Twisty/Turn-y Things: Single Channel Polarity/Phase Reversal

Discussion in 'Modifications and Tweaks' started by Torq, Oct 3, 2016.

  1. Torq

    Torq Last Remaining Good HF Poster

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    This is a cheap, and relatively simple, to try “tweak” that does not involve modifying your existing components or headphones. It does require an audio player with a DSP/plug-in capability, and/OR balanced DAC/amp/headphone setup and a very easy to make adapter cable*.

    Before saying anything else, I should say that this idea/practice is something that @johnjen shared with me at a local mini-meet back in January. He’s been playing with this sort of thing for a lot longer than I and any credit really should go to him!


    I’m writing this now for several reasons:

    In part, because I was talking to a colleague about this earlier today, they asked me to make them the necessary cable so they could give it a try, and in doing so I figured I might as well write the thing up, including the instructions for making the cable.

    Another part is down to me mentioning building another phase-reversal cable in the DIY forum last week and only just having gotten around to it.

    But mostly it’s because my fiancé has taken her mother to visit some friends for a few hours, and I’m all alone in the house with a nice hot soldering iron, a freshly-topped-off glass of Scotch, my music and bugger all else to do for a bit.

    (*I’ll describe how to make/where to get the necessary cable in the following post. It’s not a bad first-cable-project as the connectors involved are big and easy to work with and there’s lots of leeway for those whose tendency is to solder their thumbs, rather than the components, to still get a working result!).

    Anyway … what’s this all about?

    In short, the idea is to more efficiently and completely utilize the full power capacity of an amplifier, and the available rail-to-rail potential difference/swing, by driving left and right channels in opposite phase/polarity within the DAC/amplifier, and then correcting phase/polarity before getting to the headphone (we do it in the headphone cable, with a simple adapter).

    In theory, driving the channels in offset like this will cause less sag against each rail and draw current from both of them independently, rather than in a common mode. At headphone power levels, the relative power demand differences are not going to be huge, but then we’re not dealing with very much available power to begin with.

    How do we do this?

    We invert the polarity/phase of one channel as it goes to either the DAC or the amplifier, and then re-invert that channel (putting it back to its original polarity/phase) as it goes to the headphone.

    Yes, yes … but how do we do THAT?!

    There are two straightforward ways to do this, both of which require a balanced headphone connection/cable:
    1. If you have a fully balanced DAC/amp/headphone setup, you can use two “polarity/phase reversal cables”, one between the DAC and amp, and the second between the amp and your headphones.
    2. Alternatively, you can invert the polarity/phase of one channel in your music player software** and then use a single “polarity/phase reversal cable” between your amp and your headphone.
    In theory, the second approach gives the same benefits to both the DAC’s output stage and the amp, whereas the first only benefits the amplifier.

    (**Options and configuration settings for various software/platforms will be discussed in this follow-up post, including entirely free ways to give this a try).

    But what is polarity/phase reversal?

    In the simplest terms, it involves swapping the positive and negative connections/signals to the amplifier or DAC. Doing that results in what would have been a positive voltage differential at the output becoming a negative one (and vice-versa).

    Quite a few DACs allow you to swap absolute phase for both channels with a simple button push. Yggdrasil has this ability for example, though it exists to allow for accommodating recordings mixed out of standard phase and isn’t the same thing as we are talking about here.

    We only want to invert the polarity/phase on ONE channel (and then switch it back again later in the chain).

    We can do this in software, which inverts the polarity or phase of ONE channel before the signal reaches the DAC (and this is the preferred way to do it if possible). Players like JRiver Media Center have DSP functions that can do this, and there are plug-ins for players like Foobar2000 and Audirvana+ that can do the same thing.

    However, if we stopped there, the left and right sides of our headphones would play out of phase with each other. If you did that with a speaker system, you’d wind up with some cancellation effects, most notable in the bass region. With headphones it’ll just do odd things to the sound and imaging.

