Expensive Speaker, can be = Disappointment Sound.
Class a b all day.
Low watts all day
@@reconstructionwouldhavesav9472 not a argument.
Very BEST EXPLANATION