Gemini MM-1800/2400 19" 4 Channel Mixers Operations Manual

Introduction

Congratulations on your purchase of the Gemini MM-1800/2400 19" 4 channel stereo mixer. This state-of-the-art mixer features the latest technological advances and is backed by a 1-year warranty, excluding the crossfader. The crossfader is backed by a separate 90-day warranty. Prior to use, it is suggested that you carefully read all instructions.

Features

• 5U, 19" rack-mounted mixer
• 4 stereo channels
• 7 line, 3 Mic, 2 phono/line convertible RCA inputs
• Master, record, booth, & zone RCA outputs
• 1/4" balanced master output
• 2 x 1/4" Mic inputs
• Dual 10 band graphic EQ with on/off switch & LED indicator
• Rotary zone, booth, & cue volume controls
• Assignable crossfader
• Push button cue section per channel with LED indicator
• CUE/PGM fader control allowing cue mix
• XLR-1/4" combo Mic input
• 2 band rotary Mic EQ & volume controls
• Talk over feature
• BNC lamp port
• MM-2400 specific: 6 digital samples with volume, & speed rotary controls
• Master/Mic assignable echo effect switch with repeat & delay controls

Precautions

1. All instructions should be read before using this equipment.
2. To reduce the risk of electrical shock, do not open the unit. Please refer all servicing needs to a Gemini-qualified service technician.
3. Do not expose this unit to direct sunlight or a heat source such as a radiator or stove.
4. This unit should be cleaned only with a damp cloth. Avoid solvents or other cleaning detergents.
5. When moving this equipment, it should be placed in its original carton and packaging. This will reduce the risk of damage during transit.
6. DO NOT EXPOSE THIS UNIT TO RAIN OR MOISTURE.
7. DO NOT USE SPRAY CLEANERS OR LUBRICANTS ON CONTROLS, SURFACES OR SWITCHES.

IN THE USA ~ IF YOU EXPERIENCE PROBLEMS WITH THIS UNIT CALL GEMINI CUSTOMER SERVICE AT: 1 (732) 346-0061. DO NOT ATTEMPT TO RETURN THIS EQUIPMENT TO YOUR DEALER.

Connections

1. VOLTAGE SELECTOR: Before plugging in the power cord, ensure the VOLTAGE SELECTOR switch is set to the correct voltage.
2. POWER CORD: Located on the rear panel is the 115 V/230 V PLUG. Before plugging in the power cord, ensure the POWER SWITCH on the face panel is turned OFF.
3. MASTER RCA OUTPUT: Connects the mixer to your main amplifier using standard audio cables with RCA-type connectors.
4. RECORD RCA OUTPUT: The RECORD output jacks can be used to connect the mixer to the record input of your recording unit, enabling you to record your mix with RCA cables.
5. ZONE OUTPUT: The ZONE output jacks allow the connection of an additional amplifier with RCA cables.
6. BALANCED MASTER: Alternatively, the BALANCED MASTER output jacks connect the mixer to the main amplifier using standard 1/4" TRS connectors. Balanced cables are recommended if the distance to your amp is 10 feet or more.
7. BOOTH OUTPUT: The BOOTH output jacks allow the connection of an additional amplifier with RCA cables.
8. GROUND LIFT SWITCH: Used to reduce background noise & hum when using multiple outlets to power audio equipment. The switch should be in the position that provides the least amount of noise or hum. If noise remains the same in both positions, the GROUND LIFT SWITCH should be kept in the GND position. NOTE: MAKE SURE THE MIXER AND/OR AMPLIFIER IS OFF BEFORE SWITCHING THE GROUND LIFT SWITCH TO PREVENT A TRANSIENT POP THAT MAY DAMAGE YOUR SYSTEM.
9. PHONO/LINE INPUTS: Located on the rear panel are 2 PHONO (PH) /LINE (LN) convertible RCA inputs, & 5 LINE RCA INPUTS. The convertible RCA inputs for CH 2 & CH 3 allow PH and LN level equipment to be connected to the mixer.
10. GROUNDING SCREW: When using a turntable(s), you will need to ground the RCA cable(s) by screwing in the grounding fork(s) to the GROUNDING SCREW located on the rear panel of the mixer. Attach a PHONO (Turntable) ground line to the silver GROUND THUMB SCREW situated at the bottom middle of the rear panel.
11. CONVERTER SWITCHES: To adjust the CONVERTER(s), flip the switch UP to operate PH 1 or PH 2. Flip the switch DOWN to operate through LN 2 or LN 4. The PH INPUTS only accept turntables with a magnetic cartridge. When using turntable(s), ground the RCA cable(s) by screwing the grounding fork(s) to the GROUNDING SCREW. The stereo LN INPUTS only accept line level inputs such as a CD, DAT, MP3, etc.
12. MIC (MICROPHONE) INPUT: The MIC 1 input (face panel) is a combination XLR & 1/4" connector. MIC 2 & MIC 3 inputs (rear panel) accept only 1/4" connectors. The mic inputs accept balanced & unbalanced connections.
13. HEADPHONE OUTPUT: The HEADPHONE OUTPUT located at the front bottom right corner of the MM-1800/2400 accepts any headphone with a standard 1/4" connector and/or adapter. It allows you to CUE your music program before playing it. You can adjust the volume and PGM mix of the HEADPHONE (see CONTROLS). Then, when all connections are made, turn on the mixer by pressing the POWER SWITCH.

