• Country
• United States of America (USA)

• Manufacturer / Brand
• KLH R&D Co.; Cambridge (MA)

• Year
• 1978 ?

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

• Radiomuseum.org ID
• 99204

• Number of Transistors
• 4

• Semiconductors

• Wave bands
• - without

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

• Loudspeaker
• - For headphones or amp.

• Material
• Metal case

• from Radiomuseum.org
• Model: Dynamic Noise Filter DNF1201A - KLH R&D Co.; Cambridge MA

• Shape
• Rack

• Dimensions (WHD)
• 485 x 90 x 200 mm / 19.1 x 3.5 x 7.9 inch

• Notes
• 2-channel dynamic noise filter for audio signals. 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 predecessor of this model (with additional setup for '78') is the Burwen DNF1201. Entitled as 'KLH Burwen Research' the manufacturer is KLH, even though they wrote 'Burwen Research Inc., a subsidiary of KLH' on the back.

• Source of data
• -- Collector info (Sammler)

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

• Other Models

• Here you find 23 models, 21 with images and 5 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from KLH R&D Co.; Cambridge (MA)