TRS input has preamp gain, while the manual says not.

all my line level devices are coected to my SL32 using TRS jacks for 2 reasons:

- no possibility to tu on phantom power by accident (+48V only on XLR coectors)

- no extra gain stage as per manual (page 10, preamp bypassed): simpler, cleaner.

However, I recently noticed that the preamp gain does work for TRS inputs. I'm not saying this is bad, but:

- is this normal?

- is the preamp byapssed when setting it to +0 dB?