Speed Twin Bias Setting

[dpm309]

What would be a target bias setting for a 100 Watt TE Speed Twin using KT77s. Swapping out the original 18 YO EL34s. The bias probe and adjustment pot are easily accessible from the rear.

[SILVERGUN]

You need to consider plate voltage to determine proper mA

[dpm309]

Plate voltage is about 425VDC. I reinstalled the Weber bias Calculator (hard drive crashed and lost all of my bookmarks) and according to it, I should be looking at 35mA. I read that you can bias the KT77s a little hotter, so I might go for closer to 40mA. Sorry, should have checked the bias calculator first.

[SILVERGUN]

That sounds good. No need to be sorry. Its just you cant tell one without the other.

[dpm309]

 Thanks,