Gemini PMX-80 User manual

Page 1
SERVICE MANUAL
PMX-80
Stereo Preamp Mixer
CONTENT’S:
Connections & Operations:.......................................................Page 2-4
Specifications:..............................................................................Page 5
Parts Lists:.................................................................................Page 6-8
PCBs:..........................................................................................Page 7-9
Schematics:.................................................................................Page 10
Gemini Sound Products Corp.
120 Clover Place P.O. Box 6928
Edison, NJ 08818-6928
732-738-9003 (Phone) • 732-738-9006 (Fax)

Page 2
7 6
1
1
2
2
3
3
4
4
5
5
810
9

Page 3
19
11
12 20
29
30
33
23
24
16 34
25
28
27
13 21
22
14
15
31
32
26
17 35
36
18

Page 4
Connections
1. Make sure that the POWER (6) switch is in the OFF position. This unit
comes supplied with a 15 volt AC adaptor. Plug the male pin of the
adaptor into the rear panel POWER JACK (7). Then plug the adaptor
into a proper power source.
2. The MASTER OUTPUT (1) jacks are unbalanced and used to connect
to your main amplifier.
3. The DJ MIC (18) input (found on the front panel) accepts a 1/4"
connector and balanced and unbalanced microphones.
4. On the rear panel are 2 stereo PHONO/LINE (3, 4) inputs, 1 stereo
PHONO (5) input and 1 stereo LINE (2) input. The PHONO/LINE
SWITCHES (8, 10) enable you to set the (3, 4) inputs to Phono or Line.
The phono inputs will accept only turntables with a magnetic cartridge.
A GROUND SCREW (9) 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.
5. Headphones can be plugged into the front panel mounted PHONES
(36) jack.
Operation
1. POWER ON: Once you have made all the equipment connections to
your mixer, press the POWER (6) switch. The power will turn on and
the POWER LED (23) will glow RED.
2. CHANNEL 1: The GAIN (11), HIGH (12), MID (13),and LOW (14)
controls allow you to fully adjust the selected source. Switch # (15)
allows you to select either the PHONO 1 (5) or the PHONO 2/LINE 1
(4) input. The CHANNEL SLIDE (16) controls the output level of this
channel.
3. CHANNEL 2: The GAIN (29), HIGH (30), MID (31),and LOW (32)
controls allow you to fully adjust the selected source. Switch # (33)
allows you to select either the PHONO 3/LINE 2 (3) or the LINE 3 (2)
input. The CHANNEL SLIDE (34) controls the output level of this
channel.
4. KILLING LOW FREQUENCIES: You can use the Kill Feature on each
channel to remove Low band frequencies to create special effects
and improve your mix. Move the KILL SWITCH (17) down to remove
the low band of Channel 1 from your mix. Move the KILL SWITCH
(35) down to remove the low band of Channel 2 from your mix.
5. CROSSFADER SECTION: The CROSSFADER (27) allows the mixing of
one source into another. The left side of the CROSSFADER (27) is
CHANNEL 1 and the right side is CHANNEL 2. The CROSSFADER (27)
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.
The CROSSFADER CURVE SWITCH (28) allows you to adjust the kind
of curve the crossfader has. When the switch is in the left position,
the curve is gradual and gentle. When the switch is in the right
position, the curve is steep and cutting (perfect for scratching). The
CROSSFADER REVERSE SWITCH (26) allows you to reverse the
crossfader so that CHANNEL 2 is controlled by the left side of the
crossfader and CHANNEL 1 is controlled by the right side of the
crossfader.
NONO
NONO
NOTETE
TETE
TE: When the CRCR
CRCR
CROSSFOSSF
OSSFOSSF
OSSFADER REVERSE SWITADER REVERSE SWIT
ADER REVERSE SWITADER REVERSE SWIT
ADER REVERSE SWITCHCH
CHCH
CH
(26)(26)
(26)(26)
(26) is activated (moved to the right), only the crossfader
reverses. The Channel Slides, Gain, Kill Switches and tonal
controls do not reverse.
6. OUTPUT CONTROL SECTION: The level of the MASTER OUTPUT (1) is
controlled by the MASTER (21) control.
7. 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 (19) switch has three settings. When
the MIC/TALKOVER (19) switch is in the left position, the mic and
talkover are both off. When the MIC/TALKOVER (19) switch is in the
center position the mic is on, the MIC INDICATOR will glow, but
talkover is off. When the MIC/TALKOVER (19) switch is in the right
position, the mic and talkover will be on and the volume of all sources
except the Mic input are lowered by 16 dB. MIC LEVEL (20) controls
the level of the MIC.
8. CUE SECTION: By connecting a set of headphones to the PHONES
(36) jack, you can monitor either channel or both together. Move the
CUE SWITCH (25) to the left to monitor CHANNEL 1. Move the CUE
SWITCH (25) to the right to monitor CHANNEL 2. Move the CUE
SWITCH (25) to the center position to split the signals from each
channel so that CHANNEL 1 will be heard in one earphone and
CHANNEL 2 will be heard in the other earphone. Use the CUE LEVEL
(22) control to adjust the headphone volume without effecting the
overall mix.
9. DISPLAY: The DISPLAY (24) indicates the MASTER output.
Specifications
INPUTS:
DJ Mic..............................................................1.5mV 600 Ohm
Phono.........................................................................3mV 47Kohm
Line.......................................................................150 mV 27Kohm
OUTPUTS:
Amp.................................................................0 dB 1V 400ohm
Max..............................20V Peak to Peak
GENERAL:
Low (Channels 1 - 2)........................................................+ 12dB/-32 dB
Mid (Channels 1 - 2).........................................................+ 12dB/-32 dB
High (Channels 1 - 2).....................................................+ 12dB/-32 dB
Gain (Channels 1 - 2)...........................................................0 to -20dB
Frequency Response....................................20Hz - 20KHz +/- 2dB
Distortion................................................................................0.02%
S/N Ratio...............................................................better than 80dB
Talkover Attenuation..............................................................-16dB
Headphone Impedance.........................................................16ohm
Power Source........................................................115V/15V AC 7.5W
230V/15V AC 7.5W
Dimensions.......................................6.5” x 14” x 3” (165 x 355 x 85 mm)
Weight........................................................................................5 lbs (2.27 kg)

