[R-390] SS VR replacement for 3TF7

[Flowertime01 at wmconnect.com]

DW Holtman,

An idea back when was to just stuff a silicon diode rated at 1amp and 
100volts into pins 2 and 7 of the 3TF7 socket.

This blocks the 25.2 volts 1/2 of  the time. The net effect is 12.6 volts of 
DC.
No 3.6 watts of heat to radiate.
The transformer gets a 1/2 cycle rest.

As long as you are poking stuff in the socket add a filter cap.


We will get yada yada yada all week for my use of the S word. 

Yes, a regulator may offer better performance if the power line shifts.

I live with real weather and when my lights blink, I do not set and wonder 
why my receiver is drifting off frequency. As I am not an OP trying to get a 
copy these days. When my receiver drifts I get the head sets off and look out my 
window. There is more to life than my receiver and I would like to continue to 
enjoy life. My QTH is not a bunker these days. Power line shift is my first 
clue to bad weather.

Tubes are getting costly. So some do not want to run them on DC filaments 
because some 1920 - 1950 text books suggest DC filaments tend to burn open at one 
end and thus give tubes a short life. We will likely toss the tube for noise 
before we burn its filaments open operating it on DC.

DC filaments with no filter are more noisy than AC filaments. This could be. 
But some filter caps would go a long ways. Maybe DC filaments are better for 
noise if the source is filtered.

Any way the idea has been presented before. It does work. 
Is it better? I do not know. Is 31 flavors of ice cream enough? What flavor 
is best?

Why have we not heard about this approach before?
Read some of the other mail from today.

Roger AI4NI