- Jan 1, 1970
Is the hiss originating from the LM386 chips or from some
other component? Phil's data shows the result of a test of
the LM386 generated noise.
He did specify that the input pins were grounded. In real life, simple
chips like this tend to run the input stage at high currents, which
skews things towards low voltage noise and high current noise. So if
the input were driven from a reasonable non-zero impedance, or just
left open, there would be a bunch more noise.
Amplifiers with grounded input pins tend to have a bad s/n ratio,
especially if you measure it in dB.
I wonder what's the absolutely worst noisy amplifier thing around. I
recall seeing opamps that ran over 100 nv/rthz somewhere.