Power Supply units!

[silviajulieta]

Can anyone prove that using a separate power supply degrades performance? Since I'm not an electrical engineer, I sure can't make that statement. So, if someone enjoys a product that has a one-box or multi-box approach, what's the problem? I don't believe that folks in either camp bought their component JUST because of the power supply location.

Perhaps the external power supplies are chosen when compromises in board layout, etc. would otherwise occur. Why not recruit a designer or two to offer interviews here? Or invite them to join and participate? Most of us are simply making guesses about this subject.

I'm sorry, but it still seems that we're picking at nits.

Lee

Dear Lee: Yes maybe you can bring here: Halcro, Dartzeel, Lamm, Boulder or Atmasphere. What do you think you can get with?.

The ones like Halcro/Daretzeel can prove through its own units that it is posible to achieve top quality performance through one-box designs and not only with the PS subject but with two different circuit stages in that single box: line stage and phono stages.

The multi-box designers: what do you think they can prove? How a multi-box proponent ( any one ) can prove that in a top design we can hear quality performance differences due to that PS outboard design against its similar/mimic one box design?
I think that only facts can help and Halcro/Dartzeel and many other are facts about the one box design PS subject. You already know that each designer will talk in favor of what he is doing now. Do you think that Lamm could say that its 42K four boxes line stage design can be manufactured in one or two boxes at 10K with similar quaality performance?, no way my friend.

I can see that some of you has difficulty to think " out of the AHEE rules ". I can say that sometimes could be " fun " and interesting to ask:
WHY WE ARE HERE? WHY I THINK LIKE I THINK? IS OUT THERE A DIFFERENT WAY TO THINK? THAT COULD HELP ME? HOW? or IT IS AN ERROR TO THINK DIFFERENT? HOW DO YOU KNOW THAT WHAT YOU ALREADY LEARN IN AUDIO ( AHEE ORIENTED ) IS THE " BEST " WE CAN GET TO ENJOY MUSIC THROUGH OUR EACH ONE HOME AUDIO SYSTEM?

Don't be afraid to questioning your self even questioning each link in your home audio system, sooner or latter maybe you will learn and will be questioning the AHEE and how and in which audio areas it help you and where was against " you ".

I already ask me all those question and I learn a lot for the better. I know that no one likes that " something " step on/flatten our fingers ( put the nail in the eye or where hurts.. ) but my experiences tell me that we can take advantage of that and we can contribute to real improvements ( customer oriented. ) in the AHEE.

Regards and enjoy the music,
Raul.


This is what Gregadd posted here, I hopw could help to read it again:


+++++++ " I think that often good ideas become obsolete or unnecessary. A noisy transformer with stray magnetic fields may at one point been a nuisance. Rather than construct a complex solution to the problem, designers may have just decided to put it in a separate box. Custom dictates that the best designs have a separate power supply. Raul may have a point there. On the other hand. Along comes the toroidal transformer that eliminates a preponderance of the problems of the previous designs. That could make it perfectlly acceptable to make a one box design. It does however ignore that ARC Ref3 was a one box design. That did not seem to bother Steve at all. There is enough great one box designs like Allnic to make this almost a non-issue.
I remember there was a time no one would buy a sports car without a manual transmission. Today's technology suggests a manual transmission may actually be a handicap. " ++++++

 

[Steve williams]

What we're seeing is various displays of childish and rude behavior. If the preamp is quiet, how can someone say that it is a bad design? How could it benefit someone to make the owner of a certain piece of gear (which that owner enjoys immensely) uncomfortable? I would agree that divulging one's real name should be required when critical comments are being posted. Without some way to ascertain an individual's background/credentials and intentions, it makes no sense to give any credence to comments that stray into the negative or superlative categories. Often, these comments are accompanied by slurs: Anyone knows that (insert name of company, designer, etc. here) is the only one to implement this circuitry in a (right/wrong) fashion, and is really out to (make money/provide value). Comments of an absolute nature should be backed up by some type of reference, not merely one poster's declaration.

I would love to see Vladimir Lamm, etc. offer some insight on the design decisions and how certain topologies bring about compromises, etc. in the final product.

Lee

Lee

I'll call Vladimir and send him this thread link and see if he is interested. Honestly I have never seen him post anywhere.

