Here is a link on how to convert a computer ATX power supply to a lab power supply:


http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply

 

Doubtfull that you'll need fans. You have to have a heatsink on the regulator though !

 

You have to have a heatsink on the regulator though !

Is that a must? The circuits only powering the few LEDs, and they won't be on for long periods of time.

 

yes, even for fairly low currents the regulator can heat up substantially. It does have a thermal shutdown feature i think but it's standard to use a heatsink.

 

Ok cheers, I'll install one of them aswell.

Is there a 'better' type? I've been looking on Rapid and there's some brass ones, for about 27pence I think.

 

Copper is one of the better materials to use.

Aluminum is about 60% as effective as copper, but by far the most common material used as it is lighter and less expensive than copper. Some CPU heat sinks are all copper, or a combination of copper near the CPU and aluminum for the fins.

Use a small amount of heat sink compound between the heat sink and the regulator.

Note that the "tab" on the regulator is connected to OUT. Be careful to not short the heat sink against anything.

 

There is a cheaper method still scrap a couple of thrown out old amplifiers house hold amps which are capable of delivering 35 watts to 50 watts rms Plenty of these in the bins these days Use the transformers from these and the bridge rectifiers smoothing banks , regulators and you save yourself a fortune In most cases these will be ample to handle your current needs and then use Sgt Wookies Idea of LM317 or using a fixed voltage regulator LM7812 LM1715 depending on the voltage output you want and a bypass current transistor for obtaining the current that you require a bit of maths involved there but quite simple to do
Again there are untold circuits for this on the web You could also use op amp driven supplies with voltage and current feedback so that you can build in over current protection and over voltage protection If you really want to get clever with this you could even monitor voltages using Pic Micro with your very own LED display , design in to this automatic switching for your XLR inputs so that you only feed The XLRS via relays as and when required but that’s time and quite extensive knowledge

 

Nice idea Harrington. But I don't have any old household amplifiers etc about. In our household we tend to get rid of them the minuite they stop working.

Cheers to SgtWookie and Steinar96 for their replies about the heatsinks. I've gone with the brass one, as judging by the image on the Rapid website, it's made to fit the regulator just right. I'll be careful not to short it on anything. I'm also concerned about the copper touching the plastic of the box the circuit will be housed in. Obviously this won't short it, I'm concerned of heat melting the plastic slightly. However, I need not worry yet as I have got neither of them yet.

Going back to the fans, the mains one I've pointed out, would it be ok to connect it directly to the mains input? I'd like to use one as it's just and extra bit of cooling inside the main power supply unit, it saves me having to drill about 10 indervidual small and ugly holes in the box enclosure. that the method I have says to do. I think it's a bit more 'attractive' to replace the holes with the one fan.

H.