Kitsrus bipolar power supply - any comments?

[simonkibble]

Hi again all

The DIY bug has really bit now, and I am thinking about having a go at building the transformer coupled splitter from geofex. I'd like to build it with a genuine 9v bipolar power supply using a centre tapped transformer rather than use batteries or a charge pump (just so that I can say I have made one!!) and I've found this kit online

http://www.quasarelectronics.com/3083-5-18vdc-1a-universal-dual-polarity-power-supply.htm

which uses this pcb

http://www.kitsrus.com/jpg2/k83_pcb.jpg

Anybody have any experience with this supply? I'll most likely be using a transformer from Maplin, as they have a suitable 12v centre tapped transformer off the shelf.

Thanks

Simon

[smallbearelec]

If you do this, your biggest concern has to be the mechanical and electrical setup of the primary connections to the transformer. You will need a 220-volt power entry module and line cord, and I can't help you there; I only do 110. Also, if you have never done wiring to the AC mains, Get Knowledgeable Help! You don't want to be the subject of an obit in the Times, and AC power wiring offers Mother Nature numerous opportuinities to knock you off. I expect that R. G. Keen and others may show up here and say the same, but in much greater detail.

NB: I think that if you want, for example, + and - 9 Volts, you will need a transformer with a 24-volt center tapped secondary. Please confirm this with others here.

If you want to pursue this with greater safety, I would consider getting the AC input from a couple of plug-in wall transformers. Much easier to work with and already short-circuit protected.

Regards
SD

[simonkibble]

Hi Smallbear...

Thanks for your comments - and don't worry, I'm surrounded by some very experienced electronics builders so I wouldn't be tackling anything using 240v mains without some serious support! One of my friends works for our power supply companies, installing power meters, fixing 3 phase supplies, etc... what he doesn't know about mains safety probably fits on a very small postage stamp! Seriously, I am going to make sure that the transformer side of things will be very very safe. Maplins over here sell a suitable centre tapped tranny -

part #N64JB which is a 24VA 12 - 0 - 12v 1A transformer (http://www.maplin.co.uk/Module.aspx?ModuleNo=454504)

and I will ensure that everything is properly isolated and fuse protected in the case I end up using, based on advice from my properly qualified buddies....

I suppose I was really asking about how 'quiet' the supply on the dc side was likely to be, after the rectification of the ac based on the pcb design. It looks like it might be pretty good but I am still working on getting my head round the geofex article and beating my maths back into shape to deal with the equations! Was hoping somebody might have practical experience of that kit being used to power effects before I parted with my cash!

Btw - your weber multi - secondary transformer is on my shopping list for a spyder build soon too!

Regards

Simon