Can someone point me in the direction of a design for a cheap/simple 12V DC - 6V DC voltage converter/power supply.

I want to test out my idea of using a standard DAB tuner in-car. I've bought a Matsui DA-1 DAB Radio Adapter (basically a DAB radio without speakers).



In some ways it is perfect for the task:

- it was cheap (£60)
- it is small (and its inerds smaller still)
- it will require less ripping apart to make it fit somewhere in the dash

It has some downsides:

- it doesn't have and buttons on the unit itself, it is all controlled from the remote (even the power on)
- it doesn't start playing as soon as power is applied (you have to turn it on via the remote)
- it doesn't have an antenna socket, but maybe I can extend the length of wire that is uses ?

It has a 6V 500mA power supply, so I need to knock up something to turn 12V in car power into 6V so I can test it out. I guess I could just wire two resistors across the supply and take my power off the middle of them (I'm sure that isn't a recommended long term solution though)

Regulated Car Power Adaptor



Maplins L17AR £7.99

That looks perfect for testing.

However, I still need a power supply design if I decide to install it permanently.

You could crack the adapter open and wire it in directly with an inline fuse.

The 7806 voltage regulator should do the job - the usual places should stock it. They do tend to get warm but nothing a heatsink can't sort out.

Gareth

Beware how much current the adaptor can deliver vs how much the receiver wants.
Also beware of the regulating properties of some cig.plug adaptors... some are nothing more than a set of diodes that gets put inline on the + wire, each dropping about .7V, but exact drop depends on current drawn, the adjustable properties being the number of diodes getting pur in series. They typically work fine for stuff that normally runs on batteries (as they're normally designed for a fair swing in supply voltage - fresh vs almost dead batteries), but might be harmful for items expecting a better regulsted voltage....

I would imagine that because it says regulated it actually does contain a voltage regulator. I know the one I bought from Maplin a while ago did, albeit a different model at a similar price.

There is a gadget that the classic car guys use after installing a 12v alternator in a 6v car.

So, for adapter, read tuner: Is it any good? I've gone over to freeview for most of my recording/listening, which is as cheap as this and adds in TV channels. But I do like BBC 6 and 7.
I was tempted by the write up of this until I saw the price. You could buy three cheapos for kichen, bedroom etc. for the price of this thing and at £200, car units are going to freeze it out.

I think it is a pretty good choice if you just want a tuner and are in a good reception area. The tree biggest minus points of the device are:

- no buttons on the device itself (though the supplied remote is decent)
- antenna is just a length of wire, with no socket
- you can't turn the display lighting off (is has a good blue lit lcd display)

The sound quality is as good as any DAB device that I have heard. At £60 it is the cheapest DAB tuner I am aware of. I think it looks quite good as well.

You could look at www.sunpower-uk.com