Inter-m EMI-300 User manual

EMI-300 7-Channel 2 x 150W Mixing Amplifier
150Wx2 MIXING AMPLIFIER
EMI-300
EMI-300_E(215.9*279.4) 05.12.13 7:20 PM 페이지2

Contents
Contents
Welcome
Warning...............................................................................................................................1
Unpacking ............................................................................................................................2
Installation
Environment..........................................................................................................................2
Important Safety Instructions...................................................................................................2
Features..................................................................................................................................3
Operation ..............................................................................................................................3
Panel
Front Panel............................................................................................................................4
Rear Panel ............................................................................................................................7
Operational Modes............................................................................................................. 9
Speakers Connections....................................................................................................... 10
Connection of Sound Sources.......................................................................................... 13
Initial Settings......................................................................................................................14
Ducking Functions...............................................................................................................14
Insert I/O Jacks ..................................................................................................................14
Master 2 Out.......................................................................................................................15
Mono Sub Out.....................................................................................................................15
Rec Out.................................................................................................................................15
Applications.........................................................................................................................16
Block Diagram ....................................................................................................................17
Specifications ......................................................................................................................18
Service
Procedures..........................................................................................................................19
Schematic ...........................................................................................................................19
Parts List .............................................................................................................................19
Variations and Options .....................................................................................................19
Warranty..............................................................................................................................19

1
EMI-300
7-CHANNEL 2 X 150W MIXING AMPLIFIER
Welcome
Welcome
A personal welcome to you from the management and employees of Inter-M
All of the co-workers here at Inter-M are dedicated to providing excellent products with inherently good value,
and we are delighted you have purchased one of our products.
We sincerely trust this product will provide years of satisfactory service, but if anything is not to your complete
satisfaction, we will endeavor to make things right.
Welcome to Inter-M, and thank you for becoming part of our worldwide extended family!
RISK OF ELECTRIC SHOCK
DO NOT OPEN
CAUTION
CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK.
DO NOT REMOVE COVER (OR BACK).
NO USER-SERVICEABLE PARTS INSIDE.
REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
WARNING
To prevent fire or shock hazard, do not
expose the unit to rain or moisture.
*Do not install this equipment in a confined space such as a book case or similar unit.
*The apparatus shall not be exposed to dripping or splashing and no objects filled with liquids, such vases, shall be placed on the apparatus.
*Worded: “WARNING FOR YOUR PROTECTION PLEASE READ THE FOLLOWING-WATER AND MOISTURE: Unit should not be used
near water(e.g. near a bathtub, washbowl, kitchen sink, laundry tub, in a wet basement, or near a swimming pool, etc). Care should be taken
so than objects do not fall and liquids are not spilled into the enclosure through openings.”
This symbol is intended to alert the user to the
presence of uninsulated “dangerous voltage” within
the product’s enclosure that may be of suf-ficient
magnitude to constitute a risk of electric shock to
persons.
This symbol is intended to alert the user to the
presence of important operation and mainte-nance
(servicing) instructions in the literature accompanying
the appliance.
Caution: To prevent electric shock do not use this (polarized) plug with
an extension cord, receptacle or other outlet unless the blades
can be fully inserted to prevent blade expo-sure.
Attentions: Pour prévenir les chocs électriques ne pas utiliser cette
fiche polarisée avec un prolongateur, une prise de courant
on une autre sortie de courant, sauf si les lames peuvent
étre insérées à fond sans en laisser aucune partie à
découvert.

2EMI-300
7-CHANNEL 2 X 150W MIXING AMPLIFIER
Installation
Installation
Environment
Never place this product in an environment which could alter its performance or reduce its service life. Such
environments usually include high levels of heat, dust, moisture, and vibration.
Important Safety Instructions
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with dry cloth.
7. Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including
amplifiers) that produce heat.
9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades
with one wider than the other. A grounding type plug has two blades and a third grounding prong. The wide
blade or the third prong are provided for your safety. If the provided plug does not fit into your outlet, consult
an electrician for replacement of the obsolete outlet.
10. Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and
the point where they exit from the apparatus.
11. Only use attachments/accessories specified by the manufacturer.
12. Use only with the cart, stand, tripod, bracket, or table specified by the manufacturer, or sold with the apparatus.
When a cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.
13. Unplug this apparatus during lightning storms or when unused for long periods of time.
14. Refer all servicing to qualified service personnel. Servicing is required when the
apparatus has been damaged in any way, such as power-supply cord or plug is
damaged, liquid has been spilled or objects have fallen into the apparatus, the
apparatus has been exposed to rain or moisture, does not operate normally, or has
been dropped.
S3125A
S3125A
Unpacking
Please take a few minutes to read this brief manual and familiarize yourself with the important information
regarding product features, setup and operation.
As with most electronic devices, we strongly recommend you retain the original packaging. In the unlikely event
the product must be returned for servicing, the original packaging (or reasonable equivalent) is required.

