Sorry for going off-topic but i have some points to add at the safety section:
· Some posts seem to encourage to connect the amplifier ground to the "neutral" wire. Here in spain there are three wires, the ground (yellow-green), the neutral (brown) and the live (blue). If somebody misunderstands this and connects the amplifier to the brown one should know that plugs fit into the outlet in both directions so at some point he will connect the live wire to the amplifier board and at least make some impressive fireworks. The use of grounding is here to protect if the transformer fails to provide galvanic isolation between the mains network and the amplifier and it has only adverse effects on the sound, anyways, does it matter how it sounds if you are dead?
·Output of power supplies can also be dangerous. A 100W amp typically runs on 55V rails which make 110V (if it has discrete output transistors these go from heatsink to heatsink if isolating pads aren't used). It's not uncommon to see people comparing temperatures with both hands. This should never be done.
· The worst thing you can do is to mix electricity with water. If you touch pair of live wires with your dry hands you will probably have a very hard time, but if you touch it with your hands wet you will not live to explain it for sure.
· If there is some live wire on your test bench then keep one hand on your pocket and work with the other. This has been said a lot of times in the tube forums i don't remember having read it in the chipamp section, anyways, there is no reason why 220Vac should be less/more dangerous than 200Vdc.
· Don't be panicked! Some safety advises deter people from building theyr amps. I've got a couple of 220Vac shocks, none from diy but rather from burned power cords at the kitchen. People die electrocuted when they plug a shaving machine with a damaged cable while thinking on an important meeting with theyr boss, when theyr last concern is electrical safety. If you attach to strict safety practices nothing will happen to you. I don't feel it to be more dangerous than driving, if you can drive in a highway without having nightmares about what would happen if you move your hand ten centimeters and get into the wrong lane, then you can build an amp without having nightmares about what would happen if you move your hand one meter and touch a live wire.
Edit: Another safety issue is about playing music in the test bench. When you have just finished a great-sounding amp and you get loud, emotive and high-quality music from it it becomes easier to forget that there are a lot of dangers there. Never forget that the lab is not a dance floor. Listen to it as if you were reading a volt-meter and if everything is fine then enclose it so as there is no chance you touch a high-voltage wire.
· Some posts seem to encourage to connect the amplifier ground to the "neutral" wire. Here in spain there are three wires, the ground (yellow-green), the neutral (brown) and the live (blue). If somebody misunderstands this and connects the amplifier to the brown one should know that plugs fit into the outlet in both directions so at some point he will connect the live wire to the amplifier board and at least make some impressive fireworks. The use of grounding is here to protect if the transformer fails to provide galvanic isolation between the mains network and the amplifier and it has only adverse effects on the sound, anyways, does it matter how it sounds if you are dead?
·Output of power supplies can also be dangerous. A 100W amp typically runs on 55V rails which make 110V (if it has discrete output transistors these go from heatsink to heatsink if isolating pads aren't used). It's not uncommon to see people comparing temperatures with both hands. This should never be done.
· The worst thing you can do is to mix electricity with water. If you touch pair of live wires with your dry hands you will probably have a very hard time, but if you touch it with your hands wet you will not live to explain it for sure.
· If there is some live wire on your test bench then keep one hand on your pocket and work with the other. This has been said a lot of times in the tube forums i don't remember having read it in the chipamp section, anyways, there is no reason why 220Vac should be less/more dangerous than 200Vdc.
· Don't be panicked! Some safety advises deter people from building theyr amps. I've got a couple of 220Vac shocks, none from diy but rather from burned power cords at the kitchen. People die electrocuted when they plug a shaving machine with a damaged cable while thinking on an important meeting with theyr boss, when theyr last concern is electrical safety. If you attach to strict safety practices nothing will happen to you. I don't feel it to be more dangerous than driving, if you can drive in a highway without having nightmares about what would happen if you move your hand ten centimeters and get into the wrong lane, then you can build an amp without having nightmares about what would happen if you move your hand one meter and touch a live wire.
Edit: Another safety issue is about playing music in the test bench. When you have just finished a great-sounding amp and you get loud, emotive and high-quality music from it it becomes easier to forget that there are a lot of dangers there. Never forget that the lab is not a dance floor. Listen to it as if you were reading a volt-meter and if everything is fine then enclose it so as there is no chance you touch a high-voltage wire.
ionomolo said:
No grounding for Spain! Got it! Thanks so much!!
*Therefore, folks in Spain, with easily reversable plugs and/or really confusing mains, should OMIT the groundloop breaker / safety disconnect portion (top section of this thread), and just build only the basic power supply board. For other people, with non-reversable, non-confusing, mains wiring, a simple ohmmeter can decipher if the amplifier will be grounded correctly.
Workbench! This is why I had to specify a wooden amplifier enclosure. U.S. regulations have strong cautions against having both voltage and a reference (ground) present where fingers can touch. This is also why my power supply is pictured shoved into a Ziploc (tough plastic) bag--yes, it was on the workbench and I didn't want a kitty paw (or my own paw) on the rails. A handy clear glass or plastic bowl can be quickly flipped over components as well. Its all just an insulating barrier to fingers (and paws).