Controls

Microphone Section

1. MICROPHONE VOLUME: Plug your main MIC into the MIC 1 combination XLR-1/4" input. The rotary controls for MIC 1 VOLUME CONTROL adjust the decibel level of MIC 1. You may also plug a second & third MIC into the rear panel's MIC 2 & MIC 3 1/4" jacks. MIC 2's decibel level is controlled by the MIC 2 VOLUME CONTROL. MIC 3's decibel level is controlled by the CH 1 SLIDE CONTROL.
2. MICROPHONE EQ and TALKOVER SWITCH: The MICROPHONE EQ lets you control the low frequency and high frequency of the microphone signal. The TALKOVER switch allows you to quickly attenuate the main output so the microphone can be heard over the main music program.

Equalizer (EQ)

1. EQUALIZER (EQ): These units feature dual 10 BAND GRAPHIC EQUALIZER that will allow you to adjust the sound to fit any room. By adjusting any of the 10 EQ SLIDE CONTROLS, you can cut or boost the tonal characteristics of the sound coming from PGM to the speaker(s) by ±12 dB.
2. EQ SWITCH: To activate the dual 10 BAND GRAPHIC EQ, switch the EQ SWITCH to ON, and the EQ LED will light up to indicate that the EQ has been engaged. To deactivate the dual 10 band graphic EQ, switch the EQ SWITCH to OFF, and the EQ LED will turn OFF. When activated, the EQ controls the LEFT and RIGHT side of your stereo speakers. The PGM & EQ are controlled by the MASTER VOLUME. To balance the sound of the PGM playing through the MASTER VOLUME on the LEFT & RIGHT side of your speakers, you must mirror the EQ levels on the LEFT & RIGHT EQ controls.

Mixer Channel (Note: All 4 Channels Have the Same Features)

1. CHANNEL INPUT SELECTOR: The CHANNEL INPUT SELECTOR switches allow you to choose which input will be controlled by that channel's corresponding volume FADER. For example, on CHANNEL (1), the INPUT SELECTOR allows you to choose between LINE 1 and MIC 3. On CHANNEL (2), you can choose between PHONO 1/LINE 2 and LINE 3. On CHANNEL (3), you can choose between PHONO 2/LINE 4 and LINE 5. On CHANNEL (4), you can choose between LINE 6 and LINE 7.
2. CHANNEL CUE SELECTOR SWITCH: The CHANNEL CUE SELECTOR SWITCH allows you to choose which channel you wish to monitor in your headphones. By pressing this switch on any channel, you will be able to listen to that channel's input in your headphones. Multiple CHANNEL SWITCHES can be pressed to monitor more than one input at a time.
3. CHANNEL VOLUME FADER: After you have chosen which input you will use with the INPUT SELECTOR, the corresponding CHANNEL FADER will allow you to adjust the volume for that particular CHANNEL.
4. CROSSFADER ASSIGNMENT: The fader assignment rotary allows you to assign which two of the 4 channels will be controlled by the CROSSFADER. There are 5 selections for either side of the CROSSFADER: CHANNEL 1, 2, 3, 4, or OFF. In the OFF position, the CROSSFADER will not affect the volume of any CHANNEL.