    So … what is a “polarity/phase reversal cable”?


    It’s just a balanced cable that swaps the positive and negative connections on ONE of the two channels it carries.

    If you were going to wire that, something I’ll describe in detail in a follow-up post, assuming 4-pin DIN connections, you’d wire pins from source to destination as: 1-1, 2-2, 3-4 and 4-3. That would have the effect of inverting the polarity/phase of the right-hand channel.

    You could do it for the left channel instead, but @johnjen suggested “right is reversed” as a simple way to remember which channel had to be inverted in the player, so I stuck with it.

    The Net Result?

    We feed the amplifier (and DAC) an inverted signal, and convert it back to the correct polarity before reaching the headphone driver, putting less stress/or getting better utilization out of the available amplifier power/rail-potential-difference.

    There should be no effect to the phase of the rendered signal at the headphone.

    Okay … but how will this change what I HEAR?!

    This is very hard to say. You might not hear any difference. Indeed, there might not BE any difference in a particular setup. At the power-levels involved in headphone listening the effects are smaller than in speaker systems‡.

    It is likely that any specific differences will vary significantly from system to system. I would imagine driving IEMs there’d be no discernible effect at all. With less efficient systems or those without gobs of excess power, things might be very different.

    If you’re expecting bold claims as to what I personally hear, or what you should expect, you’re about to be disappointed, this is, for now, a “see what for yourself” tweak; I’m not even sure how much of what I do/don’t hear is down to expectation bias as I have not spent any serious time attempting to discern a difference in blind listening, though I suspect that’s only part of it.

    The point is that the tweak has a testable theory behind it (something one could easily setup a measurement case for as well – I might do that myself if I get the time) is easy to experiment with, is cheap and entirely non-destructive/non-invasive.

    (‡Very easy to do in a speaker system; no special cable is required – just swap the +/- connections on ONE speaker. BUT, make sure you swap the polarity/phase on the same channel either in your software player or before the amplifier input, otherwise your speakers will be out of phase and that’ll kill your bass and generally sound entirely wonky!)

    Finally …

    I'll post what my experiences have been with this once some others have a chance to give it a try.

    Also, expect the usual flurry of edits and corrections resulting from me only seeing the myriad mistakes/typos I have no doubt made in my fermented-grain-induced euphoric haste to type and post this.
     
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  2. Torq

    Torq Last Remaining Good HF Poster

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    Building a "Polarity/Phase Reversal Cable":

    This tweak requires a balanced cable that reverses the polarity/phase of ONE channel as it comes out of the amplifier and feeds a headphone. While you could build a headphone cable that had one channel wired in reverse, building an adapter allows you to use your existing balanced cables/headphones with this tweak a lot more easily (just plug the adapter into the amp, and your existing headphone/cable into the adapter).

    One nice thing about this tweak is that the necessary cable is a very easy build; ideal, in fact, for a first-cable-build project. The total BoM is minimal and inexpensive, the connectors involved have large, non-fiddly connections, making soldering very straightforward even for a first-time builder/DIYer, and you're not making critical changes to your existing cabling/headphones. So if something goes wrong, you've not affected your existing rig/gear at all.

    What is a "Polarity/Phase Reversal Cable?

    It is simply a balanced cable that swaps the positive and negative connections on one channel, thereby inverting/reversing the signal on that channel.

    For those that understand how to wire a balanced headphone cable, that's all you need to know. In essence, going form a 4-pin female to 4-pin male XLR connector, you wire pins from male-to-female as follows:
    • 1 -> 1
    • 2 -> 2
    • 3 -> 4
    • 4 -> 3
    I tend to use shielded cables for these, in which case I connect the shield to the grounding lug on the male XLR connector ONLY (i.e. the amplifier end of the cable).

    The rest of you ... read on:

    What do I need?