 

[Ron Party]

I can see that some of you has difficulty to think " out of the AHEE rules ". I can say that sometimes could be " fun " and interesting to ask:
WHY WE ARE HERE? WHY I THINK LIKE I THINK? IS OUT THERE A DIFFERENT WAY TO THINK? THAT COULD HELP ME? HOW? or IT IS AN ERROR TO THINK DIFFERENT? HOW DO YOU KNOW THAT WHAT YOU ALREADY LEARN IN AUDIO ( AHEE ORIENTED ) IS THE " BEST " WE CAN GET TO ENJOY MUSIC THROUGH OUR EACH ONE HOME AUDIO SYSTEM?

Don't be afraid to questioning your self even questioning each link in your home audio system, sooner or latter maybe you will learn and will be questioning the AHEE and how and with audio areas it help you and where was against " you ".

I already ask me all those question and I learn a lot for the better. I know that any one likes that " something " step on/flatten our fingers ( put the nail in the eye. ) but my experiences tell me that we can take advantage of that and we can contribute to real improvements ( customer oriented. ) in the AHEE.

Regards and enjoy the music,
Raul.

Raul, I for one am always ready to question existing thoughts regarding audio reproduction and I think many others share the same willingness. In fact we are seeing this sort of questioning play out in many different areas of recording and reproduction and the results are panning out for the betterment of all of us.

Witness, for instance, the studies performed by Todd Welti and Allan Devantier on the one hand and Earl Geddes on the other to which I made reference in starting this thread on multiple subwoofer placements. It used to be the case that many just assumed subwoofers ought to be placed in the front corners of the room, then scientifically derived evidence proved that there were other, usually if not always better, places for multiple subwoofer placement.

As an aside, can you answer a few questions? I keep reading your reference to an "AHEE". I read back through your posts to find out the meaning of this acronym. But what is it really? For instance, who gets to define what is *high end*? How does one become a member of this *establishment*?

I ask these questions because I think it is relevant to the ongoing discussion of 1 versus 2 box electronics (and speakers are not excluded from this discussion). There are an awful lot of excellent products out there and I get the sense that for you the price of one's gear is the main determinant whether one is an AHEE member.

 

[RBFC]

Raul,

I do hope that we get some actual designers join in and illustrate the concerns of one-box vs. multi-box. You say that Halcro/Dartzeel can prove certain things (that may have many causes & be impossible to fairly duplicate in an inboard vs outboard study), but seem to think that the multi-box designers have no hope of proving anything.

I'm glad that you feel your equipment and choices are superior. I sincerely hope that you enjoy every minute you spend with them. However, I do feel that your tone of posting and your comments to others have been rude and condescending. Therefore, I will now utilize my "ignore" feature for the first time. I've tried to explain why you seem to be fighting an uphill battle, but you behave like you are the only one who has "learned for the better". I am truly disappointed.

Lee

 

[Gregadd]

There are in fact many myths and customs in the high end. Aesthetix Atlas amplifier has a high pass filter to facilitate the use off subwoofers. I think a lot of preamps would benefit form tone controls. It's a lot less expensive than mutli-kilobuck cables. In fact I prefer an all out equalizer to deal with room problems and doctored recordings. The presence of these devices were regarded as an attempt to cure a flawed design. In fact, less we forget, that two of the top dog amplifiers are integrated! Dartzell and the ASR Emitter II.
I've always been a one box man. Thtat includes amplification and cd players. I make an exception for speakers. It is clear there is a lot of mischief going on inside that cabinet. I even like the idea of external crossovers. A vibration is a vibration.

Finally ,I just can't help but tease Raul. He painted himsel in a corner by suggesting his inclusion of an outboard power supply was a pure marketing decison. A "a jagged little pill" to swallow coming from such an anolgog purist.
raul

 

[mep]

Lee-me thinks you are being too harsh on Raul. Raul is not a master of the King's English, but he has many good points to make. He took some pot shots at my speakers before (Defintivie Technology BP7000 SC speakers), but I didn't lose any sleep over it. His posts are sometimes hard to read, but there are usually some nuggets of information in there if you read closely.

Mark

 

[RBFC]

Lee-me thinks you are being too harsh on Raul. Raul is not a master of the King's English, but he has many good points to make. He took some pot shots at my speakers before (Defintivie Technology BP7000 SC speakers), but I didn't lose any sleep over it. His posts are sometimes hard to read, but there are usually some nuggets of information in there if you read closely.

