L1 &L2 are constant current loads. Just there for the simulation so you can get an idea of the ripple voltage and ripple current in the caps and such. You bridge should be more than good enough, but we might find one cheaper.
Yes the pass transistor is the way to go. This really wants to be a switching power supply but this can work.

What do you mean by switching supply? After some thought, I think I could live with 2-3 amps. If I understand the example from the 317 datasheet right, I could use only 2 317's with pass transistors on the +v side and get between 3-4 amps of current, and I should only need 1 on the -v side correct? I cant see me needing more than 1.5-2 amps for -v right? If I use the bridge rectifier I already have (the mb354w) how would I connect the transformer for the +v side and the -v side and still use the center as gnd? and would the center be gnd or 0v ? Thanks again for tolerating my million questions. I think after all the thought and assistance here, I have finally came down to earth and finally settled on a realistic setup that will suit my needs and then some.

 

I already provided a lots of infos but you seems didn't see it as #26

Sorry, it seems that did get by me.. thanks

 

Power Supply 1-30V 10A with LM317.

Circuit 10A Variable Power Supply Symmetric - LM317,LM337 current expanding, you can change the NPN transistors which you can get.

 

Switching regulators are what is used in like PC power supplies. Unlike linear regulators they are very efficient. One way to look at it is that they only turn on when they need to. Here is an example of one you might be able to use by repacing the trim pots with potentiometers.
http://www.ebay.com/itm/DC-to-DC-co...854?pt=LH_DefaultDomain_0&hash=item4acc08bdd6

The trouble with the datasheet circuits is that a lot of them assume a small voltage drop or a huge heat sink. If I were you and wanted to build my own I think I would use the pass transistor for both the plus and minus supply. But I'm just a symmetrical kind of guy.
In the set up I showed the center tap is ground. The minus output from the bridge goes to the negative supply and the plus output for the positive supply.

 

Switching regulators are what is used in like PC power supplies. Unlike linear regulators they are very efficient. One way to look at it is that they only turn on when they need to. Here is an example of one you might be able to use by repacing the trim pots with potentiometers.
http://www.ebay.com/itm/DC-to-DC-co...854?pt=LH_DefaultDomain_0&hash=item4acc08bdd6

The trouble with the datasheet circuits is that a lot of them assume a small voltage drop or a huge heat sink. If I were you and wanted to build my own I think I would use the pass transistor for both the plus and minus supply. But I'm just a symmetrical kind of guy.
In the set up I showed the center tap is ground. The minus output from the bridge goes to the negative supply and the plus output for the positive supply.

Ive attached a schematic scottwang has shared, It seems like this is exactly what I want. How is it capable of such high currents? are switching supplies really that efficient? I feel this would be a great starting point and will work well with my transformer and rectifier.

 

If you want to get a image clearly then you have to press on the circuit diagram, it will shows an enlarge image.

If you want to get a good rating for the ripple voltage, then you just don't think about the switching power, because you will got the nightmare when you try to do the audio experiment.

 

It's a good starting point. See if you and Scott can make it for 2 or 3 amps.

 

its supposed to be rated for 10 amps already... is this not a good idea or was I better off on the track I was on?

 

The following listed are what you just using the heatsink for each 2N3055 that it only needs about 50mm*50mm.
If you using the LM317,LM337 and 2N3055, it will be like this:

2A - LM317*1, 2N3055*1
4A - LM317*1, 2N3055*2
6A - LM317*1, 2N3055*3
8A - LM317*1, 2N3055*4
10A - LM317*1, 2N3055*5

2A - LM337*1, 2N3055*1
4A - LM337*1, 2N3055*2
6A - LM337*1, 2N3055*3
8A - LM337*1, 2N3055*4
10A - LM337*1, 2N3055*5


The following listed are what you have to using the heatsink for each 2N3055 that it needs about 100mm*100mm,If you using the LM317,LM337 and 2N3055, it will be like this:

3A - LM317*1, 2N3055*1
6A - LM317*1, 2N3055*2
9A - LM317*1, 2N3055*3
10A - LM317*1, 2N3055*4

3A - LM337*1, 2N3055*1
6A - LM337*1, 2N3055*2
9A - LM337*1, 2N3055*3
10A - LM337*1, 2N3055*4 (each 2N3055 for 2.5A)


The following listed are what you have to using the heatsink for each 2N3055 that it needs about 100mm*100mm, and plus fan.
If you using the LM317,LM337 and 2N3055, it will be like this:

5A - LM317*1, 2N3055*1
10A - LM317*1, 2N3055*2

5A - LM337*1, 2N3055*1
10A - LM337*1, 2N3055*2

Although I saw some one did it as above, but I don't want you to do it now, it just let you to know, maybe someday in the future that when your skill and knowledge are enough to do.

 

its supposed to be rated for 10 amps already... is this not a good idea or was I better off on the track I was on?

Don't believe everything you read on the internet.

You guys should do the math for this one.

This is a better path.

 

Don't believe everything you read on the internet.

You guys should do the math for this one.

This is a better path.

haha.. I don't always believe everything, just new to this and thought that there was something special the power transistor was doing to increase the current. So was I on the right track before? I am working on a schematic of what I think im going to build. Ive always been hands on and this planning and drawing thing is killing me, Im about to just build it and then make the necessary changes.

 

So I need the 337 to do the -v, do I need a pnp transistor for the pass transistor on those and an npn transistor on the 317's for the +v?

 

Like Scott's schematic. PNP positive NPN negative. But use the 2N3055 for the NPN and the one I suggested as the PNP. I'll simulate it for you after you draw it up. That will give us a better idea that it might work.

 

im trying to learn ltspice, Is there a way to choose a rectifier with it, or do I have to use diodes? I seen it in your schematic you posted and thought I would try it. it seems like a nice program, I try to use eagle sometimes.

 

They have several diodes in the built in library, but no bridges that I am aware of. You can probably download some from the LTSpice users group but I usually just use the right sized diodes instead. It takes some experimentation to use it but it helps with the basic design. It won't keep you from using components incorrectly but it will help you know the basic design can work.

 

What is an equivalent transistor to the pnp 2n2955? I want one that is like the lm317 not the kind in a round metal case. and what would be the npn equivalent?

 

If I understand the example from the datasheet, using the 2n2955 pnp power transistor as a pass transistor to the lm317t the total current is around 4.3a with the supply being 5.5v higher at the input than at the output. And the heat dissipation at full load would be 23 watts. So I could have 4a with a single 317 and 2n2955 with a decent sized heatsink. I could do the same with the 337t and the npn equivalent of the 2n2955 for the -v right? I forgot to mention that the 23 watts is at a full load of 25vdc

 

Hello,

The following transistors might interest you:
BDW51B NPN to be used with the LM337 negative regulator
BDW52B PNP to be used with the LM317 positive regulator
There are also some darlingtons:
BDW83B NPN to be used with the LM337 negative regulator
BDW84B PNP to be used with the LM317 positive regulator

Bertus

 

Whats the difference between a darlington and a transistor? Do they come in the 3 leg through hole style? If the case is the collector, how do you mount them or put heat sinks on them without shorting them? I would like to use the metal ones but I just don't understand how to use them.

 

Well, Here is a first draft of my idea. I think its pretty complete as far as my knowledge and using examples and schematics posted here. Im not sure if it needs anything else or if all the values are correct. Im still struggling with some things and the math part. check it out and give me some feedback please.