We found this active crossover in a Radio Electronics magazine from June 1961. Note the different adjustment ranges. The signal must be applied to the amplifier input.
We found this interesting configuration in a 1976 technical documentation. Equivalent diodes can...
Indicated by the Maxim Engineering Journal in the 90's edition, this circuit uses only one...
The gain of this circuit is given by the value of R1 that depends on the current in the...