EH Toroidal - Rectifying and ground?

Started by Alex C, January 02, 2005, 06:50:42 PM

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Alex C

Hello, I'm currently working on a Hotbox clone, using the EH toroidal transformer (and a 12V wall wart) and the EH tube box.  It's turning out great, but I have some noob-tastic questions.  The only experience I have with transformers  is with the Hammond 269EX used in my AX84 P1 and my Firefly (thanks to Doug).  I do not understand how to use a non-centertapped transformer.
With the 269EX, the center tap was connected to ground, and each of the two red secondary leads had a diode in series and then the cathodes were connected together and that was the source of the B+ (after filtering).  

In my project, there is no center tap, and I'm not sure where my ground will come from or how to go about rectifying this.   I am very inexperienced with transformers, and these are no doubt basic questions (but I have searched a lot and didn't come up with an answer).
If I use diodes for rectification as described above, where is the ground?  Or is one secondary (high voltage) lead my B+ and the other ground?

I'm not about to screw with high voltage if I don't know what's going on
I realize this could be dangerous since I don't know what I'm doing, that's why I'm asking.  I'm very comfortable working with high voltage, as long as I know I'm hooking things up right.  Thanks.  

Alex

P.S. -Ton, these transformers and boxes are great!  I love 'em!

Jason D


puretube

you`ll want a bridge rectifier (or 4 diodes wired as such, e.g.: 1N4007);

the xfrmr`s 2 HV pins go to the 2 "~" pins of the bridge,

the "+" of the bridge is the raw B+,
where the pos. pin of the 1st electrolytic load cap* is connected to;

the "-" of the bridge is the ground, where the neg. pin of said cap is going.

(* e.g.: 22µF/385V or larger).

the raw B+ is probably too "rimply", so some R/C combination(-s) should follow.
this ought to be part of any tube-schematic;
if it`s not, it can be looked up in the usual suspect places...

Alex C

Excellent.  Thanks for the link Jason, and thank you very much, Ton, for answering yet another of my questions.

Alex