    The parts list is pretty minimal, and my recommendations here are based on easy of use/assembly, as well as quality and price (they're also what I used for this particular cable):
    • Neutrik NC4MXX-B (4-pin Male XLR cable-mount connector) - $4.54
    • Neutrik BXX [Red] (Colored Boot for XX series XLR) - $0.83
    • Neutrik XXR [Red] (Colored Ring for XX series XLR) - $0.18
    • Neutrik NC4FMXX-B (4-pin Female XLR cable-mount connector) - $5.59
    • Canare L-4E6S [1 foot] - $0.50
    • #550 Paracord [2 feet] - $1.00
    • 3:1 Black 3/16" or 1/4" Heat shrink [4 inches] - $0.50
    • 3:1 Black 3/8" Heat shrink [4 inches] - $0.50
    As a general note, if this is your first cable build, you might choose to double up on everything in case you manage to destroy something and don't want to have to wait for new parts to arrive (generally saves on shipping).

    I'm not going to post a complete tools list/soldering tutorial here, but if this is your first time, and you decided to read some tutorials on the subject, take serious heed of the use of good flux (it makes everything WAY easier). And buy 4 small crododile/alligator clips. There are myriad little tools and tricks to making soldering easier/faster, but a decent iron, flux, 60/40 solder, a little reading and some patience are all you really need.

    The Build:

    If this is your first cable-build, feel free to skip all the fancy stuff and just leave the main cable intact and not worry about the paracord sleeving ... that's just for aesthetics/weight/flexibility ... it has no effect on how the cable works.

    So ...

    Take a foot of your Canare L-4E6S cable:

    01 - Canare L4E6S.jpg

    Then with a razor blade (be careful), safety cutter or box cutter, gently cut about a two-inch slit in the cable. You can press down progressively until you feel the metal shield underneath, then lighten up a bit. The cable will try and twist as you cut if you try to do more than a few inches at a time, so it's easier to cut a few inches, pry the outer layer apart and pull out the shielded inner assembly a bit at a time:

    02 - Cut Jacket.jpg

    Continue cutting/pulling out the core of the cable until you have the entire shroud removed:

    03- Shielded Core.jpg

    Twist the ends to smooth them out a bit and then wrap some tape (I like to use teflon plumber's tape, but simple Scotch tape will work too) around the ends to keep the smooth and snag-free for an upcoming step.

    If you're going to sheath the cable with paracord, the next step is to prepare that. This is very easy ... if not entirely intuitive until you've worked with the stuff a little.

    You want about 14" of paracord for 12" of wire, since the braiding of the paracord causes the paracrod to shrink as the braiding expands to accommodate the cable you're going to feed through it (it's a bit thicker than the normal filler inside the paracord.).

    Cut the paracord with the sharpest scissors/shears/knife you have. Inside are some fiber strands (usually 7 for #550 paracord) ... which you'll want to tease out a little ...

    04 - Cut Paracord.jpg

    Holding the outer jacket of the paracord close to the opposite end to that which you just cut, grasp the exposed fiber and pull it all out:

    05 - Remove Fibers.jpg

    You can throw those internal fibers away, unless you have a cat, as we won't be needing them for this build.

    Next you want to "finish" the ends of the paracord. Don't get fancy here ... just take a simple BIC lighter and apply it to the ends of the paracord for about half a second and it'll melt and bond in on itself (if you use a torch, or a fancy cigar lighter like the four-burner red-flamed monster that I like for my cigars ... you'll obliterate your paracord and probably burn yourself).

    After this step the ends of your paracord should look like this:

    06 - Melt Ends.jpg

    Next up is the "fun" part ... running the paracord over the still-shielded Canare cable. You need to wrap tape around the ends of the cable, and make it nice and smooth (I wrap it into a cone and then melt it a little with the lighter to make it nice and smooth).

    Then you get to slide it into the paracord and inch it along.

