Speakers and Speaker Wiring, Time Tones

Speakers and Speaker Wiring

The MCP35A control panel of the SI and PI products is designed to use 25-volt distributed speakers. These speakers have line-matching transformers with various power level taps. 8-ohm speakers or speakers without line-matching transformers cannot be used with the SI and PI products.

Distributed speakers can be tapped at various power levels and this is determined by which wire from the speaker’s transformer is used for connection. The user must determine which power tap gives acceptable vol- ume in a given location. However, it is best to tap the speakers at the lowest acceptable power tap in order to ensure that enough speakers can be connected to the system without overloading the system amplifier.

The chart below shows the wire colors and power taps for the T725 transformers used in all Bogen distributed speakers.

		T725
Leads	25V	70V
Black	COM	COM
Brown	4
Red	2
Orange	1
Yellow	1/2	4
Green	1/4	2
Blue	1/8	1
Violet		1/2
Gray		1/4
White		1/8

For SI35A and PI35A applications,

use the 25V column for speaker connections.

Caution

Do not attempt to connect a 25V speaker directly to the MCP35A, using GND as one of the connecting points. This could seriously damage the MCP35A because the unit uses a balanced output when con- nected to the speakers lines.

The MCP35A control panel of the PI and SI contains an internal amplifier with 35W power handling capability. Therefore, the combined power of all the system speakers cannot exceed 35W. To determine the required power that the system amplifier must handle, add up all the power taps selected for all the speakers in the sys- tem. This is the total system power requirement. If the total of the speaker power taps is too high for the sys- tem to handle, it may be necessary to tap the speakers at the next lowest setting in order to keep from overload- ing the amplifier. In many instances, the required speaker tap setting will be either 1/4 or 1/2 watt (you should also factor in 20% additional power loss through wires, transformers, etc. as a safety margin). The MCP35A’s 35-watt amplifier should provide sufficient power for most applications.

If the system’s power requirements are greater than 35 watts and cannot be lowered, it may be necessary to use an external booster amp. The booster amp replaces the internal amplifier of the MCP35A. Booster amp con- nections are described later in this manual.

Time Tones

A tone signal sounds through all speakers when the clock terminal is grounded through a closure from a master clock. Reference call out #6 on page 7.

PI35A, SI35A specifications

The Bogen PI35A is a versatile and high-performance amplifier that is designed for commercial sound reinforcement applications. With its robust construction and advanced features, the PI35A is perfect for schools, conference rooms, and various public address environments.

One of the main features of the Bogen PI35A is its powerful 35-watt output capability. This ensures that audio can be delivered at a sufficient volume to cover medium-sized areas, making it an ideal choice for both speech and music playback. The amplifier is designed to provide clear and intelligible sound, which is essential for effective communication in any setting.

The PI35A also boasts a range of input options, including microphone, line-level, and auxiliary inputs. This flexibility allows users to connect various audio sources, such as microphones for live speaking engagements, mixing consoles, or even portable media players. The built-in tone controls, including bass and treble adjustments, enable users to tailor the audio output to suit their specific needs and preferences.

Technologically speaking, the Bogen PI35A incorporates advanced circuit designs to ensure reliability and longevity. The amplifier includes built-in protection circuitry that safeguards against overloads, short circuits, and overheating, allowing it to operate efficiently in demanding environments. Additionally, the amplifier operates quietly, ensuring that background noise does not interfere with important announcements or presentations.

One of the standout characteristics of the PI35A is its compact and lightweight design. Weighing in at just a few pounds, this amplifier can be easily mounted in various configurations, whether it be on a rack or wall-mounted, optimizing space while maintaining accessibility. The durable enclosure is engineered to withstand the rigors of installation in busy public areas.

In conclusion, the Bogen PI35A is a reliable and feature-rich amplifier that offers flexibility and excellent sound quality for various applications. Its combination of powerful output, multiple input options, advanced protection circuitry, and compact design makes it a solid choice for users seeking a high-performance sound reinforcement solution. Whether used for educational purposes, corporate events, or public announcements, the PI35A delivers a professional audio experience tailored to meet diverse needs.