Originally Posted by Doug Young
The effects of impedance on passive piezo pickups is absolutely real. But people often get confused about it, and there seems to be a bit of marketing designed to confuse people. James May posted one of the clearest technical descriptions I've seen here recently, so it's worth looking that up. But for K&K's, it's pretty simple, and comes down to anything above around 500K (+/-) is fine, including the 1M, 5M, 10M, 20M, etc. Below 500K or so, you start losing low end. Above that, it makes no discernable difference (you might want to be careful with very long, low quality cables at very high impedances, tho). There are lots of anecdotal reports that contradict that, but it's always with different preamps, different brands, different gain structures, etc. It's not surprising that different products sound different, but there's more to preamps than impedance, and two different designs are, well, different. Get a preamp with variable impedance, like the Grace Felix, and you will be able to compare apples to apples and see when impedance matters and and when it doesn't without changing 100 other variables at the same time.
Of course in the end, it all comes down to "does product X sound good to me". I've yet to encounter a preamp or amp that sounds noticably "bad" with a K&K. Some seem to sound better (with any pickup), but I've never seen anything to indicate that the reason was impedance (unless the impedance was very low, like 47K).
|