[Boatanchors] amp internal shielding

[Carl]

The TL 922 has a complete RF cage around the tubes and tank. Most other 
quality amps also.

Close steel detunes the tank coil, adds extra stray C, changes the 
loaded Q. Not good.

You can see the effect with various Dentron, Amp Supply and Heath 
products by lifting the covers. Several other less popular brands also.

Carl
KM1H


----- Original Message ----- 
From: "BLIMPY" <blimpboy at sonic.net>
To: <boatanchors at mailman.qth.net>
Sent: Thursday, November 13, 2008 11:47 AM
Subject: [Boatanchors] amp internal shielding


>
> most Grounded Grid  rf amps dont have shielding between the PA coil 
> and the power transformers.
>
> why would they need it ?
>
> whole xfmr core is like a giant choke anyway.
>
> distance is the deal...and some pretty nice amps have been made with 
> precious little of that ( Ken TL-922 , Collins 30-L1  etc )
>
>
>
>
>
>
> _______________________________________________
>