3 Band Dynamic Range Expander 3BX

dbx Inc.; Waltham (MA)

  • Year
  • 1977 ?
  • Category
  • Audio Amplifier or -mixer
  • Radiomuseum.org ID
  • 187560

Click on the schematic thumbnail to request the schematic as a free document.

 Technical Specifications

  • Number of Transistors
  • -1
  • Semiconductors
  • Main principle
  • Audio-Amplification
  • Wave bands
  • - without
  • Power type and voltage
  • Alternating Current supply (AC) / 220 Volt
  • Loudspeaker
  • - For headphones or amp.
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: 3 Band Dynamic Range Expander 3BX - dbx Inc.; Waltham MA
  • Shape
  • Tablemodel, with any shape - general.
  • Dimensions (WHD)
  • 450 x 95 x 255 mm / 17.7 x 3.7 x 10 inch
  • Notes
  • Tape noise reduction system continuously ajustable from 1x to 1,5x. S/N 110dB; Z-in: 50K; V-in:300mV; Z-out: 0,1K; Freq-range: 20-20000Hz.
    This apparatus must be inserted between the amplifier and the recorder. Works with any recorder because the compression is linear in contrast to Dolby-NR or Dolby-B where the reproduction level must match the recording level.
    No DBX disc capability.
    Splits the audio band in 3 bands which are treated apart.

    Exspansion: 1:1.5 maximum each band
    Dynamic Range: 110dB (peak signal to weighted background noise ratio)
    Transition Level range (treshold): 30mV to 3V (mid-band)
    Attack and Release Rates (response time): Programe dependant, optimized for each frequency band
    Frequency Response: +-0.5dB, 20hz to 20kHz at an expansion ratio 1.0:1
    Harmonic Distortion: 0.1% 20Hz to 20kHz at any exspansion settings
    Intermodulation Distortion: less than or equal to 0.5% per SMPTE method
    Input noise: 90dB below 1 Volt "A" weighted
    Input impedance: 50kOhms
    Output impedance: The 3BX is designed to feed tape recorder inputs of 5kOhms or greater
    Maximum output level: 7 Volts RMS at 1kHz into 5kOhms load
    Power requirements: 117V AC, 50 or 60Hz, 30Watts Maximum, EU models wired for 220V and 240V

  • Net weight (2.2 lb = 1 kg)
  • 3.9 kg / 8 lb 9.4 oz (8.59 lb)
  • Price in first year of sale
  • 42'500.00 Bfr
  • Source of data
  • -- Original prospect or advert
  • Author
  • Model page created by Dirk Bladt. See "Data change" for further contributors.

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