On Feb 19, 10:48 am, Doug Smith W9WI wrote:
wrote:
I have been looking around the web for a complete kit for an audio
amplifier, for a circuit that I am building that needs to have a wide,
flat as possible frequency response (0Hz - 100Khz). Need to be able to
bring 400mV up to line level. I have seen several kits based on a
LM386, but I can't find any specs that show that circuit is reliable
beyond 20hz - 20Khz. I am a beginner, so keep that in mind when
responding.

What exactly are you trying to do?

400mV isn't that far from line level going into a computer soundcard.
Is there a gain, volume, or full-scale adjustment you can make in
software that'll pull up the signal?

If you do need the gain, as others say a standard op-amp circuit will do
the trick. I've found the NE5534 to be a decent low-noise choice. Stay
away from the LM386; it's great if you need a bit of audio fast and
cheap, but that's about all it's good at.
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66http://www.w9wi.com

100Khz band width seems like a lot of overkill to me to be feeding a
sound card. Several years ago I built something like is beig asked
about using and instumentation grade op amp with a bipolar emiter
follower circuit . Negative feedback to the opamp was taken at the
output of the amp. Specs on this thing was unbelievable. DC to
500khz(limit of the test equipment) with about 1.5 mv of noise. How I
dream of the days of having a bench stock like that to select parts
from again. Made a great headphone amp.

BTW, initally used a 741 in the circuit and it had about 5mv of noise.
If this OK it could still do the job for you.