Crossfader

1. CROSS FADER: The CROSS FADER allows you to mix evenly from one source to another. On the MM-1800/2400, the CROSSFADER is assignable between either channels (1) and (2) or channels (3) and (4), depending on the position of the fader assignment push button. The CROSS FADER on the MM-1800/2400 is also removable and can be replaced if the need arises. The RG-45 (RAILGLIDE™) DUAL-RAIL CROSS FADER, which has internal dual stainless steel rails that allow the slider to ride smoothly and accurately from end to end, can be purchased from your local GEMINI dealer.

Stereo/Mono

1. STEREO/MONO SWITCH: You can convert your sound output from STEREO to MONO & vice versa by using the STEREO/MONO SWITCH. Switch to the LEFT to convert to STEREO. Switch RIGHT to convert to MONO.

Zone and Booth Controls

1. ZONE VOLUME ROTARY: Controls the volume level of the ZONE OUTPUT.
2. BOOTH VOLUME ROTARY: Controls the volume level of the BOOTH OUTPUT.

Master Controls

1. MASTER VOLUME CONTROL: Once you are comfortable with the sound level of your music, you may adjust the decibel level of the PGM with the MASTER VOLUME CONTROL. MASTER RCA & BALANCED MASTER OUTPUTS are controlled by the level of the MASTER VOLUME control.
2. BNC LAMP PORT: The BNC LAMP PORT connects a 12 V BNC goose neck lamp, such as the Gemini GNL-700, to the mixer. The goose neck lamp will be powered by your mixer. To turn ON the goose neck lamp, you must first attach the goose neck lamp to the BNC LAMP PORT. Make sure the mixer is OFF when connecting the 12 V BNC lamp. To connect the goose neck lamp, simply align the screw cap of the goose neck lamp to the locking nodules of the BNC LAMP PORT, push down, & twist the screw cap clockwise to lock the 12 V BNC goose neck lamp in place. Then turn ON your mixer. The goose neck lamp should light-up. To detach the goose neck lamp from the BNC LAMP PORT, first make sure your mixer is OFF. Turn OFF your mixer and the goose neck lamp will turn OFF. Unscrew the screw cap by twisting it counterclockwise, then pull up & remove the goose neck lamp.

Monitoring and Output

1. VU METER: The VU METER indicates the decibel level of the MASTER RCA & MASTER BALANCED outputs of the LEFT & RIGHT stereo levels.
2. CUE/PGM FADER: The CUE/PGM FADER determines the mix between the chosen CHANNEL CUE SELECTION and the MAIN OUTPUT mix. To the left is the CUE program and to the right is MAIN OUTPUT.
3. CUE VOLUME ROTARY KNOB: The CUE VOLUME ROTARY KNOB adjusts your HEADPHONE MONITOR OUTPUT volume.
4. POWER SWITCH: Once all of your connections have been made in the rear panel, turn ON the mixer by pressing the POWER SWITCH. Once turned ON, the POWER BAR LED, containing the power symbol located in the VU METER, will be illuminated. Turn OFF the mixer when not in use by pressing the POWER SWITCH to OFF. When the mixer is turned OFF, the POWER BAR LED will not be illuminated.

