I'm curious about the effective input impedance of various op-amps, in various circuits.

Consider, as an example a TL072 vs. an LM833, -the LM833 has better specs overall. -The selling point for the TL072 (in a guitar stompbox..) is the bi-FET input's ultra-high input impedance,
-but, configured as a non-inverting amplifier, won't the LM833 have very high input impedance also?

For an ideal non-inverting op-amp the input impedance is infinite , so for a real LM833 it should still be at least a...

Been trying to measure output voltage of different OD pedals of mine cranked up by putting DMM to pos and neg poles of guitar jack, and using either AC or DC voltage measurement but I get nothing!!

Do you need some kind of special oscilloscope to measure that or is there something i'm doing wrong?

My electronics knowledge is pretty basic.

I want to run my Maestro Fuzz-Tone FZ-1A, which runs on 1.5vdc, off my pedalboard psu. It's a Voodoo Labs, so I could dial -down one of the outputs, but I'd be worried that it might accidentally get bumped up.

Is there a circuit diagram available for a simple 9vdc - to - 1.5 vdc converter, either stand-alone or something I'd build into the pedal? - Having variable voltage would be even better, though I could of course just swap-in a pot.

How do you go about figuring out the total input impedance of a circuit which uses a buffered bypass? I have read that the input impedance of a buffered circuit is very high, but I am a bit confused having never been formally taught the characteristics of buffer amplifiers as a switching mechanism, and the answer may be entirely too simple. I am only concerned with the input impedance of the effected circuit when the pedal is in activated mode. I will attach a schematic so that you can have a...