It's amazing how far these things have come. The power densities of modern SMPS are unreal.
Yes, those monster power SMPS show their worth plenty.
In fact, the threads concerning them on here are quite lively!
Take a look at the automobile power amps threads, with endless chatter over how to repair them.
SMPS can be sensitive.. GANs in a bridge mode need careful design, they may remove the diode resulting in improved efficiency but the result is that the switch of A/uS spikes need careful design or you'll end up blowing one of the GANs. Not to mention designing in the wiring and other such fun and not presenting a dead short to a boost converter etc..
From my days being bothered enough to wire in speakers etc, I'd probably guess a large portion of failures are more todo with bad wiring, overloading 😀 or essentially presenting a dead short with caps etc.
Still.. probably cheaper to replace than the rising petrol cost for lugging around and powering all that linear iron 😉 Although in cold states.. I think making your engine part of the linear power supply should keep enough heat in to make starting the car in the morning easier 😀
Seems in the world of SMPS designers, there's considerable points about designing to avoid stress on specific components. However as others have said.. are you designing for longer life or short term lining of pockets.
There are some really inexpensive SMPS modules around. I just tried one 24V 4A (under $9) for 10 minutes or so last night with 8 ohms dummy load and it provided 3A without even getting warm to touch.
Uninformed as usual. Maybe the old-man-yelling-at-cloud forum would be more your style.
Car audio with plenty of power but no unreliable SMPS
Wiseoldtech, is that your car on the picture?
Wiseoldtech, is that your car on the picture?
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Nice gentlemen, bashing someone as moral majority crowd. Avid linear PSU builder here, experienced repairer of industrial stuff. That explains a bit.
In my latest nearly 20 built PSU of which SMPS and polished SMPS with guru filter all SMPS lost from my linear PSU's whether they are old or recent designs. Nearly all SMPS polluted mains voltage, ripple voltage was higher than data sheet values. These were all way under 50VA, some even way less as they are intended for DACs, streamers and such. The SMPS got all possible chances (I refuse to oppose any topology just because) but now they are all gone in the recycling. Positive was of course the lack of excess heat, smaller size and low weight, let that be clear. However my devices don't need those parameters.
* I would definitely use SMPS for high(er) power applications though. A JLH 1969 works excellent on SMPS with no serious heat and practically no ripple. Been there, done that. Better results than the transformer - diode bridge - filter cap combo.
For applications under 25 ...50VA I won't even think of keeping or using an SMPS as the majority of those whine like a drunk cat, exhibit mains pollution or even RF radiation, lack a power switch and/or they prematurely die when you are not at home. The ever returning answer is that excellent adapters do exist but those are not delivered with any of the audio devices I buy. The excellent PSU's that replace them are the linear ones I build myself and these have a power switch too. The reasons these SMPS are delivered with the device are low weight, low cost and liability/certification issues that are handed to the manufacturer of the cheap PSU. Not because of their superior qualities (maybe except for efficiency and ease of replacement as the buggers die again 🙂).
Even a LT1084/1085 based PSU wins hands down from any of the switchers as delivered with devices. I lend out my creations and I am told the same experiences. One can keep defending ultra cheap stuff (why exactly?) but then make sure to mention the audio related positive sides of SMPS for low power audio devices. Linn anyone? Also make sure to mention the negative side(s) of linear PSU's.
In my latest nearly 20 built PSU of which SMPS and polished SMPS with guru filter all SMPS lost from my linear PSU's whether they are old or recent designs. Nearly all SMPS polluted mains voltage, ripple voltage was higher than data sheet values. These were all way under 50VA, some even way less as they are intended for DACs, streamers and such. The SMPS got all possible chances (I refuse to oppose any topology just because) but now they are all gone in the recycling. Positive was of course the lack of excess heat, smaller size and low weight, let that be clear. However my devices don't need those parameters.
* I would definitely use SMPS for high(er) power applications though. A JLH 1969 works excellent on SMPS with no serious heat and practically no ripple. Been there, done that. Better results than the transformer - diode bridge - filter cap combo.
For applications under 25 ...50VA I won't even think of keeping or using an SMPS as the majority of those whine like a drunk cat, exhibit mains pollution or even RF radiation, lack a power switch and/or they prematurely die when you are not at home. The ever returning answer is that excellent adapters do exist but those are not delivered with any of the audio devices I buy. The excellent PSU's that replace them are the linear ones I build myself and these have a power switch too. The reasons these SMPS are delivered with the device are low weight, low cost and liability/certification issues that are handed to the manufacturer of the cheap PSU. Not because of their superior qualities (maybe except for efficiency and ease of replacement as the buggers die again 🙂).
Even a LT1084/1085 based PSU wins hands down from any of the switchers as delivered with devices. I lend out my creations and I am told the same experiences. One can keep defending ultra cheap stuff (why exactly?) but then make sure to mention the audio related positive sides of SMPS for low power audio devices. Linn anyone? Also make sure to mention the negative side(s) of linear PSU's.
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Let the ones vehemently attracted to those switcher/chopper supplies enjoy the trip they're on.
Because I'm going to remain in my world.
Because I'm going to remain in my world.
The fact that some manufacturers sell a linear PSU as an upgrade for the switcher says at least something. Also the comments of upgraders to LPS are clear as water. This even for the crowd that only uses ears, those hat also measure are even more convinced. For those that grew up with linear and analog, that have some repair experience there is little to worry about with well designed LPS. For some reason public opinion on diyaudio.com seems to have an aversion against LPS but then why? Unknown? Many Silicon Valley designers/procurers or any other professional interest with SMPS? Linear PSU's prove themselves quite easily, I can not think of a faster way of judging an audio device as fast and effective as replacing external wall wart SMPS for LPS and vice versa. A non discussion really.
