2. amps-preamps
  3. 147027-10803

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
testpilot
233 posts
 
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.
aberyclark OP
594 posts
 
"That is because they do not read the manual."

No mention in the Rogue manual
tonykay
856 posts
 
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.
atmasphere's avatar
atmasphere
7,068 posts
 
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.
bdp24's avatar
bdp24
4,908 posts
 

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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