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VU Meter and Meter Amplifier

A two-stage IC operational amplifier is used to isolate the VU meter from the VT-15 output. An output sample is derived from the primary of the output transformer. The meter calibra- tion is set with a 20-turn trimmer potentiometer. Reference level (0 VU) can be set from -20 to over +20dBm. The level indictor is a custom true VU meter conforming to ASA Standard C16.5-1954.

Power Supplies

Primary power from the AC mains is connected to the VT-15 through a standard IEC power input connector. A rear-panel voltage selector slide switch selects either 120 or 220V opera- tion (the switch is labeled “115/230”). The VT-15 can also operate on 100V power with an internal wiring change. The mains fuse is slow-blow type 3AG, rated at 2A for 100/120V operation and 1A for 230V operation. The VT-15 can operate on either 50 or 60Hz power.

The Power switch energizes all power supplies. The Pilot lamp is a type 1819 bulb, operated far below its rated voltage of 28. The life of the bulb is lengthened, and the light output is more compatible with other modern studio equipment. The power transformer is a toroidal unit custom-made for the VT-15.

Filament Supply

The power transformer output is rectified by a bridge rectifier and filtered before being reg- ulated by a three-terminal regulator. This supply also powers all the switching relays in the VT-15, as well as the pilot lamp and VU meter lamps.

+/- 15V Supply

The solid-state control circuitry for the VT-15 compressor requires regulated +15 and -15V supplies.

B+ Supply

Seven separate regulated voltages are required for the plates of the VT-15. The B+ is filtered with long-life, low-leakage, computer-grade filter capacitors before being regulated and exten- sively bypassed and decoupled. The negative side of the supply is grounded.

+48 Supply

The regulator circuitry is on the power supply printed circuit board. The actual output of this supply is 51 volts, which is reduced to 48 volts through the decoupling resistor at the micro- phone input (see Phantom Power, above).

VT-15 Recording Channel

D.W. FEARN

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Crown Audio VT-15 manual VU Meter and Meter Amplifier
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VT-15 specifications

The Crown Audio VT-15 is a robust loudspeaker system that has gained recognition for its advanced technologies and impressive audio performance, making it ideal for various applications, including live events, installations, and broadcast scenarios. Built with durability and sound quality in mind, the VT-15 serves both professionals and enthusiasts in the audio industry.

One of the standout features of the VT-15 is its high-efficiency design, which is achieved through advanced driver technology. The loudspeaker is equipped with a premium 15-inch woofer that delivers powerful low-end reproduction, ensuring a solid bass presence that enhances the overall listening experience. This, combined with a high-frequency compression driver that operates at 1 inch, ensures clear and articulate treble frequencies, resulting in a balanced sound profile suitable for different musical genres.

The VT-15 incorporates Crown’s patented Waveguide technology, designed to provide consistent and controlled sound dispersion. This feature allows the loudspeaker to effectively cover large areas without experiencing significant drop-off in audio fidelity, making it a great choice for medium to large venues. The controlled directivity also means that listeners in various positions within the space can enjoy a similar audio experience, enhancing the performance of any event.

Another defining characteristic of the VT-15 is its rugged construction. Built with a reinforced enclosure, it is designed to withstand the rigors of touring and heavy use in fixed installations. The cabinet is constructed from high-quality materials that minimize vibration and resonance, further contributing to the clarity of sound. Its lightweight design allows for easier transport and setup, making it a practical choice for audio professionals on the go.

In terms of connectivity and compatibility, the VT-15 features versatile input options, allowing it to integrate seamlessly with various audio systems. Whether used in conjunction with other Crown products or compatible equipment from different brands, the VT-15 ensures flexibility in configuration.

Overall, the Crown Audio VT-15 stands out as a high-performance loudspeaker that combines advanced technologies, durability, and sound fidelity. Its powerful drivers and innovative design make it a reliable choice for any professional audio application, providing users with the quality and performance they demand. Whether for live music, presentations, or installations, the VT-15 delivers exceptional audio experiences that elevate any event or setting.
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