I was thinking that I had read an article published by RCA explaining that the series grid resistor on 807/1625s, 20K as I recall, was placed in circuit for linearity reasons. It was having something to do with a dip or a peak in transconductance mid way in the drive. The solution was simple but it did not come to the engineers right away. Does anyone else remember the article or am I just imagining it, age you know does funny things? Of course it would protect the grid as well but I was thinking it was mainly for linearity.
John, WA5BXO -----Original Message----- On Behalf Of ne1s Sent: Monday, April 10, 2006 12:04 PM Subject: [AMRadio] Re: Triode connecting 803's for a Modulator Elaborating on Don's comment, the reason this is done with the triode-connected 807 is that if the control & screen grids were simply tied together, the control grids would be exceeding their maximum dissapation before the screens could be driven hard enough to provide reasonable output. We don't want to vaporize the control grids now, do we :>) I suspect this would hold true for other tetrodes & pentodes in a triode connection.