Operating instructions

3
INTRODUCTION
Congratulations on your purchase of a Gibson Super ‘Goldtone’ valve guitar amplifier.
Please take a few minutes to read this owners manual so you may fully understand the
extensive capabilities of this unit. With a little care your new amplifier should provide
you with years of satisfactory service.
The Super ‘Goldtone’ range currently consists of the following products:
GA-30RV 30 watt Class A 1x10 + 1x12 combo
GA-60RV 60 watt Class A/B 2x12 combo
GA-30RVH 30 watt Class A head
SGT Cabinet 2x10 + 2x12 Mono/Stereo speaker cabinet
The main preamp functions on all models are more or less the same, with different valve
power stages and/or speaker configurations used in each particular unit. All features and
differences between models are described further on.
The circuit topology has been based on traditional guitar amplifier designs, with new
ideas incorporated where beneficial.
The complete signal path; preamp, effects loop, reverb and power stage, on all models is
100% valve.
The switching circuitry for the different functions is all based around momentary switches
controlling CMOS logic devices which then switch relays or FET’s within the audio
circuitry. This provides very low switching noise, excellent sonic performance and the
ability to switch all the functions from multiple sources.
All Power and Output transformers and Chokes are custom made for maximum
performance using high grade laminations. Windings are resin soaked and made to pass
international approvals.
A highly regulated DC supply is used for heater filaments in all preamp valves for
minimal hum levels.
Where appropriate an external biasing facility is featured - this enables techs to
check/reset output bias at any time without removing the chassis. This also enables the
use of several different valve types including EL34, 6L6, 6550 and KT88.
Internal wiring and glass epoxy circuit board layouts use multiple return, star earthing, for
low noise and hum. All audio sections have been laid out for maximum sonic
performance using ‘point to point’ wiring principles.
Porcelain valve sockets and gold plated jack sockets are used exclusively throughout.