[R-390] SS VR replacement for 3TF7

[DW Holtman]

You would have to put in a rectifier and filter caps. Ths whole 78XX 
series  regulators only work on DC.

 I have never heard of them causing noise. Most newer solid state low 
noise amps, VFO's etc use the low power series of these reguators in the 
TO-92 packages. This type of circuit could not deal with noise.

This mod is very simple and straight forward.

The voltage regulation will be excellent.


73's
DW Holtman
WB7SSN




Barry wrote:

>The only reason I might try it is lack of a ballast tube for one of my
>R390A's.  It doesn't seem to be that much more difficult than a simple
>resistor and if it gives better regulation, then why not give it a try.
>
>One thing I don't understand about this is I thought solid-state voltage
>regulators worked on either a positive or negative voltage, not AC.  Does
>this arrangement still regulate both positive and negative half cycles?
>
>Also, wasn't there an issue with solid-state noise?
>
>Barry - N4BUQ (kicking more dead horses than you)
>
>----- Original Message ----- 
>From: "Tom Norris" <r390a at bellsouth.net>
>To: <r-390 at mailman.qth.net>
>Sent: Tuesday, January 03, 2006 1:41 PM
>Subject: Re: [R-390] SS VR replacement for 3TF7
>
>
>  
>
>>Where's the Kielbasa? The Lutefisk? The Damp Sheep??
>>
>>But seriously...  I've heard this discussed in and among the Dead
>>Horse Graveyard, and since I have a radio apart, now is as good a
>>time as any to try it. Just need to pick up the parts in a few days.
>>And I need to set up the GPS standard that I've been meaning to for
>>the past two years that sits on the shelf pointing and laughing.
>>I've got a serious roundtuit deficiency.
>>
>>Who else has tried the simple DC regulator method and written down
>>what the results were versus that of a current regulator?  I'd hate
>>to think a team of experienced engineers screwed up something as
>>simple as a ballast arrangement.  Maybe if we stepped into our TARDIS
>>and took them a boxful of 7812's we could have nipped the whole
>>ballast problem in the bud, as Barney Fife would have said?
>>
>>73
>>
>>Tom NU4G
>>"Better Living Through Lutefisk"
>>    
>>
>
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