[AMPS] 4-1000 is this a good tube?+

[measures]

>
>At 12:40 PM 5/18/00 -0400, N6BUU@aol.com wrote:
>>the above comments reminded me of a fellow I ran into on 40 mtrs a few years
>>back he was running 5KV ON A PAIR OF 813s! i wondered, but forgot to asked
>>him what his idle current was, as the (2) 813 give only 250 w of plt. dissp.
>>anybody here had any experience running 813s at this voltage?? (seems just a
>>tad high to me!)
>> 
> >
>>                          HANK
>
>
>Hank,
>
>I run 813's at 3000 with no problem, other than taking the usual 
>precautions when running a device much higher that the manufacturer's 
>suggested ratings. However, recently I inadvertently ran the same amp with 
>about 3400 key down volts and had it start to drop output power and 
>increase anode current as the tubes got hot. There was no sign of 
>"parasitic type oscillation". Switching back to 3000, the amp immediately 
>returned to normal operation. I did not have time to analyze the problem as 
>I was in the middle of another problem at the time. I hope to get back to 
>this when I get time. It would be good to know if the cause of the 
>difficulty was the tubes or some other component.
>
>5KV would certainly be an interesting experiment. Rich, have you ever 
>hi-potted an 813 at 5 KV?
>
 T. simulate the flywheel effect of the tank, tubes are usually 
high-potted at 2x the anode supply volts.  
>
later, Larry
>
>
>
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>


-  Rich..., 805.386.3734, www.vcnet.com/measures.  
end


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