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( )
Use the remaining wire to connect lug #3 Of R40 (solder) to circuit board point ''H" (solder).
( )
Solder the tinned end of the braid of the fourth harness to lug #2 of R42.
( )
Use the short wire coming from the center of this harness to connect lug #2 of R41 (solder)
to circuit board point ''K" (solder).
( )
Use one of the two longer wires to connect lug #1 of R42 (solder) to circuit board point ''M"
( solder) .
( )
Use the remaining wire to connect lug #3 Of R42 (solder) to circuit board point ''L" (solder).
( )
Prepare a 6 inch length of co-axial shielded cable by stripping 3/4 inch of the outer
insulation from each end to expose the braided shield.
At one end of this cable cut the
shielding braid off even with the end of the outer insulating jacket.
On the other end of
this cable car.efully push the braided shield back and use a pencil to form a hole in the
braid at a point near where the outer insulation ends.
Loop the inner conductor through
this hole as shown in figul.e 7.
Strip 1/4 inch of insulation from the exposed inner
conductor at each end of the cable.
( )
Solder the shield of the wire just prepared to the shield already connected to lug #2 of R42.
Make this connection as close to lug #2 of R42 as possible.
( )
Solder the inner conductor of this cable to lug #2 of R44.
( )
Connect and solder the inner conductor at the opposite end of the cable just installed to
circuit board point ''T''.
( )
In a manner identical to the first, prepare a second piece of co-axial cable 3 inches long.
( )
Solder the shield of the cable just prepared to lug #1 of R41.
This operation will be similar
to soldering the cable harness shields, a crimped mechanical connection is not necessary.
( )
Solder the inner conductor of the cable just installed to lug #2 of R43.
( )
Connect and solder the inner conductor at the opposite end of this cable to circuit board
point ''P''.
( )
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clips are a tight fit, it may be necessary to bend the narrow end of the clips slightly to fit
the holes.
( )
With all front panel controls rotated fully counter-clockwise push on the knobs with the
pointers aligned as follows:
Pan pots to the ''t" in "left".
Level controls to the ''n" in "min''.
Master gains to the ''m" in "min''.
Once installed, these knobs will be difficult or impossible to remove - make sure that they
are aligned as above and that the potentiometer hardware is completely tight before installa-
tion.
THIS COMPLETES ASSEMBLY OF THE PAIA 4711 MIXER.
TESTING
Before beginning testing, thoroughly check the bottom of the circuit board for solder bridges and
ccold solder joints.
Check parts placement and orientation or polarization.
Pay particular attention
to the extremely tight area between the upper and lower rows of potentiometers to make sure that
none of the solder lugs on the lower row of potentiometers are touching the bodies of the potentiometers
aleovethem.
Begin testing by applying power to the flea clips on the rear edge of the circuit board; " + " to a
source of +9 volts, ''-" to -9 volts and the connector at the ground symbol " i " to the common
ppoint of the two voltage sources.
If a stereo power amplifier is available, use shielded cable to
comect the left and right outputs of the 4711 to the left and right inputs of the amplifier.
If only a
mono amplifier is available the procedure to be outlined can be followed but it will require that the
amplifier's single input be moved back and forth between the two outputs of the mixer.
Connect a signal source with an output level between .1 and I volt peak to peak to input i of the
471.1.
The triangle output of a PAIA Voltage Controlled Oscillator works well for these purposes.
If the 4711 Mixer and the signal source that you are using for testing do not share a common power
supply it will be necessary to use shielded cable to connect the two, otherwise the common ground
iB established through the power supply.
NOTE: The bottom of the circuit board can pick up 60 Hz. hum from the wc>rk surface.
If excessive
hum is observed during testing place the mixer on a sheet of aluminum foil connected to the amplifier
ground.
A piece of paper or other insula,tor must be placed between the 4711 and the foil to prevent
shorts from the bottom of the board.
This hum should be eliminated when the unit is installed in its
no rmal housing.
Set the channel 1 level control to "max. " and the left and right Master Gains to ''max. " Turn the
channel 1 "Pan" control from fully left to fully right and observe that the sound coming from the
amplifier's speakers follows the action of the pot first coming fully from the left channel then
fully from the right.
With the pan pot knob pointer aligned with the dot under the"pan" designation
observe that the sound comes from both channels of the amplifier.
With the pan pot set fully left, rotate the left Master Gain control from ''max. " to ''min. " and
observe that the volume of the tone from the left channel of the amplifier is attenuated to the point
that it is almost inaudible (NOTE: the master gain controls are not designed to turn the respective
channels completely off).
Repeat this procedure for the right channel and observe equivalent results.
Once again align the pan pot with the center dot and set the left and right master gain controls to
''max. " Rotate the channel llevel control from "max. " to "min. " and observe that at the ''min. "
setting the tone is completely inaudible from either chamel of the amplifier.
Repeat these procedures for each input channel of the mixer.
USING
As the name implies, a mixer is used to mix signals together in such a way that the output
contains only the information presented to the inputs without adding any harmonic distortion or
spurious signals of its own.
But, as we shall shortly see, a mixer can also be used as a signal
routing device allowing the user to select from a number of different input signals and route them
to various destinations.
Operation of the controls is as follows:
INPUTS 1. 2. 3 & 4
The four miniature phone jacks along the lower edge of the module provide
10K ohm inputs to the mixer.
These inputs are direct coupled to the mixer's internal amplifiers
and any signal applied to them should not have a significant d. c. component. All PAIA 272o & 4700
series synthesizer modules meet these requirements.
LEVEL CONTROIjs
Above each input jack is the level control for that input.
At the "min. "
setting of these controls the associated input is considered to be tuned off and signals at that
input will not appear in the output.
Clockwise rotation of the control increases the percentage
of signal from the corresponding input that will appear in the output.
PAN POTS
The pan pots above each channel's level control allows the corresponding input
to be asigned either to the left or right outputs or split in any proportion between the two.
The
pan pots are arranged so that the mid-range of the control splits the signal equally between the
left and right chalmels.
Rotation to the left or right of center causes a much greater attenuation
of the unused channel than it does boost to the selected channel.
For example, as the pan pot is
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