Value of Resistors of EL34

[hungmao]

Hi Bros,

I am green in DIY. Recently, I have add a CLC filter to high voltage power supply of my EL34 power amp. As I know, there is an internal resistance for the choke and which makes the voltage drops.

In attachmented picture, the red text is the intented voltages of design. But after applied the CLC filter, the voltages dropped to the values in green color. Could any bros teach me how to calculate the values of R1 and R2 in order to raise the dropped voltages to the intended voltages.

Thanks a lot!

Eric.

[Colt45]

I don't see any picture?

Should be a pretty negligible drop though.

[hungmao]

I'm so sorry that the previous attachment may has sth wrong.

Pls refer to the following image.
Thanks all for your kindly help.

http://i104.photobucket.com/albums/m...06/DZ_EL34.jpg

[hungmao]

could any one help?

[Ty_Bower]

All you need to know is V = I * R.

For example, the case of R1:

Original case:
Voltage across R1 = (376 - 314) = 62 volts
Current through R1 = 62 volts / 5.1K ohms = 12.15 milliamps

New case:
Voltage across R1 = (352 - 314) = 38 volts
Current through R1 = 12.15 milllamps (from above)
new value of R1 should be 38 volts / 12.15 mA = 3.125 kOhms

Hope this helps. Of course, you will not be able to correct the reduced B+ supplied to the output tubes. Also be aware that as you change the current drawn by the driver tubes, the 352 volts seen at the end of the new choke should increase slightly. This will throw off your calculations a little bit.

Good luck!

[hungmao]

Thank you very much Ty_Bower, i got it!