Preamp using LM386

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JordiGPS

Member
2008-01-02 11:55 am
Hi everyone.

First of all, this is my first post. Before posting this I've read a lot around here but I could solve my problem. Please help...:cannotbe:

OK. Here we go. I need a preamp to raise output vol out from my CD changer before it is fed in the car HU. Before that, a "CD interface" (so are called...) does media interface (DIN 8 jack to radio input harness).

The problem in the chain CD changer- CD interface - Radio HU is that the sound level is too low. So I decided to implement a preamp before the CD interface.

My first design was based on LM386:

An externally hosted image should be here but it was not working when we last tested it.


The results have been VERY disappointing. White noise was unacceptable (it was rather a hiss...).

My question would be: What if I used a MUCH better IC such as LME49710?

An externally hosted image should be here but it was not working when we last tested it.


The above delivers 40 dB which is enough.

What do you think?
 
The LM386 isn"t idealy suited for a low noise preamp...The LM386 is actually a low Power amp IC which is Internally Biased for single Supply opperation, They are used quite a lot in Distortion pedals because of there High current output and they actually sound OK when Clipped which is also probably why they are used in Distortion pedals but not good for a Low noise pre-amp.....

You should get better results with just about any Audio grade op-amp like the NE5534 or TL071 Or OPA134 or OPA627 or LM4562 ect.....
 
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