[Amps] Follow-up...re: Time to ask for help.

[Vic Rosenthal]

I suggested to the original poster that he make it a swamped class AB1
amplifier. He will get plenty of drive with a 50-ohm swamping resistor.
The only tuning he needs is a small coil to balance out the input
capacity of the tubes. That should be unconditionally stable, as long as
he bypasses the screens properly.

73,
Vic, 4X6GP/K2VCO
Rehovot, Israel
http://www.qsl.net/k2vco/

On 28 Jul 2015 04:14, donroden at hiwaay.net wrote:
>
>> REPLY:
>>
>> I see a potential problem with that. Having only the single
>> variable capacitor will case a phase shift when adjusting it. By
>> comparison the bridge neutralization circuit with it's two voltage
>> dividing caps will not.
>>
>> I think. :-)
>>
>> 73, Bill W6WRT
>
>
> I used SK-630 sockets on four 4CX250Bs on six without
> neutralization.
>
> I think the secret to a stable six meter amp is well RF grounded
> screens.
>
>
> Don W4DNR