QA471 Low Noise Mic Pre-amp

This product will be replaced by a QA472, which is similar to the QA471 but with much more flexibility (0, 10 and 20 dB of gain), tighter limits on gains, and a very low-noise 30 dB JFET amp . Expected release is fall of 2023. The QA471 is the same product as the QA470, but with 10 dB of mic gain instead of 20 dB. The QA471 is a low-noise, fixed gain (10 dB ± 0.2 dB typical) microphone amplifier, with a switchable +48V phantom supply. The QA471 also features two general purpose amplifiers (with 30 and 10 dB of gain) based on the ultra-low-noise OPA1612 opamps and powered from split ±12V rails, with nearly 18 dBV = 8 Vrms of signal output. The amplifiers inputs are AC coupled and can withstand up to 50V of DC, making them the perfect choice for measuring the noise on DC power supplies and LDOs.  When used with the QA401 and a calibrated microphone, you can read dBSPL directly from the display and make dBA measurements over a specified bandwidth. The 20 dB of mic gain was tailored to wor