Advertisement
Unlike other single tone controls on other amplifiers, which act merely as a treble roll off, this
control works in a different way. It is a dual gang potentiometer which controls two functions
simultaneously. In the fully anti-clockwise position the midrange is dominant in the sound,
turning the control clockwise decreases the mids while at the same time increasing the higher
frequencies.
REVERB
This single control is for adjusting the amount of reverb effect in the sound. The effect is
produced by a three spring reverb tray inside the cabinet.
FOOTSWITCH SOCKET
This socket is for connecting to a latching footswitch and allows the user to turn the reverb
effect on or off during a performance.
EXTERNAL SPEAKER OUTPUT
This is provided so that the user can connect the GA-15RV to an external 16 speaker
cabinet, such as a 4x12, for a different sound. This is useful for both live and studio use and
can radically change the sound of the amplifier. Try it at high volume into a 4x12 and you will
not believe you are playing a 15 watt amp!
When a jack is inserted into this socket the internal speaker is disconnected. Always ensure
that the amplifier is correctly loaded when in use.
PENTODE/TRIODE SWITCH
This allows the user to set the power stage to either PENTODE or TRIODE operation.
PENTODE position is the full power mode and has generally a more powerful sound with a
spread of both even and odd harmonics, when pushed into distortion.
TRIODE mode produces around half as much power. It therefore has less headroom and
produces power amp distortion earlier. It also has less high frequency content, therefore it is
not as bright as pentode mode, and produces mainly even order harmonics.
The choice as to which mode to use will depend on several factors including playing situation,
instrument used and, most importantly, personal taste.
POWER SWITCH (OFF/STANDBY/ON)
As the name implies, this switches the amplifier from OFF to STANDBY mode, where only the
valve heaters are on, to ON for actual use. This should be used correctly every time the unit is
used to prevent problems with valves and to increase their life.
Advertisement
