This preamplifier module offers excellent sound performance, with a reproduction marked by great transparency and deep bass. Its careful design has been thought to avoid any sound coloration. It uses four JRC 5534D AOPs mounted on DIP8. These are therefore easily modifiable, allowing you to adapt the sound reproduction of the module according to your listening or your system. The power supply stage is equipped with LM317 and LM337 voltage regulators, allowing to provide a clean electrical signal to the audio circuits. The module is delivered with a volume control card and its potentiometer.

To set the OPA offset to 0mV, use the variable resistors marked "p1", "p2", "p3" and "p4" in the diagram below. Using a voltmeter, measure the following points to obtain a value of 0mV by adjusting the variable resistors:

• P1 -> measure with a voltmeter at points E and A
• P2 -> measure with a voltmeter at points E and B
• P3 -> use a voltmeter to measure at points E and C
• P4 -> use a voltmeter to measure at points E and D