5F6-A question

[labb]

I am considering building a 5F6-A and I want to use a diode rectifier with a 300-0-300 volt 200 ma. transformer. Should give a B+ of about 420 volt. Any issues using this set up? ie: voltage too low, not enough current. Thanks.

[eleventeen]

No problems I can think of. 100 mils is enough for 2 qty 6L6 and a pile of preamp tubes. You may be ten volts low on the schematic-indicated B+ and then again, you may not; with our generally higher line voltages. And if you were it wouldn't mean spit. No issues I can see. Make it so!

[TIMBO]

Hey labb, I bought two Hammond 372jx (300-0-300)trannys a few years ago and have found that the builds I have been doing lately they have been a bit shy on volts, should have bought 325-0-325 trannys.

Anyway what I have been doing is a SS rect, that will give you the most volts @ node A and reduce the dropping resistor between nodes B and C. This will bring the PI and preamp volts up to Spec.
Doing this will drop the plate voltage on the power tubes a bit, to about 410v but if you have an adjustable fixed bias that can be tweaked if needed or again for cathode bias the resistor can be tweaked.
That tranny has plenty mAs to play with so you could add a 1-2 tube reverb and tremolo.

I built a silver jubilee with that tranny and to me sounded great. 

[labb]

Thanks for the replies. Sometimes I just need some hand holding...Timbo, I am surprised about the Hammonds. Usually they run high..Are you on the 120 winding or the 115 winding?

[TIMBO]

Hi lab, Where on 240v here and I just measure and at the wall i'm getting 238v and the tranny is 310v at the standby and after rect at node A i'm getting 406v. Hope this will give you a starting point.