Hi poobah,
Hate the politics, but really like the paycheck and benefits? 😉
Me too, but I hate the politics more.
-Chris
Hate the politics, but really like the paycheck and benefits? 😉
Me too, but I hate the politics more.
-Chris
😉 you betcha'
Really focus on what an inductor is... it is your key to grasping switchers. Don't get bogged down in all the iron issues at first...just the coil.
Learn Buck... then Boost... then Flyback...
Capacitors are springs (storing potential energy)... inductors are flywheels (storing kinetic energy)... that will make alot more sense down the road a bit.
Really focus on what an inductor is... it is your key to grasping switchers. Don't get bogged down in all the iron issues at first...just the coil.
Learn Buck... then Boost... then Flyback...
Capacitors are springs (storing potential energy)... inductors are flywheels (storing kinetic energy)... that will make alot more sense down the road a bit.
Great Quote!
I never heard that before. Perhaps you need to take a year off to get a teaching license? You could teach all those young minds in college? And drop a few posts on the DIY Forum in between classes? 😀
Shawn.
poobah said:
I never heard that before. Perhaps you need to take a year off to get a teaching license? You could teach all those young minds in college? And drop a few posts on the DIY Forum in between classes? 😀
Shawn.
LOL!
Shawn, do you think the students would survive poobah's sense of humour? Of course there will be a lesson in each gag.
Poobah, what do you say? Teaching as a career? You would get the entire summer off too!
-Chris
Shawn, do you think the students would survive poobah's sense of humour? Of course there will be a lesson in each gag.
Poobah, what do you say? Teaching as a career? You would get the entire summer off too!
-Chris
I look at Sound and Vision, June 2006, an advertising page.
I see the Kef home theater 3000, www.kef.com
I also look at another of their products.
http://www.kef.com/products/subwoofers/kht3000.asp
These also look like they could be transformerless.
While they could use a SMPS, I wonder.
Notice how the driver surround is designed. Notice that the cone is not concave, but a flat disc, so you never could get close to the voice coil wires without tearing it apart. Notice that the front face is also designed to fully cover any mounting screws.
So you can never have contact with the voice coil, basket frame, or with mounting screws.
I first noticed some designs like this on the market about 4 years ago.
Small boxes, lots of power, very small circuit boards sometimes being shown, not even a SMPS type transformer, and this unusual type of woofer and mounting.
This thread is the first time I've ever tried to discuss such matters with anyone.
I see the Kef home theater 3000, www.kef.com
I also look at another of their products.
http://www.kef.com/products/subwoofers/kht3000.asp
These also look like they could be transformerless.
While they could use a SMPS, I wonder.
Notice how the driver surround is designed. Notice that the cone is not concave, but a flat disc, so you never could get close to the voice coil wires without tearing it apart. Notice that the front face is also designed to fully cover any mounting screws.
So you can never have contact with the voice coil, basket frame, or with mounting screws.
I first noticed some designs like this on the market about 4 years ago.
Small boxes, lots of power, very small circuit boards sometimes being shown, not even a SMPS type transformer, and this unusual type of woofer and mounting.
This thread is the first time I've ever tried to discuss such matters with anyone.
Hi zenmasterbrian,
Flat diaphragms have existed for years. They have nothing to do with how the thing works, although one Cyrus speaker used a number of motor units against a flat panel.
The diaphragm shape will have more to do with fashion than any other motivator.
Consider Electrostatic speakers. They contain very high voltages. Protection from penetration is minimal.
The drive to produce directly powered electronics would be the cost savings in weight and the cost of other light weight components that would normally be substituted for a standard power transformer.
-Chris
Flat diaphragms have existed for years. They have nothing to do with how the thing works, although one Cyrus speaker used a number of motor units against a flat panel.
The diaphragm shape will have more to do with fashion than any other motivator.
Consider Electrostatic speakers. They contain very high voltages. Protection from penetration is minimal.
The drive to produce directly powered electronics would be the cost savings in weight and the cost of other light weight components that would normally be substituted for a standard power transformer.
-Chris
Do you agree that the KEF unit seems to have the surround and face plate designed to prevent access to the basket?
It just seems that the flat cone might also be invoked here to prevent access to the voice coil, or the wires that feed it.
It just seems that the flat cone might also be invoked here to prevent access to the voice coil, or the wires that feed it.
Hi zenmasterbrian,
I used to do warranty service for KEF in Canada a few years ago.
Now, if the basket and screws were exposed, I'd say definitely not a line powered sub unless they want a law suite.
-Chris
I used to do warranty service for KEF in Canada a few years ago.
