Kai Nordland has a pretty cool post about the history and design of the Nobels ODR-1, in which he goes into a lot of detail about specific choices and the circuitry.
https://nordland-electronics.de/en/blog/odr-1.html
Cool post on the development & design of the Nobels ODR-1
I read that just recently. Actually just picked up a Sound Studio 1 SST-1 and am looking for repair pots, these always break off. I have another renamed black one i bought in 86' and it's what i always used when headphones are required. Always wanted a ODR1 and guess i have to build one.
AGF refugee