Hi, I was looking to design a relatively high gain mic-preamp for an audio interface I'm building. It's a USB audio interface with an ADC that nominally takes a fully differential 2.8V p-p signal, and most of the chip amps either required buffer stages or a higher supply voltage. This might not be the most practical solution, and I might just go with a voltage doubler and an INA849, but I wanted to try my hand at a preamp design. I'm relatively new to audio and electronics in general, so I would appreciate any criticism. Note that R11 is a logarithmic gain adjustment pot, and this is designed to have a high enough input impedance to also be used as an instrument pre-amp. The LTSpice and circuit image files are attached below.
To the mods--unsure if this was supposed to go in "Analog Source" or "Analog Line Level", my apologies if I guessed wrong.
To the mods--unsure if this was supposed to go in "Analog Source" or "Analog Line Level", my apologies if I guessed wrong.
Attachments
The equivalent input noise voltage will be high (rough order of magnitude estimate: 35 nV/√Hz) because of the low currents at which the input JFETs are biased. What kinds of microphones do you want to use it with?
Are the output stages strong enough to drive their loads and is the circuit stable?
Are the output stages strong enough to drive their loads and is the circuit stable?
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