Posted by Wayne Parham [ 66.139.39.22 ] on June 09, 2004 at 02:45:56:
In Reply to: Re: Feedback posted by metasonix on June 08, 2004 at 04:59:43:
I never really thought much about this subject, but I can sure see what you mean. The SE idea is really neat for simplicity - It's usually less than a dozen parts and can be built on an open chassis or breadboard by practically anyone. But with no feedback mechanism, it is particularly sensitive to load impedance fluxuations and without having any complementary components, there's no real way to cancel asymmetries with an "equal and opposite." I suppose you can try to counter the output amp curve with a driver amp curve, but that's not complementary-symmetry, it's more like pseudo-symmetry. So maybe it can be made close, but it's a hack. And the load impedance thing can only be dealt with by brute force, which is kind of an oxymoron when discussing Class A amps.
You mentioned the DeHavilland 845. What are some of your other favorites?