21 AUDIO FREQUENCY AMPLIFIERS COMPRISING ASSEMBLED UNITS FOR AMPLIFYING ELECTRIC SIGNALS AND INCLUDING AUDIO FREQUENCY TRANSFORMERS, POWER TRANSFORMERS AND CHOKE COILS; HIGH VOLTAGE IGNITION TRANSFORMERS; INTERCOMMUNICATING SOUND AMPLIFYING AND TRANSMITTING SYSTEMS AND PARTS THEREOF COMPRISING SPEAKERS, AMPLIFIERS, MICROPHONES, INTERCONNECTING CIRCUITS, AND ENERGIZING DEVICES WHEREBY CONVERSATION AT SPACED POINTS MAY BE HEARD AT SUCH POINTS; SOUND PRODUCTION EQUIPMENT COMPRISING A SUITABLE HOUSING AND ELECTRIC AMPLIFIER, ONE OR MORE ELECTRIC LOUD SPEAKERS, AN ELECTRIC PHONOGRAPH INCLUDING DRIVE MEANS, TURN TABLE AND PICK-UP, A MICROPHONE AND SUITABLE CONTROLLING DEVICES WHEREBY MUSIC OR OTHER SOUND MAY BE REPRODUCED AND/OR AMPLIFIED; ONE WAY SOUND DISTRIBUTION SYSTEMS
Trademark: 71591389
