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

Showing 2 responses by bdp24

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bdp24
9,400 posts
 
There is a book on the sole subject of absolute polarity, The Wood Effect by Clark Johnson.
bdp24's avatar
bdp24
9,400 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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