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" I N P U
Fig. 3.2 Micro-Tech 1000 Rear Panel
Fig. 3.3 Banana (MDP) Plug
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Fig. 3.4 Typical System Hookup
plug (Fig. 3.3). Check for a snug fit because plugging
and unplugging loosens these connections.
Figure 3.4 shows a typical system hookup.
Use speaker cables of sufficient gauge (thickness) for
the length used. Otherwise power is lost through cable
heating, and damping factor is decreased due to cable
r e s i s t a n c e . R e f e r to the nomograph ( F i g . 3 . 5 ) for
recommended wire sizes.
To prevent high-frequency oscillations:
1.
Lace speaker cables together.
2.
Keep speaker cables well separated from input
cables.
3.
Never connect the amplifier's input and output
grounds together.
4.
As a last resort, lowpass filter the input signal.
3.5 Monophonic Operation
Parallel mono mode is recommended for loads less
than 4 ohms. Bridge mono mode is recommended for
loads 4 ohms or greater.
Bridge Mono Operation - Method A
1.
Remove the bottom cover.
2.
Add a jumper wire as shown in Fig. 3.6.
3.
Replace the cover.
4.
Push in the "Parallel Mono" pushbutton switch on
the rear of the amplifier.
5.
Plug the input line into the Channel 1 input jack,
and adjust the level with the Channel 1 input-level
control only.
) è
6.
Do not use the Channel 2 input; otherwise distortion
may result. Unplug the input to Channel 2 when
operating in mono, and turn the Channel 2 level
control fully CCW.
Fig. 3.5 Wire-Size Nomograph
Bridge Mono Operation - Method B
This method is desirable for installations in which the
amplifier is converted frequently between stereo and
mono operation. With this method, the amplifier can
be r e p l a c e d without r e - s e t t i n g the p a r a l l e l - m o n o
switch, because switching is automatic.
For an unbalanced input signal, m a k e a Y-adapter
using stereo phone plugs a s follows:
1.
Connect the signal cable HOT lead to Ch. 1 tip and
Ch. 2 ring.
2.
Connect the signal cable S H I E L D to Ch. 1 sleeve
(ground) and ring, and to Ch. 2 sleeve and tip.
3.
Connect the speakers a s shown in Fig. 3.6.
For a balanced input signal, make a Y-adapter using
stereo phone plugs as follows:
1.
Connect the signal-cable POSITIVE lead to Ch. 1
tip and Ch. 2 ring.
2.
Connect the signal-cable NEGATIVE lead to Ch. 1
ring and Ch. 2 tip.
3.
Connect the signal-cable SHI ELD to Ch. l a n d Ch.
2 sleeves (grounds).
4.
Connect the loudspeakers a s shown in Fig. 3.6.
Caution: Be certain that all equipment (meters,
switches, etc.) connected to the mono output lines is
balanced. To prevent oscillations, both sides of the line
must be totally isolated from the input grounds.
The output from the Micro-Tech in B R I D G E MONO is
BALANCED and is isolated from the chassis, and from
the input grounds. B e c a u s e of the panel-mounting
configuration of the dual-banana output j a c k , it is
possible to use only one banana plug. Connect both
load leads to the red or "hot" connectors only.
3-3
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