NKI1480B DAX60 and DAX120 Amplifiers—Installation
Page 7 of 18 (Jul-98)
Input Connections
The input is unbalanced. The input screw terminals are labeled "COM" (-) and
"INPUT" (+), respectively. The terminal strip is located on the lower right corner,
as viewed from the rear of the chassis. The signal source should deliver at least 300
millivolts into a 13-kilohm load.
To prevent coupling, route the input cables as far from the speaker cables as
possible.
Output Connections
The output screw terminals are located on the upper right corner, as viewed from
the rear of the chassis. The following illustration shows how the output
transformer's split windings are connected with a factory-installed link for most
applications (for applications with the link removed, see "Split-Center-Tap
Operation," below).
Figure 1
The output impedances are as follows:
DAX60
70.7V = 83.3 ohms
25V = 10.4 ohms
DAX120
70.7V = 41.6 ohms
25V = 5.2 ohms
Selecting Balanced or Unbalanced Output
Connections
The balanced outputs for 70.7 volts and 25 volts are for speakers designed for
constant-voltage lines. Each speaker must have a line-matching transformer, and
the speakers must be connected in parallel. The impedance taps on the primaries of
the line-matching transformers indicate how much power will be taken from the
line. Speakers can be added as required until the total wattage absorbed by all of
the transformers is equal to the rated power output of the amplifier. However, it is
good practice to allow an amplifier a headroom of 10% to 20%. For a 60-watt