3
EMI-300
7-CHANNEL 2 X 150W MIXING AMPLIFIER
Features
Features
- COMPACT, PORTABLE POWERED MIXER
Five selectable stereo line inputs, plus two microphone inputs with integrated “ducking” function on mic input #1.
- POWERFUL AMPLIFICATION
Left and Right 150W amplifiers can be bridged together to provide 300W of power to a single loudspeaker,
with built-in limiter to prevent overload distortion.
- MASTER EQ CONTROLS
Master High/Low EQ on main output.
- PHANTOM POWER
Built-in +20V Phantom Power for condenser microphones.
- BALANCED MONO SUBWOOFER OUTPUT
Line level low-pass output for connection of active subwoofers.
Operation
Operation
Make certain that speakers and input sources are properly connected before switching on.
Keep volume levels at minimum gain and equalization set to 0dB position before switching on.
NOTE: The system’s operation is delayed by approximately three seconds after pressing the AC Mains power
switch. This is due to the built-in protection circuitry, designed to protect the speakers and other system
components.

4EMI-300
7-CHANNEL 2 X 150W MIXING AMPLIFIER
Front Panel
Front Panel
1. POWER SWITCH
This switch is used to switch the unit on and off. When the unit is on, the corresponding power indicator LED
is lit.
CAUTION: Decrease the MASTER gain levels (7) and (8) before switching the EMI-300 on or off.
2. MIC 1 VOLUME CONTROL
This knob controls the MIC 1 channel’s input signal level.
3. MIC 2 VOLUME CONTROL
This knob controls the MIC 2 channel’s input signal level.
4. LINE INPUT VOLUME CONTROL
This knob provides master control of the line input signal level. The active line input is selected using Line
Input switches (12 – 16). Individual line input levels can be set using the rear panel LINE INPUT GAIN
Controls (26).
5. BASS EQ CONTROL
This knob controls the Bass EQ, applied to all input channels. This is a shelving type EQ, providing a boost or
cut of ±6dB at 100Hz.
6. TREBLE EQ CONTROL
This knob controls the Treble EQ, applied to all input channels. This is a shelving type EQ, providing a boost
or cut of ±6dB at 10kHz.
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150Wx2 MIXING AMPLIFIER
EMI-300

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EMI-300
7-CHANNEL 2 X 150W MIXING AMPLIFIER
7. MASTER 1 VOLUME CONTROL
This knob controls the output level of AMP 1 and AMP 2 when in stereo mode, and the output level of AMP 1
when in mono mode. It controls the Mono Sub Out in either mode.
8. MASTER 2 VOLUME CONTROL
This knob controls the output level of the MASTER 2 Out. In stereo mode, the MASTER 2 Out signal is
identical to the signal sent to AMP 1 and AMP 2. In mono mode, it controls the output level of AMP 2, and
carries a signal identical to the signal sent to AMP 1.
9. DUCKING SWITCH
This switch is used to switch the Ducking function on and off. When Ducking is switched on, the
corresponding indicator LED is lit. See page 17 for more information on using the Ducking function.
10. MIC INPUT 1
MIC 1 is a low impedance (“low-Z”) input on a balanced XLR jack for mic-level sources such as condenser
and dynamic microphones. Pin 2 and Pin 3 carry +20V phantom power for condenser mics that require
external power. This input also provides the Ducking function (9).
11. MIC INPUT 2
MIC 2 is a low impedance (“low-Z”) input on a balanced XLR jack for mic-level sources such as condenser
and dynamic microphones. Pin 2 and Pin 3 carry +20V phantom power for condenser mics that require
external power. The Ducking function is not available on this input.
12. CD 1 LINE INPUT SWITCH
Pressing this switch will activate the CD 1 line input of Line Inputs 1-5 (Rear Panel 25). The physical
connectors for the CD 1 input channels are on the rear panel, with the level being controlled both by a rear
panel stereo Line Input Gain Control (Rear Panel 26) and a front panel master Line Input Volume Control
(Front Panel 4).
13. CD 2 LINE INPUT SWITCH
Pressing this switch will activate the CD 2 line input of Line Inputs 1-5 (Rear Panel 25). The physical
connectors for the CD 2 input channels are on the rear panel, with the level being controlled both by a rear
panel stereo Line Input Gain Control (Rear Panel 26) and a front panel master Line Input Volume Control
(Front Panel 4).
14. AUX LINE INPUT SWITCH
Pressing this switch will activate the AUX line input of Line Inputs 1-5 (Rear Panel 25). The physical
connectors for the AUX input channels are on the rear panel, with the level being controlled both by a rear
panel stereo Line Input Gain Control (Rear Panel 26) and a front panel master Line Input Volume Control
(Front Panel 4).
15. VIDEO (AUDIO SIGNAL) LINE INPUT SWITCH
Pressing this switch will activate the VIDEO line input of Line Inputs 1-5 (Rear Panel 25). The physical
connectors for the VIDEO input channels are on the rear panel, with the level being controlled both by a rear
panel stereo Line Input Gain Control (Rear Panel 26) and a front panel master Line Input Volume Control
(Front Panel 4). This input is intended for the audio output of a video playback deck or VCR.

