It occured ro me that balancing the current in Push Pull PA that doing this
using grid voltage may not be the best way to go. Perhaps tweaking the
screen voltage may be better Dont remember any audio circuit s that uses
theis but Used to work on an old radar scope that used 6146's in the
deflection circuit and there was an adjustment for on of the pair of P-P
tubes to adjust the screen voltage for idle current balance. If they would
not balance then you had to switch the pair of tubes around and try again.
Anyone have any thoughts on this.

Hey Jimmy ,

Never tried and tested it , but it crossed my mind also .......
So at least you're not alone ;-)))

Ronald .


"Jimmy" schreef in bericht
. com...
It occured ro me that balancing the current in Push Pull PA that doing
this
using grid voltage may not be the best way to go. Perhaps tweaking the
screen voltage may be better Dont remember any audio circuit s that uses
theis but Used to work on an old radar scope that used 6146's in the
deflection circuit and there was an adjustment for on of the pair of P-P
tubes to adjust the screen voltage for idle current balance. If they would
not balance then you had to switch the pair of tubes around and try again.
Anyone have any thoughts on this.

I would imagine screen bias changes headroom (that is, peak current for a
given load resistance which is low enough to stay out of the low-Vp range,
where Rp is low and Is is high) more than grid bias. Of course, that
parameter is probably just as matched as Ip @ Vg, so it's kinda a moot
point.

In the case of headroom, the effect of mismatch is one tube hitting its head
on the ceiling before the other - asymetrical clipping.

Tim

--
"That's for the courts to decide." - Homer Simpson
Website @ http://webpages.charter.net/dawill/tmoranwms

"Jimmy" wrote in message
. com...
It occured ro me that balancing the current in Push Pull PA that doing
this
using grid voltage may not be the best way to go. Perhaps tweaking the
screen voltage may be better Dont remember any audio circuit s that uses
theis but Used to work on an old radar scope that used 6146's in the
deflection circuit and there was an adjustment for on of the pair of P-P
tubes to adjust the screen voltage for idle current balance. If they would
not balance then you had to switch the pair of tubes around and try again.
Anyone have any thoughts on this.