Sunfire TGA7401 User Manual

Page of 20
User's Manual
9
4.  XLR Inputs
If your preamplifier has XLR 
outputs, connect them to these XLR 
inputs. These balanced connections 
offer superior noise rejection com-
pared to the unbalanced RCA inputs, 
particularly for long cable runs.
The female XLR inputs are wired 
as follows:   
 
Pin 1 is ground
Pin 2 is positive (hot)
Pin 3 is negative (cold)
Balanced connections pass the 
input signal along two conductors. If 
there is any external noise and inter-
ference passing into the audio lines, 
both conductors will receive the same 
amount of noise. This noise is then 
rejected in the balanced input stage of 
the Theater Grand Amplifier. 
5.  Current Source Outputs
 
and:
6.  Voltage Source Outputs
The front left and front right chan-
nels each have a Voltage Source 
output and a Current Source output. 
The remaining channels have Voltage 
Source outputs only.
The Voltage Source outputs have 
a source impedance of approximately 
zero ohms. The Current Source 
outputs have a source impedance of 
approximately one ohm.
The top post of each binding post 
pair is the positive output, and con-
nects to the positive post of your 
speaker. The bottom post of each pair 
is the negative, and connects to the 
negative post of your speaker. The 
posts can accept bare wire, spade 
terminals, and dual or single banana 
connectors.
According to your musical taste, 
you may select the Current Source for 
driving electrostatic, planar magnetic 
or ribbon speakers. For cone based 
systems, use either. For a biwired sys-
tem, use the Current Source for mid-
range and treble drivers, and use the 
Voltage Source for the subwoofer(s). 
These are suggestions only. By all 
means, please feel free to experiment 
with other wiring options. (See page 
14.)
NOTE: The Current Source output 
is a Voltage Source modified to yield 
an impedance of one ohm. This cor-
responds approximately to a vacuum 
tube amplifier's output impedance and 
constitutes the dominant factor in the 
soundstage delivery of classic vacuum 
tube power amplifiers.
7.  Current Source Fuses
Each Current Source output has an 
in-line fuse to protect your speakers. 
If one ever opens, there will be no 
output to that speaker. 
Unplug the amplifier from 
the AC mains power supply 
if you ever have to change 
a fuse.
8.  IEC connector 
The amplifier comes with a detach-
able Linecord which attaches here. 
Make sure it is firmly pushed in place. 
Connect the other end to an AC outlet 
which is properly configured for the 
type of plug and has the correct volt-
age for your model.
9.  Power Switch
Press the top edge of this power 
switch to turn the amplifier on. The 
power LED will turn blue.
The auto/on/off switch (1) controls 
how the amplifier turns on (signal 
sensing, 12V trigger, etc.).
10.  AC Line fuse
If this fuse fails, replace it with the 
exact same type and current rating. 
Note: Always unplug the 
power cord from your AC 
outlet before removing the 
fuse. 
Gently turn the fuse carrier counter-
clockwise to release the fuse.
11.  LED Dimmer
This switch allows you to set the 
brightness of the front panel power 
LED, from low, medium and high. Ad-
just this to match the brightness of the 
other components in your system.
CHAPTER 1