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willie_M
17-09-2004, 09:46 PM
Hey guys,

I got a tape/reciever out of my car (was replaced by CD) and I want to put it in my server box.

I have a few query's tho, and I don't want to be dissuaded into doing anything else. I want a car stereo in my server and thats that. I want strate answers here k?

A) PSU=12VDC, CAR ACCESORIES LINE=12VDC(or is it 3VDC?). Is the amp difference going to cause problems? I assume there is amp differences, one source starting a car, and one starting electronics.

B) OUTPUT. Is the speaker outs on the stereo going to blow anything its inputting to in my computer (be it, line in, audio jumpers, or aux in)?

Cheers,
Willie_M

tweak\'e
17-09-2004, 10:03 PM
only real problem is if your powersupply can supply enough power. check what the fuse rating is on the radio, DOUBLE it and make sure your psu has that to spare (thats IF you are attaching speakers directly to the stereo).

best way is to use the rca outputs from the stereo not the speaker outputs. however be carefull as some scar systems have 4 volt, 9 volt etc outputs which the sound card may not handle.

Pheonix
18-09-2004, 12:04 AM
Don't use the speaker outputs of the radio if the stated power rating is anything over 5 Watts. This is because the higher outputs had the 2 speaker wires above earth. Ground either one and kiss goodbye to your output chips. At best it will have no output, at worst it will happily blow 10 Amp fuses.
Generally, you can tell the low power versions as the have a wire for left, another for right and one common wire. (for the other side of the speakers)

Also if the volume is wound right up, even accidently, then it can damage your sound card.

Best deal, use the preamp outputs to connect to the sound card, if it has them. Also, as you are not driving speakers, then the power requirements will be low.

Things are never easy eh?

willie_M
18-09-2004, 12:57 AM
>Best deal, use the preamp outputs to connect to the sound card, if it has them.

Where/whats that?

godfather
18-09-2004, 09:08 AM
IF the radio has preamp outputs (not all/many do) they will be RCA sockets on the rear of the radio.

Basically there is nothing on the computer that the speaker outputs on the radio will or should connect to. All computer connections are at line input level, and the radio is low inpedance speaker level output.

You can still connect real speakers (not amplified computer speakers) to the radio of course.

Billy T
18-09-2004, 10:00 AM
To keep it real simple for you Willie:

1) If your PSU is rated 350 watts or above it should be OK. Lower wattages may also work, depending on how much power your tape radio will need at the desired volume level.

2) Use external speakers only, because if you are not an expert, the results from most other options will either give disappointing sound quality or create copious amounts of smoke.

3) If you want to listen to FM radio you will need some sort of antenna attached. Computers generate moderate levels of RF interference so you may need to postion it a couple of metres away from the box.

Most cars have built-in aerials these days, but 2-3 metres of coax cable with the correct plug on one end and a 500-750mm length of wire from the inner conductor at the other end should work fine. You don't need to connect anything to the outer shield.

4) Don't try to run the stereo at full blast. That may well stress the power supply to the point where smoke is generated or your server malfunctions.

Apart from those provisos, it is an entirely workable idea.

Cheers

Billy 8-{)

tweak\'e
18-09-2004, 10:51 AM
>If your PSU is rated 350 watts or above it should be OK.

with the amount of elcheapo psu's and a lot of pc's running undersized psu's adding a radio could be easly enough to overload the psu requardless of what wattage the psu has. you need to make sure you have enough SPARE wattage.

the problem with current draw from amps/stereo is that its not constant. the adverage currant draw may be ok but the peaks can be 3-4 times the adverage. its not uncomman to see amps/stereo draw more than double of the fuse rating.

Billy T
18-09-2004, 03:55 PM
> the problem with current draw from amps/stereo is
> that its not constant. the adverage currant draw may
> be ok but the peaks can be 3-4 times the average.
> its not uncomman to see amps/stereo draw more than
> double of the fuse rating.

Point 4 of my post covered this issue tweak'e. It doesn't really help getting too detailed with non-technical users, just the basic principles will do, and a warning not to try to drive it too hard.

Most power supplies should be output-overload protected anyway and the server make it pretty obvious if the supply is dropping out.

Cheers

Billy 8-{)

willie_M
18-09-2004, 06:54 PM
can i not put it like, so the speakers out on the radio run through like, a resistor or something then into the soundcard?

I want to stream it through the network to my pc to listen to it on my pc speakers.

