Focus Coil circuits?

[Yamamaya42]

The 17BP4 & 17HP4 are identical mechanically and size wise, but differ as is the biasing, as in the 17BP4 is an older version, other than that, no dif, but that SHOULD have been stated on the box that it is a 17B not a 17H...

But it's pretty certain you have a 17BP4 there and it will be a pain to rig a circuit for focus for it.

[Kevin Kuehn]

Originally Posted by Yamamaya42

The 17BP4 & 17HP4 are identical mechanically and size wise, but differ as is the biasing, as in the 17BP4 is an older version, other than that, no dif, but that SHOULD have been stated on the box that it is a 17B not a 17H...

But it's pretty certain you have a 17BP4 there and it will be a pain to rig a circuit for focus for it.

Are you by chance confusing biasing with basing? Both share the same standard 12 pin basing with the exception a 17HP4 normally should have a focus pin in location 6.

[Yamamaya42]

Originally Posted by Kevin Kuehn

Are you by chance confusing biasing with basing? Both share the same standard 12 pin basing with the exception a 17HP4 normally should have a focus pin in location 6.

yeah, i got the words intermixed, :/

key being that 17HP4 has 12L and 17BP4 (which that tube seems to be) has 12D basing.

and if bandersen has a PM assembly that will work, then that's the best way to go, cause as mentioned, the one I have from the broken 21EP4B is too strong for this tube.