# Passive/Active RIAA EQ For Semiconductor Phono Amplifier

Using this page you can calculate the component values for an active/passive RIAA equalization stage.

### How to use the calculator:

• Select a value for C1 and C2
• Select the gain of the whole stage (including the attenuation of the passive stage) at 1kHz
• Press “Calculate resistors”
• The form calculates the exact values for R1 to R2. Resistors are usually not available with exactly these values. However, with a parallel circuit of two E24 resistors, you can often approximate these values quite good. The calculator finds 2 E24 resistor values that best matches the value.

## Inputs

C1 = nF
C2 = nF
Gain = db @ 1kHz

## Calculations

Attenuation 1st stage = db @ 1kHz
Voltage gain 2nd stage = = dB @ 1kHz

 R1 = kΩ = kΩ   parallel    kΩ = kΩ R2 = kΩ = kΩ   parallel    kΩ = kΩ R3 = kΩ = kΩ   parallel    kΩ = kΩ R4 = kΩ = kΩ   parallel    kΩ = kΩ

## RIAA Playback Curve Attenuation in dB relative to 1kHz

 > Frequency > Attenuation in dB > Frequency > Attenuation in dB 10 19.74 1000 0 20 19.27 1200 -0.61 30 18.59 1500 -1.4 40 17.79 1800 -2.12 50 16.95 2000 -2.59 60 16.1 3000 -4.74 80 14.51 4000 -6.61 100 13.09 5000 -8.21 120 11.85 6000 -9.6 150 10.27 8000 -11.89 180 8.97 10000 -13.73 200 8.22 12000 -15.26 300 5.48 15000 -17.16 400 3.78 18000 -18.72 500 2.65 20000 -19.62 600 1.84 30000 -23.12 800 0.75 40000 -25.6

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