Mark

Mark,

I understand your concern over the second language difficulties. Unless I'm really far off, I still get a sense of I know better than you from the individual in question. Let's leave it at this: If Raul cares to apologize to the forum for posting statements that seem inflammatory, then all will be OK by me (and others who've contacted me about this... I hope they'll feel the same way). I simply don't think someone who doesn't design the gear (and makes definitive statements) has a foundation for those opinions.

As to your choice of gear, I've read enough from you to believe you're level-headed and have given your selections a great deal of thought. To the matter at hand, I don't think a multi-box preamp would muddle up the sound of your system or mine.

Lee

 

[MylesBAstor]

An excerpt from the writeup on the new no-holds barred Constellation Audio Orion phono section from John Curl (http://www.constellationaudio.com/ca/products/orion), one of the most respected and best designers in the world (Constellation also makes the Continuum tt and had their products on display this year!).

Curl's past achievements include phono preamps for CTC, Mark Levinson, Parasound, SOTA, and Vendetta Research. In the Orion, he draws from our exclusive stock of the world's quietest FETs to achieve a noise level of just 0.4 nanovolts per square Hertz, approximately equal to the noise level of a single 10-ohm resistor. Completing Curl's fully balanced dual-mono circuit are metal-film Vishay resistors, custom-made polypropylene and Teflon capacitors, and internal cabling made from custom-extruded PCOCC wire drawn from a single copper crystal.

Pyxis / system controller
Because signal levels inside a phono preamp are so low, the circuits tend to be microphonic-they pick up external vibrations and emit them as audio signals, which causes distortion. To eliminate this effect, we have mechanically isolated the circuit boards to an unprecedented degree. The circuit boards are built on a “raft” composed of a pliable polymer layer sandwiched between thick sheets of stainless steel. The raft is attached to an elastomeric suspension designed to damp vibration. The surrounding chassis is milled from a solid billet of aluminum, with a wall thickness of 8.2mm to block all electromagnetic interference.

To prevent the power supply's energy from disturbing the audio circuits, we enclose it in a separate chassis. Separate R-core power transformers for the left channel, the right channel, and the control circuitry are provided for complete intra-circuit isolation.

 

[RBFC]

Myles' comments above show why this is the What's Best Forum rather than the What Can We Get By With Forum. I stand firm on my comments regarding separate power supplies until someone can show that they cause decreased performance in the component. If they can be shown to be equal or better, that would be interesting to see as well. I sincerely hope that some designers can join in to illuminate the topics involved in this build-up decision.

Lee

 

[silviajulieta]

Raul, I for one am always ready to question existing thoughts regarding audio reproduction and I think many others share the same willingness. In fact we are seeing this sort of questioning play out in many different areas of recording and reproduction and the results are panning out for the betterment of all of us.

Witness, for instance, the studies performed by Todd Welti and Allan Devantier on the one hand and Earl Geddes on the other to which I made reference in starting this thread on multiple subwoofer placements. It used to be the case that many just assumed subwoofers ought to be placed in the front corners of the room, then scientifically derived evidence proved that there were other, usually if not always better, places for multiple subwoofer placement.

As an aside, can you answer a few questions? I keep reading your reference to an "AHEE". I read back through your posts to find out the meaning of this acronym. But what is it really? For instance, who gets to define what is *high end*? How does one become a member of this *establishment*?

I ask these questions because I think it is relevant to the ongoing discussion of 1 versus 2 box electronics (and speakers are not excluded from this discussion). There are an awful lot of excellent products out there and I get the sense that for you the price of one's gear is the main determinant whether one is an AHEE member.

Dear Ron: I knew/know that several a lot of people made and make that kind of " questioning " exercise, I insist on it because I posted and people stay in silence. Glad to confirm that many of we are in the same " channel ".

Yes, the subwoofer subject maybe is not full " understand " subject. I use subs ( two because I can't use four. ) and are not at the room corners but in an unusual placement.


Now, how gets to define what is high end?, we can't find it in a dictionary for sure. IMHO the High End is an audio level community that form part of the whole audio industry. In some ways is a concept where the main people targets is to attain the best quality performance ( at different price levels. ) in a home system to enjoy the music and where that target can be achived. The high end represent too a overall status level that only can be achieve it inside the HE environment/space.
The audio items/links in the audio chain, recording industry, concepts like: room treatment, system know how for set up, own audio experiences, reviewers, audio dealers, audio forums, some audio magazynes, etc, etc are only " tools " to achieve the main target.
Everyone has his own high end definition, this is my today opinion about.

