Jas-Audio BRAVO 3.1 - Manual (Page 3)

They are of uniformity with the panel in color and material in production. Lined on both
sides of the front transformer cage with wooden cover are two rows of tubes, including one
row of rectifiers and another row of tubes on the other side for signal amplification, drive
stage and output stage. The 805 output tube is fitted on the antique “holdover–socket”, a
design that requires a gentle push downward and an action to turn in releasing the tube. All
the transformers are housed in two separate cages mounted on the chassis as a T-joint.
Apart from the IEC power inlet and the taps for 4Ω and 8Ω impedance matching with
speakers, there is also a by-pass switch located at the back of the chassis. The
operating mode is selectable by switching the by-pass switch left or right. Please make sure
that switches on both chasses are set to the same side so as to work on the same operating
mode before powering up the amplifier.
This pair of monoblocks is recommended to match with Bravo 1.1 vacuum tube pre-
amplifier of the same series to build a high-end set up for optimal performance.
Power Switch Volume Control Knob
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It is important to be careful with tube installation. Please do not force anything, easy
does it! This precaution is mentioned to help you obtain pleasing results and avoid
damage! If you have any trouble replacing or changing tubes, please don’t hesitate to
call your dealer!
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Tube Replacement
Caution: Make sure the amplifier has been unplugged for 30 minutes from the AC mains
before replacing the tubes, to avoid any risk of shock or discomfort from high
temperature. Although tube life span varies depending on the nature and degree of use,
under normal home use, the 805 output tube and the 2A3 driver tube should last years in
the Bravo 3.1. The 6J4P input tubes and the 5Z3P rectifier tubes should last longer
though.
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