Diode Isolation of Logic Controls

Two or more control functions using the same logic pins can be isolated with diodes. In this manner a channel can be muted by an overall group mute switch, or by its own cough button (see Figure 19-Channels 1, 3 and 5 modified).

D = 1N4148 OR

GROUP EQUIVALENT

MUTE

Mixer logic may be used with 15-volt CMOS logic if a pull-up resistor is used with each GATE output (see Figure 20-Channel 1 modified).

+

5.1 K

15 V

POWER

 

 

SUPPLY

–

M1 M3 M5

COUGH

BUTTONS

LOGIC

GROUND

CMOS

GATES

LOGIC

GROUND

G1 M1

O1

DIODE ISOLATION OF LOGIC CONTROLS

FIGURE 19

15-VOLT CMOS

FIGURE 20

External Logic Devices

SCM810 logic levels are directly compatible with TTL and 5-volt CMOS log- ic families. For information on logic gate use, refer to the TTL Cookbook and CMOS Cookbook, both by D. Lancaster, Howard Sams Publishing Co.

Digital Controls or Microcomputers

The SCM810 logic pins can interface with custom-designed digital control circuitry or microcomputers for unlimited possibilities of system control functions.

VOLTAGE SELECTION

The SCM810 can be internally modified to operate from 230 Vac, 50/60 Hz power.

WARNING: Voltages in this equipment are hazardous to life. No user-serviceable parts inside. Refer all servicing to qualified service personnel. The safety certifications of the SCM810 do not apply when the operating voltage is changed from the factory setting.

To change the operating voltage, follow these steps.

1.Disconnect the SCM810 from the AC power source.

2.Remove the eight Phillips head screws securing the top cover.

3.Locate Voltage Selector switch SW903 adjacent to power transformer T901 and, using a screwdriver, turn the center rotor to the 230 V posi- tion.

4.Locate Fuse F901 and remove it. Replace it with a 100 mA, 250 V, time delay fuse for 230-volt operation (200 mA, 250 V, slow-blow fuse for 120-volt operation).

Fuse part numbers are:

Fuse Type

Shure Part No.

Whitefishes Part

 

 

No.

 

 

 

100 mA, 250 V

80C258

218.100

 

 

 

200 mA, 250 V

80BC8196

239.200

 

 

 

5.Replace the power cord with a cord rated for 230 V operation, i.e., an IEC appliance connector on the equipment end and a CEE 7/7 (“Schuko”) mains connector on the other.*

Similarly, the SCM810E can be internally modified to operate from 120 Vac, 50/60 Hz power.

*For systems requiring other mains connectors, obtain a power cord with an IEC 320 type mating connector for connection to the SCM810, and an appropriate plug on the other end for connection to the mains. The supplied cord uses Harmonized IEC Cordage with color coding as follows: Brown = Line, Blue = Neutral, Green/Yellow = Ground

13

Page 12 Page 14
Page 13
Image 13
Shure SCM810 manual Voltage Selection, Diode Isolation of Logic Controls, External Logic Devices
Page 12 Page 14

SCM810 specifications

The Shure SCM810 is a state-of-the-art automatic mixer designed for audio professionals seeking precision and reliability in various environments such as live events, broadcasting, and recording studios. This mixer is an integral part of speech reinforcement and meeting applications, providing seamless integration of multiple microphones while ensuring clarity and minimizing feedback.

One of the defining features of the SCM810 is its automatic mixing technology. It employs an advanced algorithm that intelligently manages microphone levels. Instead of manually adjusting levels for each microphone, the SCM810 automatically reduces the gain of inactive mics while boosting those in use. This results in improved sound quality and prevents unwanted noise interference, allowing for a professional audio experience.

The SCM810 supports up to eight microphones, making it versatile enough for panel discussions, roundtable meetings, or larger conferences. In addition to its mixing capabilities, the device boasts a unique "automatic gain control" system that maintains consistent audio levels regardless of the number of active microphones. This ensures that the audience receives a balanced sound across the room without sudden volume fluctuations.

Another notable characteristic of the SCM810 is its low noise operation. The mixer features high-quality preamps that reduce self-noise, providing clear audio reproduction. This is particularly important in environments where clarity is paramount, such as in broadcast applications. The device also includes individual channel gain controls, allowing audio engineers to fine-tune levels to suit specific needs.

In terms of connectivity, the SCM810 features balanced XLR inputs and outputs, ensuring compatibility with a wide range of professional audio equipment. Additionally, it is equipped with a built-in signal processing capability, including a 3-band EQ per channel, which allows for further customization of the audio signal.

Robust and reliable, the Shure SCM810 is built with durability in mind, making it suitable for both permanent installations and portable setups. Its intuitive front-panel controls simplify operation, ensuring that even less experienced users can achieve high-quality audio without extensive training.

In summary, the Shure SCM810 automatic mixer stands out in a crowded market with its advanced automatic mixing algorithms, low noise operation, versatile connectivity, and durable construction. It's an essential tool for anyone requiring dependable, high-fidelity audio control in diverse applications, helping to elevate the audio experience to a professional standard.
Top Page Image Contents