10
labeled POSITIVE, "+", POS, 8 OHMS). The
RIGHT RED
output binding post terminal on the
amplifier (labeled BRIDGED MONO OUTPUT "-") should be connected to the BLACK
loudspeaker terminal (or labeled NEG, "-", C, COM, COMMON, G, or GROUND).
Although the GFA-585se can generate a substantially greater amount of power in the bridged
mono mode than when it is in its normal stereo mode, it requires the use of loudspeakers the
nominal impedance of which does not drop below 4 ohms. It is not recommended that the
GFA-585se be used in the bridged mono mode into loudspeakers, or multiple loudspeaker
loads, which drop in value substantially below 8 ohms. Otherwise, you may trigger the
THERMAL PROTECTION or blow one of the AC RAIL FUSES. Please refer to the section
RIGHT/LEFT STEREO SPEAKER OUTPUT for further clarification. A little known fact is that
when any amplifier is operated in the bridged mode, the load is "split" between the two
amplifiers in the bridged configuration. Therefore, an 8-ohm loudspeaker will be seen by the
amplifier as if it were a 4-ohm load; a 4-ohm loudspeaker load will be seen by the amplifier
as a 2-ohm load.
NOTE
If the connections described above are followed exactly, the GFA-585se will be polarity
correct, that is, it will
not
invert "phase". Any positive-going signal at its input will appear
as a positive-going signal at the loudspeaker.
AC RAIL FUSES
The AC RAIL FUSES provide protection for the output stages and power supply in the event
of excessive current demands from the amplifier, either long-term or short-term.
If the amplifier ceases to operate, either on one or both channels, particularly during high-
level passages, or long-term high-volume playback, and the POWER LED glows while the
THERMAL PROTECTION LED is out, the chances are that one or both of the AC RAIL
FUSES on that channel, or both channels, are blown.
If the current drawn by this stage exceeds a safe level due to a load impedance below 1 ohm
or short circuit at the speaker terminals, the LIMIT PROTECTION LED glows, it means the
output relay will open immediately to prevent the output transistor or other parts from failing.