We are inside the HE when its happen that the HE target even our main target and we use those tools trying to be " there ".

No I don't think that the price is a determinat factor to be inside the AHEE, the price even can't tell for sure at what real HE level we are in our main target quest and in the HE audio ladder. It is more determinant the " tools " you choosed and your own skills to " handle " those tools in favor of the main target.

For many years the price was determinant in the audio items I bought till I learn what is important and what not to take a buy decision that can put me near of the main target where the price tell me only if I can afford or not.

Regards and enjoy the music,
Raul.

 

[silviajulieta]

Raul,

I do hope that we get some actual designers join in and illustrate the concerns of one-box vs. multi-box. You say that Halcro/Dartzeel can prove certain things (that may have many causes & be impossible to fairly duplicate in an inboard vs outboard study), but seem to think that the multi-box designers have no hope of proving anything.

I'm glad that you feel your equipment and choices are superior. I sincerely hope that you enjoy every minute you spend with them. However, I do feel that your tone of posting and your comments to others have been rude and condescending. Therefore, I will now utilize my "ignore" feature for the first time. I've tried to explain why you seem to be fighting an uphill battle, but you behave like you are the only one who has "learned for the better". I am truly disappointed.

Lee

Dear Lee: It is obvious that Halcro, Dartzeel and many other one-box manufacturers already give you an answer through what they already designed and has on sale.

Of course that multi-box manufacturers can provide many things but IMHO it seems to me that we can't " sin " of ingenuity ( from ingénue. ) thinking that a manufacturer advocate to multi-box commercial items can come here and tell us that one-box is the way to go. The multi-box manufacturers has to support their designs and they can tell us all the advantages in their approach and why not one-box or when could be one-box.
This seems to me but maybe some one of them come here and tell us something different and : surprise!


Now, I don't feel my choices/equipment are superior ( btw, superior to what?. ) and I don't posted that anywhere, so it does not makes sense to me that I argue on something that I don't posted.

+++++ " the only one who has "learned for the better". " +++++

this has no sense either, I think that no one can take for it self that statement and certainly not me.

Btw, we all are and have an audio learning curve/ladder, some of us are even at some ladder step, some other of us are below and some other are over us.
If you tell me that you are two or three steps ahead of me in that learning ladder: do you think that I will be " angry " for that?, no what that fact tell me is that I have to learn faster someway and that give me or put the right " emotion " to do it.
Do you think that you or me could think that we already know everything in audio?, not even close.

Am I rude? why? or how?. IMHO maybe this is more an each one personality subject that any other thing.

An apologize?, I don't have any problem with that but first you and each one of the persons that " call/email " you must post and tell me why I need to do it and how or which sentences " hurt " each one sensibility.

The " ignore " future?, I don't know what is that but you are free to do any thing you want: it's your privilege.

Regards and enjoy the music,
Raul.

 

[amirm]

There are sound engineering reasons for both schools:

Separate box:
1. Heat separation. This is the reason you often see separate power supplies such as in Xbox 360. The power supply heat does not cook the rest of the gear and vice versa, increasing equipment life and reducing the need for more cooling apparatus. In some cases this can mean the difference between having a fan and not.

2. Weight distribution/Size reduction. Two boxes are easier to carry than one box. And on size front, this is why laptops don't build the power supply inside the machine (the other reason is the heat issue above).

3. Separation of design so that different designers can work independently.

The one box solutions' main advantage was mentioned before. No matter how good the interconnect cable between the two boxes, a short path inside the equipment is preferable. And usually, the cost is lower due to one less enclosure (if the above factors don't make the design more complicated).

 

[silviajulieta]

There are in fact many myths and customs in the high end. Aesthetix Atlas amplifier has a high pass filter to facilitate the use off subwoofers. I think a lot of preamps would benefit form tone controls. It's a lot less expensive than mutli-kilobuck cables. In fact I prefer an all out equalizer to deal with room problems and doctored recordings. The presence of these devices were regarded as an attempt to cure a flawed design. In fact, less we forget, that two of the top dog amplifiers are integrated! Dartzell and the ASR Emitter II.
I've always been a one box man. Thtat includes amplification and cd players. I make an exception for speakers. It is clear there is a lot of mischief going on inside that cabinet. I even like the idea of external crossovers. A vibration is a vibration.

