06-10-2019, 07:18 PM
Guess how I learn that myself, about the transformer positioning? 
I was making a compact chassis myself!!
Earthing... Earthing the chassis and having an (isolated) 0V bus will work, but it's not so convenient as having the whole chassis 0V.
The little mains transformer you have is heaters only, how are you getting HT? As your PY81 is dumped. I get the idea you are rectifying direct from mains. It's quite possible (I have a completely open chassis, connected direct to mains neutral, in my workshop). However, safety is important, and an isolating transformer for HT is highly desirable. If you can find one of those, you are sorted; if not, I will do a bit of digging around for you.
I was making a compact chassis myself!!
Earthing... Earthing the chassis and having an (isolated) 0V bus will work, but it's not so convenient as having the whole chassis 0V.
The little mains transformer you have is heaters only, how are you getting HT? As your PY81 is dumped. I get the idea you are rectifying direct from mains. It's quite possible (I have a completely open chassis, connected direct to mains neutral, in my workshop). However, safety is important, and an isolating transformer for HT is highly desirable. If you can find one of those, you are sorted; if not, I will do a bit of digging around for you.
