Magnavox Whistle Filter

The Benjamin Magnavox Whistle Filter was a tunable audio-frequency filter introduced in 1936 to suppress the objectionable 9,000-cycle carrier heterodyne whistle often encountered on high-fidelity radio receivers. Designed particularly for use with the Duode 33 loudspeaker, the filter connected in series with the speaker voice coil and provided adjustable attenuation of the whistle frequency while minimising degradation of programme quality.

Technical Details

• Tunable notch (rejector) filter.
• Intended to remove whistles around 9,000 cycles per second (9 kHz).
• Adjustable by top-mounted tuning screw.
• Connected across receiver output terminals.
• Special version designed for the Duode 33 loudspeaker.
• Installed in series with the speaker coil.
• Claimed attenuation:
  • Approximately 15-20 dB at 9,000 cycles.
  • Negligible loss at 8,000 and 10,000 cycles.
• Suitable for high-fidelity receivers and loudspeakers reproducing frequencies above 10,000 cycles.
• Available in versions for:
  • 1-2 ohm speaker coils.
  • 15 ohm speaker coils.

Donde encontrará 7 modelos, 7 con imágenes y 1 con esquemas.
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