Only to the extent that they don't want customers getting in there. There are many good reasons for this. A "hot" basket would qualify, but I'd still say that cosmetics has a lot to do with it.
Now, if the basket and screws were exposed, I'd say definitely not a line powered sub unless they want a law suite.
-Chris
Actually UL is not as picky as some would think. It is basically about 2 things. First, don't shock people. Second, don't start fires.
As long as an item is designed durably in accordance with its intended usage and reasonable accidents; you're good to go. That does assume that live parts are tested for access... or perhaps lack of access.
They use an official finger thingy ($250😱 ) to test for access. The tip of this thing has childish proportions:
As long as an item is designed durably in accordance with its intended usage and reasonable accidents; you're good to go. That does assume that live parts are tested for access... or perhaps lack of access.
They use an official finger thingy ($250😱 ) to test for access. The tip of this thing has childish proportions:
Attachments
Now... if you decide to take a bath with your speakers or cut your amp in half with a chainsaw; U.L. could not care less about you getting shocked. In that regard, they still support Darwin. They would however, still be a bit cranky on the fire side of things.
🙂
🙂
http://www.klipsch.com/products/details/rt-12d.aspx#specifications
This has three drivers, one on each face. Not much room inside.
It can do 800W continuously, or 2000W peak. This peak is about the most you could get out of a 15A outlet. No power to spare here.
This was built to get the maximum punch out of a small box. Clearly 3 woofers in three boxes could do more. This was built to be compact.
Maybe the special custom drivers and the face plate are only designed for looks. But it also looks much like the Bob Carver sub.
I first saw ads that showed the circuit boards, transformerless, for some of these products, about 4 years ago. I think other folks are following suit.
Its the same design. Class D with minimal heat sinks, and a custom radicallized huge magnet driver, and the small box.
This Klipsch sub has all types of digital controls. Going digital solves any problem with opto isolator nonlinearities.
This has three drivers, one on each face. Not much room inside.
It can do 800W continuously, or 2000W peak. This peak is about the most you could get out of a 15A outlet. No power to spare here.
This was built to get the maximum punch out of a small box. Clearly 3 woofers in three boxes could do more. This was built to be compact.
Maybe the special custom drivers and the face plate are only designed for looks. But it also looks much like the Bob Carver sub.
I first saw ads that showed the circuit boards, transformerless, for some of these products, about 4 years ago. I think other folks are following suit.
Its the same design. Class D with minimal heat sinks, and a custom radicallized huge magnet driver, and the small box.
This Klipsch sub has all types of digital controls. Going digital solves any problem with opto isolator nonlinearities.
About this 2000W Klipsch unit. It's no accident that that is their top of the line, most expensive. Its the most power you could get from a portable appliance.
It will even draw more current than the 2000W would suggest, because it will have a poor, capacitive, power factor.
This might even have pre filtering regulation, lowering the peak voltages on the capacitors. This will make the power factor even worse.
I'm not sure which would trip first, the thermal shut downs inside the Klipsch unit, or the 15A mains breaker.
It will even draw more current than the 2000W would suggest, because it will have a poor, capacitive, power factor.
This might even have pre filtering regulation, lowering the peak voltages on the capacitors. This will make the power factor even worse.
I'm not sure which would trip first, the thermal shut downs inside the Klipsch unit, or the 15A mains breaker.
My own curiosity about the possibility of a high power transformerless amp goes back decades. It seems so logical.
But it also seemed impractical and unsafe.
First, the power seemed excessive for residential use.
But today, that might have changed. There are higher power drivers. There is lower frequency program material, lower than vinyl. There is better class D technology to work with it.
There is also better SMPS technology, so one could run at a lower power supply voltages, by regulating before the filter capacitors.
I am also interested in going into the infrasonic range. So huge powers could be legitimate.
It was four years ago that I started to look at the audiophile mags. Mostly I don't like those mags. But I saw these subs, some with super high power. Some really did seem to be tranformerless.
I believe that the trend is spreading. Carver may have started it. He doesn't advertise that aspect of it.
I think it probably started when he decided to make such an extreme driver, huge magnet, big xd. The idea of making it also an isolating driver probably began their.
This is my suspicion.
But it also seemed impractical and unsafe.
First, the power seemed excessive for residential use.
But today, that might have changed. There are higher power drivers. There is lower frequency program material, lower than vinyl. There is better class D technology to work with it.
There is also better SMPS technology, so one could run at a lower power supply voltages, by regulating before the filter capacitors.
I am also interested in going into the infrasonic range. So huge powers could be legitimate.
