HELP w/Preamp Polarity Inversion Problem

A polarity switch on a DAC is not 'another switch in the circuit' in the sense that it would be on a piece of analog gear, because it operates by reversing the polarity in the digital realm, with no sonic penalty.

Thanks Zaikesman (patting self on back)

And excellent point, Bob-- in my particular case, the preamp makes an audible click as a relay is triggered to invert phase, but whether that relay is open or shut, the signal passes through its contacts.

Last night I found a pretty good example of this phenomenon on a disc that many folks probably have-- On the Stevie Ray Vaughn posthumous release "the Sky is Crying" check out "Little Wing" and "Chitlins Con Carne" in and out of phase then report back. I'll be interested to see if you all hear what I hear, and how system-dependent it is...

I don't want to tell you now because I think that might color the continued conversation-- people might just come out to snipe and say I'm full of crap or be lazy and agree with me, but I'm curious to see what you all hear so hopefully someone does their "homework" on this.

Plato, I don't understand your reluctance to use the polarity switch on one of your DACs, stating that using the switch introduces a switch into the cicuit. The signal still goes through the switch whatever position it is in!

Bob P.

Pmkalby, your experiential results conform both to what the reality of the situation and the laws of probability dictate...congratulate yourself on possessing hearing more sensitive than some audiophiles seem to be to the placebo effect... :-)

Zaikesman-- This is pretty late, but I hit on this thinking about phase from another thread, and now I'm reading old phase threads instead of starting a new one.

Anyhow, I recently got into this discussion with a technical advisor at Jeff Rowland design group-- he sent me an article written 10 or so years ago by an audio journalist including a table of what labels in his experience inverted phase on their LPs. He found that there were some labels where most LPs were inverted, some where most were correct, and some where from track to track the phase changed. He mentioned that in some instances, the phase of certain instruments on a track could well not be in the same phase mode as others (drummer is 180 degrees out, the guitar player is correct, etc).

Since my attention was drawn to phase inversion because my Rowland preamp uses a different pin out on the XLRs than my new amps, thereby inverting phase, I've been playing with the phase button on my remote much more frequently, and have found that you are basically correct, with most recordings the difference between "in" and "out" of phase is inaudible. There are times, however, when there is a substantial difference. Unlike Plato, I neither fear, nor hear any deleterious effect of using my phase invert button. Thus far I've not found anything approximating a "golden rule" for CDs and phase-- different CDs from a given label don't seem to follow any pattern at all, it's all over the place--on most there is no improvement one way or another, but on the few where phase makes a difference, they appear to be split more or less 50/50.

Elgordo, your contention that the whole catalogs of certain record labels were issued with inverted polarity doesn't make sense to me, considering that many recordings have no absolute 'correct' phase orientation to begin with, particularly multi-tracked studio recordings. I for one don't believe the situation is so cut-and-dried, and that there will be variations from record to record, with many records not being particularly sensitive to absolute phase orientation at all. Just consider for a moment all the different studios and venues all the records from all those labels were recorded in - do you really think for a second that the absolute phase, if applicable, of all those master tapes was always 'correct' before the labels you mention pressed up the actual releases and supposedly 'inverted' them? Impossible. This has got to be a trial-and-error determination made by the listener, not some kind of 'rule' to be applied according to label name.

But Saxo, Elgordo is correct about your wiring question. With a single-stage tube preamp that is known to invert polarity for all signals passing through it, you should reverse your speaker leads black for red at either the amp or the speaker end, just not both. Without a polarity switch being available on either the preamp or your sources, I wouldn't worry about it further after that. As Plato's dilemma points up, if the supposed benefit of reversing polarity on some recordings is not going to outweigh the perceived effect of the switch used to compensate for it, then polarity must often be considered a not-too-crucial variable to begin with in many systems.

Elgordo is correct about many recordings being recorded in reverse phase. On some very phase-coherent speakers, this will make a difference and having a polarity inversion switch on the preamp or DAC is a convenient thing to have. That said, many systems are not phase coherent, which makes switching polarity a moot point. Also, in my personal experience, the effects of polarity inversion are harder to hear in an all solid-state system than a system that uses tubes. But it appears that you are using tubes, so in your case, you may well hear the difference.

This seems to be one of those issues that can make you crazy if you let it. For example, I have two DACs and prefer the performance of one to the other. Unfortunately the one I like best lacks the polarity invert feature. Yet, my preamp has an invert feature but I don't use it because I feel that going through that extra switch degrades its performance to a small degree. As you can see, I just can't win!

Yes, switching at the amp will do it. Now the bad news - about half of the record and CD labels out there (RCA, Mercury, MCA, Warners, Capital, London to name a few) were recorded with the absolute phase reversed. These labels would sound better if you left it alone. Bottom line is that you need a component such as a CD player, DAC or "jitter box" that has a phase reversing switch.