Sennheiser HE 1 User Manual page 17

Putting the HE 1 into operation | Connecting the tube headphone amplifier to audio sources
Connection possibility of the audio source: analog, XLR-3, balanced
A
BAL
ORPHEUS
Connection cable: 2 balanced XLR-3 cables
Connection possibility of the audio source: analog, RCA, unbalanced
B
UNBAL
ORPHEUS
Connection cable: stereo audio cable with 2 RCA connectors at each end
L
R L
L
L R
R
R
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