Precision Series Transformers

Precision Series Transformers

Note: please contact customer service for latest pricing.

These are our top of the range, state of the art output transformers. All are meticulously built to perfection, with proper test and measurement being done before shipment.

Note: Standard as well as customized towards user requirements Z11 EI core transformers are available. Below are some of our past products that is available for order.

Actual frequency response curve - courtesy of our users that sent us the plot.

211, 845 output transformer, 10K, 60mA, 80mA, 100mA, 120mA frequency response curve

211, 845 output transformer 10K frequency response plot

300B output transformer 3.5K 60mA, 80mA, 100mA, 120mA frequency response curve

300B output transformer 3.5K frequency response plot

5K:8 Ohm Z11 EI Push-Pull Output Transformer (20W) - US$399/pair

• Bandwidth: 5Hz - 100kHz
• Tube: EL84, 45, 5842, 6C45, 6V6GT and etc

Frequency             Impedance              +/-dB      Phase

        5Hz                  3850                     -1.13

      10Hz                  4310                     -0.64

      20Hz                  4585                     -0.38      14.4 deg.

      30Hz                  4661                     -0.30      12.0 deg.

      50Hz                  4775                     -0.20

    100Hz                  4790                     -0.20      7.5 deg.

    500Hz                  4990                     -0.01

  1000Hz (ref)           5001                     -0.00      1.1 deg.

  2000Hz                   4997                     -0.00

  5000Hz                   4960                     -0.03

10000Hz                   4890                     -0.09      9.3 deg.

15000Hz                   4888                     -0.01

20000Hz                   4799                     -0.18      18.4 deg.

25000Hz                   4685                     -0.28

30000Hz                   4550                     -0.41      27.1 deg.

35000Hz                   4150                     -0.81

40000Hz                   4250                     -0.71

45000Hz                   4092                     -0.87

50000Hz                   3910                     -1.07


4.8K:8 Ohm Z11 Single Ended Transformer (10W) - US$399/pair

• Bandwidth: 20Hz - 100kHz
• Tube: EL84, 45, 5842, 6C45, 6V6GT and etc

Frequency             Impedance              +/-dB      Phase

      20Hz                  2659                     -2.56      43.8 deg.

      30Hz                  3159                     -1.81      37.3 deg.

      50Hz                  3711                     -1.12      28.3 deg.

    100Hz                  4141                     -0.64      19.3 deg.

    500Hz                  4670                     -0.12        7.3 deg.

  1000Hz (ref)           4808                     -0.00       5.2 deg.

  2000Hz                   4858                     -0.05

  5000Hz                   4875                     -0.06       1.2 deg.

10000Hz                   4863                     -0.06       4.5 deg.

15000Hz                   4837                     -0.03       7.2 deg.

20000Hz                   4799                     -0.00       9.9 deg.

25000Hz                   4750                     -0.05      12.4 deg.

30000Hz                   4590                     -0.20      15.0 deg.

35000Hz                   4616                     -0.17      17.4 deg.

40000Hz                   4531                     -0.25      19.9 deg.

45000Hz                   4425                     -0.35       22.3 deg.

50000Hz                   4289                     -0.49       24.5 deg.


5.0K (12:1) Ohm Z11 Single Ended Preamplifer Output Transformer - US$399/pair

• Bandwidth: 5Hz - 130kHz
• Tube: EL84, 45, 5842, 6C45, and etc
• Below data are obtained using load of 33 Ohm.

Frequency             Impedance              +/-dB   

        5Hz                  1779                     -4.49

      10Hz                  2659                     -2.74

      20Hz                  3571                     -1.46    

      30Hz                  4001                     -0.97    

      50Hz                  4381                     -0.58

    100Hz                  4671                     -0.30     

    500Hz                  4962                     -0.03

  1000Hz (ref)           5035                     -0.03     

  2000Hz                   5060                     -0.05

  5000Hz                   5071                     -0.06

10000Hz                   5073                     -0.06    

15000Hz                   5070                     -0.06

20000Hz                   5061                     -0.05     

25000Hz                   5049                     -0.41

30000Hz                   5036                     -0.03     

35000Hz                   5037                     -0.03

40000Hz                   5239                     -0.20

45000Hz                   5899                     -0.72

50000Hz                   5267                     -0.23
55000Hz                   5093                     -0.08
60000Hz                   5007                     -0.01
65000Hz                   4948                     -0.04
70000Hz                   4894                     -0.09
75000Hz                   4842                     -0.14
80000Hz                   4788                     -0.19
85000Hz                   4732                     -0.24
90000Hz                   4675                     -0.29
95000Hz                   4615                     -0.35
100000Hz                 4553                     -0.41
110000Hz                 4421                     -0.54
120000Hz                 4259                     -0.70
130000Hz                 3911                     -1.07


1.0K:8 Ohm Z11 Push Pull Preamplifer Output Transformer U$ASK

• Anode/plate current 700mA, max 100mA!
• Bandwidth: 5Hz - 60kHz
• Tube: 6C33C, 6080, 6AS7 and etc
• Specially made for excellent low frequency response!

