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?
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
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.
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.
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.
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!
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.
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.
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