It was four years ago that I started to look at the audiophile mags. Mostly I don't like those mags. But I saw these subs, some with super high power. Some really did seem to be tranformerless.
I believe that the trend is spreading. Carver may have started it. He doesn't advertise that aspect of it.
I think it probably started when he decided to make such an extreme driver, huge magnet, big xd. The idea of making it also an isolating driver probably began their.
This is my suspicion.
Hi poobah,
I like Darwin. A lot. 😀 Unfortunately his effect has been diminished to the detriment of the rest of us.
Hi zenmasterbrian,
You really can not tell much about a unit from a few pictures and it's external appearance. Without first hand knowledge, it is unsafe and unwarranted to guess at it's technologies. There are simply not enough hard facts to go on. I'll keep an open mind on this one until there is proof one way or the other. All we can do is make wild guesses without more information.
When you think about it, it really does not matter how the unit(s) in question derive their power supply, unless you are concerned with safety. One also has to be very cautious about the maximum power levels being quoted. I would read very carefully, and I'll bet the information is a little light in those areas. Possibly even misleading. It wouldn't be the first time.
Another question. Why the devil do people rush to very high power levels? You should be looking at maximum SPL by frequency in a standard room volume. That might be a better way to characterize these products, along with power consumption.
-Chris
I like Darwin. A lot. 😀 Unfortunately his effect has been diminished to the detriment of the rest of us.
Hi zenmasterbrian,
You really can not tell much about a unit from a few pictures and it's external appearance. Without first hand knowledge, it is unsafe and unwarranted to guess at it's technologies. There are simply not enough hard facts to go on. I'll keep an open mind on this one until there is proof one way or the other. All we can do is make wild guesses without more information.
When you think about it, it really does not matter how the unit(s) in question derive their power supply, unless you are concerned with safety. One also has to be very cautious about the maximum power levels being quoted. I would read very carefully, and I'll bet the information is a little light in those areas. Possibly even misleading. It wouldn't be the first time.
Another question. Why the devil do people rush to very high power levels? You should be looking at maximum SPL by frequency in a standard room volume. That might be a better way to characterize these products, along with power consumption.
-Chris
<<
You really can not tell much about a unit from a few pictures and it's external appearance. Without first hand knowledge, it is unsafe and unwarranted to guess at it's technologies. There are simply not enough hard facts to go on. I'll keep an open mind on this one until there is proof one way or the other. All we can do is make wild guesses without more information.
>>
True, this is speculation. But look at where speculation on diyaudio has already gotten us. We now know with certainty about the Carver Sunfire sub. We have more information about that than I could have possibly hoped for. One learns a great deal by looking at how other things have been designed.
Maybe there is a big metal doughnut in the bottom of that $3K Klipsch sub. But maybe its just like my electric toaster.
There is another type of powered speaker now on the market. I was planning to talk about this here anyway. I've seen them in stores. They are for musicians, often keyboard, to use at home, in gigs, or for a monitor. Typically they have a 15" woofer and a MF/HF horn. The enclosure is molded plastic. It is no bigger than necessary. The back of it tapers, meaning the cross section is nearly triangular.
The front housing piece includes the horn flare. It also holds a small holed and non-removable metal grill. That grill was put on from the inside. You would have to destroy it to get it off.
These units are multi-amped with active crossovers.
They are designed to be carried with one hand. They are designed to give the most sound per pound.
The amp power is substantial. Is there a transformer in there? Maybe only the input circuits and the horn amp are transformer isolated?
Maybe someone reading this actually knows?
<<
When you think about it, it really does not matter how the unit(s) in question derive their power supply, unless you are concerned with safety. One also has to be very cautious about the maximum power levels being quoted. I would read very carefully, and I'll bet the information is a little light in those areas. Possibly even misleading. It wouldn't be the first time.
>>
Of course I am concerned with safety. I never liked the old radios and televisions that were transformerless. But I am not saying that they were unsafe. It was just a limited type of design. Difficult to have external connections to it. All the controls had long plastic knobs.
A problem to service, unless you have an isolation transformer. Most people don't. To fully exercise that Klipsch sub, you would have to have a bigger bench isolation transformer than I have ever seen.
<<
Another question. Why the devil do people rush to very high power levels? You should be looking at maximum SPL by frequency in a standard room volume. That might be a better way to characterize these products, along with power consumption.
>>
SPL by frequency for a room volume is more important. Klipsch does list that. It is substantial.
Its just like hp and automobiles. They boast that, instead of acceleration, cornering, or top speed specs.