Can I not just like, leave the volume at like 1/4, lock it there somehow, and then run it through the soundcard. I have/have access to old soundcards for trial and error...is anything else gonna go buzz?

godfather
18-09-2004, 08:11 PM
If, as Pheonix details above, the negative side of the speakers are not at ground potential, then no, you cannot do that without a high probability of destroying the soundcard or the radio (or both).

Otherwise, you could ideed make a resistive divider to supply a quasi-line output level, if the radio is not a "pumped" power supply type (and one side of the speaker is common/ground).

If you have no problems with destroying the sound card or radio, its never going to be a problem.

You obviously have the radio. Why don't you check with a multimeter and with the radio cover off, just what the story is?

Until you do, we are just guessing blindly.

tweak\'e
18-09-2004, 08:18 PM
>can i not put it like, so the speakers out on the radio run through like, a resistor or something then into the soundcard?

if the radio dosn't have rca outputs there is a speaker to rca converters advailable which will do that. however its still far better to use a radio that has rca outputs.

george12
18-09-2004, 09:54 PM
Stick an old card in there and you should be able to confidently pump the end of the world through it. Well maybe not quite, but it should be quite isolated from the motherboard. For example, a 24V current -> line in will not kill the motherboard, just the sound card. It will hit the audio components, kill them and stop there.

But if you keep the volume down low it should work OK. Most audio devices are *reasonably* tolerant - I have never had problems putting speaker outputs into a line input at any volume.

godfather
18-09-2004, 10:18 PM
> But if you keep the volume down low it should work
> OK. Most audio devices are *reasonably* tolerant - I
> have never had problems putting speaker outputs into
> a line input at any volume.

But if the radio has a high output (pumped power source) speaker circuit, then you have no ability to ground the speaker negative without causing major damage. That means you cannot connect it to the sound card (well, only one side of the speaker can connect and thats not going to work)

A sound card is no more isolated than on-board sound in this respect.

A typical sound card input is 1 volt, 10,000 ohms.
The speaker is ~12 - 18v (or more) but at 4 ohms.

These will give a higher level of distortion, (but probably not so noticeable with the intended music?) but its the fact that the ground wire of the speaker will be several volts negative to ground (possibly).

Large and destructive currents will flow. But it depends on the radio type.

willie_M
19-09-2004, 02:49 PM
OK, well maybe I should have done this a while ago, but here's what written on the side of the thing...

OK, now I know why I didn't do it before.... theres nothing written on it. :D

However it aint no hot shot radio... its the standard(?) alpine tape/reciever 7179EZ out of a 1990 toyota corolla (my new car :D).

Should provide too much power should it? And how do i tell if the speaker negative isn't grounded or watever?

godfather
19-09-2004, 03:22 PM
Simple questions.

How may wires out the back of the radio for the car speakers? 3 or 4?
(i.e. is the negative lead for the speakers common to both left and right, or is it a separate wire for each?)

Is the speaker negative wire(s) connected to the case of the radio. Use a multimeter to check. Should be 0.2 ohms or less.

willie_M
19-09-2004, 03:36 PM
There are four... what kind of f88ked up radio would have 3?

Dunno whether its connected to the casing, can't find the multimeter....

godfather
19-09-2004, 05:03 PM
A lot of lower powered radios with negative grounded speakers would have 3. Only 3 are needed, R, L and Ground.

If yours is actually negative grounded, then both the speaker negatives will *probably* be electrically connected together inside the radio.

But if you can't be bothered to find out, we cant make you. Or advise you.

Bazza
19-09-2004, 06:38 PM
I admire your patience GF. You and others have tried to help this person, with valid helpful information, which he seems unable to accept or understand.

It's hopeless, and so I guess it's time to discontinue advising on this thread, but I'm sure PF1'ers will value your continuing advice.

Susan B
19-09-2004, 08:29 PM
Don't be too harsh Bazza, Willie is only a kid. You have to be patient with them while they are young and silly. :p :D

Susan B
19-09-2004, 08:30 PM
> Willie is only a kid.

Well, I think he is, anyway! :D

willie_M
19-09-2004, 08:34 PM
Wait, what?

What am I doing? ?:| Put up with me? huh?

I said it had four wires, I have to get cold_fu5ions multimeter before I can tell if its negatively watevered...

Kid... lol.. i'm 18... and a half! :D

Bazza
19-09-2004, 08:38 PM
Thanks Susan, I did not know. How could we?.

And so I am sorry. Hopefully he will learn & accept advice.