ICOM SM-10 Compressor/Graphic Equalizer Desktop Microphone

Introduction

Thank you for purchasing the ICOM SM-10 desktop microphone for your ICOM transceiver. This microphone is designed for base station use and includes an electret condenser microphone element with a compressor amplifier and a tunable equalizer to provide maximum control over your transmitted signal's audio characteristics. The SM-10 is highly sensitive and produces clear, crisp audio. Please read these instructions thoroughly before operation to fully enjoy the benefits of your high-performance transceiver with the SM-10.

Description

The SM-10 features several key components designed to enhance audio quality:

• Graphic Equalizer Amplifier Included: With four individual equalizer amplifiers, the transmit audio can be adjusted for different applications. Higher frequencies can be accentuated for DX contacts to give your signal more punch, or lower frequencies can be emphasized for softer, more pleasant audio during casual conversations.
• High-Quality Compressor Amplifier Included: The compressor ensures constant transmit output power even when voice levels fluctuate. The compression level can be set to one of three different values (HIGH, MED, LOW) for maximum operating flexibility.
• Uses Uni-Directional Microphone Element: A uni-directional microphone element is used to achieve a high audio-to-noise ratio, effectively suppressing background noise.
• Level Meter and Output Level Control Included: The output level can be monitored using the VU meter on the SM-10's top panel, and the output can be continuously adjusted with the OUTPUT LEVEL control.
• UP/DOWN Function Switches: These convenient switches allow for easy frequency shifts.

Specifications

1. General

• Current drain (13.8V DC): EQUALIZER ON Approx. 15mA, EQUALIZER OFF Approx. 8mA
• Dimensions: 230 mm (W) x 110 mm (D) x 30 mm (H)
• Weight: 1.9 kg

2. Microphone Circuit

• Microphone: Broadband electret condenser
• Number of semiconductors: Transistors 13, Diodes 5
• Type of microphone: Uni-directional
• Output impedance: 100 Ω
• Output level: 0 ~ 30 mV
• Compression level: HIGH 45dB, MED 35dB, LOW 10dB

3. Equalizer Circuit

• Number of semiconductors: ICs 3
• Signal-to-noise ratio: 80 dB
• Distortion: 0.05 %
• Equalizer: 4 stages (±12 dB)

Note: The SM-10 may be used with the following ICOM transceivers: IC-761, IC-751/A, IC-745, IC-735, IC-575A, IC-275A/E/H, IC-271A/E/H, IC-28A/E/H, IC-27A/E/H, IC-375A, IC-38A, IC-37A, IC-475A/E, IC-471A/E, IC-48A/E, IC-47A/E, IC-45A/E, IC-1271A/E, IC-1200A/E, IC-120, IC-3200A/E, IC-900A/E.

Control Functions

1. Graphic Equalizer Controls: The graphic equalizer has four stages with center frequencies at 250, 600, 1200, and 2400 Hz. Adjusting these controls in the positive (+) direction emphasizes voice at the respective frequencies. For example, to boost high-frequency components of a bassy voice, move the 1200 and 2400 Hz controls in the + direction.
2. Output Level Control: Rotate this control clockwise to increase the output level. Adjust for the correct output level as indicated by the meter (refer to item 8).
3. Compressor and Equalizer On/Off Switch: Slide the switch to COMP to power the compressor circuit. Slide the switch to EQUALIZER ON to activate the graphic equalizer controls.
4. Power Indicator: A red LED indicates when the POWER switch is ON. The LED also blinks during transmission when the PTT or LOCK switches are depressed.
5. Compression Level Switch: Select one of three speech compression levels:
   • HIGH: Compressor amplifier gain is approximately 45 dB. Use for soft voices or when speaking from a distance. Note that background noise may also be amplified.
   • MED: Compressor amplifier gain is approximately 35 dB. This is the normal operating position. Maintain a distance of about 10 cm (4 inches) from the microphone while speaking.
   • LOW: Compressor amplifier gain is approximately 10 dB. Compression is noticeable only with loud voices. Normal voice levels do not trigger the compressor.
6. PTT Switch: Push this switch to transmit and speak into the microphone. The red LED power indicator blinks while this switch is held down. Release the switch to return to receive mode.
7. Lock Switch: Push this switch once to lock the transmitter in transmit mode. The red LED power indicator blinks while in transmit mode. Push the PTT switch to release the lock function and return to receive mode.
8. Output Level Indicator: This meter monitors the output level from the SM-10. Adjust the OUTPUT LEVEL control for a 0 dB meter reading on the top scale.
9. Up Switch: Push to increase the operating frequency. Holding the switch down causes the transceiver to step continuously through frequencies.
10. Down Switch: Push to decrease the operating frequency. Holding the switch down causes the transceiver to step continuously through frequencies.
11. Microphone Element: The SM-10 uses a sensitive, uni-directional condenser microphone element to produce the clearest audio signal possible.

Manufacturer Information

ICOM INCORPORATED
6-9-16, KAMIHIGASHI, HIRANO-KU, OSAKA 547, JAPAN