[Amps] Initial test of 813 amplifier

[Vic K2VCO]

Yes, there are VHF suppressors.

I am thinking that the neutralization was upset because I adjusted it before I installed 
the plate transformer, which is not that far from the neutralizing capacitor. This, 
combined with the large amount of feedback caused by the missing shielding may be the 
reason. Grid-driven tetrodes have a lot of gain!

I think I'm going to finish up the shielding, readjust the neutralization with it in 
place, and try it again.

I really don't like arcing because I'm afraid it might damage the capacitor or the vacuum 
relay on the output, etc.


On 8/15/2010 4:53 AM, Bill, W6WRT wrote:
> ORIGINAL MESSAGE:
>
> On Sun, 15 Aug 2010 00:04:22 -0700, Vic K2VCO<vic at rakefet.com>  wrote:
>
>> Here's my question: Should I bother with this oscillation at this point? Or is it normal
>> to have instability when no load is connected to the amplifier?
>>
>> I suppose the fact that there's no enclosure or bottom plate is also a cause...
>
> REPLY:
>
> The amp should be stable with or without a load (both input and
> output), but the shields should be in place too. Try it again when
> they are.
>
> Is there a VHF parasitic suppressor?
>
> 73, Bill W6WRT
-- 
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/