[Amps] Size of Parasitic Chokes

[Carl]

The YC-156 doesnt use a socket and hasnt shown any need for a suppressor.

With a spectrum analyzer its rather easy to spot a parasitic and then design 
whats needed. Many of the big triodes are extremely stable. Tetrodes respond 
well to grid suppressors, adequate screen bypassing and with a Carborundum 
style plate suppressor.

I cant say what these big tubes are like on VHF but Id be tempted to build a 
rather big cavity for 6M to get around the output C problem. I believe that 
is used on the FM and TV frequencies.

Is it worth the bother?

Carl
KM1H


----- Original Message ----- 
From: "Roger" <sub1 at rogerhalstead.com>
To: <Amps at contesting.com>
Sent: Thursday, July 15, 2010 8:21 PM
Subject: [Amps] Size of Parasitic Chokes


> How do you determine the size of a parasitic choke for a given tube
> other than using "The Handbook" as a starting point and going with "cut
> and try" from there?
> Say with a YC156, 4CX3000A7, or 4CX5000?
> Unfortunately sockets for those 4CX tubes are a tad pricey (Look like
> the socket for a 4CX1500B on steroids.) I don't see all that many of the
> 3000's any more, but I have one and know of possibly a couple good ones
> for a reasonable price. I think that socket (and 360 watt filament) keep
> the price more reasonable. Course it takes a rather chunky filament
> transformer too.  That tube would make some nice 6 meter and 2-meter amps!
>
> 73
>
> Roger (K8RI)
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