Paul Barker wrote:
I haven't spent any time thinking about the filament, it would surely be better as two individual supplies but I expect parallel would be fine. Series is naturally out of the question.
I didn't realise the filament were not 6.3v.
So 2.1v or 4.2v depending how you wire them.
4.2v @ 0.325 would mean we could run a pair from one of Andrews modules with a resistor added ?
The only thing necessary for the triumph of evil is for good men to do nothing.
No it is only in A2 less than 50% of the time because it is negatively biased, due to the autobias across the interstage of +20v at the cathode which translates to -20v at the grid.
Yes there is grid current but the serendipity is selecting the valve the operating point to suit the interstage transformer available (you could specify an interstage for other valves/operating points, but that would be a bespoke design which would cost you much money).
The grid current does not affect the grid bias at the grid because the current exits the grid straight to ground with no dc resistance to negotiate.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
Only if you bias it as such and we would then be starting from scratch a whole new design. That is not what I have designed. If you concluded the above I would suggest your reading is in advance of your ability to assimilate the knowledge into successful cogniciense.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
Paul Barker wrote:Only if you bias it as such and we would then be starting from scratch a whole new design. That is not what I have designed. If you concluded the above I would suggest your reading is in advance of your ability to assimilate the knowledge into successful cogniciense.
Most probably Paul.
I'll leave my 811a mutterings for another time, when (hopefully ) brain cells A & B have assimilated the required knowledge.
The only thing necessary for the triumph of evil is for good men to do nothing.
I'm looking at that last picture, trying to work out how the DC magnetisation is cancelled in the interstage . Both grids are grounded, both cathodes are positive, the current is going the same way in each half... but is it just down to which way you connect-up the secondary winding ?
Do you have that choice, which just inverts the driving signal , which is no problem ?
"Once you find out ... the Circumstances ; then you can go out"
what the hell is with the A3. Only person i know who tried to invent that stupidity was Thorston i assumed for marketing purposes. The world does not need another class. In this case if its good enough for rdh its good enough for me.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.