[Amps] Manual tuned inputs

[Bill, W6WRT]

ORIGINAL MESSAGE:

On Fri, 9 Apr 2010 05:58:35 -0700, "Jim Thomson" <Jim.thom at telus.net>
wrote:

>  My patience ran out a long time ago, with trying to build  9 x tuned inputs.  

REPLY:

I agree, building 9 tuned inputs is a drag, but with some tubes (8877,
pair of 3-500z) you don't need a pi-network input, which simplifies
things considerably.Their input impedance is already close to 50 ohms.
A simple LC tank coil provides the flywheel effect and requires only a
single wafer bandswitch, a simple coil and one cap per band. I used 9
Arco compression trimmers, which admittedly is a bit expensive, but
once set, never needs to be touched again. 

Jim's method works. To each his own.

73, Bill W6WRT