Yeah, I'm not aware of the differences in op amps. I'm still learning how to read opamp datasheets. So I can assume it's not so much about the power supply, but the right opamp for the project?
And say your building some else s circuit that calls for pos and neg supply to the opamps, is a dual supply required without tweaking the circuit(not knowing how they powered it)? I mean, are there any stable virtual ground circuits?
When you refer to 7v supply of the TL072, are you referring to the positive and negative voltage combined? That's pretty much right where I am now. If I connect a weak 9v battery, the signal seems to drop somewhat on the LM3915 outputs.
I tried just reading the positive side of my synth signal, but sometimes the wave form goes from 0v and lower, so it wasn't til I supplied a negative voltage to the TL072 that the Lm3915 saw it.
I guess my next question would be...what are the new rail to rail opamps? Can these amplify the full ac signal?
That looks like a nice circuit audioguru. I wanted to try an LM3915 with an electret mic as well at some point. Can I assume Q2, C8, and R13 make up the peak detector, or is the second opamp part of it to?
And thanks for the sticky Nigel.