[ARC5] MW and the BC-375

[Kenneth G. Gordon]

On 14 Jan 2021 at 14:40, arc5 at ix.netcom.com wrote:

> Finding suitable substitute tubes for the BC 375 has been one of my Holy Grail projects for a long 
> time. Stumbling block is the oscillator. 811 substitute just fine for the rest. One of these days. I 
> haven't given up on it.

Dave:

The 811 is a "zero-bias" triode. As such, it needs considerable external feedback to oscillate. 
Connect a suitable capacitor directly between the plate and the grid, and I am certain any 811 
you wished to try there would work as the oscillator.

You might also consider doing the same thing with a 572B.

It should work the same way.

Being careful to arrange some way to keep the plate voltage off the grid if your capacitor 
failed might be advisable. ;-)

Ken W7EKB