Scribd
Upload
1K views1 page

Stereo Tape Head Preamplifier For PC Sound Card: T.K. Hareendran

This document describes a stereo tape head preamplifier circuit that can playback audio cassettes through a PC sound card. The circuit uses an LA3161 stereo head preamp IC to amplify and equalize weak electrical signals from tape playback heads. The amplified signals are then sent to a line amplifier and volume control circuit before being output. A relay switching circuit is also included to selectively connect either the tape preamp output or an external audio source to the sound card input. The complete circuit can be built on veroboard and enclosed in a small case with input/output jacks.

Uploaded by

kasamvasu
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
1K views1 page

Stereo Tape Head Preamplifier For PC Sound Card: T.K. Hareendran

This document describes a stereo tape head preamplifier circuit that can playback audio cassettes through a PC sound card. The circuit uses an LA3161 stereo head preamp IC to amplify and equalize weak electrical signals from tape playback heads. The amplified signals are then sent to a line amplifier and volume control circuit before being output. A relay switching circuit is also included to selectively connect either the tape preamp output or an external audio source to the sound card input. The complete circuit can be built on veroboard and enclosed in a small case with input/output jacks.

Uploaded by

kasamvasu
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
You are on page 1/ 1

CIRCUIT

IDEAS

STEREO TAPE HEAD PREAMPLIFIER


FOR PC SOUND CARD
MAR
IL KU
SUN

T.K. HAREENDRAN
ere is a stereo tape head preamplifier circuit for your PC sound
card that can playback your
favourite audio cassette through the PC.
Audio signals from this circuit can be di-

The amplified and equalised signals


available at output pins 3 and 6 of IC1
are coupled to the inputs of line amplifier
circuit built around transistors T1 (via capacitor C5, potmeter VR1, resistor R8, and

rectly connected to the stereo-input (lineinput) socket of the PC sound card for
further processing.
The circuit is built around a popular
stereo head preamp IC LA3161. Weak
electrical signals from the playback heads
are fed to pins 1 and 8 of IC1 via DC
decoupling capacitors C1 and C6, respectively. Components between pins 2 and 3
and pins 6 and 7 provide adequate
equalisation to the signals for a normal
tape playback.

capacitor C12) and T2 (via capacitor C10,


potmeter VR2, resistor R19, and capacitor C16), respectively. Left and right playback levels can be adjusted by variable
resistors VR1 and VR2. The audio signals
are finally available at the negative ends
of capacitors C13 and C17.
The circuit wired around relay driver
transistor T3 serves as a simple source
selector. This is added deliberately to help
the user share the common PC sound card
line-input terminal for operating some

ELECTRONICS FOR YOU  OCTOBER 2001

other audio device as well.


When the preamplifier is in off state,
switching relay RL1 is off and it allows
connection of external signals to the sound
card. When the preamplifier is turned on,
the relay is energised by transistor T3
after a short delay determined by the values of resistor R21 and capacitor C23. On
energisation, the relay contacts
changeover the signals to internal source,
i.e. the head preamplifier.
After constructing the whole circuit
on a veroboard, enclose it in a mini metallic cabinet with level controls and sock-

ets at suitable points. Use a regulated


1A, 12V DC power supply for powering
the whole circuit including the tape deck
mechanism. (A 1A, 18V AC secondary
transformer with 4700F, 40V electrolytic
capacitor and 78M12 regulator is sufficient.)
You can use any kind of tape deck
mechanism with this circuit. Use of goodquality playback head and well-screened
wires are recommended.

You might also like