Gemini Sound PDM-16 Service manual

SERVICE MANUAL

PDM-16

Stereo Preamp Mixer

CONTENT’S:

Connections & Operations:.......................................................Page 2-5

Specifications:..............................................................................Page 5

Parts Lists:.................................................................................Page 5-7

PCBs:........................................................................................Page 8-10

Schematics:.................................................................................Page 11

Gemini Sound Products Corp.

120 Clover Place P.O. Box 6928

Edison, NJ 08818-6928

732-738-9003 (Phone) • 732-738-9006 (Fax)

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36

Connections

1. Before plugging in the power cord, make sure that the VOLTAGE
SELECTOR (36) switch is set to the correct voltage.

NOTENOTE

NOTE: This product is double insulated and not intended

NOTENOTE
to be grounded.

2. Make sure that the POWER (29) switch is in the off position. The
POWER LED (30) will be off.

3. The PDM-16 is supplied with 3 sets of amp output jacks. The MAIN
OUTPUT (37) jacks are unbalanced and used to connect to your

main amplifier. The REC OUTPUT (39) jacks can be used to connect
the mixer to the record input of your recorder enabling you to record
your mix. The BOOTH OUTPUT (38) jacks allow you to hook up an
additional amplifier.

4. The MIC 1 (1) input (found on the front panel) accepts a 1/4" or XLR
connector. The MIC 2 (51) input (found on the rear panel) accepts
1/4" connectors. All accept balanced and unbalanced microphones.

5. On the rear panel are 3 stereo PHONO/LINE (43, 46, 49) inputs and
5 stereo LINE (40, 41, 42, 45, 48) inputs. The PHONO/LINE SWITCH

(44) enables you to set the (43) input to Phono or Line. The PHONO/
LINE SWITCH (47) enables you to set the (46) input to Phono or

Line. The PHONO/LINE SWITCH (50) enables you to set the (49)
input to Phono or Line. The phono inputs will accept only turntables
with a magnetic cartridge. A GROUND SCREW (52) for you to
ground your turntables is located on the rear panel. The stereo line
inputs will accept any line level input such as a CD player, a
cassette player, etc.

6. Headphones can be plugged into the front panel mounted
HEADPHONE (35) jack.

7. The PDM-16 comes with a front panel BNC LIGHT (28) jack. This
jack is for use with a gooseneck light like the Gemini GNL-700.

4. CHANNEL 3: Switch # (13) allows you to select the PHONO 3/LINE
5 (43) or the LINE 6 (42) input. The CHANNEL SLIDE (14) controls
the input level of this channel.

5. CHANNEL 4: Switch # (15) allows you to select the LINE 7 (41) or
the LINE 8 (40) input. The CHANNEL SLIDE (16) controls the input
level of this channel.

6. CROSSFADER SECTION: The CROSSFADER (18) allows the mixing
of one source into another. The PDM-16 features an assignable
crossfader. The ASSIGN (17, 19) switches allow you to select
which channel will play through each side of the crossfader. The
ASSIGN (17) switch has 5 settings (OFF, 1, 2, 3 or 4) and allows
you to select channel 1, 2, 3 or 4 to play through the left side of the
crossfader. The ASSIGN (19) switch has 5 settings (OFF, 1, 2, 3 or

4) and allows you to select channel 1, 2, 3 or 4 to play through the
right side of the crossfader. With the ASSIGN switch in the off
position, that side of the crossfader will be inactive. The
CROSSFADER (18) in your unit is removable and if the need arises
can be easily replaced. Crossfader units are available in three
varieties. Part # RF-45 (which is identical to the crossfader supplied
with the mixer) has a 45 mm travel from side to side. Part # RF-30 is
available with a 30 mm travel distance. Also available is the PSF-45
with a special curve designed for scratch mixing. Just purchase
one of these crossfader units from your Gemini dealer and follow
these instructions:

1. Unscrew the outside FADER PLATE SCREWS (B). Do not
touch the INSIDE SCREWS (C).

2. Carefully lift the fader and unplug the CABLE (D).

3. Plug the new fader into the cable and place it back in the
mixer.

4. Screw the fader to the mixer.

Using the Ground Lift Switch

Depending on your system configuration, sometimes applying the
ground will create a quieter signal path. Sometimes lifting the ground
can eliminate ground loops and hum to create a quieter signal path.

1. With the mixer on, listen to the system in idle mode (no signal
present) with the ground applied (the GROUND LIFT SWITCH (53)
in the left position).

2. Then turn the power off before moving the GROUND LIFT
SWITCH (53). Lift the ground by moving the GROUND LIFT SWITCH
to the right, turn the power back on and listen to determine which
position will provide a signal devoid of background noise and hum.
Keep the GROUND LIFT SWITCH in the ground position if the noise
level remains the same in either position.

CAUTION: DO NOT TERMINATE THE AC GROUND ON THE POWER
MIXER IN ANY WAY. TERMINATION OF THE AC GROUND CAN BE
HAZARDOUS.

Operation

1. POWER ON: Once you have made all the equipment connections to
your mixer, press the POWER SWITCH (29). The power will turn on
and the POWER LED (30) will glow RED.

2. CHANNEL 1: Switch # (9) allows you to select the PHONO 1/LINE 1
(49) or the LINE 2 (48) input. The CHANNEL SLIDE (10) controls the
input level of this channel.

3. CHANNEL 2: Switch # (11) allows you to select the PHONO 2/LINE 3
(46) or the LINE 4 (45) input. The CHANNEL SLIDE (12) controls the
input level of this channel.

7. EQUALIZER SECTION: This unit features dual 7 band GRAPHIC
EQUALIZERS (8, 22) to allow you to adjust the sound for any room.
To activate the equalizer, press the EQ BUTTON (31) (the EQ LED
will light). By adjusting any of the 7 left equalizer slide controls (8),
you can cut or boost the tonal characteristics of the sound coming
from the left speaker by ±12 dB. By adjusting any of the 7 right
equalizer slide controls (22), you can cut or boost the tonal
characteristics of the sound coming from the right speaker by ±12
dB. Deactivate the equalizer by pressing the EQ BUTTON (31) again
(the EQ LED will turn off).

8. OUTPUT CONTROL SECTION: The level of the MAIN OUTPUT (37) is
controlled by the MASTER (24) slide. Activating the MONO (23)
button (the mono LED will light) makes the overall output mono. The
BOOTH (32) control adjusts the level of the BOOTH OUTPUT (38).
HINT: The BOOTH OUTPUT is used by some DJs to run monitor
speakers in their DJ Booth. You can also use it as a second ZONE
or AMP output.

NOTENOTE

NOTE: The

NOTENOTE
The level is set by the channel slides of the selected
channel. The tonal qualities can be controlled by the
equalizers.

9. TALKOVER SECTION: The purpose of the talkover section is to allow
the program playing to be muted so that the mic can be heard above
the music. The MIC/TALKOVER SWITCH (7) controls MIC 1 and MIC
2 and has three settings. When the MIC/TALKOVER SWITCH (7) is

REC OUTPUT (39) REC OUTPUT (39)

REC OUTPUT (39) has no level control.

REC OUTPUT (39) REC OUTPUT (39)

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