[AMPS] Amp using 833A

[Phil (VA3UX)]

Now this is little more useful. Thanks for the input Tom.

As I mentioned to Jeff,  g-g would not be considered for this tube. Neither
would upper HF (these things are only rated for 30 Mhz max anyway).  IF I
do anything with these bottles, it will likely be moderate power on one to
three of the lower HF bands, just for hacking around.  Nostalgia rather
power will be the motivation.

Thanks

Phil

At 09:10 PM 9/18/2000 -0400, you wrote:
>The problem is the tube will have low gain. That's because the gain 
>of a grounded grid PA is related to the ratio of output impedance to 
>input impedance of the tube.
>
>With it's low-mu construction, the 833 would take a heap of voltage 
>swing on the input meaning driving impedance would be high and 
>gain would be very low.
>
>It would be OK to grid drive the tube, but then stability becomes an 
>issue. The IMD also goes up because the heavy negative feedback 
>inherent in cathode driven systems (the output is in series and out-
>of-phase with the input) would disappear.
>
>The tube could certainly be used, but it wouldn't be a good choice 
>(especially since they have long leads and are prone to self-
>oscillation at upper HF).
>
>
>73, Tom W8JI
>w8ji@contesting.com
>
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