A-119 is mono: "The pre-amp has two inputs: an unbalanced input for line level signals, with a gain factor of from 0 to 20, and a balanced input with a gain factor of from 0 to 500, for insertion of low level signals, for instance from a microphone or electric guitar"
On p. 4 in the manual it says that:
Symm. In
The 6.3 mm stereo full-size jack socket " is the
A-119’s balanced input, for low level signals such as
from a microphone, electric guitar, and so on.
A-139-2 is a headphone amplifier. You need to bring down the level going into the computer.
-- wiggler55550
I thought one needed to amplify the output signal. I wonder if there's some other Doepfer module that can handle the output.