Well — about half the day..actually more! Spent trying to get a rudimentary single op-amp circuit functioning. I mean…maybe I’m a bit distracted and maybe in a rush. Either way — this should be going easier.
I ended up stripping everything off the breadboard and starting fresh. I even went back to an LM741. My biggest confusion through all this was the split-rail supply and how to hook it up. I made a simple circuit using a TLE2426. But then..I was a little flumuxed about what to do with the VGND signal. But I figured it out in between bouts of frustation and lots of shrugging. Basically, the -V of the TLE2426 circuit goes to the “GND” or negative supply of the op-amp. Turns out — the VGND of the TLE2426 goes to “ground” of the rest of the circuit. The +V and -V from the TLE2426 goes straight to the supply terminals of whatever op-amp you’re using.
Well — I sorted it out. Just stayed a bit late Friday after helping make a little film. Once things quieted down I could focus on debugging the circuit. I started from scratch. I basically wanted to go back to the rudiments. Build an inverting amplifier; a non-inverting amplifier; and a circuit I could use as a pre-amp for a microphone or something. And then just put signals up on the scope to see what sort of power I’d need in order to support mixing and amplifying signals without distortion.
I tried with two different op-amps — the LM741 and the LM348. I don’t know which is better than the other. They look like they perform similarly. The upside of the LM348 is that it comes dual in an 8 pin package. I tried them both in inverting and non-inverting set ups.
I’m working with all this on a breadboard cause, basically I’m rewiring stuff left and right and I haven’t worked with op-amps since college and I’ve been mucking up bad enough that I didn’t feel comfortable at all spinning a PCB even though these circuits are stupid simple.
Here’s a comment.