Diy regulated power supply

[JebemMajke]

Schematic

Transformer, primary measures 1.3 Kohm and secondary 5.6 ohm. I guess that's fine. If not please do tell me.
I'm from Serbia and here we have 220v instead of 120v. But the transformer I have is 220v-12v so that's cool, I guess.
Is there any difference between building your own diode block and buying one? And are 1n4001's the only diodes that could be used in diode block?
Why does this Russian schematic requires different capacitor values?

Also here, different values and the overall capacitor quantity

[R.G.]

Transformer, primary measures 1.3 Kohm and secondary 5.6 ohm. I guess that's fine. If not please do tell me.

It is not possible to tell from wire resistances whether it works or not.

I'm from Serbia and here we have 220v instead of 120v. But the transformer I have is 220v-12v so that's cool, I guess.

That's OK. The voltage rating matters. The only issue once you have the correct voltage specification is whether the wire resistances will make the voltage sag too much under load. For this, resistances matter.

Is there any difference between building your own diode block and buying one?

No. As long as you hook up the diodes correctly, it works electrically. The diode block just makes wiring quicker and easier.

And are 1n4001's the only diodes that could be used in diode block?

No. Any diode intended for rectifying AC to DC or general purpose diode which has a current rating of 1A or more, and a voltage rating of more than 50V should work. The 1N4001-1N4007 series all work OK.

Why does this Russian schematic requires different capacitor values?  Also here, different values and the overall capacitor quantity

It's designed for different loads and/or ripple suppression. Read "Power Supplies Basics" at geofex.com for how to calculate the minimum capacitance for a given load and ripple voltage. Each designer decides how much capacitance is enough. More capacitance provides more filtering, but costs more, is bigger, harder to wire, etc. The additional small capacitors in parallel with the main one is a practice from hifi insan... er, I mean hifi extreme practices. It may or may not help with musical instrument stuff, which is in general more realistically designed.

[JebemMajke]

Thanx.

Ps
Russian used 7809 and spyder 78l09. Why? I mean wil the L version melt or stop working?

[amptramp]

This:

http://www.duncanamps.com/psud2/index.html

may help you design and understand what is going on with any values you choose.

[R.G.]

Russian used 7809 and spyder 78l09. Why? I mean wil the L version melt or stop working?

The 7809 has an internal current limit at about 1.0A and comes in a TO-220 package to get more heat out. The 78L09 has an internal limit of 0.1A, and comes in a TO-92 package for compact circuits, but cannot dissipate as much heat as the big brother.

[JebemMajke]

Ok, another thing. My transformer has 3 wires at secondary, 1 black ( ground ) and 2 orange. Can I use them with 2 780l9's to put out + and - 9v?

Ps
I will be using this cable , which is the same cable amps and PC's require. It has 3 lugs ( as you may already know ). How should I wire them, for my transformer has only 2 wires coming from primary?

Pss
Do i need the fuse switch, and what does it do?

[PRR]

> How should I wire them, for my transformer has only 2 wires coming from primary?

PLEASE get _local_ *qualified* advice about connecting to 220V wall-power.

This is deadly and dangerous stuff. Electrocution, or burn the house down.

Also, many/most of the folks here have never seen that type of plug. I have, and I could tell you, and I could be wrong.

It might REALLY be better to BUY one of the several brands of power supplies, pre-made and tested to _your_ country's electrical needs and rules, than to roll your own.

[darron]

It has 3 lugs ( as you may already know ). How should I wire them, for my transformer has only 2 wires coming from primary?

Pss
Do i need the fuse switch, and what does it do?

Not to sound insulting, please don't take it that way, but the fact that you're asking how to wire up an IEC plug/cable really worries me (us). Like PRR says there are many safety concerns for more reasons than I'd like to list (I don't want to make a half-arsed list).

The yanks aren't always as familiar with the 3 pin power plug. In Australia they are absolutely mandatory (I've never seen a 2 prong power point in my life!) and all metal bodied appliances must be Earthed, or in the case of a plastic device (say a video player) live wires must be double insulated.

The Earth lead connects the enclosure of the device to our Physical Earth (look down). This is the most important lead. It must be mechanically double secured to the metal enclosure of the device. I say double, because you will use something like a nut/bolt as well as a cerated washer and nylon gripping nut and/or some locktite.


The active and neutral wires L1, L2 will go to the two primary windings of the transformer, the 220/230/240V side. edit: it shouldn't really matter which way around.

