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2.29 RIAA equalizer
Circuit 70: RIAA equalizer
Setup information
Install the three transistors, the eight resistors and the two ceramic capacitors as shown in Fig. 2.70. Install
the three electrolytic capacitors. The 18 jumper wires are next. Finally connect the Piezo element. Check the
placement on the board again and only then connect the battery.
You can significantly increase the sensitivity of the Piezo element by using a sound plate or even a sound
box. Read more about it in Chap. 1.2.3
Experiment
We need an RIAA equalizer to play vinyl records. This corrects the cutting frequency response inversely
and amplifies the low-power pickup signal to a level that meets modern audio amplifier expectations. Our
circuit is doing the trick. The magnetic pickup is connected to the input. You will need two identical circuits
without the Piezo element to play stereo.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.70.
Components required:
2 x 2N3904 transistors,
1 x 2N3906 transistor,
1 x 1 kΩ resistor, 2 x 22 kΩ
resistors, 2 x 100 kΩ resis-
tors, 2 x 220 kΩ resistors,
2 x 10 nF ceramic capaci-
tors, 2 x 10 μF electrolytic
capacitors, 1 x 100 μF elec-
trolytic capacitor, 1 x Piezo
element, 1 x breadboard,
1 x 9V battery with clip
connector
Fig. 2.70: RIAA equalizer
95
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