Circuit

Siren with 7400

Originally there is used Russian chip К155ЛА3, but you can use analog device SN7400N.

Datasheet of SN7400N you will find here .
Basic datasheet of К155ЛА3 is here .

70W power amplifier

The power of all resistors, except R1, R3, R13, R14 and potentiometers should be at least 0.5 W. R13 and R14 is wiry resistors. C9 and C11 are not required, but it may be necessary to tune amplifier. Amplifier's  maximum output is about 70W at load of 4 ohms.

20W power amplifier

R3 is termo - resistor. Amplifier's  maximum output is about 20W at load of 4 ohms. R13 and R12 is wiry resistors.

This is a simple music mixer scheme. Inputs of the device can be connected to three different music signal sources. The signal on output You can mix with R1, R2, R3. Operational amplifier U1 - MC1456 or MC1741.

Datasheet of MC1456.
Datasheet of MC1741.

Simple siren 4