Page 91 - Build Your Own Transistor Radios a Hobbyists Guide to High-Performance and Low-Powered Radio Circuits

(gain of about 1) for buffering the detected audio signal and providing a

low-impedance drive to the audio output stage.
However, in the typical transistor refiex radios, the RF/AF amplifier provides voltage
gain (e.g., >1). These two-transistor radios sometimes were called "boy's radio"
because they were more like toys. The performance of the two-transistor radio was
very poor in sensitivity, selectivity, and audio output compared with the
superheterodyne types, but it was adequate for listening to local stations.

Typically in the 1960s, two-transistor radios cost about $3 to $4, whereas
superheterodyne radios cost at least $6 or $7. The average price for a
superheterodyne radio was about $9 to $10 for imported versions (e.g., from
Japan) and at least $14 to $15 for those made in the United States.
Now let's look at a typical two-transistor reflex radio made in the 1960s, the

Windsor radio, as shown in Figure 6-1.

WI~IlISOI
t·

---------

--------
--_ _----
..

Figure 6-1 Commerciallv made two-transistor reflex radio.
Figure 6-1 shows the front side and its back cover with a schematic for the Windsor
radio. This radio drained about 8 mA to 10 mA at 9 volts. When tuned to a strong
local station, it delivered sufficient volume to fill a room.

If one looks carefully at the schematic, there is a radio-frequency choke (RFC)
transformer and two audio transformers in this radio. The audio transformers are
still available today, but the RFC transformer is not.