writes:

Hello,

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.

-Scott, WU2X


Who's definition of line level? For consumer audio gear, line level
is 0.1 milliwatt into 1000 ohms, or roughly 320mVrms. If your source
impeadance is sufficiently low (most gear has input impeadance in the
several-thousand ohm range), you're done.

If you need it for studio gear, then you've got to get your singal up
to 2.5 milliwatts into 600 ohms, or about 1.2 Vrms, and any of a
million op-amps can give you the gain you need to reach those levels.

The ubiquitous 741 is cheap and easy to use, but the now 40-year-old
design is kinda noisy.

I cannot imagine that a 386 would be a good match just because it's
designed for much lower output impeadance and much MUCH higher levels.

--
Lawrence Statton - m s/aba/c/g
Computer software consists of only two components: ones and
zeros, in roughly equal proportions. All that is required is to
place them into the correct order.

Also, don't forget that the sampling rate of the sound card doesn't have
anything to do with the preamlifier stage that you are trying to build. A
stage that is limited to the audio range will be fine. Any of the higher end
op-amps will be fine.
The Analog Devices OP275 is a good choice, because of its fast settling
time.

Pete

"Lawrence Statton XE2/N1GAK" wrote in message
...
writes:

Hello,

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.

-Scott, WU2X


Who's definition of line level? For consumer audio gear, line level
is 0.1 milliwatt into 1000 ohms, or roughly 320mVrms. If your source
impeadance is sufficiently low (most gear has input impeadance in the
several-thousand ohm range), you're done.

If you need it for studio gear, then you've got to get your singal up
to 2.5 milliwatts into 600 ohms, or about 1.2 Vrms, and any of a
million op-amps can give you the gain you need to reach those levels.

The ubiquitous 741 is cheap and easy to use, but the now 40-year-old
design is kinda noisy.

I cannot imagine that a 386 would be a good match just because it's
designed for much lower output impeadance and much MUCH higher levels.

--
Lawrence Statton - m s/aba/c/g
Computer software consists of only two components: ones and
zeros, in roughly equal proportions. All that is required is to
place them into the correct order.