[HBR] HBR Under Construction - info and pix

[Don]

Bill,

Very nice. You must be very pleased. What a wonderful job you have done
so far. The metal work is great and certainly has met your design goal
for a classic BA appearance. Thank you for the preview. And since I am
mechanically inept, thank you for some good ideas for future projects.
Metal work in not one of my best skills. Thank goodness for greenlee
punches, Online Metals and Bud chassis. I would be interested in knowing
how well the toroids work for the input and how well the IF homebrew IF
transformer functions.

This weekend I worked on a tube transmitter recently built. I rebuilt
the power supply and mounted certain circuits and HV lines in a safer
manner. I raised the plate voltage on the 6146 from 560 to 750VDC. I was
using the 400ct from an 800VCT transformer with a capacitive input
filter. Voltage regulation was ok but the whole supply was not very
safely built. Also, I was using dropping resistors to reduce the voltage
from 560vdc to 300vdc for the plates of the 5763 buffer and 5763 driver.
Again, not very good technique. Certainly not efficient with lots of
waste in the form of heat. 

I replaced the former setup with a 550VCT transfomer and a bridge
rectifier for 750vdc and used the center tap for 300vdc. I also
connected two as yet unused regulator tubes for 180vdc for the 6146
screen. All this meant replacing the filter capacitors and re-routing
some HV lines. Even though I raised the power out from 45W to 65W the
rig runs cooler.


I have been reading about all the new and underconstruction tube
projects here on this site while working on a solid state SSB
transceiver. It was fun to do some tube homebrew. 

What's in your workshop?


Don K5UOS