Crown Audio 2400 Test 14 Odep Limiting, Test 15 LF Protection, Test 16 Signal to Noise Ratio

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Micro-Tech 2400 Amplifier Service Manual

Electrical Checkout Procedures

Procedure Short: Inject a 60 Hz sine wave at 5 VAC minimum output. After establishing signal, short the output for 10 seconds.

TEST 14: ODEP LIMITING

Spec: No oscillation on ODEP Limiting wave form; either channel controls limiting in Parallel Mono Mode. Initial Conditions: Controls per standard; rag or other obstruction blocking fan so that it does not turn.

Procedure: Load the amplifier to 4 ohms on each channel. Inject a 60 Hz sine wave and adjust for 35 Vrms at the output. After a few minutes observe a wave form similar to Figure 5. Remove the input signal from both channels and allow the amplifier to cool for a few minutes. Switch the amplifier to Parallel Mono and remove the load from Channel 1. Inject the signal into Channel 1 and observe that ODEP limiting occurs at the output of both channels. Remove the load from Channel 2, and install the load on Channel 1. Again, observe that both channels limit. Return all amplifier controls to standard initial conditions. Remove the fan obstruction.

Figure 5. ODEP Limiting Wave Form

TEST 15: LF PROTECTION

Spec: Amplifier mutes for low frequency.

Initial Conditions: Controls per standard.

Procedure: No load. Inject a 0.5 Hz 6 volt peak-to-peak square wave, or a 2 Hz 6VAC sine wave into each channel and verify that each channel cycles into mute.

TEST 16: SIGNAL TO NOISE RATIO

Spec: 100 dB below rated 8 ohm power 20 Hz to 20 kHz. 105 dB A-Weighted.

Initial Conditions: Controls per standard. Short inputs.

Procedure: Load each channel to 8 ohms. Measure less than 645 µV at the output of each channel (20 Hz- 20 kHz bandpass filter).

TEST 17: TURN ON TRANSIENTS

Spec: No dangerous transients.

Initial Conditions: Controls per standard.

Procedure: From an off condition, turn on the amplifier and monitor the output noise at the time of turn on. Note: Turn on noise may increase significantly if the amplifier is cycled off and on.

TEST 18: TURN OFF TRANSIENTS

Spec: No dangerous transients.

Initial Conditions: Controls per standard.

Procedure: From an on condition, turn off the amplifier and monitor the output noise at the time of turn off. Note: Turn off noise may increase significantly if the amplifier is cycled off and on.

TEST 19: INTERMODULATION DISTORTION

Spec at 0 dB Output: 0.01%.

Spec at –35 dB Output: 0.05%.

Initial Conditions: Controls per standard.

Procedure: Load each channel to 8 ohms. Inject a SMPTE standard IM signal (60 Hz and 7 kHz sine wave mixed at 4:1 ratio). Set the 60 Hz portion of the sine wave to 51.5 Volt RMS. Set the 7 kHz portion to 25%. With an IM analyzer measure less than 0.01% IMD. Repeat test at –35 dB (reference 51.5 Volt RMS, 60 Hz portion) and measure less than 0.05% IMD.

TEST 20: CLIPPING

Spec: No protective action during test.

Initial Conditions: Controls per standard.

Procedure: Load each channel to 8 ohms. Inject a 1 kHz sine wave at each input and drive output 6 dB into clip for 10 seconds. The amplifier should not activate any protective circuits (ODEP, Fault, or LF Protection).

POST TESTING

After completion of testing, if all tests are satisfactory, the amplifier controls should be returned to the posi- tions required by customer. If conditions are unknown

or unspecified, factory settings are as follows:

 

Level Controls: 9 to 11 O’Clock.

 

Sensitivity Switch: 0.775V U.S., 1.4V International.

 

Stereo/Mono Switch: Stereo.

 

Ground Lift: Lift.

 

Power: Off.

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Contents MICRO-TECH-2400 Avis Table of Contents Warranty IntroductionScope Parts Information Power SpecificationsVoltage Conversion Front END Operation FeaturesTheory OverviewVoltage Translators Voltage AmplificationGrounded Bridge Topology Last Voltage Amplifiers LVAsLow Side LS High Side HSOutput Device Emulation Protection Odep Positive Electrical Checkout Procedures Test 8 Level Controls Test 7 Phase ResponseTest 12 Output Power Test 6 Voltage GainTest 15 LF Protection Test 16 Signal to Noise RatioPost Testing Test 14 Odep LimitingSupplimental Items Parts List Non-ModulePower Supply Output Assembly ONE PER ChannelOutput Assembly CONT. ONE PER Channel Back Panel AssemblyChassis Front Assembly Miscellaneous Main Chassis AssemblyFuse Module Module InformationModule History Main ModulesResistors M46330-3 Fuse Module & Q43327-8 Display Module Parts ListDiodes LedsTransistors Q43354-2 Output Module Parts List P10429-2 BoardCapacitors InductorsQ43328-6 MT-2400 Original Main Module Use Schematic J Q43328-6 Main Module Parts List D8679-9 BoardResistor Networks Q43328-6 Main Module Parts List Cont. D8679-9 BoardTest Points SwitchesQ43328-6 Main Module Parts List Cont. D8679-9 Board Q43399-7 MT-2400 Main Module Use Schematic J Q43399-7 Main Module Parts List D8827-4 BoardQ43399-7 Main Module Parts List Cont. D8827-4 Board TP1 TP2 U103A U203A Open

2400 specifications

Crown Audio is a well-respected name in the audio industry, known for its powerful and reliable amplifiers. Among its notable products is the Crown Audio 2400, a high-performance amplifier that has garnered attention for its impressive range of features and technologies.

The Crown 2400 is part of the XTi series, which is renowned for delivering exceptional sound quality and performance. A key feature of the 2400 is its innovative Class-I technology. This design allows the amplifier to remain highly efficient while producing substantial power output, making it suitable for a variety of applications, from live sound to installation settings. With a power rating of 2400 watts per channel at 4 ohms, the XTi 2400 provides ample power for driving multiple speakers, ensuring that audio can fill even the largest spaces.

Another standout characteristic of the Crown 2400 is its built-in DSP capabilities. This onboard digital signal processing allows users to tailor the audio output to their specific needs. The DSP features include adjustable crossover settings, EQ adjustments, delay settings, and limiting functions, all accessible through an intuitive LCD interface. This user-friendly design enables quick adjustments in real-time, which is critical in dynamic live performance environments.

The amplifier also boasts advanced connectivity options, including both XLR and 1/4-inch input connectors, allowing for versatile integration with various audio sources. Additionally, the inclusion of Speakon outputs provides secure and reliable connections to speakers, minimizing the risk of accidental disconnects during performance.

Thermal management is another area where the Crown 2400 excels. The amplifier is equipped with a comprehensive cooling system, which includes a variable-speed fan and extensive heat sinking. This design ensures that the amplifier operates efficiently even under heavy load, prolonging its lifespan and maintaining optimal performance.

Finally, the Crown Audio 2400 is designed with durability in mind. Its rugged construction makes it suitable for the rigors of touring and demanding live environments, reinforcing Crown's commitment to quality and reliability.

In conclusion, the Crown Audio 2400 stands out as a powerful and versatile amplifier, offering Class-I technology, robust onboard DSP, excellent connectivity options, advanced thermal management, and durable construction. These features make it an ideal choice for audio professionals seeking reliability and high performance in their sound systems.
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