[R-390] 6082's and regulators

Thu, 02 Jan 2003 17:45:58 -0500

Hi,

I guess the first question to ask is:

Can you even measure a change in the supply voltage as you tune a signal and
if so how much?

I've never even looked to see.

    Enjoy!

        Bob Camp
        KB8TQ

----- Original Message -----
From: "Drew Papanek" <[email protected]>
To: <[email protected]>
Cc: <[email protected]>
Sent: Thursday, January 02, 2003 4:05 PM
Subject: [R-390] 6082's and regulators

> Hello All,
>
> I've always found the R-390 non-A / 6082 regulator topic to be very
> interesting.   Some have installed MOSFET pass elements to replace the
> 6082's, saving filament heat production.  Some have advocated moving a
solid
> state regulator outboard to remove even more heat.   Others have tossed
the
> solid state idea overboard.   Subbing the easier to find 6080 for the 6082
> has been discussed, complete with schemes to reduce heater voltage to 6.3v
> to operate 6080.  Attendant has been a free-for-all in the spirit of the
> BallasTube  thread.
>
> A few have run the R-390A on completely regulated B+ (from an external
> supply) and report a "different feel" when tuning.   Maybe the "different
> feel" was due to a different AGC effect with regulated B+ not varying with
> AGC-induced power supply loading changes.  Maybe it was a different
soreness
> in the wrist caused by tuning drag variation with different heating of
those
> gummed-up geartrain lubricants.
>
> I wonder if anyone has found any real measurable differences when
operating
> an R-390A from a regulated B+ supply.
>
> Drew
>
>
> >Subject: RE: [R-390] 6082 tubes...
> >Date: Thu, 2 Jan 2003 10:24:06 -0800
> >From: "David Wise" <[email protected]>
> >To: <[email protected]>
> >
> >In the R-390, they took the brute-force approach and
> >regulated all B+.  During the Cost Reduction project,
> >they found that the only really sensitive spots are
> >the conversion oscillator screen grids.  In the R-390A,
> >that's all that is regulated.  It's feasible to regulate
> >this small load current with a VR tube.  With proper
> >selection of circuit constants, this was found to be
> >Good Enough.  They didn't even have to regulate the BFO
> >screen.
>
> <snip>
>
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