What causes oscillation at clipping?

I have the resources now to go back to school if I wish - I didn't finish the first time around... :) I have fantasies of getting an EE degree, but honestly I think that's a degree that's best done when one is younger. I think now that I'm in my 30s the only way to have a career in electronics would be to go into business for myself, and clearly I'm not at that level. It's pretty unlikely that corporations are hiring newly minted 36 year old American EEs! I'd leap at the chance to get a degree in the sciences/engineering,though, if I thought that I could actually make a living doing it so late in the game.

Have you tried using Octave or NumPy for numerical computation? The learning curve is not all that bad for doing things like matricies/systems of equations, particularly for Octave, which is an open source MatLab clone.

The youngest of our 4 would be 38, had he not died of colon cancer 5 years ago :-(

Our oldest just turned 49!

Our oldest grandchild is 21 ;-)

Our youngest (of 8) is 3.

So we have a spread-out crowd ;-)

And I'm ten days away from turning 71 :-(

It's not simply computation that I need to do, rather some exotic curve fitting. ...Jim Thompson

Try using a 2H mechanical pencil and some 11x17 Clearprint H1000 fade-out vellum, 10x10 squares to the inch. A plug-in electric eraser (mine was $15 on eBay) is nice too. Makes penmanship easy.

Cheers

Phil Hobbs

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You should probably be including the load impedance in your modeling. You may need to add some R/L/C network in series/parallel with the output to help stabilize the loop. But yes, you've got 'way to many stages. Look at op amp designs (the old ones, before they started hiding all the goodies) - you won't find the number of stages that you have!

I always design on paper as well. 5mm quad / quadrille a4 pad and Pilot Vball 0.5 tip pens. You soon learn to draw straight lines and get stuff to some sort of scale. I find it much easier to sketch around a design, pen following mind, working out component values, levels, signal polarities etc. In the time it would take fire up schematic edit, you can usually be there with an outline and rough component values by using pen and paper. Doesn't matter if it's scribbled and untidy to start, you just redraw on a new page and the delay involved in doing that makes you think more about what you are doing...

Regards,

Chris

I've been buying quadrille pads in bulk for close to 50 years.

Famous quote of first child about 45 years ago, "Mom, Dad is wadding up paper and throwing it behind the couch" ;-)

(Behind the couch was actually the dining room :-)

All but three of my patents are for chips designed strictly on paper... no simulator existed then.

When something doesn't play in simulation, I often drop back to paper to sort out what I did wrong. ...Jim Thompson

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Not really that hard to pick up using Macsyma (free and like = Mathematica), of Mathcad, or even using most any ordinary spreadsheet that has graphing capabilities (older versions of M$ excel will be easier to get useful graphs from).

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Only if you insist that the common connection be grounded.

Not with an equation... rather with straight line segments... piece-wise-linear fitting. ...Jim Thompson

Yeah, what he said!

Jamie

Would you have a pointer to a schematic that demonstrates using a bridged design with stereo output but only 3 wire connections (say, L+, R+, and then L- and R- common)? It's not clear to me how this is done.

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Including piece-wise linear fits. Send me a data set and i will do it with a spreadsheet to show you how. With Macsyma as well if you want to try it. Same method.

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Rather simplified, for concept. In fixed spacing

Lt in -+---------------|\+ | | >-------------- Lt out | |/- | | Rt in -)-----+---------|\+ | | | >-------------- Rt out | | |/- | | R R R R | | |\+ | | | >-------------- C out (-Rt/2 -Lt/2) +-----+---------|/-=20

about 50% more swing, over 100% more output power at same Z.

The obvious trade-offs with supply voltage and bipolar vs MOS at 5V and below apply.

Thanks! Will do! Is Excel 97 old enough ?:-) ...Jim Thompson

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Excel 97 is fine. Working on it.