The use of a 75 watt-per-channel amplifier can also bring added benefits in certain Installations. For instance, there is often a need to drive one or two full-range high-quality loudspeakers — say, for foreground music — in addition to a CV paging line. (One could imagine such a situation in a small airport terminal that included a restaurant or bar, for example.) In such situations, combining music and paging on a single branch may impose a compromise in sound quality that will frustrate the client. The solution here is to use one channel of a high-quality 75-watt amplifier to drive the CV line, and the other to drive the foreground music system.

Use of Autotransformers

Realistically speaking, many installations will present demands, which cannot be satisfied by the techniques that we’ve discussed thus far. One such case would be a moderate-sized 70-volt music-and-paging system which comprises two separate branches, each of which requires approximately 100 watts from the power amplifier.

In a small application such as this, which clearly does not demand anywhere near the power capability of two bridged 150-watt amplifiers, (one per 70-volt branch) must we go back to using dual-winding step-up transformers in order to match a lower-powered amplifier to the CV lines? Not necessarily.

Consider that the DC isolation afforded by a dual-winding transformer could easily be waived if we employ a professional solid-state amplifier, which incorporates protection against output offsets (as most do nowadays). This opens up the possibility of using an autotransformer to boost the output voltage of the amplifier.

Autotransformers offer a significant advantage over dual-winding transformers in that they impose far less insertion loss (chiefly because of tighter magnetic coupling and lower coil resistance). This translates into far more efficient power transfer.

Remember that insertion loss must be factored into all CV design calculations: power transfer is the name of the game here. An insertion loss of only 1dB corresponds to a power loss of over 20%, and an insertion loss of 3 dB cuts the available amplifier power in half!

Such losses directly affect the number of speakers that can be connected to a CV line. The ElectroVoice Model AT100 is a wide-range autotransformer designed specifically for use in high- quality distributed systems. The AT100 features multiple taps at specified impedance ratios, which were chosen, for maximum utility in CV system implementations. Rated at 100 watts long- term average power capacity, the AT100 can operate with very low distortion at peak levels far exceeding 100 watts, and may be used in CV applications either in step-up (amplifier output matching) or step-down (loudspeaker matching) mode.

Applying the AT100 to a typical installation, we could connect each output of a power amplifier with a 4-ohm power rating of 100 watts to the brown and black terminals of an AT100. The 70-volt lines would then be connected across the respective yellow and black terminals (common carries through). Operating the power amplifier at the equivalent of a 4-ohm load utilizes all of its available power, for further cost efficiency. The extremely low insertion loss of the AT100 allows virtually all of that power to be transferred to the line, maximizing the capabilities of the system.

ElectroVoice/Dynacord BGM Guide

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Dynacord Stereo System manual Use of Autotransformers

Stereo System specifications

The Dynacord Stereo System is a remarkable audio solution designed for audiophiles and professionals seeking superior sound quality and versatility. Renowned for its exceptional engineering, Dynacord emphasizes clarity, power, and precision in all of its products, and this stereo system is no exception.

One of the standout features of the Dynacord Stereo System is its advanced digital signal processing technology. This allows for precise tuning of audio output, ensuring that users experience optimal sound quality regardless of the input source. The system includes various presets tailored for different environments, whether it’s a small room or a large auditorium. This flexibility makes it ideal for both personal and professional settings.

Another significant characteristic of the Dynacord Stereo System is its robust build quality. Constructed from durable materials, the system is designed to withstand rigorous usage, making it a reliable choice for mobile DJs, event organizers, or even studio applications. Additionally, the aesthetics of the system are both modern and stylish, fitting seamlessly into any décor.

The Dynacord Stereo System also features a powerful amplification system. With a high output capacity, the system delivers rich, dynamic sound that fills the space without distortion. It supports a wide frequency range, allowing users to enjoy everything from deep bass to crisp highs, making it versatile for various music genres.

Connectivity is another strong point of the Dynacord Stereo System. The system is equipped with multiple input options, including Bluetooth, USB, and traditional analog inputs, offering convenience for connecting various devices such as smartphones, computers, and instruments. The Bluetooth capability also allows for seamless wireless streaming, further enhancing its usability.

In addition to its audio performance, the Dynacord Stereo System includes user-friendly controls and settings. The intuitive interface allows for easy adjustment of volume, tone, and effects, making it accessible for users of all experience levels. Whether you’re a casual listener or a seasoned sound engineer, the Dynacord system caters to all.

In conclusion, the Dynacord Stereo System stands out with its exceptional sound quality, durable construction, versatile connectivity options, and user-friendly features. This system is not only designed to meet the needs of audio professionals but also aims to enhance the listening experience for everyone. Whether at home, a concert venue, or on the go, the Dynacord Stereo System delivers a powerful performance that truly elevates audio enjoyment.