Too bad many LPS now also come from the country of Cheap. Not exactly the best in general. Building very good LPS is one of the more rewarding items in DIY Audio as results are fast and clear. Not sexy as they just work after that.
Too bad many LPS now also come from the country of Cheap. Not exactly the best in general. Building very good LPS is one of the more rewarding items in DIY Audio as results are fast and clear. Not sexy as they just work after that.
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Bashing? I see no bashing, just some no ill meant humor. I really feel that wiseoltech could drive Ford T. And it is not a question of moral but technical standpoint.
Yes, that is what is discussed here with no final judgment. Nobody contemplates using SMPS for DAC or preamplifier supply. KW power levels were mentioned as well.
These hard-switching converteres have been crap from the very beginning and are copied for decades now. Generalising from that tiny fraction of smps topologies is not what I call wisdom.
@Jean-Paul. I widely agree on your experiences with both worlds.
At first I want to stress the fact that EU-regulations do not allow linear AC-adapters anymore for efficiency reasons and standby requirements.
The remaining question is what makes these wall-warts inferior to linear PS?
They are noisy:
Consider a primary bridge rectifier and bulk cap in every wall wart. This gives some ugly 100hz distorted noise that is coupled to the secondary via the 1nF Y-cap. An audible noise current that may creep into any sensitive analog circuitry. The solution to this problem is redirecting this Y-cap to PE-Gnd. But there is no GND prong on wall-warts. And that, in my humble opinion is the elephant in the room. A 3-prong wall wart would skip some real problems associated with this al cheapo technology. And this is the reason why you will find many DIYers happy reports with 3-prong notebook-bricks- being "evil" smps as well.
They fail:
The smaller the ac-adapter, the more sensitive it will be against overvoltage surges on the mains. This starts with the size and surge capacity of the primary bulk capacitor. There is not much you can do about this...
What is forbidden in the EU does not make any difference to sane guys as these people are busy with redesign of toothpicks and vacuum cleaners as they think Europeans vacuum their houses 24/7. Most measures have caused a counterproductive result.
A well designed LPS has a power switch and is way safer therefor. Greener too. Transformer based wall warts are meanwhile non existent so no issue whatsoever.
Let me stress that any modification of ready made class II SMPS is also forbidden in the EU 😀 Also wall outlets do have PE so LPS can have PE and are then safe and they have a PE path for any possible leakage, Audio GND to PE referencing and also for mains filters. Even small transformers and well rated filter caps will survive short voltage surges with ease. Win-win-win-win-win 🙂
So many arguments to build one of the most rewarding upgrades to source devices and what do we do? We use the worse of the worst/cheapest of the cheap and then add filters...
A well designed LPS has a power switch and is way safer therefor. Greener too. Transformer based wall warts are meanwhile non existent so no issue whatsoever.
Let me stress that any modification of ready made class II SMPS is also forbidden in the EU 😀 Also wall outlets do have PE so LPS can have PE and are then safe and they have a PE path for any possible leakage, Audio GND to PE referencing and also for mains filters. Even small transformers and well rated filter caps will survive short voltage surges with ease. Win-win-win-win-win 🙂
So many arguments to build one of the most rewarding upgrades to source devices and what do we do? We use the worse of the worst/cheapest of the cheap and then add filters...
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Theoretically you are right. Like you I support "hard" primary switches. I am the only one here who disconnects the washing machine after use. Primarily not to save energy, but to prolong lifetime. Practically no one cares about switching off myriads of chargers in the households - which gives some reason for low-standby-regulations. Don't get me wrong - I have a critical eye at all these EU-regulations, I had to work with them. Luckily not anymore😉
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Till now I got many fire trainings and I alway learn 4 families die every month because of wall warts or phone chargers catching fire. Just that fact is enough to NOT want stuff plugged in under voltage 24/7...
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Btw some yrs ago I experienced a fail of a 230V toroidal transformer supplying my stereo amp in the holiday home. It was leaking on the primary side, you could see arcing at the end of the windings. I suppose it was the result of some mains surge not rare in this area. So I built my own "mains filter": A 22uF x-rated motor capacitor parallel wired to L & N inside the switch box. No problems since😀
Everything can break down (or made to...) but the numbers of toroids failing will look favorable compared to the number of wall wart SMPS failing on annual basis.
I can make a 1000 watt supply for an amplifier just by buying a 1500VA toroid, 50 amp bridge rectifier and two 22,000 uF caps (and maybe a thermistor, and 15 ohm resistor and a .01 uF x-cap for the snubber if it needs it). Plug it in, turn it on and it works. No ifs, ands or buts. That supply can be loaded with 5000 watts average (with pi times that in peaks occurring every 50 milliseconds) during sine wave testing at low impedance at low frequency repeatedly over the course of several minutes - without going into hiccup mode. Try doing that with an SMPS for *any* reasonable amount of money, not to mention the 10 iterations over a year’s development time with many blown IGBTs along the way getting there.
Hi-Power smps is certainly not as DIY-friendly as old school toroids. And yes, this requires some steep learning curve. But it is doable. Been there, done that.😉
I made a SMPS long time ago based on the following:
https://www.diyaudio.com/forums/solid-state/238768-amplifier-hifi-ns450-200w.html#post3550902
Made the PCB via toner transfer and wound my own transformer. It is not too hard once you have the PCB and know how to wind the transformer. But playing with mains voltage is dangerous and can be lethal.
https://www.diyaudio.com/forums/solid-state/238768-amplifier-hifi-ns450-200w.html#post3550902
Made the PCB via toner transfer and wound my own transformer. It is not too hard once you have the PCB and know how to wind the transformer. But playing with mains voltage is dangerous and can be lethal.