3 Band Dynamic Range Expander 3BX
- United States of America (USA)
- Manufacturer / Brand
- dbx Inc.; Waltham (MA)
- 1977 ?
- Audio Amplifier or -mixer
- Radiomuseum.org ID
Click on the schematic thumbnail to request the schematic as a free document.
- Number of Transistors
- Main principle
- Wave bands
- - without
- Power type and voltage
- Alternating Current supply (AC) / 220 Volt
- - For headphones or amp.
- Metal case
- from Radiomuseum.org
- Model: 3 Band Dynamic Range Expander 3BX - dbx Inc.; Waltham MA
- Tablemodel, with any shape - general.
- Dimensions (WHD)
- 450 x 95 x 255 mm / 17.7 x 3.7 x 10 inch
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
- Model page created by Dirk Bladt. See "Data change" for further contributors.
- Other Models
Here you find 24 models, 19 with images and 4 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
All listed radios etc. from dbx Inc.; Waltham (MA)