I am new to DIY. Please help

[boxedin]

Hi,

I am new to DIY..

I thought of making small Class A headphone amp to start with.

Before i do that i wanted to get a regulated powersupply. Buying powersupply is expensive with different voltages.

I need voltages of 9v,12v,15v,24v,30v,35v ranges with 5A rating.

Is there a good working regulated powersupply design already available with regulator IC?.

Anyone have done it?

Let me know. That will be my first project before amp.

Thanks
Alexk
toronto

[lineup]

That is best start when doing DIY.
To get yourself a good Lab Power Supply.
With selectable voltage output.

LM317 is a good and easily found IC.
You can get voltage output upto like 25-30 V
And is possible to supply at least 1.0 Ampere of current, with a proper heatsink.

Here is a link to one such project:
http://www.seattlerobotics.org/encod...e.html#Circuit

At that page you can also download the LM317 datasheet in PDF
to see some ways to use this IC.

Here is the circuit in that project:
http://www.seattlerobotics.org/encod.../schematic.pdf

I am sure there is some such projects at this site, before.
I just couldnt find it.
Search can be:
lab power supply
or LM317

[amplifierguru]

Hi boxedin,

As lineup says but you will likely need -ve supplies as well so you can use an LM337 negative reg for up to 1A.

Alternatively an LM338K will take you straight to 5A and if you build a dual (floating) positive reg according to the datasheet, you can join GND of one to output of the other for a +/- Vs using just +regs, which generally offer better performance.

Discrete can be better again.

Cheers,
Greg

[lgreen]

Hi, you have selected a good first project. First build an LM317/337 power supply using the datasheets. If you use the adjustable devices you can simply switch in resistors or use a variable resistor to change the output voltages. use the circuit on the datasheets at national.com. The circuits are very simple and work great.

Edit- using heatsinks you can approach 5A rating, but this is kind of high.

[poobah]

Here's another approach...


http://cgi.ebay.com/BK-Precision-160...QQcmdZViewItem

[boxedin]

I have gone through various design from DIY forum links. Most of the designed to drive the amp with single voltage like 40v.

What i need is Multiple output Powersupply with max 5A rating.

I am planning to build AR3 then followed by AR20 amps from this site.

AR3: http://www.rudistor.com/sound%2Dlab/ar3eng.htm
AR20:http://www.rudistor.com/sound%2Dlab/ars20eng.htm

There is a thread mainly for that Headphone amp this site.


Here is some dedicated power supply design(only 24V).
http://www.tcaas.btinternet.co.uk/jlhnewps.htm
http://www.tcaas.btinternet.co.uk/jlhlm3x7cb.htm

http://users.verat.net/~pedjarogic/a...e/supplies.htm


Anyway if anyone have super duper Powersuppy design with multiple outputs (kind of lab power supply). Let me know.


Thanks
AlexK
Toronto

[lineup]

This the Pedja Rogic supply

If you look at LM338T there is a PIN called Adjust.
To that pin is C1 and a 2.2K resistor connected.

When you change the value of this resistor, output voltage change.
If you put a variable resistor, Potentiometer, instead of 2.2K
then you can ADJUST to whatever voltage, within the limits of LM338T.

More info and data:
LM338 1.2 to 32V 5A positive power supply regulator
Datasheet download:
http://www.national.com/ds.cgi/LM/LM138.pdf


If you build two such adjustable circuits
and use one of them as the negative voltage,
you get a positive+negative Power Supply.

Max output will be, 2x32V 5 Ampere.
this is a total voltage of 64 Volt, if used as a single output.
In that case you set ground, 0 volt at the negative output.

[Pingrs]

Switchable current limit comes in handy, too!

Brian.

[lineup]

Originally posted by Pingrs
Switchable current limit comes in handy, too!
Brian.

Yes, it is a good thing.
A little simple current sensing circuit with output to a couple of relays,
that can switch off, in case too much current.
A few transistors and some resistors is all that is needed.

For a new DIY-er it might be better to leave out this more complicated advanced stuff.
Better to get some learning the cruel way ... overload and burning smell
... or maybe I am totally wrong here

[amplifierguru]

Hi lineup,

...."This the Pedja Rogic supply".............

that's the one I had in my head. Didn't know it had a name.

Cheers,
Greg