Adcom GFA-555MS Stereo Amplifier User Manual


 
accommodate either bare wire, tinned wire, terminal pins, spade lugs, or "banana plugs",
both single and dual. The output terminals are color-coded RED and BLACK to indicate
polarity. To insure correct stereo phasing, you must connect the RED output terminal
(labeled "+") to the loudspeaker input terminal color-coded RED (or labeled POSITIVE, "+",
POS,8OHMS or 4 OHMS). The BLACK binding post terminal on the amplifier (labeled "-")
should be connected to the BLACK loudspeaker terminal (or labeled NEG, "-", C, COM,
COMMON, G, or GROUND).
NOTE
The GFA-555ms is polarity correct; that is, it does not invert "phase". Any positive-going
signal at its inputs will appear as a positive-going signal at its outputs.
The RIGHT STEREO OUTPUT should be connected to the right-channel loudspeaker, as
you face the pair of loudspeakers, and the LEFT STEREO OUTPUT to the left-channel
loudspeaker.
Be certain, when the GFA-555ms is used in Its stereophonic mode, the
STEREO/BRIDGED MONO INPUT switch is in the STEREO position. Otherwise, the
amplifier will not operate in the stereo mode. You will amplify only the left channel through
both outputs of the amplifier. For further clarification, please refer to the section
STEREO/BRIDGED MONO INPUT/OUTPUT.
In order to insure that connections to the loudspeakers are correct, you must be able to
identify each wire conductor of the loudspeaker cables at both ends of the cables. This is
relatively easy to do since most loudspeaker cables consist of two parallel, stranded
conductors in a flexible insulation, with a coding system for wire identification. Sometimes
there is a colored "tracer" wrapped around one of the conductors; some cords have one of
the conductors colored silver and the other copper; some have a "ridge" molded on the
insulation on one of the conductors, while others are marked with a "+" and/or "_". Your
ADCOM dealer also sells special loudspeaker interconnecting cables and these are most
often labeled with respect to polarity.
Generally speaking, when making connections to the loudspeakers from the amplifier, it is
very important to use the correct type and size of wire in order to avoid unnecessary loss of
amplifier power in the cable, reduction of amplifier damping factor (DF) and other
undesirable conditions. For runs up to 12 feet, ordinary "zip" or lamp cord, made of AWG18
stranded wire and available in a variety of insulation colors may be used. For runs up to 40
feet, AWG16 stranded wire should be used to prevent power losses. For lengths over 40 feet