> say you are doing a 10/1 division.
Say you are doing a 2/1 division to get 120VAC to power a USA Fender Twin from a 240VAC line.
I have 1Meg resistors handy. Two of these, my Perfect Voltmeter shows 120V.
The Fender Twin probably draws 120 Watts from the wall. At 120V, that is 1 Ampere. We may approximate this as 120V/1A= 120 ohms.
Stick that on your 1Meg+1Meg divider. You now have a 1Meg+119.99r divider, and get less than 0.03V from your 240V supply.
DRAW THE WHOLE PLAN!!
If there is a load (and there always is), draw it and figure it.
> avery high impedance piezo pickup
Oh?
IDK, but a 1,000pFd piezo is 10Meg at the bottom of the audio band and 10K at the top of the audio band. You think it is high impedance because low loads suck bass, but it is fairly moderate further up.
The Fender is 1Meg+100pFd, so 1Meg to 2KHz declining to 100K at 20Khz.
Not an easy network.
Because the piezo won't be harmed by a dead short, if it is "too hot" the quickest way to get 1/10th the voltage is to put 10X the capacitance directly across it. Try 10,000pFd (0.1uFd). This will also make it less fussy about bass-loading.