Why does the headphone output on my SP6 sound like it is in mono?


There have been two different headphone circuit designs employed in SP6 production.

Earlier units (sn# C9818J5N3850 and earlier – smaller number) featured a headphone circuit which employed Automatic Mono Sensing and delivered a “what you hear in the headphones is what the audience hears via the line outs” feature. In these earlier units, to hear the SP6 headphones in stereo, 1/4″ cables must be connected to the Left and Right Audio Out jacks, or (alternatively) a single balanced 1/4″ TRS cable (or simple plug adapter) can be connected to the Right Audio Out jack.

Later units (sn# C9818J5N3851 and later) do not employ Automatic Mono Sensing and the headphone circuit operates in stereo and independently of the audio line outputs.

The table below summarizes the switching behavior of the audio and headphone outputs in those earlier models:

No connections Mono
Left (mono) jack only Mono
Right jack only (TRS plug) Stereo
Both Left & Right jack Stereo


Note: in all cases, using balanced 1/4″ TRS audio out connections will provide optimal dynamic range and signal-to-noise ratio.