Goddamned lying simulators

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NewYorkDave

Well-known member
Joined
Jun 4, 2004
Messages
4,378
Location
New York (Hudson Valley)
Some of you might remember these two circuits from another message I posted back at the old forum:
twopreamps.gif

I had remarked on a curious thing that happened when I simulated the circuits in Circuitmaker. Contrary to expectations, the circuit with grid-leak bias on the second stage had much better overall performance into the relatively heavy load presented by the feedback resistor and the 250K volume pot.

Well, guess what? A couple of days ago, I finally had enough free time to wire up the circuits for real, and guess what I found? No real difference at all! Maximum output and distortion are about the same for both circuits.

I resisted SPICE for many years because of an innate distrust of man-made simulations of physical phenomena. Although I've since found it handy for checking out very simple passive circuits with little or no parasitic effects involved, it's done nothing but lie to me when it comes to predicting the performance of active circuits. When I've entered known, tested circuits into the simulator, the results are always better than what the real circuit was able to achieve.
 
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