[R-390] SS VR replacement for 3TF7

[Les Locklear]

Uh Oh..................do I smell another Dead Horse moldering in the 
background?????

Maybe the infamous Keilballast, or the <gasp> 12BH7 or even worse.......Ta 
Da.......Shades of the Salem Witch Hunt, "TOTALLY" solid state Chuck 
Rippel's adjustable "Ballst Tube Eliminator."  Who knows what eveil lurks 
behind closed 
doors...............MUAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA!!!!!!!!!!!!!!

The Shadow Knows........................

----- Original Message ----- 
From: "Cecil Acuff" <chacuff at cableone.net>
To: <Flowertime01 at wmconnect.com>; <r-390 at mailman.qth.net>
Sent: Tuesday, January 03, 2006 7:39 PM
Subject: Re: [R-390] SS VR replacement for 3TF7


> My Favorite is a piece of Teflon coated aircraft wire with a couple of Mil 
> spec RS-232 male crimp pins installed, shoved into the socket in the 
> appropriate place and a pair of very common (read cheap) 12BA6's in place 
> of the 6V versions.  It don't regulate but neither does the 
> resistor....not in the same way as the ballast tube.  The ballast tube 
> absorbs voltage changes by varying it's resistance and corresponding 
> voltage drop....something a resistor can't do.  In fact I would think the 
> tubes are ballasting the resistor in that method of substitution....but it 
> does work acceptably....as does the jumper and 12V tubes.
>
> Cecil....
> ----- Original Message ----- 
> From: <Flowertime01 at wmconnect.com>
> To: <r-390 at mailman.qth.net>
> Sent: Tuesday, January 03, 2006 6:29 PM
> Subject: Re: [R-390] SS VR replacement for 3TF7
>
>
>> 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
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>
>
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