Page 5
Description Part #
Cabinet Parts and Packing
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Item #
Parts Lists
002-223
034-020
032-027
021-776
022-367
023-674
002-531
002-704
003-110
148-236
148-239
148-238
003-970
003-969
049-206
159-171
159-216
146-710
049-190
121-003A
111-043A
111-046A
111-049A
111-051A
110-172A
102-025
PANEL CONTROL
PANEL REAR
BOTTOM COVER
BRACKET VR (SUB CHASSIS)
HOLDER FADER
KNOB SWING (LONG)
KNOB PUSH (SMALL)
KNOB SLIDE (BIG)
KNOB ROTARY (B TYPE)
INLAY KNOB (BLACK)
INLAY KNOB (GRAY)
INLAY KNOB (RED)
TRIM VR
HOLDER LED (3f 17mm)
PAD FOOT
DUST PROOF CLOTE-VR
SWING DUST PROOF CLOTH
GND SCREW
BUSHING WIRE
BAND-HEAD TAPPING SCREW/TW-E 3×6(AB)
FLAT-HEAD TAPPING SCREW 3f×6(AB)
BAND-HEAD TAPPING SCREW 3×6(AB)
FLAT-HEAD TAPPING SCREW 3f×12(AB)
BAND-HEAD TAPPING SCREW 3f×5(AB)
BAND-HEAD TAPPING SCREW (TWIN) 3f×8 (AB)
PAN-HEAD MACHINE SCREW 2.6f×4(B)
262-073
262-074
262-075
PRINTED CIRCUIT BOARD PMX80-1
PRINTED CIRCUIT BOARD PMX80-2
PRINTED CIRCUIT BOARD PMX80-3
Description Part #
Printed Circuit Boards
Item #
1
2
3

Page 6
079-027
079-012
081-038
092-135
161-105
161-106
RECTIFIER DIODE 1N4002 (1N4003,1N4004)
ZENER DIODE 1/2W 12V
SLIDE SWITCH
DC JACK 2.5
4P RCA JACK
6P RCA JACK
D3, D4
D1, D2
SW3
J4
J1
J2
Designators Description Part #
Electrical Parts
Item #
1
2
3
4
5
6
074-145
074-114
074-107
INTEGRATED CIRCUIT NJM2068LD
INTEGRATED CIRCUIT NJM7912FA
INTEGRATED CIRCUIT NJM7812FA
IC1, IC2, IC3
IC5
IC4
Designators Description Part #
ICs
Item #
1
2
3
080-104
081-038
082-019
071-161
071-066
071-158
LIGHT EMITTING DIODE (GREEN) 3.15f
SLIDE SWITCH
LEVER SWITCH 4P2C
ROTARY VR 16f L=20 GAIN 10KA×2
ROTARY VR 16f L=20 MIC 50KA
ROTARY VR 16f L=20 MASTER, 500KA×2
D9-12
SW4
SW2, SW5, SW7
VR3, VR9
VR8
VR6
Designators Description Part #
Electrical Parts
Item #
1
2
3
4
5
6
074-145
074-100
074-104
074-154
INTEGRATED CIRCUIT NJM2068LD
INTEGRATED CIRCUIT NJM4556AD
INTEGRATED CIRCUIT NJM4558LD
INTEGRATED CIRCUIT OR LB1423N
IC4
IC10
IC1-2, IC6,
IC8, IC9
IC3, IC7
Designators Description Part #
ICs
Item #
1
2
3
4
Parts Lists - PCB1 Input Output
Parts Lists - PCB2 Main

