[Amps] Helping a Uruguayan Ham build an Amp.

[Patrick Barthelow]

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 region 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 at live.com 
 

 		 	   		  
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