1/4 inch Master,
In 1967 Abbey Road Studio used two Studer J37 to record the world famous Beatles production "Sgt. Pepper". In the same year the well known Revox A77 was introduced, with over 400'000 units sold the worldwide best sold tape recorder of its class. This famous machine was used in nearly every studio worldwide. The completely modular A77 was built in more than 50 versions for applications such as broadcast, voice logging, education etc..