We'll do some more workbench safety before connecting power to the board.
Thanks again! Wow. This info is very much on topic.
Daniel, I sincerely hope that you have a good lawyer! You are unable to understand what people are telling you because you don't have enough knowledge. You are then trying to 'translate' what you read so that newbies will understand it.
As regards building a simple GC, it is slightly amusing. When it comes to safety, it is getting scary! Please don't give any safety advice until you check it with the likes of AndrewT!
Nuuk said:Daniel, I sincerely hope that you have a good lawyer! You are unable to understand what people are telling you because you don't have enough knowledge. You are then trying to 'translate' what you read so that newbies will understand it.
As regards building a simple GC, it is slightly amusing. When it comes to safety, it is getting scary! Please don't give any safety advice until you check it with the likes of AndrewT!
Due to this conflict, I cannot proceed. Therefore, the demonstration on how to build the power supply board is cancelled.
That's certainly decreased risk. This unit has no power cord, and thus it has no ability to pose a shock risk. Neither power hookup, nor transformer, was illustrated. And, now it won't be illustrated. Don't connect a power cord.
The liability of presenting a complete power supply is simply too great. This project is cancelled.
oh no..
i tought and wish that soon we will have a pictural safety guidance in daniel's new amp as a precious conclusion.
dear Nuuk, and all,
some newbies incl me, may need thousand years to understand hows things works.
unlike some trial n error to improve our audio Q, we better follow to our trusted source/s than do some dangerous test with main a/c.
i mean some guidance from Mr AndrewT, Mr Gareth or soundwesthost page, etc.
but some informative picture will help us to crosscheck and feel safer.
if the kind volunteer is not daniel, maybe someone capable will continue? a diyAudio rule? something for Wiki?
yes there are vary regulation for the main, but i think its only 2. at least we know our prongs or sockets contains 2 or 3. so there will be 2 kind procedure/rule i think.
Maybe our netlist?
Pls help,
the opposite of life is'nt dead but care
your information will runs person to person like MLM, you load of thankful blessings
or we just have to stop here?
Brgds Eka
i tought and wish that soon we will have a pictural safety guidance in daniel's new amp as a precious conclusion.
dear Nuuk, and all,
some newbies incl me, may need thousand years to understand hows things works.
unlike some trial n error to improve our audio Q, we better follow to our trusted source/s than do some dangerous test with main a/c.
i mean some guidance from Mr AndrewT, Mr Gareth or soundwesthost page, etc.
but some informative picture will help us to crosscheck and feel safer.
if the kind volunteer is not daniel, maybe someone capable will continue? a diyAudio rule? something for Wiki?
yes there are vary regulation for the main, but i think its only 2. at least we know our prongs or sockets contains 2 or 3. so there will be 2 kind procedure/rule i think.
Maybe our netlist?
Pls help,
the opposite of life is'nt dead but care
your information will runs person to person like MLM, you load of thankful blessings
or we just have to stop here?
Brgds Eka
I didn't say that there was no ground wire, but rather that there is a wire called neutral and a wire called earth, and that the wire that should be connected to amplifier ground is the earth wire, not the neutral wire. The earth wire is connected on the lateral of the plug and is impossible to mistake with the neutral/live ones.
There is another reason to connect the amplifier to ground and not neutral. If you connect the amplifier ground to mains earth and then something like an ipod (whose case is connected to signal ground) and then touch a live wire while holding the ipod, the differential switch at your home will break the line immediately (this live wire may be for example from a broken computer cable so not having a "fault" in your amplifier doesn't mean being safe). This will not happen if the amplifier is connected to neutral.
Doing a psu is easy, i will do one this afternoon so i can post the pictures if you want.
There is another reason to connect the amplifier to ground and not neutral. If you connect the amplifier ground to mains earth and then something like an ipod (whose case is connected to signal ground) and then touch a live wire while holding the ipod, the differential switch at your home will break the line immediately (this live wire may be for example from a broken computer cable so not having a "fault" in your amplifier doesn't mean being safe). This will not happen if the amplifier is connected to neutral.
Doing a psu is easy, i will do one this afternoon so i can post the pictures if you want.
ionomolo said:
Hi,
Are you sure that someone here said this?
In North America, we have 120VAC mains through the standard household receptacle. There are 2 conductors and a ground wire (or earth wire). The two conductors are white (neutral) and black (hot, live). The ground wire is normally bare copper.
For the purposes of building power supplies and other electronics that run off the mains, the 2 conductors should be treated the same, as live wires. It's ideal to switch or fuse the hot lead, and it takes a second to determine the correct one on the back of the IEC connector. Both of these wires need to be insulated to avoid contact with each other and your body.
The ground wire will connect directly to the exposed metal of the chassis. This is shortest route to ground for any problem that occurs, and it's there mainly to prevent accidental death by electrocution. If a live wire comes loose inside the chassis and touches the exposed metal, it will be grounded and trip the circuit breaker at the main panel.
