Does not matter either way. I do it at the amp end for convenience when I demo other equipment. My phono stage is also inverted. I switch it at the cartridge with preamps that are not inverted. This could drive you nuts. The inverted phono stage is in phase with an inverted preamp. |
I hope this is not a tangent, but my Marantz SA-1 SACD player inverts polarity through its balanced outputs, which I've been using (inverted) for 1 1/2 years. Since I was recently alerted by another thread about this player, I have been reversing polarity via a switch on my BAT preamp (can switch it back and forth via the remote) and do not LIKE the sound w/the corrected polarity! It sounds "brighter" to me, less rounded and tubey, which I consider the strengths of this system. So I'd like to know what you think if you listen to your preamp both ways. Why do manufacturers even build equipment that reverses the polarity and just causes all this angst?? Why can't they wire it right to begin with?
consider me,
Confused |
Sarah; Reversing polarity is not necessarily the same as being out of phase. You may be reversing polarity of the AC power, much like reversing the AC plug. This is not changing the phase of the output to the amp. I am not familiar with BAT preamps to know if that switch reverses the phase to the amplifier or just the AC polarity. You should consult with BAT on that (check the manual). Reversing the AC polarity to the wrong polarity will usually make it brighter as you describe. Preamp makers make their preamps out of phase (going out the amp outputs) usually because less is more. Their designs are simple and clean (and out of phase), and would require an additional gain stage to bring them back in phase. The addition of another gain stage would degrade the signal. Conrad Johnson preamps are out of phase. You could call them or drop by on your way around the beltway and have them explain it better than I can. They are behind the Home Depot at Route 50 and Route 29 in Fairfax.
Sometimes CDs are recorded with the polarity reversed (by mistake), but reversing wires won't help. It needs to be corrected at the DAC. Some CD players have a switch on the remote to reverse the polarity for these CDs.
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additional questions....does bridging an amp reverse phase and how does one go about bringing it back into phase if it does? also, how does one know if a cd is recorded out of phase? |
sarah: my boulder 1012 also allows remote polarity inversion, which the (very handsome) manual explains nicely as being different from phase inversion. heres what it says:
NOTE: Often polarity is mistakenly called phase. As phase indicates any angle between two channels from 0 to 360 degrees, the correct term of polarity is preferred to indicate the 180º phase change, or inversion, available on the 1012 DAC Preamplifier.
so, as I understand it, cds and even tracks on the same cd are frequently recorded, intentionally or not, with positive or negative polarity. By toggling between these settings on a polarity inverter of the same form employed on the boulder 1012, you can replicate the polarity of the original recording. my experimentation has also shown that positive polarity is the preferred setting for normal listening of cds or lps. this translates, i believe, to the pre being connected "in phase" or in "common polarity" with the amp.
-cfb |
I think you can only tell if a CD is recorded out of phase by guessing with your ears?? |
some recordings are quite intentionally produced "out-of-phase" to maximize soundstage width. the most recognizable of these are "q sound" products, including roger water's "amused to death" and madonna's "music." -cfb |
Cornfed and Sugar, thanks for the additional info. I don't know if the BAT "polarity" switch actually reverses phase or not, I'll ask them. That Boulder piece is certainly a marvel, wish I had a chance to hear it, or even see it, around here.
Off topic tangent to Sugarbrie/Monotrub--my FM antenna that I had installed blew down in the recent high winds! and it was only that Magnum dynalab wand antenna. Next time around, I'm going with an actual rooftop installation, hopefully shielded by the chimney. |
Just read an article on this.If you have 2 items out of phase--say a cd payer and pre-- no need to change the speaker wire. They cancell each other out. 1 item/3 items;change the speaker wire. |
If it's out of phase won't you lose a lot of bass response because the woofers are working against each other, where as inverting polarity just switches left to right and vice-versa? My Bel Canto DAC 1.1 can do this in the digital domain so I can invert on the fly, but I rarely find a need to. Boy this is a confusing topic. |
cfb: for these purposes, "phase" and "polarity" could be considered equivalent terms, since when it comes to an electronic component like a preamp, the only question is of either 0deg. total shift (maintain correct absolute phase) or 180deg. (what Boulder rightly calls an "inversion"). Their needlessly confusing explanation implies the possibility of some degree of electrical phase differential between the two channels - not an issue here. Gunbei: what you are thinking of is wiring the two speakers 180deg. out of phase with each other (reversing the leads for one speaker only). This would indeed cause the woofers to work "against" one another, but this is also not the issue at hand when referring to a preamp or DAC "phase" switch. For those preamps, like my own c-j unit, that do invert absolute signal phase, changing both the left and right speaker leads (at either the amp end or the speaker end, but not at both ends) will change the system to correct absolute electrical phase (assuming no other selected component also inverts phase), with no electrical phase difference between the two speakers themselves. Sugar: Sarah could not be reversing AC polarity from the remote control - this would indeed be for signal phase inversion. (As for why this would make the sound "brighter", I haven't any idea.) Nick, Sugar, cfb: for most non-audiophile recordings, talking about "in" or "out of" phase is a moot point. For music that is not minimally mic'ed and produced, and is not performed acoustically and recorded in "live" performance, there is likely to be an unknowable number of different phase inversions between the many "tracks" of separately recorded and processed instruments and vocals, let alone synthesized sounds where the concept doesn't really apply at all. And all that comes before any question of whether a CD itself is mastered in "correct" phase. This is why I believe that phase switches are largely useless - either the recording will be from an audiophile label, where we should be able to assume correct phase has been carefully maintained through the production chain, or the whole question is pointless, because there will be no absolutely "correct" phase to choose from on a typical recording. (That, plus I can never hear much of a difference anyway, even where one might theoretically apply.) Sugar, Sarah: you guys are within visiting distance of c-j too? |
zaikesman: i agree with you on all points but one: i CAN here differences in cd playback using the polarity/phase control function on the boulder. most experiences are subtle. some are not. and, we're not just talkin' about "audiophile" recordings here, whatever that description may mean. -cfb
ps-FWIW, the "needlessly confusing" manual for the boulder was written by a guy with a MSEE. |
cfb - If, as some folks claim to do, you can hear some difference on a recording that has no one "correct" absolute phase to refer to, it might simply mean exactly that: not that the result is correct, only different. Obviously, if you can determine that you prefer to listen one way and not the other, then right on brother. As for the notion that a degreed scientist couldn't possibly write anything that was needlessly confusing - well, let's just say I've got a BYOB that trumps his MSEE every time! ('Course, if I had sprung [better make that "could spring"] what it takes to buy a Boulder, I'd probably stick up for the guy too.) Happy listening, Z |
