"Don Pearce" wrote in message
...
On Wed, 14 Nov 2007 18:55:28 GMT, "Ian Iveson"
wrote:

Don Pearce said

Yes, it is a good idea. Make the resistor about ten times
the value of
the pot, or you will be changing the way the volume
control reacts.


10-1 rule again :-)


I was considering 9.72, but on balance...

I often see volume control pots with their wiper connected
directly to
the grid of the following tube. Trouble is as they wear
they get a bit
scratchy and often lead to the grid becoming disconnected.
Would you
agree it is good practice to add a resistor (say 1Meg)
directly across
the grid?

Disconnected grids are bad news.

Why, in this case?

cheers, Ian


Because the anode current will rise until the valve hits saturation.

d



Most input stages are cathode biased.

Iain