Mackie M1200/M1400 owner manual Gain, DB for those of you sittin’ there with your calculator

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FEATURE DESCRIPTIONS

GAIN

These giant knobs control the levels to the output section of the M•1200/M•1400 amplifi- ers. You’ll notice that their travel is detented, meaning there are 40 built-in “resting points” so you can easily set both controls to the same level. Usually, these controls are set all the way up.

The gain structure of the amplifier is de- signed so that a +4 dBu (1.23V rms) input signal drives the amplifier to full rated power into 4 ohms (40V rms @ 4 ohms = 400 watts for the M•1200). This is how the sensitivity

of an amplifier is defined. In this case, it equates to a voltage gain of about 30 dB (okay,

30.24dB for those of you sittin’ there with your calculator!).

The graphics around the knob depict two different methods for setting the gain. The in-

ner circle is marked in dB, calibrated from off (∞) to 30. This represents the amount of volt- age gain from input to output. When using professional equipment with +4 dBu output levels, set the GAIN control all the way up to 30.

The outer circle is labeled in volts, with in- dications of 1V, 2V, and 3V. These correspond to the input sensitivity of the amplifier. With the GAIN control all the way up (fully clockwise), the input sensitivity is 1.23V, which works well with professional equipment operating at a nominal +4 dBu level.

On the other hand, you may want your lis- tening level to be quieter than the M•1200/ M•1400’s maximum level. For instance, if you’re using the M•1200/M•1400 as a control room amp, and your control room is the size of a telephone booth, you’ll probably never want to hear the amp at its maximum level.

You can set the GAIN con-

trols as low as you like.

However, reducing the

GAIN controls requires an

increased input level to reach full power at the amplifier’s output. See the sidebar “Constant Gain vs. Constant Sensitivity” for a better understanding of how this works.

Like all amplifier controls, you’ll typically determine the optimal settings during installa-

Constant Gain vs. Constant Sensitivity There are two viewpoints, or philosophies,

regarding the gain structure of power amplifi- ers — constant gain and constant sensitivity.

Constant gain means that regardless of the output power of the amplifier, the gain from in- put to output remains the same. (By the way, this refers to the full gain of the amplifier, with the gain or level controls all the way up.) Within a product line of constant gain power amplifiers, as the output power rating of an amplifier increases, the level of the input volt- age must also increase.

For example, if an amplifier is rated at 100W into an 8-ohm load, and it has 26 dB of gain, it requires an input signal of 1.4V rms to drive it to full power. This is about +5 dBu, a reasonable operating point for professional gear.

Now take an amplifier rated at 200W into an 8-ohm load. If it also has a gain of 26 dB, it re- quires an input signal of 2.0V rms to drive it to full power, or +8 dBu.

This can become problematic as the power of the amplifier increases. What if you have a power amp rated at 800W into 8 ohms? This will require an input signal of 4.0V rms to drive it to full power. This equates to a whopping +14.3 dBu!! You’ve just robbed your mixer of

10 dB of headroom. You’ll either have to have a good limiter to keep the transient peaks down, or turn down the level from the mixer and not use all the power available from the amplifier.

Constant sensitivity means that regardless of the output power of the amplifier, the input sensitivity of the amplifier (the input voltage required to attain full output power) remains the same. As the output power of an amplifier increases, the gain of the amplifier must also increase.

Referring back to the previous example, an amplifier rated at 100W into 8 ohms with a gain of 26 dB requires an input signal of 1.4V rms to drive it to full power. It has an input sensitivity of 1.4V rms. In order for the 200W amplifier to reach full power into 8 ohms with a 1.4V rms input signal, it must have a gain of 29 dB. And the 800W amplifier will require a gain of 35 dB to reach full power with a 1.4V input signal.

