Electronic question
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Postmaster
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From: Bixby, OK
Electronic question
I've always wondered this.. say I have a HU that runs off of 12V. Could I hook it up to a converter that does 12V DC? But they run in milliamps.. so how would it work?
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From: Southern MD
Originally Posted by RomerB2
I've always wondered this.. say I have a HU that runs off of 12V. Could I hook it up to a converter that does 12V DC? But they run in milliamps.. so how would it work?
Back around 1970, before I got my first car, I had already purchased an 8 Track stereo, for that 'first car'.
So that I could listen to it, I used a slot car transformer and mounted the whole thing to a piece of plywood and put it on my desk/table.
Ran some speaker wire and hooked up some speakers . . . it worked GREAT!
(The transformer put out [max] 13 volts, 12 volts nominal.)
As they say. . . any port in a storm!
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Joined: Jan 2003
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From: Durham, NC
Originally Posted by 00BlueOvalRanger
Back around 1970, before I got my first car, I had already purchased an 8 Track stereo, for that 'first car'.
So that I could listen to it, I used a slot car transformer and mounted the whole thing to a piece of plywood and put it on my desk/table.
Ran some speaker wire and hooked up some speakers . . . it worked GREAT!
(The transformer put out [max] 13 volts, 12 volts nominal.)
As they say. . . any port in a storm!
So that I could listen to it, I used a slot car transformer and mounted the whole thing to a piece of plywood and put it on my desk/table.
Ran some speaker wire and hooked up some speakers . . . it worked GREAT!
(The transformer put out [max] 13 volts, 12 volts nominal.)
As they say. . . any port in a storm!
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Joined: May 2004
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From: Abilene Kansas
ok i want to explain fardays law real quick, when u make voltage less the current goes up. (amps) and when you make current less voltage goes up... its how a transformer works on your house from te power lines... the power lines have a HELL of a lot of voltage but only saw 2-3 amps... when they run it through a transformer they bring the voltage down to 120 volts peak to peak and they its 110 rms (take peak to peak times the square root of 2) then you get what u really see...
so in the case of you Hu if your converting it from 110 v ac i would be worried about not getting all the ac current converted to dc... dc current looks like a line when graphed and ac looks like a wave... it has pos and neg values... if you expose dc equipment to ac it can cause diodes and capacitors to crap out as they were not designed for ac in most cases... so my reccopemendation is i wouldt try it... i took circuits and we messed with stuff like this and we could see that even in dc with just a little ac left in it that equipment would last as long as normal
Matt
p.s. class dismissed
so in the case of you Hu if your converting it from 110 v ac i would be worried about not getting all the ac current converted to dc... dc current looks like a line when graphed and ac looks like a wave... it has pos and neg values... if you expose dc equipment to ac it can cause diodes and capacitors to crap out as they were not designed for ac in most cases... so my reccopemendation is i wouldt try it... i took circuits and we messed with stuff like this and we could see that even in dc with just a little ac left in it that equipment would last as long as normal
Matt
p.s. class dismissed
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From: Durham, NC
Originally Posted by fordboy_52
ok i want to explain fardays law real quick, when u make voltage less the current goes up. (amps) and when you make current less voltage goes up... its how a transformer works on your house from te power lines... the power lines have a HELL of a lot of voltage but only saw 2-3 amps... when they run it through a transformer they bring the voltage down to 120 volts peak to peak and they its 110 rms (take peak to peak times the square root of 2) then you get what u really see...
so in the case of you Hu if your converting it from 110 v ac i would be worried about not getting all the ac current converted to dc... dc current looks like a line when graphed and ac looks like a wave... it has pos and neg values... if you expose dc equipment to ac it can cause diodes and capacitors to crap out as they were not designed for ac in most cases... so my reccopemendation is i wouldt try it... i took circuits and we messed with stuff like this and we could see that even in dc with just a little ac left in it that equipment would last as long as normal
Matt
p.s. class dismissed
so in the case of you Hu if your converting it from 110 v ac i would be worried about not getting all the ac current converted to dc... dc current looks like a line when graphed and ac looks like a wave... it has pos and neg values... if you expose dc equipment to ac it can cause diodes and capacitors to crap out as they were not designed for ac in most cases... so my reccopemendation is i wouldt try it... i took circuits and we messed with stuff like this and we could see that even in dc with just a little ac left in it that equipment would last as long as normal
Matt
p.s. class dismissed
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From: Oregon
Originally Posted by RomerB2
I've always wondered this.. say I have a HU that runs off of 12V. Could I hook it up to a converter that does 12V DC? But they run in milliamps.. so how would it work?
Your HU draws more current than most wall warts will put out. Basically, the little wall wart is the simplest power supply they can make. Pull one apart and it has: A transformer, (110ac to ~16ac), a few cheap diodes to rectify, (separate the the positive side of the wave from the negative), and a small capacitor, (this is used as a filter to "flatten" the wave to turn it into DC. This is where the guy got the idea for filtering caps on the kickin car stereos).