Frequency             Impedance              +/-dB   

        5Hz                   867                     

      10Hz                   904                     

      20Hz                   933                      

      30Hz                   948                    

      50Hz                   963                     

    100Hz                   977                    

    500Hz                  1002                     

  1000Hz (ref)           1000                     -5.92     

  2000Hz                   1006                     

  5000Hz                   1018                   

10000Hz                   1050                     -11.6 

15000Hz                   1103                  

20000Hz                   1163                     -19.6  

25000Hz                   1236                     -22.5

30000Hz                   1321                          

35000Hz                   1408                   

40000Hz                   1499                   

45000Hz                   1599                     

50000Hz                   1699                     
55000Hz                   1806                   
60000Hz                   1917        


3.5K:8 Ohm Z11 Single Ended Transformer - US$549/pair

• Bandwidth: 20Hz - 100kHz
• Tube: 300B, EL34 and etc

Frequency             Impedance              +/-dB      Phase

      20Hz                  3131                     -0.49      20.4 deg.

      30Hz                  3201                     -0.39     

      50Hz                  3331                     -0.22      10.8 deg.

    100Hz                  3391                     -0.14      7.2 deg.

    500Hz                  3473                     -0.03        2.5 deg.

  1000Hz (ref)           3478                     -0.03       1.3 deg.

  2000Hz                   3481                     -0.03

  5000Hz                   3488                     -0.02       0.8 deg.

10000Hz                   3525                     -0.03       1.3 deg.

15000Hz                   3593                     -0.11        1.5 deg.

20000Hz                   3702                     -0.24        1.3 deg.

25000Hz                   3856                     -0.42        0.5 deg.

30000Hz                   3625                     -0.15        6.8 deg.

35000Hz                   3512                     -0.01        0.9 deg.

40000Hz                   3762                     -0.31        1.7 deg.

45000Hz                   3948                     -0.52        0.9 deg.

50000Hz                   4112                     -0.70        0.5 deg.
55000Hz                   4263                     -0.86        2.3 deg.
60000Hz                   4403                     -1.00        4.5 deg.
65000Hz                   4525                     -1.11        7.0 deg.
70000Hz                   4621                     -1.21       10.1 deg.
75000Hz                   4666                     -1.25       13.6 deg.
80000Hz                   4626                     -1.21       17.6 deg.
85000Hz                   4455                     -1.05       21.5 deg.
90000Hz                   4154                     -0.74       23.8 deg.
95000Hz                   3834                     -0.33
100000Hz                 3663                     -0.20        19.8 deg.


10K:8 Ohm Z11 Single Ended Transformer - US$ASK

• Bandwidth: 20Hz - 50kHz
• Tube: 211, 845, GM70, 805, 250TH and etc

Frequency             Impedance              +/-dB      Phase

      20Hz                  6030                     -2.3       44.0 deg.

      50Hz                  8190                     -1.0       30.0 deg.

    100Hz                  9390                     -0.5       20.9 deg.

  1000Hz (ref)         10360                     -0.0        2.0 deg.

  5000Hz                 10383                     -0.1        7.6 deg.

10000Hz                 10229                     -0.1       16.6 deg.

15000Hz                   9932                     -0.2       25.4 deg.

20000Hz                   9680                     -0.3       36.6 deg.

25000Hz                   8635                     -0.8       42.8 deg.

30000Hz                   7948                     -1.2       50.0 deg.

35000Hz                   7176                     -1.6       56.7 deg.

40000Hz                   6366                     -2.2       40.0 deg.

45000Hz                   5541                     -2.6       66.6 deg.

50000Hz                   4112                     -3.1        0.5 deg.

J&K Audio Design
22/02/2014

Product Lists  
Level 0

Level 1: link 1, link 2, link 3

Level 2: link 1, link 2, link 3, link 4, link 5, link 6 

Level 3: depends on type, size and complexity. Email us for details.

Iso-trans: link 1, link 2

* Finished amplifiers, DACs, audio gadgets, upgrades and repairs - this is not our core business and we do it out of passion. We do not have fixed models, fixed price and we customize for each individuals. The sky is limit of creativity.  

* Our product lines are always improving and increasing. If you do not see what you want, contact us!  

* Please email for volume discounts, distributor and OEM pricing.