This circuit has a gain of 6 dB for low frequencies from 85 Hz and can be used in a mini subwoofer. The circuit is from a Radio Electronics from March 1990.
This circuit was obtained in an Electronic Design from the 80's. It has the adjustment of the gain...
This circuit was obtained in a 1977 magazine, but it can still be easily assembled, as the...
This circuit uses only passive components and must be tuned to the operating range. The circuit is...