These little power supplies are not filtered very well, (lots of ripple), and they aren't regulated. Exactly like when your headlights flicker when you crank the tunes, the greater the current draw, the greater the voltage drop. Except with a wall wart you might be able to turn your HU on, but as soon as you crank it, it'll turn off from "voltage starvation?" ...
(nerd joke Bob).Radio Shack sells a little 20 Amp switching power supply that is filtered, regulated and goes on sale every once in a while. It's about the same size as a HU, so would "stack" well, and is about the best bang for your buck. Then there's always your computer PS, not the best - but everyones got one laying around.
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From: Oregon
Dude! Sup, you guys need to spend more time in the audio forum. Just learn the lingo, but don't try to use it - or you'll get a response from the teenagers like, "ur mom".
I translate HU to mean, head unit = car stereo, back in the days when a system was the stereo and couple speakers.
I translate HU to mean, head unit = car stereo, back in the days when a system was the stereo and couple speakers.
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Joined: Feb 2003
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From: Oak Harbor, OH
A computer power supply works very well, but you will more than likely need a dead mother board to make it work. These head units don't draw enough current on startup to trigger the power supply, and it won't come on. I know from experience. I mounted an 80watt amp in an old computer a few years ago to power a set of speakers for my computer's audio. It worked, but I needed a large hdd (MFM) or motherboard to make it work. The power supplies now-a-days are ACPI, so when they don't detect a decent amount of draw, or an ACPI controller they trigger the power save mode.
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From: Durham, NC
Originally Posted by pfogle
A computer power supply works very well, but you will more than likely need a dead mother board to make it work. These head units don't draw enough current on startup to trigger the power supply, and it won't come on. I know from experience. I mounted an 80watt amp in an old computer a few years ago to power a set of speakers for my computer's audio. It worked, but I needed a large hdd (MFM) or motherboard to make it work. The power supplies now-a-days are ACPI, so when they don't detect a decent amount of draw, or an ACPI controller they trigger the power save mode.
Last edited by Bob Ayers; Jul 29, 2005 at 04:02 PM.
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From: Bixby, OK
HU = head unit = car stereo receiver.
I have an extra HU laying around that plays MP3 and all sorts of stuff, and I have built in cabinets so I was going to cut a hole in one big enough for a 1-DIN and slide it in. Thought it would look neat as well. My room's all modern and stuff and I just thought this might add to the effect. I know it needs to be 12V/DC. But I was just wondering since I have one of these little plugs (wall wart as someone said) and wondering if I should give it a shot. I don't understand why it wouldn't work except maybe not enough power or should I say amperage? I'm not too worried about all the AC getting filtered out because a car creates electricity in AC and then it's converted to DC so it can be stored in the battery. I don't think the AC to DC part is a problem.
Howdy - How much is that little thing from Radio Shack?
Thanks for the replies.
I have an extra HU laying around that plays MP3 and all sorts of stuff, and I have built in cabinets so I was going to cut a hole in one big enough for a 1-DIN and slide it in. Thought it would look neat as well. My room's all modern and stuff and I just thought this might add to the effect. I know it needs to be 12V/DC. But I was just wondering since I have one of these little plugs (wall wart as someone said) and wondering if I should give it a shot. I don't understand why it wouldn't work except maybe not enough power or should I say amperage? I'm not too worried about all the AC getting filtered out because a car creates electricity in AC and then it's converted to DC so it can be stored in the battery. I don't think the AC to DC part is a problem.
Howdy - How much is that little thing from Radio Shack?
Thanks for the replies.
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From: Durham, NC
Originally Posted by RomerB2
HU = head unit = car stereo receiver.
I have an extra HU laying around that plays MP3 and all sorts of stuff, and I have built in cabinets so I was going to cut a hole in one big enough for a 1-DIN and slide it in. Thought it would look neat as well. My room's all modern and stuff and I just thought this might add to the effect. I know it needs to be 12V/DC. But I was just wondering since I have one of these little plugs (wall wart as someone said) and wondering if I should give it a shot. I don't understand why it wouldn't work except maybe not enough power or should I say amperage? I'm not too worried about all the AC getting filtered out because a car creates electricity in AC and then it's converted to DC so it can be stored in the battery. I don't think the AC to DC part is a problem.
Howdy - How much is that little thing from Radio Shack?
Thanks for the replies.
I have an extra HU laying around that plays MP3 and all sorts of stuff, and I have built in cabinets so I was going to cut a hole in one big enough for a 1-DIN and slide it in. Thought it would look neat as well. My room's all modern and stuff and I just thought this might add to the effect. I know it needs to be 12V/DC. But I was just wondering since I have one of these little plugs (wall wart as someone said) and wondering if I should give it a shot. I don't understand why it wouldn't work except maybe not enough power or should I say amperage? I'm not too worried about all the AC getting filtered out because a car creates electricity in AC and then it's converted to DC so it can be stored in the battery. I don't think the AC to DC part is a problem.
Howdy - How much is that little thing from Radio Shack?
Thanks for the replies.