6EMI-300
7-CHANNEL 2 X 150W MIXING AMPLIFIER
16. TAPE LINE INPUT SWITCH
Pressing this switch will activate the Tape line input of Line Inputs 1-5 (25). The physical connectors for the
Tape input channels are on the rear panel, with the level being controlled both by a rear panel stereo Line
Input Gain Control (26) and a front panel master Line Input Volume Control (Front Panel 4).
17. OUTPUT METER AND LIMITER LED
The six-segment LED meter indicates the signal levels being sent to AMP 1 and AMP 2. When the sixth
segment “LIMIT” LED is lit, it indicates that the signal is near clipping, and that the limiter circuitry has
engaged to prevent overload distortion.

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EMI-300
7-CHANNEL 2 X 150W MIXING AMPLIFIER
Rear Panel
Rear Panel
18. AMP1/AMP2 SPEAKER OUT
The EMI-300 contains a two-channel power amp. The two channels can be used independently to supply
150W+150W, or bridged to provide 300W output power.
If the channels are used independently, two speakers may be connected to the AMP 1 and AMP 2 outputs.
When used in bridged mode, connect speakers only to the Bridged Speaker Out (19).
19. BRIDGED SPEAKER OUT
If the channels are used in Bridged mode, a single speaker may be connected to the BRIDGED SPEAKER OUT
connectors only. When connecting a speaker to the BRIDGED SPEAKER OUT, use an 8Ωto 16Ωspeaker (do
not connect a speaker that is less than 8Ω). In this case, be careful not to connect the speaker to the AMP 1
or AMP 2 outputs.
20. MASTER 2 OUT
The signal at this output is identical to the signal sent to AMP 1 and AMP 2 when the EMI-300 is in stereo
mode. Connect these balanced +4dB XLR outputs to an additional power amp or powered speakers for
additional power or monitoring capability, or to a two-track tape recorder. The output level of MASTER 2
OUT is controlled by the Master 2 Volume Control (8).
21. MONO SUB OUT
The MONO SUB OUT signal is a mono version of the signal controlled by Master 1, and is sent through a
lowpass filter with a 100Hz cutoff at 12dB/octave. Connect this balanced +4dB XLR output to your powered
subwoofer speaker. The MONO SUB OUT level is adjusted using the Master 1 Volume Control.
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MODEL NO. EMI-300

8EMI-300
7-CHANNEL 2 X 150W MIXING AMPLIFIER
22. AMP ROUTING SWITCH
This switch selects between three output mode settings for the power amp.
MASTER 1 TO AMP 1+2
This setting should be used for stereo mode, with the stereo signal being output to the AMP 1 (L) and AMP 2
(R) outputs.
MASTER 1 TO AMP 1/ MASTER 2 TO AMP 2
This is a mono setting, and allows for two independent speaker sets to be controlled by individual master
volumes.
MASTER 1 BRIDGE MODE
In this setting, the two power amp channels are bridged, resulting in an output of 300W mono. The signal is
only output from the BRIDGE OUT speaker connectors in this instance.
23. MODE SWITCHES
These switches will set either the internal amplifiers controlled by Master 1 or the Master 2 Out controlled by
the Master 2 Volume Control to either stereo or mono operation.
24. INSERT I/O JACKS
These are unbalanced TRS jacks, used for patching an effect or dynamics processor into the channel’s signal
path just before the channel fader. They are located before the power amplifier in the signal chain, and will
not affect the MASTER 2 OUT XLR outputs (20) and (21). See the INSERT I/O Jacks Section on page 17 for
more information.
A standard stereo “Y” cable can be used for this purpose, with tip=out, ring=in, and sleeve=ground. The
nominal output level/impedance is 0dB/10kΩ, and the nominal input level/impedance is 0dB/600Ω.
Connecting to the INSERT I/O jacks will break the signal flow, so completing the circuit of output to input is
necessary.
25. LINE INPUTS 1-5
Each channel provides a high impedance (“high-Z”) stereo inputs on left and right unbalanced RCA phono
jacks for connecting line-level devices such as CD players, keyboards, video and audio playback decks, etc.
One input can be selected at a time using the front panel LINE INPUT SWITCHES (12-16).
26. LINE INPUT GAIN CONTROLS
This knob controls the signal level of the Line Input 1-5 (25). Start out with each of these controls set to the
center position, then individually set these controls to compensate for the different output levels your stereo
sources.
27. REC OUT
Connect the line inputs of your mixdown deck to the REC OUT line outputs for recording your stereo mix. The
signal output from the REC OUT is identical to the signal sent to the MASTER 1 output, yet is not affected by
the setting of the MASTER EQ and MASTER VOLUME controls and works in every operational mode.