Preamp inverts phase question:


The owners manual of my preamp indicates that the preamp inverts phase: the circuit is phase inverting. Does this mean that I need to hook my speaker cables up backwards to correct the phase inversion... do I hook the positive speaker cable to the negative speaker binding post and visa versa with the negative speaker cable connections on both speakers?
adampeter
Okay, so for someone much slower than the rest of you... If my source does not invert, my preamp inverts and my amp does not invert my sysytem should be in absolute phase right? This way, my sytem would be set up properly for recordings that have been recorded in absolute polarity (although many recordings are not.) If I then wanted to confirm that my end result is absolute polarity would an absolute polarity checker accomplish that? (My amp is french and they are terrible about responding to inquiries) so, I am not 100% sure that it does not invert phase and would like to be able to confirm my end result with such a tool if that is what the tool is intended for.
No. For the connections you describe, your system phase would be inverted.

Invert: to reverse in position or relationship.
What comes out is inverted, or reversed, in relation to what went in.

Non-invert: to keep the position or relationship the same.
What comes out is not inverted, or reversed, in relation to what went in.

If only one of your components in the chain inverts phase, the end result is an inverted phase.

If you have two inverting components in the chain, the output of the first is inverted. This inverted signal then goes into the next component, which inverts the signal, resulting in an output that is now in-phase, or very close to it, from the original signal.

Lay a coin on the table, either side up. Now flip it over, or invert it, and the other side is up. Now flip it one more time. Aren't you back to the side you started with?

One thing may be confusing you about this. The components in your system do not have a clue as to what the absolute phase is, nor do they care.

Forget about phasing in recordings because this is a whole other can of worms. I've heard it said that phase is, more often than not, inverted many times through the recording process. So stick to what you can control in your system.
Thank you: Dan ed, Benie, Almarg and everyone else who took the time to help me with my understanding of these principals.

Adam
Adampeter -- Re absolute polarity checkers, looking at their website I suspect that the Smart Devices units that were suggested as possibilities in your other thread are no longer available.

In any event, they may very well not be worth the expense, considering especially that you would only be using them once, at least until you were to replace a system component.

I suggest playing a few high quality audiophile-oriented recordings that were made using just 2 or 3 mics (that will probably be indicated in the album notes), and that contain a lot of percussive sounds.

Then re-listen with your speaker connections reversed. See if you hear a difference in the sharpness, crispness, and realism of the leading edge (the very beginning) of the percussive notes. If you do, use the connection polarity that sounds best. If you don't hear a difference, assume the power amp is non-inverting, and connect plus to minus so that the inversion in your preamp is corrected for.

On another note (no pun intended :)), re the statement that 50% of recordings are out of phase, I would go further, and put it a little differently.

I would say that on 90+ percent of recordings, the whole concept of absolute phase or polarity is meaningless. The great majority of pop recordings, and the majority of classical recordings as well, are processed through complex multi-track consoles where they are subjected to a bewildering array of effects and mixing. Not to mention that the original takes were probably done with a virtual forest of microphones (particularly in the case of typical poorly engineered recordings of symphony orchestras). The end result, when it comes to absolute phase or polarity, is inevitably a random hodge-podge of different sounds with different phases.

So even if you had a preamp that provided on-the-fly polarity control, if one setting sounded better than the other on a particular recording it would more likely be due to random synergy than to your system preserving the "polarity" of the recording.

Getting the polarity of your system correct is relevant primarily to the unfortunately very small percentage of recordings that are well engineered, using purist techniques. But then again, those are the recordings that we Audiogon'ers tend to have particular interest in.

Enjoy!
-- Al
I didn't read my Cary Audio SLP98 manual when I first got it, and thought the sound was muddy and diffuse. But I thought it was just a break in symptom. When I read the manual and switched the speaker cables: AHHHHHHHHHHHHHHH!!!