Will preamp manufacturers tell you if the model is phase inverse?

A preamp that inverts simply outputs the negative of what's fed into it (the "inverse" wave). It won't harm anything.

That's why "inversion" is one thing and "phase" another. The phase of a signal is merely the delay associated with it. IIR (standard) filters cause different phasing at different frequencies. Digitized FIR filters do not.

To avoid confusion, pure delay (not frequency dependent) is called "latency" and this is what a digital delay can cure between speakers or speaker drivers that are not the same exact distance from your ears.

Phase or Polarity
http://totalproaudio.stevebunting.com/30/basics/phase-or-polarity/

Hi @pops,

don’t you mean the signal is inverting since your example cites one as non-inverting and two as interting? What am I missing?

No, that example is non-inverting.

All we're doing is adding the number of gain stages in the signal path. A non-inverting component has an even number of gain stages and an inverting component has an odd number of gain stages.

Think of it this way:

• For a non-inverting component, assign 2 (or any even number).
• For an inverting component, assign 1 (or any odd number).

So: non-inverting + inverting + inverting:
2+1+1 = 4.

Even number of gain stages = non-inverting.

Cheers,
Thom @ Galibier Design

You can use the Stereophile test CD to determine whether your polarity is correct