circuit design Q'tion - inverting stage vs. non inverting

[Greg Moss]

Polarity issues aside, what are the advantages or disadvantages of inverting and non-inverting op-amp gain stages.  Simply from a phase point of view I would think that one would usually want to just use non-inverting op-amps stages (unless of course you were intentionally   inverting a signal's phase, in the Mu Doubler circuit or a balanced line input, for example).  

Looking at a bunch of the op-amp based overdrive, booster, splitter and mixer schematics out there, I've noticed that circuits which have more than one op-amp stage will opt to have a least two inverting stages (such that one winds up inverting the signal, and the second returns it to it's original polarity).  Why is that?  Do the inverting stages have some (probably obvious) advantages which I am overlooking?  Lower part count?  Less noise?

I'm breadboarding an overdrive which is sort of like a tubescreamer, but more distortion, and with half of the Bass Paralooper built into it for recovering low end from the clean input signal.  Needless to say, there are several op-amp stages which at this point are all non-inverting.  It's sounding pretty cool so far, but I was curious if having some of the gains stages be inverting would make some kind of improvement....

I obviously still have a lot to learn about this electronic stuff.  Any advice is appriciated....

Greg

[jrc4558]

As long as you don't have two signals mixing together you are free to do whatever you want, i guess. With two parallel signals out of phase you will have phase cancellation.

Also it's nice to reverse phase to get rid of the whistling of the high gain distorions when they're true bypassed.

[Mark Hammer]

Reads the articles on inverting vs non-inverting in the back issues of DEVICE I have posted (http://hammer.ampage.org).  There are not only differences in input impedance but also different advantages and disadvantages with respect to ease of circuit design and implementing different features.  For example, the pre-emphasis and de-emphasis that BOSS uses for hiss control in their chorus pedals is difficult to implement in non-inverting op-amp stages but a piece of cake in inverting ones.

[Greg Moss]

Reads the articles on inverting vs non-inverting in the back issues of DEVICE I have posted (http://hammer.ampage.org).

Thanks Mark, I am definitely going to check those out.  It looks like the article on op amps is in issues 1.7 and 1.8 of Device, if anyone else is interested.