Miller Capacitance - Preamps

Miller Capacitance Calculator

This calculator estimates the effective input capacitance of a triode stage due to the Miller effect. Useful for high-gain stages such as ECC83/12AX7. It also calculates the filter frequency created with a grid stopper resistor.

Select Preamp Tube: ECC83 / 12AX7 (μ=100, Cag=1.6pF) ECC81 / 12AT7 (μ=60, Cag=1.6pF) ECC82 / 12AU7 (μ=17, Cag=2.5pF) 6SN7 (μ=20, Cag=3.2pF) 6SL7 (μ=70, Cag=1.7pF) Gain of the stage (Av): Grid stopper resistor (in kΩ):