MAIN PCB
SW2A SW2B SW2C SW2D
C1 10/16 C6 10/16
VR3A 10KAx2
R10 100K
2 31
4 8
IC2A 4558LD
VR3B 10KAx2
R1 2K
R33 1K5
R18 1K5
VR2A
50KEx2
VR2B
50KEx2
VR1A
50KEx2
C25 154
C11 562
C27 154 C15 103
2 31
4 8
IC1A 4558LD
R13 8K2 C12
682
R16 24K
C4 56P
R20 33K
R17 4K7
R29 33K
R30 33K
R7 5K6
R28 2K4
R32 3K6
VR11A 50KA VR11B 50KA
R81 4K3
R36 75K
R80 4K3
R35 75K
VR5A 50KA VR5B 50KA
R58 4K3
R39 75K
R79 4K3
R37 75K
2 31
4 8
IC6A 4558LD
6 57
IC6B 4558LD
C31 10/16 C32 10/16
C33 10/16 C48 10/16
R41 430
R44 47K R68 47K
R66 430
2 31
4 8
IC10A
4556
6 57
IC10B 4556
R120 47
R121 47
1 2 3
J2
D5 LED D4
LED D3
LED D2
LED D1
LED
R45 47
R42 10K R38
4K3
C29 10/16
R50 30K R74
30K
+VCC
-VCC
C44 6.8P
C38 6.8P
CUE
D7 LED
R57 1K
R55
3K3
VR8 50KA
2 31
4 8
IC4A 2068LD
C46 10/16
C16 22/16 C7 22/16
C35 68P
C41 68P
1 2 3
J1
R48 30K1 1%
R40 1K 1% R76
300K
R47 1K 1%
C50 10/16
R56 30K1 1%
6 57
IC4B 2068LD
MIC
C40 22P
D8 LED D9
LED D10
LED D11
LED D12
LED
R69 47
R75 10K R78
4K3
C53 10/16
-VCC
R73 390K R77 390K
R72 300K
VR6A 500KA
VR6B 500KA
C52
0.47/16
C80 22P C81 22P
SW4A SW4B SW4C SW4D
POWER
-15 -9 -3 0 +3 -15 -9 -3 0 +3
NORM/REV MIC OFF MIC ON TALKOVER
1
9
2
6
3
4
7
8
5
IC3
LB1403N
1
9
2
6
3
4
7
8
5
IC7 LB1403N
R53 75K
R61 75K
R43 75K
R64 75K
SW6A
SW6B
SW6C SW6D
CURVE
SW5A SW5B SW5C SW5D
X3
R31 1K5
R26 1K5
VR1B
50KEx2
VR4A
50KEx2
VR4B
50KEx2
C21 154
C3 562
C17 154 C14 103
6 57
IC1B 4558LD
R12 8K2 C20
682
R25 24K
C22 56P
R11 33K
R14 4K7
R24 33K
R27 33K
R8 5K6
R23 2K4
R34 3K6
C9 181
R15 5K6
R9 100K
6 57
IC2B 4558LD
R4 2K
C8 181
R19 5K6
R22 1K R21 1K
IC5-8 IC5-4
IC2-4
IC3-4
IC7-8
IC3-8
IC7-4
IC2-8
C28 10/16 C26 10/16
SW7A SW7B SW7C SW7D
C79 10/16 C76 10/16
VR9A 10KAx2
R111 100K
2 31
4 8
IC9A 4558LD
VR9B 10KAx2
R88 2K
R84 1K5
R101 1K5
VR13A
50KEx2
VR13B
50KEx2
VR12A
50KEx2
C58 154
C74 562
C63 154 C69 103
2 31
4 8
IC8A 4558LD
R105 8K2 C71
682
R109 24K
C75 56P
R100 33K
R112 4K7
R106 33K
R89 33K
R99 5K6
R91 2K4
R92 3K6
R83 1K5
R82 1K5
VR12B
50KEx2
VR10A
50KEx2
VR10B
50KEx2
C57 154
C68 562
C54 154 C70 103
6 57
IC8B 4558LD
R108 8K2 C62
682
R93 24K
C61 56P
R103 33K
R85 4K7
R107 33K
R86 33K
R104 5K6
R90 2K4
R94 3K6
C60 181
R96 5K6
R110 100K
6 57
IC9B 4558LD
