I'm glad these help (there is at least one article I remember from Audio Amateur that should help you as well.) As of now, jpegs are all I have from the SM6--still can't find the manual. If I get a chance, I'll scan the other 2 manuals.
WELL.....Well.....well.......I received the "Audio Amateur" CD yesterday (7/17/21) and with an internal sense of hyper-excitement, I was..........greatly disappointed!!! I couldn't believe it!!!Dang, I did not gather these when they were available. The World Radio History site was asked to take down their copies of Audio Amateur. You can still buy them on CD-ROM at
The entire collection of issues of The Audio Amateur from the 1970s is reproduced electronically on CD. Includes issues from 1970 through 1978 which are no longer available in printed form. Take a fascinating journey into the first decade of Audio Amateur's rich DIY audio history. You'll find...cc-webshop.com