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Contents Speaker Outputs Safety Instructions While this Noise level exposures shown in this chartManent hearing loss To suffi Protectors CientlyM1200/M1400 amps Be sure the Power switch is off before making connectionsQuick Start M1200/M1400 Amps can be mountedThings You Must Remember 1/4 TS connectors are wired Tip = hot + and sleeve = coldStart dancing, but don’t let the ants out of your pants Arcane Mysteries Illuminated Application DiagramsPlug for the Connectors Section General Precautions ConsiderationsContents Application M1400 Main Speakers and Stage Monitors with ONE Amplifier M1200/M1400 Stereo System with Bridged Subwoofer DB for those of you sittin’ there with your calculator GainHigh Current Design MetersOutputs. Both the Protect and the Short LEDs light up SIGProtect ShortTemp Status PowerIf you shut down your System, turn off your ampli Power CordFiers first. When powering Speaker OutputsChoose to terminate your Speaker cables with An amp’s signal routingInput Be Aware Should youPin Shield Hot + PinCold Pin Ring Constant Directivity ThruLOW CUT Filter More on Constant Directivity Horns AMP ModeNEL 1 inputs only BridgeOutput Application LimiterSelect a rolloff point, via the Frequency Here’s how to configure it Turn the M1200/M1400’s Power offTurn the M1200/M1400’s Power on. Woof SubwooferSubwoofer Frequency switch setting either 63Hz or 125Hz Thermal Considerations AC Power ConsiderationsRack Mounting Feet Input WiringOutput Wiring AC Power DistributionLoad Gauge Impedance Wire70V Distribution Systems Are both Gain knobs set to the same position? Warranty ServiceTroubleshooting Make sure the AMP Mode switch is set to BridgeWood-Red Rd. NE Woodinville, WA RepairMackie Designs Term for a sound mixer, usually a large desk-like mixer Sound Pressure Level SPL measured with an a weighting filterEMI See Hertz FrequencyControl affecting the final output of a Signal whose level falls between -10 dBu and +30 dBuMale counterpart to the phone jack. See above Unity gain TRSInstruments XLR Connectors⁄4 TS Phone Plugs and Jacks Unbalancing a LineBinding Posts SpeakonsBalanced lines offer increased immunity Balanced LinesBalanced line is a three Don’t use hardware-store light dimmers GroundingHere are some guidelines Optimizing Sound System LevelsDynamic Range Next set the master output level faderBiamplified System with Active Crossover Ohm speaker load is twice as heavy as a Do the Math OHMS, Loads and SuchAs a load gets heavier, its impedance in ohms decreases Specifications Limiter Section IndicatorsPower Consumption AC Line PowerFreq Mackie Designs Inc All Rights Reserved Colophon

M1200/M1400 specifications

The Mackie M1200 and M1400 are two prominent power amplifiers that have gained recognition for their reliability, performance, and innovative design in the professional audio field. Engineered for both live sound and studio applications, these amplifiers deliver exceptional sound quality and unmatched power, making them a favorite among audio professionals.

One of the standout features of the M1200 and M1400 is their impressive power output. The M1200 boasts a power output of 1200 watts at 4 ohms, while the M1400 takes it a step further with 1400 watts at 4 ohms. This substantial power allows users to drive a wide range of speakers, making them suitable for various settings, from small clubs to large venues and outdoor events. Furthermore, they excel in providing clean, distortion-free sound even at high volumes.

Both models incorporate Mackie's patented Smart Protect DSP technology. This intelligent thermal and signal protection system helps prevent overheating and ensures that the amplifiers operate within safe limits, enhancing longevity and reliability. The DSP also contributes to superior sound quality, maintaining clarity and detail across different frequency ranges.

Another key feature of the M1200 and M1400 is their rugged construction. Designed for the rigors of touring and live performances, these amplifiers feature a sturdy chassis that withstands the challenges of transport and heavy use. Their efficient heatsink design allows for effective cooling, ensuring the amplifiers remain operational even under demanding conditions.

In terms of connectivity, both models are versatile. They offer XLR and TRS inputs, allowing compatibility with a variety of audio sources. The outputs include Neutrik Speakon connections, providing secure and reliable speaker connections. Additionally, the amplifiers have built-in limiters that help to prevent speaker damage by controlling signal levels.

The user-friendly interface of the M1200 and M1400 includes level control knobs, LED indicators for power and signal, and a comprehensive set of output options. This simplicity ensures that audio engineers can quickly adjust settings to cater to specific acoustic environments, making setup and operation seamless.

In conclusion, the Mackie M1200 and M1400 power amplifiers are remarkable for their powerful performance, durability, and advanced technology. Whether for live sound reinforcement or studio applications, these amplifiers continue to set a standard in audio excellence, proving their worth to sound engineers worldwide.
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