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
^^ This is the same guy that was selling a CD duplicator called the RealityCheck, claiming he had upgraded the firmware somehow to justify a healthy markup. He was discredited as (although the duplicator did work well) turned out there were no mods to the duplicator other than said healthy  markup.

And this is the same person that made the amusing claims in my room at T.H.E. Show I posted about earlier. IMO we can put his claims to bed as inaccurate and move on. 50% of all CDs is a much more accurate number.  Keep in mind that our preamp was the first on the market to have an absolute polarity switch...
As long as you didn’t debunk anything yourself, I’m giving you a free pass. I always believe Wikipedia. 😛
Hey, Wiki is the authority. I defer to it all the time. So shoot me. But thanks for keeping count. I did not know you cared so much about the manner whereby I express myself, logically or otherwise. Kisses!
I won’t bring up your other logical fallacy, you know, Appeal to Authority. Twice, actually, but who’s counting?
Rupert Sheldrake was a respectable biochemist and plant biologist before he became a parapsych crackpot. PEAR is debunked.
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. 

Thanks Ralph - priceless!  
Well, Sheffield Labs recordings are actually on the Polarity List as R Reverse Polarity.

+1 for George Louis. On a sour note, FIM recordings also appear on the Polarity List as R. 

A discussion of the Polarity List somewhere in cyberspace prompted this comment. 

I know everything I've done for FIM has correct polarity.

Bruce A. Brown
Puget Sound Studios
Stereomojo reviewer
Seattle, WA


snapshot of Polarity List

Reprise – Joni Mitchell – Blue N
Rhino R
River North Records N
Rounder R
SANSTONE MUSIC – MEL TORME – THE LONDON SESSIONS R
Sheffield Labs R
SHILOH RECORDS – Greg Harris – Acoustic II R
SIRE – Talking Heads – Stop Making Sense R
Solid Air R
Solid Air Records – Grove Masters R
Sony R
Sony – Miles Davis – Kind of Blue R
Of all the thousands of recordings I have had over the years, the only recording in my collection that called for reversing polarity (at the speakers), was a LP of Dave Grusin- Discovered again. Seffield Labs.

I couldn't hear any difference in sound quality, at the time. That was many systems ago. Maybe I should re-visit that experiment and see if I hear any difference now.
That figures.

Innocent questions: How much do you know about Rupert Sheldrake? How about PEAR (Princeton Engineering Anomalies Research)?
It's my Harvard training (Ph.D. biophysics). But yes, I am from the far-friendlier Midwest.
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Confucius say man who have conversation with self have captive audience.
Of course, I omitted the NDM thread posts, for obvious reasons. You did have a dog in that “fight”. 
The ones without substance are so people like you won’t strain your brain.
And I reread them just before making my last post, as most were a quick read without substance. 
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?
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. 
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). 

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.
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.
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  
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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.
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.
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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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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. 
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.
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!
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.
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.
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.

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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