Converting Solid State to Tube Rectification on a Preamp

Oops!
one more thing, as mentioned by salectric: the resulting B+ voltage will be lower than with a solid state rectifier, that may or may not be a problem.

Imfihifan... thanks for the awesome link. 

if i decided to do just a half wave rectifier using a single tube 6x5, is that possible?   Also, with the secondary measure at 350v, that is more than enough for a single 6x5 plate voltage? 

if i decided to do just a half wave rectifier using a single tube 6x5, is that possible?   Also, with the secondary measure at 350v, that is more than enough for a single 6x5 plate voltage?

Sorry I don't have an answer for your question, but if you really want to use a single 6X5 with the existing transformer, check out this link:
http://www.antiqueradios.com/forums/viewtopic.php?f=13&t=176225