[TenTec] Need 509 schematic

[Jon Iza]

Folks,
four years ago there was a discussion on the 208 filter on this list:
http://lists.contesting.com/_tentec/2016-01/msg00036.html

It seems it was very similar to the schematics published on QST Jul
1979 pp. 45-47 by Dave and Doug DeMaw while reviewing the Tentec 544.

I have the manual for the 208A, which includes a Notch filter. The op
amp used was the RC4136 which, unfortunately, does not share the same
pinout as the typical, low noise, FET input quad op amps such as the
TL074.

Be well
jon, ea2sn