Why do some manufacturers reverse preamp polarity in the first place?


My Rogue RP-5 reverses polarity, so I switch the pos / neg at speaker terminals. The manual does not mention this, however, I wrote the company and they the amp does reverse the polarity. 

Now my question is...why? I would say 98% of buyers of this amp do not know to reverse the cable connections. I would say most reviewers did not as well. Yes, I realize, polarity reversal is not noticable in most instances. Especially, since many recordings are all over the place when it comes to polarity (at least that is what I've read).

So the question remains...why...why not just have the amp terminals set up so the buyer can just plug in as normal?
aberyclark
Each gain stage inverts polarity. A phono amp generally needs 2 amplification stages for gain and RIAA and an impedence matching buffer stage to drive the power amp. 3 stages = inverted polarity. 3 stages are better than four -less is more- so they leave polarity inverted. I believe they leave it like that for 2 reasons. It works fine with their amps. It doesn’t make a big difference to SQ.
Now my question is...why? I would say 98% of buyers of this amp do not know to reverse the cable connections
That is because they do not read the manual.
"That is because they do not read the manual."

No mention in the Rogue manual
My preamp (MFA Magus B) inverts polarity, according to the manual. I asked this same question some time ago on another thread and never got an answer. Trying to do the recommended fix, l reversed the leads to the speakers. I really haven’t noticed any big difference.
Its rare that the absolute polarity is audible- you need a purist recording that is done with only two mics.

50% of all recordings are in reverse polarity to begin with, since the recording industry does not pay any attention to this issue.

And in some pre-amps that contain a phono stage (or in a separate phono amp), that stage (or amp) may be of inverted polarity while the line stage is not (or visa versa). What are you gonna do, reverse your speaker leads depending on whether you are listening to an LP or CD?

And since, as atmasphere points out, most recordings are made without respect to absolute polarity, album mixes are made from recordings (done on a 16 or 24 track---or more---multi-track recorder) in which the channels may be a mix of both inverted and non-inverted signals (some microphones also invert polarity! Some effect boxes---EQ, reverb, compressors, etc.---do as well) ). Of that there is no solution.

And of course, many multi-driver loudspeakers have one or more of those drivers in polarity opposite to one or more of the other drivers. Of that you DO have control---don’t own such a loudspeaker!

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So at the end of the day, it really does not matter how the speakers are wired. Interesting. 

what type of speaker do you have as some speakers using 2nd and 3rd order cross overs have drivers of different polarity so you will never get the right polarity as each driver in the speaker could be different.

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We've had a polarity switch on our preamps since their inception. Changing speaker cables around is a real pain!

given so many reputed recordings are 'all over the place' regarding polarity/phase....

What then is the correct way to not adversely stress the power train when re ordering polarity?

mute the sound, then switch?

or just switch polarity on the fly as it won't matter for neither the speakers or amps will encounter undue strain or stress?

... just wondering
Much ado about polarity? Well....

Music by any polarity would sound as sweet? Nuh-uh. Scratch that.

A fool thinks polarity matters, but a wise man knows otherwise. Close, but...

There is no polarity either good or bad but thinking makes it so. That's it!
Most of the technical reasons don't hold water since it comes down to what the tap is labeled. A little dab of red will fix ya.  But a purist would still want control on a per-recording or per-track basis.
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Polarity absolutely matters. These are cheap components and these designers have no business making electronics.
There is a book on the sole subject of absolute polarity, The Wood Effect by Clark Johnson.
It actually doesn’t matter to the average person whether the preamp is Reverse Polarity or Correct Polarity because so many recordings are in Reverse Polarity. So, what’s the difference? Since there are no technical standards for Polarity in the industry one should first establish whether his system is in Correct Polarity in the first place and go from there.
Ralph, I respectfully disagree.

Well over 2 decades ago I learned 2 things (that were only accessible at a reasonable price from PS Audio), things that should be universal if a product is to be called ’High END" 

* differentially balanced AND
* either the preamp or dac has remote Polarity control

Individual songs on discs have long been mastered in various facilities, moreso on Greatest Hits, but still. Most of the time "I" have no problem hearing when polarity is in/out. Over the years I find bass is the greatest offender. When it’s out the music lacks clarity, space is more homogeneous, loses the speed of the initial attack
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Over the years I find bass is the greatest offender.
I hear it more in the brass instruments.
douglas_schroeder1,806 posts02-28-2019 10:54am

Very polarizing topic.


>>>>>Absolutely!
A point that hasn't been mentioned is that when the setting of the polarity switch that is provided on some components is changed, in addition to the polarity of the music signal being inverted the sonics of the component could conceivably change, at least slightly, depending on the specific design.

I'd expect that to not be the case with a fully balanced design, such as Ralph's (Atmasphere's), since polarity in such a design can be changed by simply interchanging two signals somewhere in its internal signal path.  But with a design having an unbalanced internal signal path it is not necessarily that simple, and in some designs I wouldn't be surprised if sonic side-effects were to occur when the position of the switch is changed.

Perhaps in some cases that is one example of how easy it can be in audio to attribute a perceived difference to the wrong variable.