Boasting speed and acceleration could be considered irresponsible. Boasting high SPLs could be too.
So far, high hp and high watts, is only seen as frivolous, yet titillating.
I drive an older, lighter, and small car, and I drive slow. 25hp is about all I ever use.
At least one of these audio builders has crossed over a line which I had imagined could be crossed, decades ago. I suspect that others are crossing that line too.
Is it safe? Are some of them doing it more safely that others?
There are published standards for isolation saftey. The most extreme that I know of is for medical equipment approved for use on immobile patients. These standards cover wiring and PCB layouts, as well as a tougher spec for the transformers.
I would like everything that is out there to be that safe.
With these new types of powered speakers, given how they are used, are they safe?
You really can not tell much about a unit from a few pictures and it's external appearance. Without first hand knowledge, it is unsafe and unwarranted to guess at it's technologies. There are simply not enough hard facts to go on. I'll keep an open mind on this one until there is proof one way or the other. All we can do is make wild guesses without more information.
>>
True, this is speculation. But look at where speculation on diyaudio has already gotten us. We now know with certainty about the Carver Sunfire sub. We have more information about that than I could have possibly hoped for. One learns a great deal by looking at how other things have been designed.
Maybe there is a big metal doughnut in the bottom of that $3K Klipsch sub. But maybe its just like my electric toaster.
There is another type of powered speaker now on the market. I was planning to talk about this here anyway. I've seen them in stores. They are for musicians, often keyboard, to use at home, in gigs, or for a monitor. Typically they have a 15" woofer and a MF/HF horn. The enclosure is molded plastic. It is no bigger than necessary. The back of it tapers, meaning the cross section is nearly triangular.
The front housing piece includes the horn flare. It also holds a small holed and non-removable metal grill. That grill was put on from the inside. You would have to destroy it to get it off.
These units are multi-amped with active crossovers.
They are designed to be carried with one hand. They are designed to give the most sound per pound.
The amp power is substantial. Is there a transformer in there? Maybe only the input circuits and the horn amp are transformer isolated?
Maybe someone reading this actually knows?
<<
When you think about it, it really does not matter how the unit(s) in question derive their power supply, unless you are concerned with safety. One also has to be very cautious about the maximum power levels being quoted. I would read very carefully, and I'll bet the information is a little light in those areas. Possibly even misleading. It wouldn't be the first time.
>>
Of course I am concerned with safety. I never liked the old radios and televisions that were transformerless. But I am not saying that they were unsafe. It was just a limited type of design. Difficult to have external connections to it. All the controls had long plastic knobs.
A problem to service, unless you have an isolation transformer. Most people don't. To fully exercise that Klipsch sub, you would have to have a bigger bench isolation transformer than I have ever seen.
<<
Another question. Why the devil do people rush to very high power levels? You should be looking at maximum SPL by frequency in a standard room volume. That might be a better way to characterize these products, along with power consumption.
>>
SPL by frequency for a room volume is more important. Klipsch does list that. It is substantial.
Its just like hp and automobiles. They boast that, instead of acceleration, cornering, or top speed specs.
Boasting speed and acceleration could be considered irresponsible. Boasting high SPLs could be too.
So far, high hp and high watts, is only seen as frivolous, yet titillating.
I drive an older, lighter, and small car, and I drive slow. 25hp is about all I ever use.
At least one of these audio builders has crossed over a line which I had imagined could be crossed, decades ago. I suspect that others are crossing that line too.
Is it safe? Are some of them doing it more safely that others?
There are published standards for isolation saftey. The most extreme that I know of is for medical equipment approved for use on immobile patients. These standards cover wiring and PCB layouts, as well as a tougher spec for the transformers.
I would like everything that is out there to be that safe.
With these new types of powered speakers, given how they are used, are they safe?
Hi Brian,
I don't think running around pointing at things is going to get anyone anywhere. What we need are schematics of such devices that are actually approved and on the North American market. Not intended for professional use. So let's just relax until someone pops up with a full schematic.
-Chris
The electronics industry has a long time-honoured history of electrocuting musicians. 😀
My choice is a large GM "B" body wagon, engine displacing 350 cu in. I use considerably more than 25 HP on a regular basis. I drive quickly. Comfy too. 😉
I am. That's why they are off the market.
I've seen them that big, but you don't power test a component on a variac or isolation transformer as a rule. So you only need to supply starting power and a little signal.
I don't think running around pointing at things is going to get anyone anywhere. What we need are schematics of such devices that are actually approved and on the North American market. Not intended for professional use. So let's just relax until someone pops up with a full schematic.
-Chris
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