Adcom GFA 7705 - Manual (Page 11)

11
Inputs (1)
To preserve the correct effects, be certain to connect the RCA cables to the proper RCA-input
connector. If the cables are color coded, then use this sequence for the connections:
Blue............................................................ Left Front
Red ........................................................... Right Front
Green.............................................................. Center
White with Blue Stripe ................................. Left Surround
White with Red Stripe .................................Right Surround
The recommended maximum RCA cable capacitance should be less than or equal to 30pF per foot
when measured between the two conductors, and less than or equal to 50pF per foot when measured
between one conductor and the shield.
Outputs (2)
NOTE: The GFA-7705/07 is “polarity correct”. That is, it does not invert phase from input to output.
Any positive signals at its inputs will appear as a positive signal at its outputs.
In connecting the amplifi er to the loudspeaker, it is vital to maintain proper polarity (positive to
positive, negative to negative). On the GFA-7705/07, the positive terminal is color coded RED and
labeled “ +,” and the negative is color coded BLACK and labeled “-.”
The positive terminal on the corresponding loudspeaker will be color coded RED, or will be labeled “+,”
“pos,” “positive,” “8 ohms,” or “4 ohms.” The negative terminal on the speaker will be color coded
BLACK, or will be labeled “-,” “neg,” negative,” “C,” “Common,” “G,” or “ground.”
It is necessary that your speaker cables be terminated with “U”-type spade connectors. These will give
the most contact area insuring long-term reliability. The spade
connector should have a maximum width of 0.57 inches and an
opening width of no less than 0.25” (see diagram on right).
To properly connect the speaker cable to the binding posts turn the insulated head of the binding post
clockwise until the wire or connector is fi rmly secured. Finger pressure is suffi cient and you should not
use pliers or other tools which could damage or over-tighten the binding-post assembly. The binding
posts have been designed in such a way that fi nger pressure is all that is required to cause a “pinching”
action among the different metal surfaces to ensure proper connection.
It is very important to use the correct size of wire in order to avoid unnecessary loss of amplifi er power
in the cable, reduction of amplifi er damping factor and other undesirable conditions. Recommended
capacitance of the speaker wire should not exceed 50pF per foot. This insures high frequencies will not
be rolled-off.