MM-2400 Controls

Echo Section

1. ECHO SECTION: An echo effect may be applied to the PGM, or MIC 1 & MIC 2 signals by switching the ECHO ASSIGN switch from MIC 1-2 on the LEFT, to OFF in the MIDDLE, to MASTER on the RIGHT & vice versa. When using ECHO, you may adjust the effect of the ECHO by using the rotary REPEAT, DELAY, and ECHO VOLUME controls. To turn the ECHO ASSIGN OFF or lower the ECHO VOLUME.
2. SOUND EFFECTS SECTION: Six different sound effects (APPLAUSE, SCREAM, COPTER, SCRATCH, H2O & GLASS) may be added to your mix by pressing the SOUND EFFECTS CONTROL BUTTONS. The volume of the effects can be adjusted using the rotary EFX VOLUME located above the APPLAUSE effect button. The pitch of the effects can be increased or decreased using the rotary SPEED CONTROL located above the SCRATCH effect button.

Fader Replacement

1. UNSCREW THE FADER (B) SCREWS. DO NOT TOUCH INSIDE SCREWS (C). CAREFULLY REMOVE OLD CROSS FADER AND UNPLUG CABLE (D).
2. PLUG IN THE NEW CROSS FADER INTO CABLE (D) AND PLACE BACK INTO MIXER.
3. SCREW THE CROSS FADER TO MIXER WITH THE FADER PLATE SCREWS (B).
4. REPLACE THE FACE OF THE MIXER AND SCREW THE FOUR SCREWS BACK IN AND REPLACE THE FADER KNOBS.

Specifications

Inputs

• Phono: 3 mV, 47 KOhms
• Line: 150 mV, 27 KOhms
• MIC 1, 2, & 3: 1.5 mV, 2 K Ohm Balanced
• Bass: ±12dB
• High: ±12dB

Outputs

• Amp/Booth: 0 dB 1V, 400 Ohm
• Max: 20V Peak-to-Peak
• Rec: 150 mV, 5 KOhm
• Zone: 0 dB 1V 400 Ohm
• Balanced: 6 dB 2V 400 Ohm

General

• Frequency Response: 20 Hz - 20 KHz +/- 2 dB
• Distortion: 0.02%
• S/N Ratio: Better Than 80 dB
• Talkover Attenuation: -16 dB
• Headphone Impedance: 16 Ohm
• Power Source: 115/230V, 60/50 Hz, 20 W
• Unit Dimensions: W 19" x H 4" x D 9.1" (482.6 x 100.6 x 231.2 mm)
• Weight: 10.34 lbs (4.7 kg)

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTIFICATION FOR IMPROVEMENT.

Safety Instructions (Multilingual Summary)

The manual includes safety instructions in English, Spanish, French, and German. Key safety points include:

• Read all instructions before use.
• Do not open the unit to avoid electric shock; refer servicing to qualified personnel.
• Avoid exposure to direct sunlight, heat sources, rain, or moisture.
• Clean only with a damp cloth; avoid solvents.
• Use caution when moving the unit, preferably in its original packaging.
• Do not use spray cleaners or lubricants on controls or surfaces.
• Ensure proper grounding and polarization of power plugs.
• Protect power cords from being walked on or pinched.
• Ground outdoor antennas to protect against surges.
• Disconnect the unit during lightning storms or prolonged periods of non-use.
• Do not overload outlets or extension cords.
• Never insert objects or liquids into the unit's openings.
• Refer servicing to qualified personnel for any damage or malfunction.
• Use only manufacturer-specified replacement parts.
• Perform safety checks after service.
• Do not mount to a wall or ceiling.
• Keep away from heat sources.

Warranty and Repair

Gemini warrants its products to be free from defects in materials and workmanship for one (1) year from the original purchase date, with exceptions for laser assemblies, cartridges, and crossfaders (90 days). The warranty does not cover damage from abuse, misuse, faulty installation, improper maintenance, or unauthorized repairs. Gemini is not liable for consequential damages. For service in the USA, contact Gemini Customer Service at (732) 346-0061. For returns, include a copy of the original sales receipt and a description of the defect. Allow 2-4 weeks for repair.