how to know if a circuit inverts the signal?

[birt]

A lot of circuits with multiple gain stages invert the signal, and sometimes it's a easy as just counting the gainstages.

but how do i know if a stage inverts the signal when i see it in a schematic? like common buffers. does a basic transistor buffer invert the signal? a JFet buffer? Opampbuffer? or a 1 transistor design like the colorsound inductorless wah, vox wah or LPB?

what do i look for in the schem?

[d95err]

In general:

* Single transistor/FET gain stage - inverts
* Single transistor/FET buffer - no invert
* Opamp buffer/gain stage:
   - If the input to the stage goes to the inverting (-) input, it inverts
   - If the input to the stage goes to the non-inverting (+) input, it does not invert

Here's a page with some info on most of the basic stuff like opamp and transistor gain stages and basic electronic building blocks in general:
http://ourworld.compuserve.com/homepages/g_knott/index1.htm

[birt]

so if i blend clean signal with the colorsound wah i need to add an inverting buffer (like the last one in the basic buffers article on AMZ) to that clean signal, right?

[petemoore]

  Dunno..
  say you have a gain stage it'd be then -, buffer [still -] andother gain stage [back to +...
  Buffer = +, that plus into gain stage = '-', and so on down the chain links.
  So if you have two parallel signal paths, a + or - needs to be found for each sidechain, and if it comes out +/- you'll have cancellations and probably choose to add something or other to bring both outputs to where they mix or 'blend to become +/+ or -/-...which doesn't particularly matter until you use say another amp, then you'll want both amps in phase [or cancellations occur again]...generally a good idea to keep outputs non-inverting, especially if there's a chance mixing might happen later, in components or air.
  A Rangemaster for instance, you just need to know it's inverting and use is so it does or doesn't matter, [important thing being you know the what's and whys when it comes time it does matter] make it non inverting and it's no longer a Rangemaster.
  Another frinstance is speakers running out of phase, of course if one speaker is pulling back when the other is pushing foreward, output will suffer, and instead of push>pushing the wave foreward, the air between the speakers moves more left/right as pressure in that area is controlled by the speakers, mostly amps are run in phase, only if theres a certain effect that out of phase produces that is desired [can't really think of any except for attenuating the output of a tube amp, or some wierd tone that running out of phase gets.

[birt]

thanks