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...and while we are on the subject, what about my Peavey keyboard amp? Is its input more likely to be 10Kohm or 100Kohm? And if so, so what?





Tell me what model and I can likely find out what the input impedance is.

As for the guitar electromagnetic pickup, the reason for a high impedance input, "high" meaning around 250,000 ohms or higher with 1 megohm being the typical desired input, is that anything lower will "load" down the small voltage output of the pickup, resulting in a change in the EQ (sound) of the pickup, for the worse. Ohm's law tells us the why of it. If the pickup can generate, say, 100mV into a 1 million ohm input, then it could not generate the same voltage into only 10,000 ohm load. A fractional percentage would be all that we could generate. Since the AC voltage that the pickup generates translates to amplitude of the soundwave, we would realize a much lower volume into that 10K input, plus there would be problems with reproducing the frequencies accurately.


Typically, a guitar jacked into a 10Kohm input will sound "weak" and with not much midrange punch. It also won't sound much like and electric guitar at that point, because a lot of the sound we know comes from the guitar amplifier and speaker(s) which are highly specialized for the purpose. Well, the plugin simulator can replace the amp, but we still should present it with the full range of the guitar pickup's voltage and frequency response first. If the input impedance is too low, we can't do that.


--Mac

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