[Amps] Designing the Cleanest Linear with RF Negative Feedback

[Tom Cathey]

Hi Peter,

Yes, that's an interesting tube line up. I'm kinda leaning that way. That's 
a great way to provide voltage for both the final's screen and driver's 
plates. One regulated supply - I like it. Richard Measure's  FET reg supply 
design wud work well there.  Looks like they are drawing some grid current 
on the final. I wonder what the final IMD figure is on that lash up?

Colin suggested the 6550 tube as a  low level driver. It's got nice, clean 
curves and they are avavilable cheap on the web.  So I can eliminate the 
6146 unless I do the series 4CX-350's.

Gary / K4FMX, I don't have access to the old 1967 QST issues, but maybe 
there is a accessible spot on the web?

73,
Tom, K1JJ

-------------
> Hi Tom,
>
> I put diagrams of the Harris linear and the Racal widebanddriver
> on the following website:
>
> http://www.pbase.com/df3kv/gallery/linear
>
> By the way,
> the TA1800 also uses 10db of negative feedback, but just to the driver
> stage, not to the pre-driver.
> All stages run class AB1, except the wideband-pre-amp which is class A.
> 25mW -> wideband pre-amp 250mW -> pre-driver 4CX350A 2.25W -> driver
> 2x4CX350A 113W -> 4CX10000D 10KW.
> The 4CX350A get their 1500V anode voltage from the screen-supply of the
> 4CX10K, clever!
>
> 73
> Peter
>
>