Problem with tube rectifier

[Leevi]

I'm using both tube and SS rectifier like in picture A


http://el34world.com/Forum/index.php?action=dlattach;topic=14469.0;attach=32505


Everything works fine with SS but when I switch to the tube rectifier the power supply
starts to crackle after a while and the rectifier tube flashes. Sometimes even the fuse has blown.
This happens randomly, sometimes it takes longer time before the problem occurs.
I have also tried with another rectifier tube (5Y3) without success.


Could some the following reasons cause this?


- The 5V filament wires are too close to high voltage secondary


- The PT is partly damaged


- I'm using the pin 7 of the rectifier tube socket for filter cap


Leevi

[HotBluePlates]

- The PT is partly damaged

- I'm using the pin 7 of the rectifier tube socket for filter cap

I'd vote for these 2 causes. Especially if you're using pin 7 as a ground lug for your filter cap (now a ground is right next to 2 high voltage points where a ground never exists in normal rectifier usage).

[Leevi]

It's pretty clear that the PT is damaged.
I used a separate 5V filament transformer and the amp worked without problems.
Thanks for your response HotBluePlates!
/Leevi