Should an active (live!) wire internally touch the casing accidentally, it should (hopefully) short to the Earth line and trip your circuit breaker rather than the whole device invisibly turning into an invisible electrocution death machine when somebody picks it up. Assuming your power point is wired perfectly too of course




Please follow up with some lots of safety reading before attempting this project. Remember that it may change hands to somebody else one day, so if you decide to build to do it perfectly (:




As for a fuse, you shouldn't need one. Some transformers have internal fuses. As long as you don't get any shorts between the tiny gap from the IEC power lead to the transformer there's not much that a fuse will help with except being something to break down. Most transformer packs don't include one as the secondary of the transformer is an inductive load and is electronically isolated from your mains.

[J0K3RX]

BTW, don't mistake black as ground... you probably have have two 120v (orange-orange) wires and one neutral (black)... not ground! Green is ground here in the US, don't know about Serbia? You can use just one side of your 240v and you can get 120v. You shouldn't have ground if you are using a transformer since it would be isolated by the secondary.

Edit: oops read it wrong, i see you said the orange\orange\black are on the secondary... my bad! In any case be very careful or you might be jammin on the other side if you know what I mean!

[JebemMajke]

Ok, here goes.

@ PRR
3 pin power plugs are the usual stuff in Euorpe, but we also use 2 pin plugs so I assumed that the 3 pin originated from your country. My bad

@darron
"The active and neutral wires L1, L2 will go to the two primary windings of the transformer, the 220/230/240V side. edit: it shouldn't really matter which way around."
Thanx for the info. The third lug is not connected, right ( the middle one )? How about three wires from secondary?
Ps, I was afraid of accidental "wire-touching-the-enclosure-and-the-certain-death-of-me" so i went with plastic enclosure for this project.

@J0K3RX
I will

[darron]

Green is ground here in the US, don't know about Serbia?

green, green/gold should be the international standard. period.

Thanx for the info. The third lug is not connected, right ( the middle one )? How about three wires from secondary?
Ps, I was afraid of accidental "wire-touching-the-enclosure-and-the-certain-death-of-me" so i went with plastic enclosure for this project.

i'm not sure which transformer you are using, but the chances are very much that the middle one is a centre tap.
on the primary there might be an allowance for half voltage input (110/120v). if that's the case you'll use the outer ones.
on the secondary if the two outer wires measure 12v then you could expect the centre one to any outer one to measure 6v. so this wouldn't work to make 2x outputs.

before assuming this though, naturally, it would be wise to check the manufacturer's specs. do you have a diagram or data sheet? don't make assumptions on my (possibly dodgy) advice.



that's cool if you're using a rugged plastic enclosure. you won't need the earth or really an IEC style lead. just make sure you use some heat shrink to insulate all the live wires on the powder socket and to the transformer primary. and the switches/fuses/whatever you decide to put in with it. a good way to get around all this mess is to just use a standard pre-made wall plug pack and make a little plastic regulator/filter box to go along side it. then you have a safe supply and your own DIY super filter. also, all the dirty AC hummy mains would be miles from your pedals (:

also, just noticed in your diagram you're only switching active. that's okay, but not acceptable practice in some parts where both active and neutral are switched.

[R.G.]

Let me restate, with emphasis what Paul said:

> How should I wire them, for my transformer has only 2 wires coming from primary?

PLEASE get _local_ *qualified* advice about connecting to 220V wall-power.

This is deadly and dangerous stuff. Electrocution, or burn the house down.

Also, many/most of the folks here have never seen that type of plug. I have, and I could tell you, and I could be wrong.

It might REALLY be better to BUY one of the several brands of power supplies, pre-made and tested to _your_ country's electrical needs and rules, than to roll your own.

This is somewhat like the story of young boy-becoming-men in Africa being given a spear and told to come back with the tail of a lion. The ones that come back are smart, fast, and quick learners. The others... well, lions don't waste much, and the hyenas and vultures clean up. You really, really, really want the advice and training of an older, more experienced person to tell you how to do your first several tries. Electricity is even deadlier than lions, because it's 100% invisible, and can kill you faster. Worse, the resulting fire can kill everyone in the building with you.

This is not meant as criticism, only advice. Your postings show that you don't have training in how to do AC power wiring safely.  We WANT you to live and make music as well as electronics. The whole body of advice of electrical safety training is really the accumulated writings of people who survived their first encounters with electricity, or who looked at the remains of those who didn't.

This is not a joke.

[JebemMajke]

This is somewhat like the story of young boy-becoming-men in Africa being given a spear and told to come back with the tail of a lion.

Loved it

Already talked to the experienced older guy ( sounds sick xD ). Middle is not connected, unless i want to make it a bit different, he gave the schematic should I decide to try and make it his way.  The transformer I've picked gave 10.4V instead of 12v. So I'm on a "hunt" for bigger transformer

Ps although I'm trying to be funny and all I'm really grateful for your comments, concern and help.

