The little plastic casing on one earpiece is popped off, and replaced with a 3D-printed version that stoutly holds a female TRS jack in place. This can then be soldered up to the wiring inside the ...

In stereo mode the impedance is for regular line level (20kohm). To save space, Press uses two ¼” TRS jacks, one for input and one for output, and this means the connection is unbalanced. Meanwhile, ...