The ADC801 is not an easy component to obtain today, but the configuration is worth reference. The circuit is from National Semiconductor's Linear Applications Handbook.
This filter, from an audio publication from 1977, passes the frequency range corresponding to the...
In the figure we have three voltage doubler configurations that can be used in high and low...
This circuit was found in Motorola documentation from 1966. The lamps are according to power and...