This equalizer has automatic level control, being designed by Sanyo for cassette recorders and radio. The maximum supply voltage of the LA3210 is 15 V and the typical idle current of 1.4mA.
Using components from the era, this 90's EDN circuit is used in analog to digital conversion...
Found in an American publication from the 90s, this circuit allows the supply of 3, 6 and 9 V...
We found this circuit in an old Popular Electronics. The circuit is experimental, driving an LED...