Quote:
Originally Posted by Brent Hahn
In my experience, even with your typical piezo + onboard preamp, higher Z is better. I'm basing my opinion on the 200-ish live radio shows I've mixed in the last 3 and half years, meaning probably >150 different folks with acoustic pickups..
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I think it's one of those "how high is high" things, and will depend on the specifics. In general, onboard preamps buffer and provide the very high input impedance piezo's need, and present a lower output impedance to the next stage. As long as that next impedance is higher than what's being output, all should be well. Since most acoustic preamps are designed with high impedances in case you use passive, maybe some manufacturers assume that's what their electronics will be going into (just a guess) and err on the high side, I don't know. Some specifically aim for low impedance, like Taylor's balanced low impedance system a while back.
Here's an experiment I did a while back with a DTar Wavelength and a variable impedance preamp. Again, just one data point, and a different pickup might have behaved differently, but in this case, the pickup was fine with all but the lowest impedance (10K). impedances in order are 1M, 10M, 10K, then 1M again, 20M, 330K
A passive pickup, like a K&K or a Barbara or an LB6, etc, start losing bass and ommph much sooner. Here's the same experiment with the K&K passively:
In any case, I'd certainly vote for having a reasonably high impedance input for any acoustic pickup. (Id also vote for using a mic if you want a decent recording sound)