ADAPTOL COMPANY

MODEL CT1

Adaptol CT - 1: Miniature Superheterodyne Data

The following data will enable you to understand your tuner, and service it with a minimum of test equipment.

The circuit is a straightforward superheterodyne of high efficiency, due to the employment of modern, best quality components and tubes. The 12BE6 is a dual purpose oscillator and mixer. The 12SF7 is used as a high gain I.F. stage, diode detector, and A.V.C. tube. The 50B5 is used as a rectifier because it does not open as readily as a conventional rectifier under overloads, and it permits a smaller value of dropping resistor, with lower dissipation below chassis.

The following voltages should appear under normal operation, with a strong Broadcast signal tuned in

A.V.C. 3-5 volts Plate at output of filter 100-120 volts Total current 20-25 milliamperes Oscillator grid bias 9-11 volts Power consumption 20 watts 110 volts D.C. 60 cycle A.C. All voltages measured with a VTVM with respect to B- (not chassis)

1.F. is 455 k.c.

I.F.'s are permeability tuned, drift free units.

The following gain checks are approximate, depending on the equipment used, line voltage, etc. Tuner set for 1000 kc.

Antenna to converter grid 4 to 5 Converter grid to IF grid 30 IF grid to diode
60 Audio Output on strong signal on five foot antenna.5 volt RMS Selectivity 10 times down 8 kilocycles off resonance at 1000 k.c.

Note: Floating ground is used
Signifies B minus
Signifies chassis
Rotating tuning condenser to extreme counterclockwise position silences tuner for " standby permits instant operation, thus eliminating necessity for extra switch on amplifier.