Finally ,I just can't help but tease Raul. He painted himsel in a corner by suggesting his inclusion of an outboard power supply was a pure marketing decison. A "a jagged little pill" to swallow coming from such an anolgog purist.
raul

Dear Reginald: Yes, I'm in many ways audio " purist " . Other than marketing an customer " proud " multi-box preamp units has some " things " where the manufacturer must be extremely care about: the kind and quality of the umbilical power cord, length of that power cord ( electrical tension change with length ), kind and quality of the umbilical connectors, filtering ( different kind ) inside PS outboard unit and inside circuit unit too due to " contamination " through the umbilical/connectors cords, maybe additional regulation inside circuit unit and go on and on.
All this means not only precise skills on the design but means more parts/complexity that means between other things $$$$. You can think that all multi-box manufacturers take care about but unfortunately only a few did/do it.

Almost all of those " issues " are elimitaded through single box approach but certainly you have to take care, a different " take care ", with single box designs, example: you can encapsulate the " dangerous " PS stages or even all the PS, you can encapsulate the critical signal circuits and even you can encapsulate the signal circuits and the PS stage. So we can aisle one stage from the other.

In both cases ( one-box/multibox. ) skills on the whole design is the critical factor. From a technical point of view and even from a customer point of view IMHO we can't diminish in any way the quality performance of a single box well designed audio item against a similar multi-box one.

In the other side, what do you think is more " easy ? that we pay 60K for a multi-box unit or the same 60K for a single box one?, so marketing is a heavy influence, don't you think?

Regards and enjoy the music,
Raul.

 

[MylesBAstor]

In the other side, what do you think is more " easy ? that we pay 60K for a multi-box unit or the same 60K for a single box one?, so marketing is a heavy influence, don't you think?

Regards and enjoy the music,
Raul.

No, I have both. I still have my totally dual mono, two box cj ART around til it's sold (something you haven't touched on as another variable), my two box King/Cello that can double as a tape or phono preamp and my one box cj GAT that is my current reference.

 

[Gregadd]

Dear Reginald: Yes, I'm in many ways audio " purist " . Other than marketing an customer " proud " multi-box preamp units has some " things " where the manufacturer must be extremely care about: the kind and quality of the umbilical power cord, length of that power cord ( electrical tension change with length ), kind and quality of the umbilical connectors, filtering ( different kind ) inside PS outboard unit and inside circuit unit too due to " contamination " through the umbilical/connectors cords, maybe additional regulation inside circuit unit and go on and on.
All this means not only precise skills on the design but means more parts/complexity that means between other things $$$$. You can think that all multi-box manufacturers take care about but unfortunately only a few did/do it.

Almost all of those " issues " are eliminated through single box approach but certainly you have to take care, a different " take care ", with single box designs, example: you can encapsulate the " dangerous " PS stages or even all the PS, you can encapsulate the critical signal circuits and even you can encapsulate the signal circuits and the PS stage. So we can aisle one stage from the other.

In both cases ( one-box/multibox. ) skills on the whole design is the critical factor. From a technical point of view and even from a customer point of view IMHO we can't diminish in any way the quality performance of a single box well designed audio item against a similar multi-box one.

In the other side, what do you think is more " easy ? that we pay 60K for a multi-box unit or the same 60K for a single box one?, so marketing is a heavy influence, don't you think?

Regards and enjoy the music,
Raul.

I think I already addressed all these points.

 

[mep]

Lee-Thanks for the very well reasoned response. I really don't have any hard feelings one way or the other regarding whether a piece of gear has an outboard power supply or not. I would not base a purchasing decision solely on that criteria. What I do know is that the power supply is the heart and soul of any audio component. Without a properly designed power supply, the circuit it feeds will never operate correctly. Since I am a fan of electrons flowing through a vacuum, I like the fact that the power supply in both my SA-5.1 and SA-2 are vacuum tube based. The SA-2 only has the power transformer in the outboard box and all 4 tubes in the power supply are located in the main chassis. My 5.1 has the rectifier located in the outboard box along with the power transformer and part of the filter network. As Amir pointed out in his post on this thread, the outboard power supply on my 5.1 runs quite hot and by having that heat in an outboard box it keeps it from stressing my main preamp components.

