car stereo mains

Hi, Will. A transformer won't cut it -- transformers put out AC (alternating current) voltage, which will ruin your car stereo instantly. It wants direct current.

You're looking for a 13.8VDC bench power supply. Since you didn't mention the power requirements of your car stereo, and you're on the other side of the pond, I'd suggest you look at the bench supplies from Maplin, and pick one:

If you know the wattage of your car stereo, just divide by 13.8 to find the current requirement. (e.g. 60 watt stereo means 60 / 13.8 = 4.35 amps. And, for car stereo use, be sure to size the power supply for continuous duty (it will be on and at volume for more than a minute). The biggest of these is only rated for 7 amps or 96.6 watts (13.8V * 7 amps).

The ones with current foldback protection are helpful if you're repairing car stereos, or there's a chance of an accidental short circuit.

If your stereo is more than 100 watts, you can look around and google something under "13.8V bench power supply". Try to get a "linear" or transformer-based supply. Units over 100 watts pretty much have to have a fan, which might be annoying.

I had a great car stereo on my workbench with a 13.8VDC bench supply for many years.

Good luck Chris

Excellent. Thanks very much.

The device you want is called a DC power supply. You will need to determine the current your car stereo requires, and get a power supply that can deliver at least that much.

--
Peter Bennett, VE7CEI  
peterbb4 (at) interchange.ubc.ca  
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
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** First off - use "googlegroups" correctly.

Do NOT simply hit reply !!!!!!!!!!!!

Hit "options" and then "reply".

That way we can see who you are replying to and about what.

• Verrrrrry simple.

Use a good car battery and a charger to keep it topped up.

The cheapest & best way.

A DC supply that can do as well costs MORE than your POS stereo.

...... Phil

It was a general reply.

Phil Allis>

Hi, Will. Sorry about that.

I suppose the "elite" here have some unofficial rules, which us groundlings from Google Groups must follow. Most of it has to do with conforming to standards which will simplify things for newsgroup readers.

1) Always apologize for being a groundling. We are indeed children of a lesser god, and not worthy of taking up space on their store-bought newsreaders.

2) In Google, you click on the "show options" link at the title bar of the post, then click on "reply". That will give you a formatted post with the entire previous post already shown (with the > character preceding each line, allowing the newsreaders of the gods to optionally obscure it). In days of yore, when 1200 baud modems ruled the earth and bandwidth was an important consideration, it was considered bad form to include all the stuff which had preceded. You just included enough to keep the conversation going. However, it's still considered good form to do some editing if it's getting long.

3) It's considered good form to bottom post. This allows the person who's seeing the post appearing out of nowhere to follow the thread. That merans putting your response after the prior post, even if you have to summarize.

4) Execeptions to 2) are typically made in cases of general short responses like OK, thanks, "plonk", &c. Yours was one of these, so I'm not sure where the other post is coming from.

There are also unofficial rules relating to common courtesy. Groups which cater to newbies are assumed not to have people waiting to ream them for their ignorance. If they wanted that, they didn't have to post on a newsgroup -- they just could have gone to their mother-in-law and asked her.

My bench stereo was an OEM from "the best car I ever had" -- a comfortable, loyal little Toyota Corolla that lasted forever. The 20 watt OEM stereo lasted for more than a decade after the car wore out at almost 200,000 miles. It cheered me up quite a bit, not least because it had wonderful signal sensitivity, and good fidelity. The original owner paid a good price for the stereo upgrade. It was even easy to repair. A remarkable example of good engineering. Or, as the other post would say, a POS stereo. Whatever.

Cheapie Automotive battery: 22 pounds Cheapie charger: 11 pounds Total cost 33 pounds

Maplin XM20W 2 Amp Continuous 13.8VDC Bench Power Supply: 15 pounds Total Cost: 15 pounds

Not only that, but you don't have to worry about disconnecting the charger during use, and reconnecting and recharging after use. The battery charger typically puts out around 15 to 16VDC, which stresses out the stereo if it's running hot.

The economics change somewhat for higher wattage stereos, but there are other considerations. Running a stereo at 100 watts is a lot like leaving your headlights on. Your battery will deep discharge fairly quickly, which really isn't good for automotive batteries. You might improve on this by placing batteries in parallel, but that doubles or triples the cost, and has it's own set of problems. If the batteries are not perfectly matched, the one with slightly higher voltage will be doing most of the work, and will want to charge up the lower voltage battery. Not an optimal solution.

Of course, if you're just repairing stereos, it _is_ more economical to pop a battery, put in a series fuse, and have at it. No cost at all, and after your stereo is repaired, just put the battery back (recharging if necessary). No cost at all. But I didn't get the impression you were repairing.

Again, sorry. S.e.b. is supposed to be newbie-friendly.

Good luck Chris

--
No, they\'re just guidelines which we should all follow in order to
make life a little easier for all of us.  The recent problem has
been that with the advent of Google groups an ever-increasing
number of the truly clueless has invaded Usenet, to the detriment of
all.

Phil Allison is _definitely_ not one of the "elite" here, no one
really is,  and his behavior is far from what you might expect from
the rest of us.

you can't blame Phil. He is annoyed at me for being a Pomme. His grandfather was a rapist.