Markku,
Once you have the data sheet, it is easy to determine the values of gm, Rp and
mu from it, especially as mu = gm times Rp.
73
Peter G3RZP
========================================
Message Received: May 06 2013, 02:43 PM
From: "Markku Oksanen" <markku.a.oksanen@kolumbus.fi>
To: "g8on@fsmail.net" <g8on@fsmail.net>, "amps@contesting.com"
<amps@contesting.com>
Cc:
Subject: RE: [Amps] 4CX5000A in common grid circuit
Peter
I am currently at the "station" some 160 km from the nearest large university
library ( in Helsinki/Finland) that could have the below book or the paper
could be found. SO, I would really appreciate your effort if you could scan the
pages for me.
I will naturally have a further question or two before this all can be
committed to MS EXCEL.
I have been playing with formulas that look like the ones below, however Rp
and mu I have not had to way to estimate, so results are kind of useless.
Thank you in advance
MarkkuWW1C
> Date: Mon, 6 May 2013 10:00:00 +0200
> From: g8on@fsmail.net
> To: markku.a.oksanen@kolumbus.fi; amps@contesting.com
> Subject: Re: [Amps] 4CX5000A in common grid circuit
>
> Hi Markku,
>
> Have a look at 'Single Sideband Principals and Circuits' by Pappenfus,
> Bruene and Schoenike - the 1964 edition. Or better, see if your local
> library can get you a copy of the article.
>
> E.L.Chaffee, A Simplified Harmonic Analysis, Rev. Sci. Instr., pp384-389,
> October 1936.
>
> If need be, I'll scan the pages from Pappenfus for you.
>
> The main difference between estimating gain in grounded cathode and grounded
> grid is that you need to take into account the negative feedback.
>
> The gain in Class A is given by {RL/(Rp + RL)}{mu + 1} = {RL/(Rp + RL)}
> {[gm.Rp] + 1}: in other classes, the variation in gm over the cycle will
> have some effect.
>
> For a tetrode or pentode, Rp is fairly high.
>
> 73
>
> Peter G3RZP
>
>
> ========================================
> Message Received: May 06 2013, 06:51 AM
> From: "Markku Oksanen" <markku.a.oksanen@kolumbus.fi>
> To: "g8on@fsmail.net" <g8on@fsmail.net>, "amps@contesting.com"
> <amps@contesting.com>
> Cc:
> Subject: RE: [Amps] 4CX5000A in common grid circuit
>
> Hi Peter, All
> First, it looks like my posts don't go to the list at all for some reason
> but naturally reach direct emails.
>
> What is mean by muu here is "muu" in the sense it appears in discussion and
> formulas for triode GG power gain.
>
> I believe I am making this a bit more complicated than necessary by trying
> to calculate the Tetrode GG power gain from first principles but I would
> finally like to understand how this works compared to a simple, high muu
> triode in GG.
> Not being familiar with the Chaffee analysis, (google helped none), could
> you point me to the correct direction here.Going through the motions with
> the characteristic curves is not a problem, just an other little interesting
> task in this project.
> The main reason for GG thinking for this tube was simplicity and perhaps
> additional better IMD from inherent RF feedback in GG setup. And I have
> build grid driven amps and would like to do something different....
> Thanks for the help!
> MarkkuWW1C
>
> > Date: Mon, 6 May 2013 00:20:30 +0200
> > From: g8on@fsmail.net
> > To: markku.a.oksanen@kolumbus.fi; km1h@jeremy.mv.com;
> villelintervo@hotmail.com; amps@contesting.com
> > Subject: Re: [Amps] 4CX5000A in common grid circuit
> >
> > I'm not sure what you mean here by mu.
> >
> > mu is dVp/dVg. Gm is dIp/dVg and ra is dVp/dIp
> >
> > so mu is Gm times ra.
> >
> >
> > So for any given screen voltage, you can figure the mu, because at a
> given grid voltage, Va has increased or decreased (depending on phase) with
> control grid voltage and you can then figure out the plate current.
> Likewise, you can fix the screen volts and calculate the plate current at
> various points in the cycle and then apply Chaffee analysis.
> >
> > OK, it's long and messy but can be done by hand from the characteristic
> curves......
> >
> > 73
> >
> > Peter G3RZP
> >
> >
> >
> >
> > ========================================
> > Message Received: May 05 2013, 09:38 PM
> > From: "Markku Oksanen" <markku.a.oksanen@kolumbus.fi>
> > To: "Carl" <km1h@jeremy.mv.com>, "g8on@fsmail.net" <g8on@fsmail.net>,
> "Ville Lintervo" <villelintervo@hotmail.com>, "amps@contesting.com"
> <amps@contesting.com>
> > Cc:
> > Subject: RE: [Amps] 4CX5000A in common grid circuit
> >
> > Hi
> > I have all the components to build the grid supplies to fit the need,
> screen to +1600 V if necessary.I know the DC operating conditions need to be
> about the same no matter what the RF configuration is.
> > I would still hope to find the a way to calculate the power gain in GG.I
> have a hard time finding the a way to translate tetrode (grid to screen
> grid) muu to equivalent triode muu.Or perhaps this is a silly question.
> > Thanks
> > MarkkuWW1C
> >
> > > From: km1h@jeremy.mv.com
> > > To: g8on@fsmail.net; villelintervo@hotmail.com; amps@contesting.com
> > > Date: Sun, 5 May 2013 09:41:01 -0400
> > > Subject: Re: [Amps] FW: 4CX5000A in common grid circuit
> > >
> > > That is a typical British understatement (-;
> > >
> > > But also typical of many European signals.
> > >
> > > Carl
> > >
> > >
> > >
> > >
> > > >
> > > > The G2DAF configuration has had, over many years, a very poor
> reputation
> > > > for producing broad signals.
> > > >
> > > > 73
> > > >
> > > > Peter G3RZP
> > > >
> > > > ========================================
> > > > Message Received: May 05 2013, 11:07 AM
> > > > From: "Ville Lintervo" <villelintervo@hotmail.com>
> > > > To: "amps@contesting.com" <amps@contesting.com>
> > > > Cc:
> > > > Subject: Re: [Amps] FW: 4CX5000A in common grid circuit
> > > >
> > > > Markku, Have you given a thought for g2daf -configuration tog serve
> your
> > > > purposes ? http://www.g4dmp.co.uk/g2daf-lin.pdfSM2CEW describes his
> > > > implementation with QBL5/3500 http://www.sm2cew.com/ampli.html
> Ville
> > > > oh1jd
> > > >
> > > >
> > > > _______________________________________________
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> > > >
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