Regards,
-- Al 
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Many a polar scholar posting peculiar picayune pieces today
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Agnew!?! Ha!

Oh, this is about polarity? Okay, that is appropriate.

By the way, I can't hear a difference when I switch my system's polarity.

The reality is that there are no standards for preamplifiers like output voltage, polarity, etc.
Preamplifiers are the biggest offenders on all things.  Most are flawed to very flawed.
I get an uncomfortable feeling when the 6 Moons author states, “there’s a 50-50 chance a given recording features Inverted Polarity.” I’m mean how does he know?” I would sincerely like to see someone, anyone, compile a list of say fifty audiophile recordings, LP and CD, with Polarity for each. That doesn’t seem too difficult. So far all we have is George Louis’ Polarity List. Which is great that he compiled that long list, but I have trouble buying into it, primarily because he concludes the percentage of CDs that are in Reverse Polarity is so high. But 50-50 assumes no audio engineers or mastering engineers check for Polarity and I don’t buy it. I’m not saying it’s impossible, just the probability is low.
in some pre-amps that contain a phono stage (or in a separate phono amp), that stage (or amp) may be of inverted polarity while the line stage is not (or visa versa). What are you gonna do, reverse your speaker leads depending on whether you are listening to an LP or CD?
Invert the phono cartridge leads!
But 50-50 assumes no audio engineers or mastering engineers check for Polarity and I don’t buy it. I’m not saying it’s impossible, just the probability is low.
Recording engineers in fact do not check for polarity. For the most part they regard polarity as so much hand waving. So 50% of all recordings having reverse polarity is correct.
Really? The Polarity pundit claims 92% of CDs are in Reverse Polarity. And he has a Polarity List to back it up. Furthermore the Polarity Pundit claims entire record labels are in Reverse Polarity. What evidence do you have? Who is right? I await your evidence. 
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Are you crazy? I’m just asking for evidence. I assume you’re just running your mouth. The Polarity Pundit has been studying Polarity for many years and has compiled a longish list. What have you done? Nothing. I never said I believe anyone. I’m asking people to support their claims with evidence. I’m not even demanding proof. Follow?
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Go play in the road.
All the sounds we hear are really nothing more than a series of compressions and rarefactions of air. Rapidly changing air pressure, in other words.

What causes the air to move like this in the first place? Strings, lips, drum skins, vocal chords. Squeaky chair. Tapping foot. 

Now this has gone on way too long already so here's the question: Compression or rarefaction: which comes first? Can't have polarity without a North and a South. Compression and rarefaction. So which comes first?

When you hit a drum, which way does the drum head move first? Down. Creates a vacuum above it. Rarefaction. Then, when it comes back up, compression. Most people would say the sound begins when the stick hits the skin. But that's down. That's rarefaction. Most people I would bet assume the sound begins with a pressure wave, not a rarefaction or vacuum. 

In other words polarity of sound does not exist. There was none to begin with, so there is none to be preserved, and none to be played back.

Yes folks it is that easy to reduce this whole conversation to the inanity that it is. Go play in the road is in this context as sensible a comment as any other.
That's the beauty of CD's, unlike digital files. If your CD is in reverse polarity, just play it upside down and the 0s become 1s and vice-versa.
Those of you who have traded in your CD players for media servers should feel pretty sheepish right about now.
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aberyclark OP
Why do some manufacturers reverse preamp polarity in the first place?
They don't do it on purpose, it's the topology of the circuit they've used that does it, and to put in an additional stage just to bring it back in phase, is probably more detrimental to the sound than leaving reversed.

Cheers George  
The Polarity pundit claims 92% of CDs are in Reverse Polarity. And he has a Polarity List to back it up. Furthermore the Polarity Pundit claims entire record labels are in Reverse Polarity. What evidence do you have? Who is right? I await your evidence.
He does and presents no evidence whatsoever. He came into our room one time and insisted that our room was in reverse polarity. I flipped the polarity switch on our preamp. Then he insisted that you couldn't hear it on LP- only CD. So I played the same track on CD as I had it on hand. Then he insisted that you couldn't hear it if the source was analog...
And then he left the room hastily, leaving behind only our impressions of him, with which we made jokes from for the rest of the show.
Be that as it may, you didn’t present any evidence, either. It’s what you choose to believe. Nothing more. Making jokes behind someone’s back is not evidence the person is wrong, actually. I find your anecdote unconvincing.
Ralph, +1, for a great story!

Geoff, -1, for missing the point about what constitutes a refutation argument (it’s not the jokes, it’s the behavior of the guy running out of the room after getting his butt kicked in a demo). 

Celander, I didn’t know you had a dog in this fight. Be that as it may I see you don’t have any evidence, either. Oh, well, I didn’t really expect any. No biggie. So, what is it, 50% or 92%, hot shot? Guess we’ll never know. 
Geoff, -1 for claiming one has to have a dog in the fight to comment about the obvious. Since when did you ever have “a dog in the fight” to justify the vast majority of your 14,000+ posts?
Nice to finally find someone who’s read all my posts.