Tube-Specific Calculators

Plate & Grid Circuit Calculator

12AY7 Medium-Mu Dual Triode

RL & RT
RK
AC
Max Ratings
Capacitance
Low-Volt Preamp
Vpp=90
Vpp=180
Vpp=300
Mechanical

The amplification factor, plate resistance, and transconductance are shown here based on the DC plate current. The various curves are for different values of DC plate voltage, which is indicated as E_b. The red, blue, and green lines represent an amplification factor of 44, plate resistance of 25k, and transconductance of 1.75mA/V, respectively, which are the approximations usually used by amplifier designers.

12AY7 AC characteristic curves

Plate Voltage:	250 volts
Grid Voltage:	-4 volts
Plate Current:	3 mA
Plate Resistance:	25k ohms
Transconductance:	1.75 mA/V
Amplification Factor:	44
Cutoff Grid Voltage:	-8 volts

DC Operating Point Plate Voltage:
300 volts

DC Cathode Current:
10 milliamps

Average Plate Dissipation:
1.5 watts

Heater-to-Cathode Voltage:
90 volts (heater positive or negative with respect to cathode)

Grid to Cathode+Heater: 1.3pF

Grid to Plate: 1.3pF

Plate to Cathode+Heater: 0.6pF

low-voltage 12AY7 preamp circuit

Low-Level Amplifier
Plate Supply Voltage:	150 volts
Plate Load Resistor R_L:	20k
Next Stage Input Resistance:	100k
Cathode Resistor R_K:	2.7k
Cathode Capacitor R_K:	40 microfarads
Voltage Gain:	12.5

Capacitor values depend on the desired bass frequency response and can be computed using the Coupling Capacitor Calculator and Cathode Bypass Capacitor Calculator. Treble response can be computed using the Grid-Stopper Resistor Calculator.

Example 1-1

Midrange Voltage Gain: 22
(measured at 2 volts RMS output)

Output Voltage: 6.9 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 1-2

Midrange Voltage Gain: 25
(measured at 2 volts RMS output)

Output Voltage: 9.6 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 1-3

Midrange Voltage Gain: 26
(measured at 2 volts RMS output)

Output Voltage: 8.2 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 1-4

Midrange Voltage Gain: 27
(measured at 2 volts RMS output)

Output Voltage: 11 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 1-5

Midrange Voltage Gain: 26
(measured at 2 volts RMS output)

Output Voltage: 8.6 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 1-6

Midrange Voltage Gain: 27
(measured at 2 volts RMS output)

Output Voltage: 11 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 2-1

Midrange Voltage Gain: 25
(measured at 2 volts RMS output)

Output Voltage: 18 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 2-2

Midrange Voltage Gain: 28
(measured at 2 volts RMS output)

Output Voltage: 24 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 2-3

Midrange Voltage Gain: 28
(measured at 2 volts RMS output)

Output Voltage: 20 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 2-4

Midrange Voltage Gain: 28
(measured at 2 volts RMS output)

Output Voltage: 25 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 2-5

Midrange Voltage Gain: 29
(measured at 2 volts RMS output)

Output Voltage: 20 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 2-6

Midrange Voltage Gain: 29
(measured at 2 volts RMS output)

Output Voltage: 25 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 3-1

Midrange Voltage Gain: 27
(measured at 2 volts RMS output)

Output Voltage: 34 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 3-2

Midrange Voltage Gain: 29
(measured at 2 volts RMS output)

Output Voltage: 45 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 3-3

Midrange Voltage Gain: 30
(measured at 2 volts RMS output)

Output Voltage: 36 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 3-4

Midrange Voltage Gain: 31
(measured at 2 volts RMS output)

Output Voltage: 45 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 3-5

Midrange Voltage Gain: 30
(measured at 2 volts RMS output)

Output Voltage: 36 volts RMS
(maximum output for 5 percent total harmonic distortion)

Example 3-6

Midrange Voltage Gain: 31
(measured at 2 volts RMS output)

Output Voltage: 45 volts RMS
(maximum output for 5 percent total harmonic distortion)

12AX7 physical dimensions

Heater Requirements

Pin 4 to Pin 5:
12.6 volts
150 milliamps

Pin 9 to Pins 4 and 5:
6.3 volts
150 milliamps each leg

The tube can be mounted in any position.

12AY7 base diagram