• Country
• United States of America (USA)

• Manufacturer / Brand
• Burwen Laboratories Inc.; Lexington (MA)

• Year
• 1972

• Category
• Miscellaneous (Other, Various) - see notes

• Radiomuseum.org ID
• 99139

• Number of Transistors
• 4

• Semiconductors

• Main principle
• something special ? Please give information (notes)

• Wave bands
• - without

• Power type and voltage
• Alternating Current supply (AC) / (110) 220 Volt

• Loudspeaker
• - For headphones or amp.

• Material
• Various materials

• from Radiomuseum.org
• Model: Dynamic Noise Filter DNF1201 - Burwen Laboratories Inc.;

• Shape
• Book-shelf unit.

• Dimensions (WHD)
• 290 x 95 x 220 mm / 11.4 x 3.7 x 8.7 inch

• Notes
• 2-channel dynamic noise filter for audio signals. Two setups including one for records with 78 RPM. Bandwidth controller with sliding low-pass cut-off frequency from 27kHz down to 600Hz, depending of signal-amplitude and -frequency. Circuit uses 16 op-amp stages plus the transistors. Originally developed to compete the Dolby NR system. The successor of this model (but without the setup for '78') is the DNF1201A by KLH.

• Net weight (2.2 lb = 1 kg)
• 3.4 kg / 7 lb 7.8 oz (7.489 lb)

• Source of data
• - - Data from my own collection

• Mentioned in
• - - Data from my own collection

• Author
• Model page created by Georg Richter. See "Data change" for further contributors.

• Other Models

• Here you find 2 models, 1 with images and 0 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from Burwen Laboratories Inc.; Lexington (MA)