Re: Using Vacuum Tube heathkit as Linear Amplifier for QRP

ajparent1/KB1GMX <kb1gmx@...>
 

The attached image was the solution of the 60 and 70s for hams (and CBers)
for 100W amp. it was cheap 10-13DB of gain.  Alas sweep tubes got expensive 
as people burnt them all up pushing those.  There were generations of them with
up to 6 (SIX!) for a KW input peak.  Not all were clean.

Some did grid driven and they worked save for over drive the grids and the
tubes protest by going away.  At 25$ each that is a bad thing.

For laughs a decade ago I took a 4CX250  and ran it grounded grid like that
and it was good for about 80W (on 6M) out in a simple circuit without forced
air cooling. The tube with screen bias (its a ceramic metal power tetrode)
added did an easy 300w out at 2000V (a very lethal power supply).  The
amp was terminally simple save for a typical tube amp tapped load coil
Pi network for multi-bands.  There are a long list of tubes that can can
be used for that that..

Allison

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