G'day Mike.
If you think it will work, you might as well go the extra yards and
use the LM338K which is the 5 Amp version It does away with the need
for the pass transistor.
Yes, I know, you don't have it on hand. Ha ha.
Anyway, let us know how your experiment goes with the 317 regulator.
73, Alek
VK6APK
At 07:02 AM 10/03/2010, MIKE DURKIN wrote:
>
>
>
>From: patriot121@msn.com
>To: jan@on6zg.be
>Subject: RE: [Amps] GS35b Bias
>Date: Tue, 9 Mar 2010 15:01:59 -0800
>
>
>
>Yea, G3SEK uses a TL431 and a PNP pass transistor .... Im just
>trying to get by on whats already there ... Does any one else have
>comments about Noise from the LM317t compared to the TL431 ???
>
>Mike
>KC7NOA
>
> > snip> Subject: RE: [Amps] GS35b Bias
> > Date: Tue, 9 Mar 2010 21:54:25 +0100
> >
> > I'm using a tip147 or BD equivalent. You can also check G3SEK triode board
> >
> > 73 Jan ON6ZG
> >
> > -----Oorspronkelijk bericht-----
> > Van: amps-bounces@contesting.com
> [mailto:amps-bounces@contesting.com] Namens
> > MIKE DURKIN
> > Verzonden: dinsdag 9 maart 2010 0:57
> > Aan: ka4inm@tampabay.rr.com; amps fourm
> > Onderwerp: Re: [Amps] GS35b Bias
> >
> >
> > thats right ... my amp does not have a PNP, only NPN trans good
> to 1200v@10A
> > .... i want to replace the minum of parts ...
> >
> > You dont see an improvement ?? I was leaning towards a variable Bias with a
> > LM317t and a NPN pass transistor .. simply because its what i have ... and
> > im trying not to buy anything.
> >
> > Mike
> > KC7NOA
> > > >
> > > Hi MIKE DURKIN:
> > >
> > > > ok, I made a quick draw of what im wanting to do .. basically replace
> > > > the Zener in the all black drawing .. I forgot to add a Blocking diode
> > > > in series ok the 1k resistor that's tied to the NPN transistor ..
> > >
> > > I see no PNP, but if the circuit on the left is the original it is an
> > "amplified Zener."
> > > The LM317 will generate much more noise and not be any improvement that I
> > can see.
> > > --
> > > Ron KA4INM - I'm proud to be Chuck's pop!
>
>
>
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