preamp inverts polarity

I'd suggest throwing out the cables that are specifically designed to color the sound. We're talking AC signals here. Both conductors see positive and negative. Anything that doesn't conduct both equally is failing. 

No, it's not. We had this discussion a while back. Phase has to do with time. 

I don't buy this nonsense about half or most recordings being out of phase or polarity or whatever you want to call it. It doesn't even make sense on it's face. Inverting the polarity completely changes the presence of the sound. Air is a single ended medium of transmission. You can compress it much more than you can decompress it. If you invert the polarity of the recorded instrument, the single ended nature of air will inject it's own distortion where none should otherwise be. Absolute polarity preservation will avoid that and not challenge the loudspeaker to replicate polarity that air cannot accurately convey. 
What more, the recording engineer I do listening for every now and then is a real fanatic about phase and polarity and most engineers understand that it's critical to achieving the sound they're looking for. 

@geoffkait
Yeah, I can hear polarity. Been playing with that a while on my amp.

@cleeds
You kinda pointed out the point I was making. You can only decompress air to a vacuum. But you can compress air until it begins to change phase. Sea level air pressure is about 16 psi. That's the absolute limit to how negative a wave can be. But it’s not very technically difficult to produce 32 psi or even 50 psi pressure waves. That’s, in short, why air is single ended, why it’s natural character of distortion is low and even order, and why single ended amps best emulate the character of the medium sound travels through.

Kalali,

It’s pretty simple. The bias level in a single ended amp defines how negative a signal it can pull it down. If the source drives it below that bias level, the gain device goes more non-linear and eventually shuts off completely. It’s the electrical equivalent of trying to pull a vacuum in air. Push-pull amps don’t do that unless they’re deliberately mis-balanced. Instead, they transition to class AB and one half of the push-pull does all the work. That's why SET amps have such devoted followers. The way a triode distorts as it runs out of bias is very organic and similar to how air behaves.

The transmission characteristics of air certainly don't resemble electrically balanced operation. And no doubt there's more to the character of a triode than how it distorts in a SET. Its undeniable that many fans of SETs like them because they distort in a way somewhat similar to how air does. 

@geoffkait 
You make no sense. What you're saying here and up above makes no sense. What's more, you can't come close to proving it this or that was mastered in one polarity or another. The polarity of the fundamentals make no difference whatsoever. The problem of polarity lies in the the overtones and distortions generated by the instrument and the recording space. If you don't have those in proper phase/polarity, it completely changes the sound and it's pretty freaking obvious to even a sophomoric listener, much less an engineer who does this stuff for a living. If you're listening to stuff recorded and mastered by engineers that can't hear the difference between polarities and phases, you're listening to some real garbage. The polarity and phase of the spacial and distortion information goes a long way in defining the presence of the sound. Generally, positive polarity even order distortion gives the sound a crisp, clear, forward pop while negative phase distortion extends the depth of the sound field and presents more smoothly. That's the going theory on why odd order harmonics really stick out. They add a stiffness to the peaks of waveforms that sounds inorganic, because it is. 
I'm certainly no SET lover myself, but at least I know why people like them. And unlike you, I've sat around and listened carefully to positive and negative polarity distortion and I'm very aware of what it's characteristics sound like. 

@geoffkait 
I figured you would since it's WAY over your level of comprehension. 

@thom_mackris 
Atmasphere will probably take me to task on this, but I ended up debating the difference between phase and polarity with another fellow and was eventually convinced that there is a clear and technical difference. Polarity isn't time dependent whereas phase is described in degrees of angle from the polarity. A phase angle of 180 degrees isn't inverted polarity. It's a half wavelength delayed. 
My amplifier is a Pass F5. It inverts the polarity twice through two gain stages to preserve absolute polarity at it's outputs. What's more, its a myth gain stages always invert polarity. It completely depends on the mode the gain devices are operated in and it's entirely possible to get current and voltage gain from a single stage while preserving absolute polarity. 

@geoffkait 
Why do you keep babbling? I know what polarity I'm working with because I've put my fingers on every single transistor. Do you want me to show you schematics and explain to you what modes every transistor is working in so you can follow along? As I explained above, phase and polarity aren't interchangeable. I wish I could remember the guy who schooled me on that one when I argued they were, but he was right. 

@cleeds 
I didn't invent the idea or make the observation that air is a single ended medium. By definition it is and it exactly parallels how a single ended class A amplifier works. Atmospheric pressure is the parallel of bias in a single ended amp. A vacuum is the parallel of driving a single ended amp below it's bias. Air DOES distort in a low, even order manner, just like a single ended amp. They are analogous. I'm not sure who I first came across the idea from, but the last person was Nelson Pass at a Burning Amp lecture and that's pretty much how he explained it. 

@geoffkait 
As usual, you're pretty much wrong. Vacuums don't exist anywhere in the known universe.

Since Geoff reported my post because "blah blah blah" hurt his feeling, I'll repeat my point. Phase coherence was an 80's fad that made bold promises and generally didn't deliver. It doesn't seem to be as important as it's been sold to be.