Home Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

RE: What to do with 412 volts

I'm inclined to agree with the choke I/P assessment.

A stereo amp is possible, if you go SE. "Fixed" bias, UL mode, KT88 "finals" will get you a fair amount of O/P power. While a little "shorter" primary impedance would be nice, Edcor's CXSE25-2.5K O/P trafo seems to be a possibility.

Use a 5R4 to rectify the 500-0-500 winding and a 5AR4 to rectify the 235-0-235 winding. I'm very dubious about those 5 VAC windings feeding 300Bs. IMO, it's $ to donuts that the vintage trafo was intended for multi-grid O/P tubes. Notice that both suggested vacuum rectifiers draw 2 A. of filament current, which will be safe. Increase the final reservoir capacitance in the LCLC filter.

Phasing up and connecting the 2 6.3 VAC windings in parallel could give you enough current for the KT88 heaters. Get something low cost from AnTek for small signal tube heating.

Eli D.


This post is made possible by the generous support of people like you and our sponsors:
  K&K Audio / Lundahl Transformers   [ K&K Audio / Lundahl Transformers Forum ]


Follow Ups Full Thread
Follow Ups
  • RE: What to do with 412 volts - Eli Duttman 18:32:57 03/08/17 (0)

FAQ

Post a Message!

Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Subject:
Message:   (Posts are subject to Content Rules)
Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:  Automagically notify you when someone responds.