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Preamp (or other solution) for connecting my Clip to my car line-in - Page 2

post #16 of 19
3/4/10 at 7:45am
Thread Starter 
Hi Fred

Quote:
Originally Posted by Fred_fred2004 View Post
Be very careful powering a cmoy from the car power, when you plug into the stereo aux socket the virtual ground of the cmoy will be shorted to the cars earth which will usually be battery negative. this tends to liberate the smoke from the opamp, just once :-)
Well, if all the smoke is liberated in one shot, then I won't have to worry a second time XDDDD

Yes, I knew, that's one of the reasons why I was looking for other solutions (line adaptor, dc-dc converter, a preamp that doesn't need a virtual ground, etc.). If none of them is acceptable, that is, cheap, small, easy, I'll probably use batteries. Finding a suitable circuit for amplifying is the easy part: finding how to properly power it is not as easy.

So far the cheapest and easiest solution I've found is a Velleman kit, but unfortunately I don't know if it uses a virtual ground or not. I have to investigate that.

Thanks for the warning!
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post #17 of 19
3/10/10 at 9:07am
Thread Starter 
I finally built a prototype using LM386. I used the power supply rejection (well, bypas...) capacitor and even with it the alternator whine is clearly audible. Not very annoying except in quite passages, but the prototype is calling for a dc-dc converter or a good voltage stabilizer. The problem is that I don't have an oscilloscope to see the kind of noise which is coming from the alternator (probably a sinus wave, but I'm not sure).

So, I won't be building a car powered preamp. I still have to think about the issue, although I think I will post in the portable headamp forum to check for a Li-ION powered headamp or something like that before trying to build a CMoy...

Thanks A LOT for all the help and suggestions
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post #18 of 19
3/15/10 at 3:15pm
Been daydreaming of something like this... CMOY -> rechargeable battery -> cheep solar charger. like this from Harbor Freight for $11.99

mounted on my dash, only issue is overcharging, need a cheep charge control circuit.
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post #19 of 19
2/17/11 at 1:53pm

Like what? I see nothing.  I am having this same problem and am looking for a solution.  Will a line driver work?  Could someone point me to examples of what would work?

 

 

Sorry for grave digging. 
 

Quote:
Originally Posted by linuxworks View Post


to be honest, battery and charging is probably more trouble than its worth. if it was me, I'd probably just buy a thing like this:



I'm sure you can find 'line drivers' at your car audio stores. even though the unbalanced to balanced part isn't what you need, you can often get enough gain from them (or even modify them to increase a fixed amount of gain).

even things like this (I have one similar in my car, built into my dash):


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