Mark

 

[silviajulieta]

Lee-me thinks you are being too harsh on Raul. Raul is not a master of the King's English, but he has many good points to make. He took some pot shots at my speakers before (Defintivie Technology BP7000 SC speakers), but I didn't lose any sleep over it. His posts are sometimes hard to read, but there are usually some nuggets of information in there if you read closely.

Mark

Dear Mark: I appreciate your understanding. I almost post with the English dictionary on hand and I take the " word " literally due that I'm unaware its " USA " real means, so I know this is a problem.

In the other side only through what the other people post in reference to what I posted I can know if what I posted was fine or people understand in a different way.
That's why I appreciate too posts like the late one by Ron where I read that my " means "/explanation was wrong and only through Ron's post I had the opportunity to emend/correct the " idea ".

Regards and enjoy the music,
Raul.

 

[silviajulieta]

There are sound engineering reasons for both schools:

.......................................................................................

3. Separation of design so that different designers can work independently.

.

Dear Amir: That is a good point. Through my experiences on electronic design I found that some amplifiers ( other items too. ) were designed that way ( two or more persons at different amp design stages. ) and not necessary in the multi-box designs even in single box design too.

The heat issue could be solve too in single box designs in different ways like: adequate heatsinks, silent fans or both.

IMHO I think that if you make a good research and has the knowledge you can ( exist the possibility. ) design in a single box approach almost any " state of the art " electronic item .

It's a designer privilege to decide his aproach on this box-multibox subject.

Regards and enjoy the music,
Raul.

 

[RBFC]

Dear Amir: That is a good point. Through my experiences on electronic design I found that some amplifiers ( other items too. ) were designed that way ( two or more persons at different amp design stages. ) and not necessary in the multi-box designs even in single box design too.

The heat issue could be solve too in single box designs in different ways like: adequate heatsinks, silent fans or both.

Regards and enjoy the music,
Raul.

Raul,

I am sorry if your use of English as a second language causes you difficulty in expressing yourself clearly here. Many of your statements did sound as though you knew things that others did not. There are some very well educated people on this forum, with many of them VERY knowledgeable about audio gear. It is not any single individual's place to say what constitutes a good design.

IMHO I think that if you make a good research and has the knowledge you can ( exist the possibility. ) design in a single box approach almost any " state of the art " electronic item .

It's a designer privilege to decide his aproach on this box-multibox subject.

Exactly. Unless we are better engineers, we should not be so critical. We are free to buy whatever component we wish.

Lee

 

[amirm]

Dear Amir: That is a good point. Through my experiences on electronic design I found that some amplifiers ( other items too. ) were designed that way ( two or more persons at different amp design stages. ) and not necessary in the multi-box designs even in single box design too.

Of course multiple people can collaborate on a design. But partitioning the interface and testing of each module allows this to happen much easier. If someone for example designed the output stage of an amp, you can't test and manufacture it independent of the driver stage.

The heat issue could be solve too in single box designs in different ways like: adequate heatsinks, silent fans or both.

Anything is possible to be sure . But consider that the fan could cause sonic anomalies of its own, costs extra, requires thermodynamics analysis to make sure it can properly cool things, and its failure, could cause the rest of the system to fail too. So there is a big trade off there. Extra heatsinks makes the device heavier and is also quite expensive. To the extent two boxes solve the same problem and provide some marketing value, that may be a better way to go.

IMHO I think that if you make a good research and has the knowledge you can ( exist the possibility. ) design in a single box approach almost any " state of the art " electronic item .

Clearly there are state-of-the-art single box designs. I was not taking a position one way or the other in the argument . But simply answering the engineering question in an objective manner having run into the same issue many times in managing design of hardware products in multiple companies. There is a reason external power supplies are so popular in electronic gear.

While I am typing this, there is another reason to have a separate box and that is regulatory certification. Getting UL/CSA mark requires long lead time tests and require multiple redesigns when they do crazy things to it like zapping it with high voltage on anything coming out of the box. By just taking the power supply to them (since that is the only thing with A/C connection), you significantly limit how much work you have to do and at any rate, can get that work done before the rest of the design is complete. This latter reason is the top explanation for why so many electronic devices have external power supplies. You get a pre-certified device and you are good to go.