Model
|
Primary Coil
|
Turn Ratio
|
Inductance at 20Hz
7Vrms
|
Secondary Impedance
|
Frequency Response (-3.0dB)
|
Recommended Circuit
|
Price (pair) THB
Ei construction
|
Impedance
|
Norminal DC current (max)
|
I-311S-2A3
|
2.5K
|
40mA (60mA)
|
1:1
|
20H
|
2.5K
|
20Hz - 55KHz
|
2A3, EL34(T), 12B4
|
11,500
|
I-311S
|
3.0K
|
30mA (45mA)
|
1:1
|
25H
|
3.0K
|
20Hz - 50KHz
|
6BL7, 6BX7, 437A, 6C45Pi
|
9,800
|
I-311SD
|
3.0K
|
30mA (45mA)
|
1:0.5+0.5
|
25H
|
750R+750R
|
20Hz - 50KHz
|
SE to PP or A2 drive circuit
|
10,500
|
I-311S-300
|
3.0K
|
60mA (90mA)
|
1:1
|
30H
|
3.0K
|
20Hz - 50KHz
|
300B
|
15,000
|
I-511S
|
5.0K
|
25mA (36mA)
|
1:1
|
35H
|
5.0K
|
20Hz - 45KHz
|
5687, 417A, 6DJ8/6922
|
9,800
|
I-511SD
|
5.0K
|
25mA (36mA)
|
1:0.5+0.5
|
35H
|
1.25K+1.25K
|
20Hz - 45KHz
|
SE to PP or A2 drive circuit
|
10,500
|
I-912S
|
10.0K
|
10mA (15mA)
|
1:2
|
55H
|
40.0K
|
25Hz - 25KHz
|
6SN7, 12AU7, 12BH7, 5692
|
9,800
|
|