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The Altec Models 632C, 633A/C
moving coil dynamic microphones

The Altec 633A

Additional documentation on these mics is available.

The Altec 633C

632C Specifications

  • Type: Moving Coil Dynamic
  • Frequency Response: 100 to 10,000 cycles
  • Output Impedance: 30/50 ohms
  • Output Level: −55 dBm/10 dynes/cm²
  • Dimensions: 2⅛ inches long, 2 inches diameter
  • Weight: 8¼ ounces
  • Finish: Instrument gray
  • Mounting: ⅝"-24 thread

633A/C Specifications

  • Type: Moving Coil Dynamic
  • Frequency Response: 35 to 12,000 cycles
  • Output Impedance: 633A 30/50 ohms,
    633C 30/50, 150/250 ohms (selectable)
  • Output Level: −55 dBm/10 dynes/cm²
  • Dimensions: 3½ inches long, 2 inches diameter
  • Weight: 633A 10 ounces, 633C 13 ounces
  • Finish: Instrument gray
  • Mounting: ⅝"-24 thread
The Altec 633C

IMPEDANCE SELECTION AND CONNECTIONS

Impedance setting

632C and 633A Microphones
The 632C and 633A Dynamic Microphones are single impedance mics. The impedance is 30/50 ohms. Lo­cated on the bottom plate (Figure 1) are three terminals. Terminal № 1 is the common terminal. Terminal № 2 is the hot or positive side of the microphone. Terminal G is ground for use with a balanced system. The 632C comes with two yellow leads connected to terminals 1 and 2. To connect the microphone to an unbalanced line, connect terminals 1 and G together.

The Altec 633C The Altec 633C Impedance setting

633C Microphone
The 633C Dynamic Microphone is a dual-impedance mic. The two imped­ances are 30/50 ohms and 150/250 ohms. For selection of 30/50 ohms (Figure 2), connect the terminal marked 30-50 to the hot or positive side of the audio cable. Connect the common lead to the Terminal marked 0. For connection of the 150/150 ohm side of the microphone (Figure 3), connect the hot or positive side of the audio cable to the terminal marked 150-250 and the common lead to the terminal marked 0. If an unbalanced line is required, connect terminals G and 0 together.

The Altec 633C

Text and illustrations are from the Altec Lansing 632C, 633A/C Operating Instructions,
Altec Lansing Publication No. 40465−1, Copyright © March, 1966. Downloadable below.

All photographs above are via the courtesy of Ellis Dawson.

vinscullydodgers

Vin Scully recaps the Brooklyn Dodgers’ history of near-misses after they lost the 1953
World Series. The Dodgers would happily get their World Series title two years later.

EDS cover

Download the 632C, 633A/C instruction sheet.

 

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