[darron]

Since you're already on the hunt for a transformer, maybe consider my idea of a regular wall transformer plug pack and building a small filtering device to go at the pedal end so you're only sending low voltage AC to your pedal board area. I've done this a few times, not only for safety and noise, but also to work around with safety laws.

[Jdansti]

Since you're already on the hunt for a transformer, maybe consider my idea of a regular wall transformer plug pack and building a small filtering device to go at the pedal end so you're only sending low voltage AC to your pedal board area. I've done this a few times, not only for safety and noise, but also to work around with safety laws.

Yes Yes Yes!!!

This is the way I do all of my power supplies. Use a plug-in transformer that has been manufactured to be safe, and use the 12V (or up to approx 30V) AC output to power your converter. The obvious issue with this approach is you don't have multiple secondary outputs as shown in the Spyder scheme. Are the isolated secondaries a requirement for you?  If so, maybe someone on the forum can help you achieve the same effect with just one secondary.

Having said all of that, if you're set on going forward with your original plan, have your local expert inspect the finished product for safety before using it. I'll repeat, you don't want to risk your life, someone else's life, or burn down your home!!!  It's not worth it!!!

[JebemMajke]

Regulated to 8.98v

220v-14v ( well it was 13,98v to be precise ). From than on I've followed the Ruskie schematic ( I had 4700uf,330nf and 100nf on my desk ). Tomorrow I'll add on/off switch. Do I need a heat sink? You know plastic enclosure and stuff, don't want a puddle of black plastic during one of the shows.

[darron]

the regulator IC should have internal thermal cutoff protection. so if you're drawing too much current and it gets too hot it will automatically start cutting in and out. a heatsink will let you dissipate more heat off it so that you can draw more current without shut-off. the current rating on the IC (1,000mA?) will be with a decent heat sink, but otherwise you should get a good amount without it.

it won't make the inside of the enclosure cooler though, unless it is external i guess. the old regulated boss power supply had the transformer and regulator right beside each other in the plastic enclosure.

you'll have to post a picture for the experts here.

[PRR]

> I assumed that the 3 pin originated from your country.

It may have been. The idea and basic shape goes back to ~~1923. Also the idea: no shock when you touch both a lamp fixture and a ground such as a heating radiator.

3-pin was uncommon in the US in 1960, normal in the 1970s.

The UK and Germany (and places influenced by them) use different plugs than the US. I have handled a BS plug and know what each pin does. I have not handled a Schuko (which seems to be what you have), and apparently it still comes in several forms (though converging on an EUR standard).

"Ground" does not necessarily mean "dirt". For inside wiring in houses with plastic plumbing, we do not care what voltage the dirt is. Yes, one wire from the street is tied to "the groundING" system usually including a dirt-rod. But the place this connection is made varies a LOT in different places.

I just wired my garage. The US has had rules about out-building wiring for decades, and yet the rule detail has changed since my 2005 NEC was printed. Electrical rules are often, like lions, a moving target.

In the US, we pretend there is a difference between White and Black. We wire white to our dangerous lamp-shells, black to the slightly less accessible tip contact. (However in my last house, 60% of outlets had white and black reversed.)

Schuko has historically treated the two pins the same, because the plug could be inserted either way. And the ground tab/contact/ring/pin is more recent and not entirely harmonized.

In your area there was Russian influence and perhaps some use of GOST 7396. GOST is transitioning toward the EUR standards. But as I know from living through several outlet-standards changes, you don't get all new (and correctly wired) outlets or plugs by magic. It takes time.

Every country has some local electrical industry which wants to be protected against competition from other countries, and lobbies for local "standards" which only they can supply.

And Denmark and Japan do things very differently.

> accidental "wire-touching-the-enclosure-and-the-certain-death-of-me" so i went with plastic enclosure

But you still have jacks. And transformer insulation can fail. Under most US electric rules, *all* touchable metal MUST be tied to the groundING system.

It's not just shock. You think it is only a 12 Watt device. However if there is a short, "infinite" current and power will flow. Yes, the house fuse will soon stop any large current, but not instantly. A short at my house can, for a very short time, deliver 240,000 Watts. This is like a hundred room-heaters!! While the power will appear in all the wires from street to short, a worst-case could make most of that power appear in a few inches (several cm) of wire. It will vaporize copper, spray molten copper, and give your eyeballs a bad sunburn. Yes, even if only a part-second before the house fuse blows.

[JebemMajke]

1400 mA. And 4 outputs. It had 1800 mA before the regulator

Pictures will have to wait, camera on my phone is dead.

[JebemMajke]

It's been some time now and this thing works great. In the mean time I've found a 27,8 v transformer with 0.7 A. I was thinking about using 3 different regulators to have 24, 12 and 9v. But, I'm not sure if 0.7A would be enough for three pedals at once. What do you think?