"boots" ? C'est pour faire du fonk à la Boostsy Collins, évidemment.
Sinon, regarde la notice (je suppose qu'il s'agit de la Deluxe ?) :
http://www.tech21nyc.com/support/manuals/sansamp/BassDriver-DLX-OM.pdf On y trouve en page 2 :
"XLR Out Pad Switch: -20dB pad to match the output to equipment with
different input level requirements. In the line level (up) position, the output
is 0dB. In the instrument level (down) position, the output is -20dB."
"1/4” Out Boost Switch: +10dB boost to match the output to equipment
with different input level requirements. In the instrument level (up) position,
the nominal output is -10dB. In the line level (down) position, the output is 0dB."