FET amplifier for transducer

Hi.

I'm looking to make a very small amplifier for a sound transducer. The transducer output is in the uV range. Only have single supply (9V available).

I'm looking to add gain between 100-500, maybe controllable with a POT.

Any suggestions on making such an amplifier from FETs or discreet parts? I'm trying to keep the cost low.

Ideally, I'd like to integrate a low-pass and high-pass to shape the frequency response.

Thank you. J.

Hello John,

Assuming with "sound" you mean something below 25kHZ why do you want to do it discrete? Any old opamp should be able to do that. The LM324 costs less than 20c at reasonable qties and you get four amps for that money. It works nicely from 9V. Ok, it's not a FET input but after all you would have to bias a FET with resistors anyway.

Regards, Joerg

If you are after 100-500 as a gain and filtering and a low cost, chances are an op-amp will be cheaper than doing it with discrete parts.