[Amps] parasitic suppressor for six meters

[Ron Youvan]

On 07/15/2018 10:20 AM, Bill Turner wrote:

> I'm thinking
>> about replacing the two burned resistors with a single 22 ohm 5 Watt metal
>> film resistor, and trimming the inductor to a single turn. Does this seem a
>> reasonable change? Does the tube require any parasitic suppressor at all?


> REPLY:

> Many amps have parasitic suppressors but actually don't heed them at
> all, especially if the leads from anode to RF choke and tune cap are
> very short. I would try the amp without the suppressor, bringing up
> the plate voltage slowly in class AB mode and see if you get lucky. I
> have built several amps using an 8877 on HF ( not VHF) without a
> suppressor and all were perfectly stable.

> I suspect many commercial manufacturers put in a suppressor "just in
> case" or because customers want to see one there.

   Most broadcast transmitters that I have see or have downloaded the IB 
for have not used any parasitic suppressor at all.
   The biggest reason to use any parasitic suppressor is because it is a 
multi-band amplifier.  (on some bands the design is wrong)
   In a single band amplifier correctly designed and implemented ovoids 
the necessity for any parasitic suppressor at all.
-- 
   Ron  KA4INM - Youvan's corollary:
                 Every action results in unwanted side effects.