Analog Audio Preamplifier



This is my very very old audio preamplifier based on the TDA1524 Integrated Circuit.
For many years it has provided volume and tone control to an old amplifier I built when I was still a secondary school student.


Design and Implementation

The whole schematic was based in the reference circuits from the datasheets.



This is the base schematic for the tone and volume controls from the TDA1524 datasheet:

preamp schematic

I added a VU-meter to the box where the circuit is assembled, based on a Sanyo LB1403 IC. This is also the reference schematic and it works very well:

The power supply uses a 7812 voltage regulator with a large filtering capacitor and powers both circuits. It's not shown here.


Unfortunately the PCB was design in Tango2 a very powerful and also very old CAD software for MS-DOS and I have no idea were my floppies and pcb files are! So no PCB for this one!



I have some pictures of the box. Please ignore the messy wire installation inside the box:

inside front back view working with pa



The volume and tone controls work very well. The VU-meter needs calibration prior to use but that is very simple to do. Just input some sine signal with 0.707V and adjust both channel trimmers in the VU-meter until the 0dB LED lights (LED at pin 3).



Some datasheets of the main components:





Published on Saturday 2007/07/21, last modified on Wednesday 2012/02/15