12AU7 -> 12BH7 Do I need to change Rp?

[zxx123]

I have a 12AU7 preamp. From an article in this diyaudio, I change 12AU7 into 12BH7. <p>Wow, I feel wider sound range and more linearity. <p>However, I hear more white noise....I think it gives more gain.<br>Do I need to change Rp for original 12AU7?

 

[SY]

You might need to change the cathode resistor. What are the current values of Rk and Rp? And what is the B+?

 

[zxx123]

Well..

Thanks...

I do not open it yet because I need a special tool. So, I did not know its exact values of resistors.
(star wrench)

How about this? 12AU7 is used for PI of 6V6PP. If I feel 12BH7 better than 12AU7, I will abolish all 12AU7s in my system.

 

[Tubesin]

Usually U7 and BH7 can be exchanged without any change to the components value, special in a preamp, however, have you checked the BH7 is noisy or not?