Difference between Sunking and Kingslayer Charge Pump ?

[drolo]

I was wondering what D4, D5, and C24 in the Sunking do compared to the Kingslayer setup.
And does the Sunking run on +18V/-9V? Or is that a typo?

[RobA]

I was wondering what D4, D5, and C24 in the Sunking do compared to the Kingslayer setup.
And does the Sunking run on +18V/-9V? Or is that a typo?

The Sunking charge pump does both negative rail generation and voltage doubling, so it does run, in some sections, at +18V/-9V (+9V/0V in others). The Kingslayer only does negative rail generation so it runs at +/-9V everywhere.

I personally find the Klon setup to be weird (possibly pointless), especially since even in the op-amp that's running at +18V/-9V it's biased up to 4.5V. But what do I know?

[juansolo]

You'd be hunted and burned for heresy for talk like that on some forums

[midwayfair]

I personally find the Klon setup to be weird (possibly pointless), especially since even in the op-amp that's running at +18V/-9V it's biased up to 4.5V. But what do I know?

Saves at least one capacitor -- on the clean blend side that would decouple pin 2 from the previous stages.

It's not like the actual bias point matters (the op amp doesn't care about anything except the difference between pins 8 and 4) unless you want the bias as ground to leave off the output cap (in which case, whee, just make it +/-18 and connect the + input pins to ground). Or maybe they had enough headroom at 18V but the -9V was a freebie so whythehellnot.

[RobA]

I personally find the Klon setup to be weird (possibly pointless), especially since even in the op-amp that's running at +18V/-9V it's biased up to 4.5V. But what do I know?

Saves at least one capacitor -- on the clean blend side that would decouple pin 2 from the previous stages.

It's not like the actual bias point matters (the op amp doesn't care about anything except the difference between pins 8 and 4) unless you want the bias as ground to leave off the output cap (in which case, whee, just make it +/-18 and connect the + input pins to ground). Or maybe they had enough headroom at 18V but the -9V was a freebie so whythehellnot.

Don't get me wrong on this, I think the trick of using the existing +4.5V bias to center the signal in the new 27V swing is pretty clever. What I meant by pointless is that I can't imagine that the extra headroom of the 18V/-9V is getting you anything in this circuit over what you'd get for +/-9V and I think it makes more sense to do the whole thing at +/-9V and be able to simplify the design. There's also the point that doing both -9V and 18V does push the charge pump harder, so if you can get the same results from using +/-9V I think it makes more sense to do it that way.

To be clear, I'm not trying to say it's a bad design or anything of the sort, just weird.

[juansolo]

Don't backpedal now... Stand by your convictions! 

Allegedly the 9v section was to get some op amp clipping along with the unicorn diodes. I'm with you though that +/-9v throughout makes more sense and much prefer 'Bean's take on the circuit with the Kingslayer (which I prefer with LED clipping, so I go quite a bit from the original in that respect). I also don't really see the point in having a 27v swing in a circuit for the buffer after the 9v section has already done the damage. Then again it'll give more headroom in bypass I suppose, but that's all I've got as to why you might do it that way.

It does some things oddly... Which I suspect all adds to the mystique/mojo of it all

[drolo]

Oh my ... I had never even noticed that in the Klon to be honest ... I built a Chimaera some time ago out of curiosity but not having much experience with charge pumps it did not occur to me. I thought one opamp was running on +9V and the other on +18V ... that does make this circuit and the choices they made all the more ... what's the word ... hmmm ...

Thanks for clearing that for me though. I had thought the extra diodes would be for protection or something ... 

[RobA]

Don't backpedal now... Stand by your convictions! 
...

Yep, you are right. I should have left the parenthetical "possibly pointless" in my comment. I'll go and hide for awhile now in case pitchfork wielding tone vigilantes from some other forum happen to wander by.