Found thread and wanted to let you know that we make a circuit board adapter that allows you to adapt two SO8 SMT dual-channel op-amps (of your choice) to the same pinout as the RC4136.
Here is the link:
formatting link
Feel free to contact me if you have any questions.
Best regards, Phil Maltby Cimarron Technology, Inc.
918-747-3874 ph
918-747-4849 fax