Buzz, in case you are interested :
A push-pull output stage has a Class A and a Class B range.
A standard output stage crosses over from Class A to B at an output current of 2 x the bias level.
In the F5T, whether peak Class A output power level follows the standard PP rule or not, depends on the diode switching point.
Two choices for the diode supercharger to kick in ;
- output current around 2 x bias level
- before output current reaches 2 x quiescent current level
For the 1st option :
standard PP output stage behavior in the Class A range, higher output level in Class B beyond the diode slide, compared to the regular F5.
For the 2nd one :
standard PP Class A behavior till the diodes start to drop the source resistor value.
The moment the diodes switch in, the output stage behaves asymmetrical within Class A range.
In effect :
- on one side of the PP stage, a voltage change across the source resistors, results in a change of current.
- on the other side, the same change of voltage (different signature) across (diode + source resistor), results in a higher current change level.
Ergo, the output stage does not leave Class A, but the range becomes elastic, like rubber.
Still will cross over to Class B eventually, but at a later hour.
And once in Class B, still delivers more peak output power than an F5, due to lower voltage losses across the source resistors.
(me off the F5T thread, I've had it with the teach relic)
A push-pull output stage has a Class A and a Class B range.
A standard output stage crosses over from Class A to B at an output current of 2 x the bias level.
In the F5T, whether peak Class A output power level follows the standard PP rule or not, depends on the diode switching point.
Two choices for the diode supercharger to kick in ;
- output current around 2 x bias level
- before output current reaches 2 x quiescent current level
For the 1st option :
standard PP output stage behavior in the Class A range, higher output level in Class B beyond the diode slide, compared to the regular F5.
For the 2nd one :
standard PP Class A behavior till the diodes start to drop the source resistor value.
The moment the diodes switch in, the output stage behaves asymmetrical within Class A range.
In effect :
- on one side of the PP stage, a voltage change across the source resistors, results in a change of current.
- on the other side, the same change of voltage (different signature) across (diode + source resistor), results in a higher current change level.
Ergo, the output stage does not leave Class A, but the range becomes elastic, like rubber.
Still will cross over to Class B eventually, but at a later hour.
And once in Class B, still delivers more peak output power than an F5, due to lower voltage losses across the source resistors.
(me off the F5T thread, I've had it with the teach relic)
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I still like your explanation the best, Jacco. I have yet to see it challenged in a understandable way. Take into account that you are doing an excellent job of putting it in terms I can understand, and i have a hard time unseating it. I am willing to do so, but not until someone presents a practical explanation otherwise. I tihnk the big mistake in this amp is to assume it follows normal rules. I am using the word normal here to represent a standard PP output stage. Although I have compared it to a bypass cap, like found in many tube circuits, i dont think it is exactly the same. It seems to be a hybrid of that theme. Believing this of course adds to the lore of Nelson, which is always fun.
Happy Canada Day to all the Dodos. Enjoying the holiday, which happens to be the hottest day of the year here, with no air conditioning, just a bathtub filled with cold water and one of them plant misting things for in between. No indoor cooking allowed today. 36º on the covered patio, 32º inside. Tough for us in the Great White North, considering we start complaining about the heat when it reaches 25º. 
Much liquid being consumed.
Much liquid being consumed.
In a standard F5T as per Pa's article, it does follow normal rules most of the time.
Learning is more fun than preaching, the P is a good reverend though, and I'm always in awe of the slide master.
(36º, darn)
Happy Canada Day to all the Dodos.
Much liquid being consumed.
Even da Dachshunds say Happy Canada Day - and gemme a beer.....
(note - classy paint job on da wallz....)
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Cal we will not see 30c for a week with lows of 21c that in Hotlanta . A very cool summer so far here.Happy Canada Day to all the Dodos. Enjoying the holiday, which happens to be the hottest day of the year here, with no air conditioning, just a bathtub filled with cold water and one of them plant misting things for in between. No indoor cooking allowed today. 36º on the covered patio, 32º inside. Tough for us in the Great White North, considering we start complaining about the heat when it reaches 25º.
Much liquid being consumed.
Thanks Thomas. You guys get an extended weekend this year huh? July 4 is Thursday so any plans?
Sure was. This mini heatwave came from out of the blue. Just got outta the tub. Man that's hard to get into but now I'll be able to sleep tonight. Amazing how cold that ****ing our tap water still is.
Heck - everyday iz an extended weekend for me!!!
Just hanging around the house and keeping the doggy's settled down.
They love their fireworks around here and use a lot of 'em. They have been setting them off for a week now and on the 4th the place will be nuts until well after midnight....
Tomorrow iz da 4th of July and here in USA and iz our day of Independence. We celebrate this day by trying to burn down the neighborhood with fireworks and lighting BBQ's with a couple of gallons of petrol.....
And then there iz the drinking of mass quantities of adult beverages - while burning food on above said BBQ's and after the sun goes down stumbling around setting off the fireworks....
Ahhhhhh - what a day!!!
Da Dachshunds say - keep me safe inside!!!
Pretty gurlz say - [fill in your favorite fantasy] !!!
And then there iz the drinking of mass quantities of adult beverages - while burning food on above said BBQ's and after the sun goes down stumbling around setting off the fireworks....
Ahhhhhh - what a day!!!
Da Dachshunds say - keep me safe inside!!!
Pretty gurlz say - [fill in your favorite fantasy] !!!
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