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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> > >
> > >
> > > -----
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