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Vintage threads from the first ten years
Which type of active circuit is used by EMG???
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 11/28/1997 8:11 AM |
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| anonymous | Which type of active circuit is used by EMG??? Hi, I wonder which type of active circuit is used by EMG. I know an active circuit by Jackson. They used a cheap and noisy dual low power op amp called LF 442. It draws a quiescent current of 1mA. EMG uses a circuitry, which draws only 80 microAmps !!! I don't know any op amp, that is satisfied with that little juice. Anyway, it must be a class B amp. Does anybody know, which sort of circuit is used with EMG pickups or with their PA-2 preamp? |
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| 1/9/1998 8:13 PM |
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Bart |
Hello, Low power comes easily if you don't need to bias up a power stage capable of driving 2000 ohm loads, which is what most OP AMPS are designed to drive. A very basic discrete FET circuit with a 10K load resistor draws what at 9V if it is balanced at Vs/2? Could it drive a 25K pot? You can probably figure it out pretty easily if you think about it a while. Low noise ALWAYS means either discrete circuitry andor LOTS of power consumption. chow, Bart sterling@netpath.net |
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