Yes, using a choke would eliminate the hum. As you found a choke usually has lower resistance so still should add a resistor to reduce voltage. You suggestion is best if there is room.
Norm
:when you you convert these wouldn't it be better to use a choke or the primary of an output xformer and a res. to make up the impedence instead of just a res.?it seems like when i have done this there is no hum of course there isn't always room.butch