Specifications

CONSTRUCTION
G.S. SAGOO
A
n electronics hobbyist always finds
pleasure in listening to a song
from a cassette player assembled
with his own hands. Here are the details
of a stereo cassette player with the fol-
lowing features, which many electronics
enthusiasts would love to assemble and
enjoy:
1. Digital 4-function selector (radio,
tape, line input, and transmit).
2. Four sound modes (normal, low
boost, hi-fi, and x-bas).
3. Bass and treble controls.
4. Function and output level displays.
5. Built-in
FM transmitter for cordless
head-phones.
Description
The functional block diagram of the ste-
REJO G. PAREKKATTU
STEREO CASSETTE PLAYER
reo cassette player is shown in Fig. 1.
The circuit may be divided into three func-
tional sections as shown in the block dia-
gram.
Section I (Fig. 2). It comprises a ste-
reo head preamplifier, a function selec-
tor, and an FM transmitter. The pream-
plifier is built around IC LA3161. The out-
puts from 200-ohm stereo R
/P (record/
play) head are connected to the left and
right input pins 1 and 8 of LA3161 pream-
plifier. A 9V regulated power supply, ob-
tained from the voltage regulator built
around transistor T1, is used for the
preamplifier. The outputs of this pream-
plifier are routed to the function selector
configured around two CD4066 (quad bi-
polar analogue switches) and an HEF4017
(decade counter).
When any control input pin (5, 6, 12,
Fig. 1: Functional block diagram of stereo cassette player
Fig. 2: Preamplifier and function selector and FM TX (Section I)
30