The metaphor of birds in post #22 can be read as "amplifier ground should be connected to a live wire so as it has a common reference point with other parts in your system".
Of course anybody with some knowledge in electricity will never do that but i can see a newbie understanding it that way.
I belive that the word "neutral" should be forbidden in all forums because it creates the false and dangerous feeling that one live wire deserves less care than the other.
Of course anybody with some knowledge in electricity will never do that but i can see a newbie understanding it that way.
I belive that the word "neutral" should be forbidden in all forums because it creates the false and dangerous feeling that one live wire deserves less care than the other.
We all like to learn through trail and error.... but not if the error includes death or burning down our houses....
What happens from the transformer secondary onwards is pretty universal, but there are major diffirences on what is upstream from the secondary, these include phyiscal diffirences as well as legal ones, depending on your geographical area.
I think most of us are allready treading over the line just connecting our amps to the mains...the problems comes when we try to get the insurance company to pay for loss of home or life...
What happens from the transformer secondary onwards is pretty universal, but there are major diffirences on what is upstream from the secondary, these include phyiscal diffirences as well as legal ones, depending on your geographical area.
I think most of us are allready treading over the line just connecting our amps to the mains...the problems comes when we try to get the insurance company to pay for loss of home or life...
I think it's important to take the time to research and understand the wiring system in your own part of the world before you attempt mains wiring. I'm sure there are lots of online tutorials reliably explaining this.
Once you have a good grip on that, you can easily avoid getting tripped up with terminology. You will know which is the ground, neutral, and hot.
Anyone who is either too dense or too lazy to do this basic learning should not attempt mains wiring.
Once you have a good grip on that, you can easily avoid getting tripped up with terminology. You will know which is the ground, neutral, and hot.
Anyone who is either too dense or too lazy to do this basic learning should not attempt mains wiring.
When it comes to mains safety DON'T take chances.In the U.K. Neutral and Earth are nowadays bonded together in the consumer unit, but they are NOT THE SAME AND MUST NEVER EVER BE TREATED AS SUCH. There seems a lot of dubious advice floating around here. Get it wrong and someone could be injured or worse.
Mooly said:
In older UK property the 'Earth' wire may be bonded to ground through the cold water system or (in these days of plastic water pipe) a ground plate buried in the soil -- an independent ground system.
The full term is 'Safety Earth', and as said, it should never be connected to a 'Neutral' wire, nor should a 'Neutral' wire ever be directly connected to a chassis. The 'Neutral' wire carries the full appliance current and, in the event of a fault, could carry the full supply voltage (as far as a relatively high-resistance human body is concerned). The 'Earth' wire only carries current under fault conditions and should be directly connected to any exposed metalwork that could come in contact with mains voltage to act as a low-resistance path to ground -- 'Safety Earth'.
A problem is, this is an international forum; mains electrical practices vary around the world and it's dangerous to generalise in a "how-to".
we have unpolarized outlets and connecting the expected neutral to the case at the consumer unit would lead to an unexpected experience. 
However in, old obsolete, two wire installations the PE at the outlet is connected to the neutral wire here, providing a three wire interface to the consumer unit.
regards
However in, old obsolete, two wire installations the PE at the outlet is connected to the neutral wire here, providing a three wire interface to the consumer unit.
regards
sneih said:
You need someone (Daniel) to tell you how to do this? Doesn't matter to you if it's right or wrong? What would the warning be:
"The following may or may not be true and may or may not be dangerous. Use this potentially dangerous advice at your own risk"? Power supplies are easy if you know what you are doing, therefore, you should put a little effort into educating yourself. It doesn't take long and there's no pain involved.
The fact that you are on here proves that you have the most powerful research tool available: the internet. Google it up.
Some sensible advice:
1: Never touch the wires of a running amplifier, it does not matter if they are signal, power, mains or B+. The best it can do to you is nothing, and you can feed signal to the amplifier that can blow loudspeakers. Bad for you, bad for the loudspeakers... don't do it.
2. Put all isolating materials you get arround any soldering that involves mains or high voltages. Driver-based chipamps usually run on +/- 55/ 70V and this gives 110 to 140 vdc which is bad to touch.
3. Don't place circuitry on the mains network. Noise killer networks are needed unless you want the amplifier to warn you each time somebody turns a light near your listening room but they should be placed on the secondary of the transformer.
4. Keep mains connections as shorter as possible and if you can place them at the back of your amplifier far away from volume knobs and circuitry.
5. Never connect any wire comming from a mains outlet that you don't know exactly what it does or that there is some chance to be connected in a different position (remember in many contries outlets fit in both directions. The transformer provides galvanic isolation from the network and should make a very good protection, grounding has extra advantages but better not grounded than live, right? If you know which one is the safety earth and you are absolutely sure that it is the safety earth and not any of the live wires then connect it to the amplifier ground.
6. Never ever work with wet hands or without shoes.
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