|  
                 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 
                  |  
              
           
          |