Hi all, I bought a Velleman K4003 stereo amplifier kit from Maplin, along with a VS15 Toroidal Transformer. My question is how to wire the transformer up. The transfomer details are; Primary 2 x 115V Brown/White - Black/Pink Secondary 2 x 12V @ 2.08A red/Yellow - Blue/Grey I know that the primary side needs to be connected to the mains, and that the secondary gets connected to the power inputs,however I have no idea which colour of wires are ground, or powered etc for either side and which are AC live, neutral etc. I take it that there would need to be a fuse on the AC side, how should this be wired ? Any advice would be greatly appreciated. Many thanks Ewan Mackie
ok, your going to need a bit of knowledge on power supplies for this one. Firstly you are going to have to connect up the two primaries in series for the uk mains voltage. since 2x 115V = 230v. To add a fuse, you will need to do this in-line with a wire on the primary. either one of the wires you are using to connect up to the mains will be fine. OK, your next big problem is that you can't just connect this transformer up to the amp, because the amp will be expecting a smooth DC signal. The Transformer will just provide an unregulated AC signal. which brings me onto my next point, your going to need to regulate this transformer. this is because when there is no load on it the voltage it produces will be above its rated voltage. when a load is applied this voltage drops, which can cause problems to your ic's and other components. Therefore a circuit is required to regulate this voltage. I can tell you how to wire up the transformer and rectify the AC signal to a smooth DC on, but i'll have to look up a decent regulating circuit, since i forgot that part of my a-level in the last few months. i think a zenor diode and power transistor had something to do with it, but i'll get back to you. in the mean time if anyone else has a design, then go for it
ooopppppssss, i have now gone and actually checked out what the k4003 actually is, and it turns out that AC is what this circuit wants. sorry bout that. i just assumed it was simillar to my k4004 amp, which needs DC voltage. so all you actually need to do is wire the primary together, and add a fise into one of the wires going into it. Hope this helps and good luck
But you need to wire the 2 primaries in series with the right two colours connected together, and line and neutral to the other two. Instructions with the transformer should give you the colours to connect for series or parallel primary.
Thanks for the responses, My problem is that the transformer did not come with any info as to what the colour coding is. All that is printed on the box (and the transformer is; Antrim Transformers TYPE C7012 MAPLIN PART No. VS15 DATE 3/02 Prim. 2x115V BROWN/WHITE - BLACK/PINK SEC. 2x12V @ 2.08A RED/YELLOW - BLUE/GREY Any advice would be great. Thanks again MacBriar
ok, here is your answer i got this pic for you. all it needed was a traul of google so, all you need to do is put the brown wire to the neutral (normally blue) pin of the plug, connect the black and white wires together, and connect the pink wire to the live (normaly brown) pin in a plug. if you want an inline fuse the put it in line with the pink wire. Stick the whole thing in a box before you use it, and if its metal, EARTH IT. hope that sorts you out. tell us if everything works Oh, i'd better put this in. DISCLAIMER - I AM NOT RESPONSIBLE IF THIS DOESN'T WORK. I'VE DONE MY BEST. BLAME THE TRANSFORMER COMPANY!
oh, i've just realised that its a bit different to yours. i promise that this is a pic for the 2 x 115V primarry with a 50VA rating. this difference in the secondary wiring is probobly because this pic is for the medical rated version. i think you'll be safe using the secondary as it says, just with the yellow wire instead of violet. if your unsure then just test the output with a multi-meter when its powered up
