Adcom GFA-555MS Operating Instructions Manual page 12

operate reliably and if triggering of protective devices is to be avoided. The preceding is
particularly true of amplifiers which have extremely wide audio bandwidth, such as ADCOM
amplifiers. Among the undertakings which must be avoided, if damage to the amplifier or to
the loudspeakers being used is to be prevented, are actions such as connecting the inputs
or outputs to or from the amplifier while the amplifier is ON, or using what has been
commonly termed the "thumb test" - that is, touching the center pin of the RCA jack on one
end of the audio interconnecting cable while the other end is plugged into the amplifier and
the amplifier is ON.
In the event that the DC RAIL FUSES need to be replaced, only one of the fuse types listed
in the table below should be used. Please note that the fuses listed in the table, and their
time-current blowing points, have been carefully selected and thoroughly tested to deliver
optimal performance while still accomplishing their protective functions. Replace these
fuses, individually, only with the specific types listed. DO NOT USE ANY SUBSTITUTE
FUSES WITH DIFFERENT RATINGS, TIME-CURRENT CURVES OR VALUES. Failure
to observe this precaution may cause serious damage to the amplifier circuits, MAY
CREATE A FIRE HAZARD, AND MAY VOID YOUR WARRANTY. For your convenience,
a replacement set of two of the correct DC RAIL FUSES is supplied with each amplifier to
facilitate restoration of the amplifier to operation in the event of a blown fuse.
The GFA-555ms has a massive power supply which remains charged for up to FIVE
MINUTES after the amplifier is turned off and the POWER LED ceases to glow. It also
remains energized when the POWER. LED glows even if the THERMAL PROTECTION
LED is ON. Therefore, you should exercise great caution when connecting arid/or
disconnecting loudspeakers to or from the RIGHT/LEFT STEREO SPEAKER OUTPUTS.
Should you inadvertently short out the RED ("+") and BLACK ("-") STEREO SPEAKER
OUTPUTS, enough power may remain in the power supply to cause sufficient current to
blow the DC RAIL FUSES on the affected channel. When connecting or disconnecting
loudspeakers to or from the RIGHT/LEFT STEREO SPEAKER OUTPUTS, always be
certain to wait at least FIVE MINUTES after turning the amplifier OFF before undertaking
any such procedure.
NOTE
DC RAIL FUSES
BUSSMAN
LITTELFUSE
BEL
AGC-7/250V
3AG312007/250V
3AG 7A/125V