R87 2K R95
5K6
R98 1K R97
1K
IC6-8 IC6-4
IC8-8 IC8-4
C55 10/16 C56 10/16
D6 LED
R59 4K3
+VCC -VCC
SW8B SW8A
SW3A SW3B
SW3C
SW3D
SW1A
SW1B
R71 10
C47 22/16
IC2-8
R49 10
C37 22/16
IC3-8
R5 10
C10 22/16
IC5-8
R102 10
C64 22/16
IC6-8
R2 10
C5
22/16
IC7-8
R114 10
C72 22/16
IC8-8
R122 10
C82
220/16
-VCC
R70 10
C51
22/16
IC2-4
R65 10
C43
22/16
IC3-4
R6 10
C2
22/16
IC5-4
R115 10
C78
22/16
IC6-4
R3 10
C13
22/16
IC7-4
R113 10
C65
22/16
IC8-4
R123 10
C83
220/16
+VCC
R46 43K R52 43K R60 43K R63 43K
X1 X5
CH1 CH2 SPL
X2
C30 0.47/16
+VCC -VCC
C19 182
C18
182
C66 182 C67 182
C77 10/16
C59 181
C73 10/16
C24 10/16 C23 10/16
VR7A 50KA VR7B
50KA
C42 47/16 C39 47/16
2 31
4 8
IC5A
4558
6 57
IC5B 4558
R116 2K R117 2K
C36 22P C45 22P
CUE LEVEL
R67 10
C49
22/16
R54 10
C34
22/16
+VCC
-VCC
R118 20K R119 20K
6 5 4 3 2 1
L R
X-FADER
GREEN
GREEN
GREEN RED RED GREEN
GREEN
GREEN RED RED
1 -2 \ 2 -1
X-F
PH1;PH2\LN1
GAIN CH-1
LN3;PH3\LN2
GAIN CH-2
R51 20K R62 20K R124 20K R125 20K
SW4
2 31
4 8
IC1A 2068LD
6 57
IC1B 2068LD
R13 100K
R9 8K2
R12 180
R11 47K
R6 8K2
R7 47K
R1 180 R5
100K
C9 822
C8 56
C11 273
C4 56
C2 273
C6 822
C1 47/16
C5 47/16
R8 1K
R4 1K
C12 10/16 C7 10/16
R14 1K R3 1K
PH1
+1 -1
X1
J1A
J1B
6 57
IC2B 2068LD
2 31
48
IC2A 2068LD
R26 100K
R24 8K2
R28 180
R22 47K
R21 8K2
R16 47K
R17 180 R18
100K
C18 822
C21 56
C23 273
C16 56
C14 273
C17 822
C20 47/16
C24 47/16
R23 1K
R20 1K
C19 10/16 C13 10/16
R25 1K R15 1K
SW1A SW1B
PH2/L2
PH2/L2
+3 -3
2 31
4 8
IC3A
2068LD
6 57
IC3B 2068LD
R41 100K
R40 8K2
R39 180
R38 47K
R35 8K2
R34 47K
R29 180 R33
100K
C33 822
C32 56
C36 273
C28 56
C26 273
C31 822
C25 47/16
C29 47/16
R36 1K
R32
1K
R43 1K R44 1K
C38 101 C39 101
C35 10/16
C37 10/16
C30 10/16
C40 10/16
R31 1K R42
1K
SW2A SW2B
PH3/L2
PH3/L2
L3
+2
X2
J2A J2B
-2
+VCC -VCC
X4X3
D3 1N4002 D4 1N4002
C44 1000/25 C47 1000/25
Vin
1
GND
2
Vout 3
IC4 7812
Vin
2
GND 1
Vout 3
IC5 7912
C43 1/50 C46 1/50
AC15V-JACK
D2 Z 12V D1 Z 12V
SW3B
SW3A
R48 750
R47 750
1 2
J4
POWER
C48 100/16 C45 100/16
R2 10
C3 22/16
+1
R30 10
C27
22/16
-VCC
+2
R10 10
C10 22/16
-1 R37
10
C34 22/16
+VCC
-2
R27 10
C22 22/16
R19 10
C15 22/16
+3 -3
J2C
MASTER
X4
IN/OUT PCB
Page 8
Schematic