Folks,
Back to the list after a long layoff...
I am helping a brilliant, motivated, YL ham in Uruguay, achieve her dream of
going
QRO at her existing HF station. She is a CW/DX/Contest Specialist. I have
many/most of the components, (chokes, roller inductors, PI net components,
coupling caps, etc) to build a 2 x 3-500Z class amp that I can ship to her,
for constuction of such an amp. I also have a few of the heavy pieces, (5 v 30
amp fil xfmr) and a Plate transformer, but want to see if any QRO types read
the list, from "near" her location that might be able to help source the
"heavies". She lives in Salto Uruguay, about 300 mi north of the Buenos Aires
area, and chances are there are some hams there, or maybe in Montevideo, that
might have parts, or basket case homebrew/commercial amps, that might want to
sell or donate them or parts to a good cause. Perhaps some radio station
engineers/hams in Uruguay, or BA area of Argentina that may have some 2KW level
components (esp B+ transformer) sitting on the floor in some station parts
storage sheds. Maybe I can get lucky and find a QRO ham in the re
gion who has some Vac Variable, tune and load caps for the amp.
This YL ham truly amazes me, with her motivation, and drive to be tops in HF
from that region. She comes from a ham family with several of her family also
hams that can mentor her in construction of the amp.
I wonder if anyone has a chassis layout drawing of the classic 2 x 3-500Z GG
amp such as Eimac featured for years in their app notes. (Socket placement,
xfmrs, Caps, etc.
I wonder also, as long as we are looking at a clean sheet for the PS and amp
design, what the higher B+ voltage is to design to, to max out tube efficiency
for 1.5KW from a pair of 3-500s. Maybe 4KV?
Maybe even use the similarly capable 4-400As that used to be used in old
commercial stations of about 2 KW level, that can be had maybe for cheap. They
are happier I think at the higher B+ voltages.
Then even the possibility of choosing a GS 35B tube as as the basis of the
amp. They used to be very cheap for NOS tubes, in original boxes, maybe still
are.
Any thoughts?
Best Regards,
73, de Pat Barthelow AA6EG apolloeme@live.com
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