# Micro off-grid stereo?



## jawnn (Apr 28, 2010)

I need a micro stereo and found some kits at &#8220;electronickits dot com&#8221;, but I do not know how small I can use for my old 40 watt 8 ohm speakers. I think I used them for years on a 7-watt per channel stereo, with plenty of volume. 

They have one that is not a kit that uses 3 to 4 amps on 12 to 18 volts, but that&#8217;s like 36 watts. I would love to not need larger batteries (two 8 amp hour 12 volt is what I have)&#8230;.power is very difficult to generate in the winter here. (Pacific northwest)

They have a kit that puts out 3 watts and others at 10 watts. Can&#8217;t I get big enough sound from small wattages?

I want to use a tape deck and mp3 player.



&#8220;c.crane&#8221; has a new mp3 radio recorder that looks very nice but at about $200 itsd just too much for me.


Am I allowed to put some links here?


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## kbabin (Aug 1, 2006)

What about using computer speakers. I use a set for my iPod in the garage. You might have problems finding a set that take RCA inputs for your tape deck, but working checking into...

Kev


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## kbabin (Aug 1, 2006)

Found a set with RCA and 1/8" mini inputs.... I don't have this set, so....

http://www.amazon.com/M-Audio-Studi...f=sr_1_23?ie=UTF8&s=pc&qid=1272573247&sr=1-23


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## 12vman (Feb 17, 2004)

Musta seen my link before it was removed.. LOL Welcome!

I took a set of these and tore them apart. I removed the speakers and extended the wires to connect to other speakers. The output is ~2 watt/channel..










It originally held 4-"AAA" batteries which is 6 volts. I wired an LM7806 voltage regulator to it and operate direct from my 12 volt system. I have it connected to two Pioneer 100 watt speakers and it sounds fantastic! Not earth shaking but very good fidelity with nice bass..










To Add..

The LM7806 is limited to 1 amp so I know it doesn't use that much. Maybe 700 milliamps at full throttle.. LOL


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## texican (Oct 4, 2003)

Dual has a car stereo, that has an input jack on the front, as well as a usb port, for usb thumbdrives or usb harddrives... for 40$. I couldn't build anything cheaper. I've thought about getting one and putting it as well as extra hard drives with music on them, in a faraday cage, just in case.


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## jawnn (Apr 28, 2010)

where can I see this ? (link) and how much power does it use?

I think this one uses less than a car stereo http://www.electronickits.com/kit/complete/ampl/CANUK194.htm



texican said:


> Dual has a car stereo, that has an input jack on the front, as well as a usb port, for usb thumbdrives or usb harddrives... for 40$. I couldn't build anything cheaper. I've thought about getting one and putting it as well as extra hard drives with music on them, in a faraday cage, just in case.


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## 12vman (Feb 17, 2004)

Jawnn..
There's no magic to this. I see that your goal is to have good sounding music with the least amount of input power from a battery to an amp of some kind, and using the speakers that you already have. To keep the power consumption down, you'll have to use an amp with minimum wattage to get your results. The more watts you use, the more power your going to consume from your battery. Pretty simple. 

By using a car stereo you are defeating the purpose. By using the amplifier that your link goes to does the same thing. You're not going to shake your neighbors windows with milliamps of power input from a battery.

The secret is to have low wattage speakers that are very sensitive or efficient. Most all speakers have a sensitivity/efficiency rating on them along with the wattage rating. ("X" amount of decibles @ 1 watt @ "X" distance)

Quote Wiki.. http://en.wikipedia.org/wiki/Loudspeaker
"Sensitivity is usually defined as so many decibels at 1 W electrical input, measured at 1 meter, often at a single frequency."

I don't know the exact speakers that you have but I'll bet they would sound great with 1 or 2 watts of input, especially if they have a tweeter seperate from the main speaker in the enclosure. (or, possibly a 3-way setup) You'll just have to humble yourself and imagine that you're at the concert.. 

Interfacing might be an issue with a few things but with my set up, I can play cassette tapes, CD's, MP3 players, my computer, anything that will accept that 1/8" plug, and the volume control is on the unit being used. You wouldn't need to put music on a thumb drive if you have an MP3/4 player. Most portable CD players will accept it, as for MP3/4 players also. An earphone jack is pretty universal on most items so working with that 1/8" jack shouldn't be an issue if you plan for your audio devices to have one.


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## jawnn (Apr 28, 2010)

can't find the mp3 speakers you have there...I saw them a couple weeks ago...must have sold out.


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## 12vman (Feb 17, 2004)

Any of them will work. I would suggest a set that operates on at least 4 batteries. The less batteries, the less wattage..


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## jawnn (Apr 28, 2010)

I found a good place for off grid stuff:
http://www.12volt-travel.com/


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## mightybooboo (Feb 10, 2004)

12VMan,you always amaze me at the efficiency of your energy usage


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## 12vman (Feb 17, 2004)

BooBoo..
The first "stereo" in my room when I was a kid was an old Delco AM radio and battery from my brothers car after he wrecked it. I even grabbed the 6x9 out of the dash.. LOL

I come from very poor beginnings so I had to make do with what I had, so I have plenty of practice..


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## texican (Oct 4, 2003)

jawnn said:


> where can I see this ? (link) and how much power does it use?
> 
> I think this one uses less than a car stereo http://www.electronickits.com/kit/complete/ampl/CANUK194.htm


http://www.dualav.com/mobileaudio/xr4110.php They're 40$ at Wallyworld. No cd player, which is a negative, but I can't remember 'when' I actually played a cd! It's all music on my Creative Nomad or Zune devices, patched into the in car stereo.

As far as mp3 speakers, I find the unpowered speakers that come with computers work just great, if your sitting nearby.


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## jawnn (Apr 28, 2010)

some one gave me one of the realy cheap mp3 speakers, but it has such a bad distortion that I am still searching.

How much power does that car stereo with out dc use at low volume?


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