Marv, WC6W pretty well said it all...........but you can add that for a
given plate voltage swing and a given power output, the tank circuit is
designed for the correct load impedance, and it doesn't give a damn what
class the tube is in.
Which is another way of saying that the tables are for desired plate load
impedance.
Grounded cathode is fine for a bit more gain, and the neutralising
requirement, as compared to grounded grid. It doesn't necessarily need input
tuning either, depending on the input capacity, the drive power, the
acceptable SWR etc. There are, as they say, more ways than one to skin a
rabbit. My way is not necessarily Rich's way, but if we both end up with the
skinned rabbit, whose to say we're either or both wrong or right?
73
Peter G3RZP
> ----------
> From: Radio WC6W[SMTP:wc6w@juno.com]
> Sent: 25 January 1999 17:39
> To: amps@contesting.com
> Subject: Re: [AMPS] Triode conected Tetrodes
>
>
> Hi Art,
>
> >While looking through the ARRL hand book (1979) I came across an
> >article for an 833a tri band amplifier. In the first part of the
> >article the author says
>
> The article seems to have survived into the 1980 edition.
>
> >"Pi-network value are given for various surplus tubes: 4-400A, 4-250A,
> >304TH and 833A.
>
> That table covers different plate impedances depending on plate
> voltage; not specific to any tube type.
>
>
> >Can other tetrodes be used the same way? i.e. 4-1000, 4CX3000,
> >4CX5000,4CX10000
>
> The 4-1000 may be triode connected, if the plate voltage is great
> enough, though as Rich & Carl observed this circuit is a sub-optimum
> methodology to use ANY tetrode.
>
> The control grid of a 4CX series tube would likely be destroyed by
> excessive dissipation in this connection should you develop sufficient
> drive to obtain any practical power output.
>
>
> ********** and from another part of the perimeter:
>
> >The 304TH and 833A are ...
> >.... specified for grid driven, AB2 (linear) service ...
>
> >? Where is this specified? There is no such thing as a triode, Class
> >AB2 grid driven linear amplifier. . Cathode - driven, yes.
>
> Probably in some audio application.
>
> Nothing precludes running a triode in that class... it just wouldn't be
> very efficient. More heat, less signal...
>
>
> 73 & Happy Monday!
> Marv WC6W
>
>
>
>
> *
>
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