This 130 V drive uses an integrated circuit not very easy to find, which is the LM143. The circuit is suggested by National Semiconductor in its 1994 Linear Applications Handbook.
This configuration was found in the Texas Instruments optoelectronics manual. PNP transistors...
These basic bass controls were obtained from an article in Electronics Now magazine in February 1995....
This circuit was obtained in a 1991 Electronics Handbook. The publication no longer exists, but...