    DO NOT try this with runs of more than about a foot. It'll work, but it'll drive you insane with how long it takes. If you remove the shield it'll go much faster (I can do 8 feet in a minute or so without the shield, and using a little sheathing tool that's too small for the cable with the shield in place), but for this build leave the shield in place unless you're having trouble.

    When you're done, you should wind up with something that looks like this, at both ends:

    07 - Sheath Cable.jpg

    Next you want to tease back the woven shield. It's easiest to work around in alternating directions. It goes slowly ... it'll take a couple of minutes to pull back the inch or so you want, at which point it'll look like this:

    08 - Unbraid Shield.jpg

    Under the shield there is some paper, which you want to pull back and cut off, and then you'll see some fibers in the cable bundle that you also want to pull out and back, and then trim at the base of the exposed cable.

    When you've done that, cut off about half of the stands of the shield, as close to the paracord as you can. Then twist that together tightly until it makes a "fifth wire". Once that is done, you want to strip about 1/8" of insulation off the four primary wires. My favorite tool for this is one of these. I actually tend to cut 1/4 of an inch, tin all of that, and then trim it down to what I actually need (just because doing so is easier and faster).

    Here's the cable tinned at the 1/4 inch length, but not yet trimmed (ignore the sloppy ends, they're about to be trimmed off and are just an artifact of dipping the twisted wire ends into flux-paste ... you ARE using flux, yes?!). And the brown/burnt marks on the blue/white wires are flux residue that will be cleaned off later!:

    09 - Strip and Tin.jpg

    Before we make any connections, we need to prepare, well, the connectors. This is very easy. Take the male and female ends and coat the INSIDES of the pin pots with flux. Then take your iron, hold it against a pin, and push the solder into the base of the pin. Once the pin is at temperature the solder will melt and fill the pin socket. There will be LOTS of flux smoke ... try not to breathe that in ... in can smell rather good, but it's quite toxic (I wear a respirator as well as using an extraction hood for this sort of thing).

    The idea here is to get all the solder you'll need into the sockets/wells on the back of the pins, so when it comes to soldering in the actual wires, you're just applying heat, melting the existing solder, pushing the wires into the holes, and then removing the iron and letting things cool!

    Takes a bit of practice, but it's really VERY easy.

    I got a bit lazy with the camera here (or phone ... but either way, ethanol was involved ...) ...

    While it is not necessary, I like to put heat shrink around my connections on XLR connectors (it's not always practical on smaller connectors/joints). I use a 3:1 3/16th heat tubing for this. The trick here is to pull back your paracord and braid a little and push the heat shrink as far up the individual wires as possible (if they get too hot when you're soldering your connections, the stuff will shrink and you're screwed).

    One thing that helps with this is to just apply very small alligator/crocodile clips to a) hold the heat shrink in place and b) act as a heat-sink:

    10 - Heatshrink and Solder.jpg

    Make all four connections (five, with the shield going to the ground lug, on the male end, if you're using the shield). And then, once the joints have fully cooled, slide the individual pieces of heat shrink down over your joints and heat them with a heat gun at 350-400 F.

    (Apparently there is a 10 image-per-message limit, so continuing this in the next post).

    [It's possible this post is more appropriate for the "DIY" forum, in which case, I'll ask the moderators to move it there and link it accordingly. I'm posting it here since it follows the tweak/mod topic, most of which have in-line/in-thread instructions for how to perform the various mods.]
     
    Last edited: Oct 4, 2016
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  3. Torq

    Torq Last Remaining Good HF Poster

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    When you're done shrinking the tubing over the individual connections, on the male end, it should look something like this:

    11  - Male End.jpg

    Note: Putting heat shrink over individual connections is, by no means, necessary. If you take apart most commercial cables, even rather high-end offerings, you'll often seen no such insulation. I like the stuff I build to be as solid as possible, as even when I cannot see it, I KNOW what is "in there" and prefer it to be the best I can do ...

    That's just me, don't feel compelled to do things this way ...

    For me it's just easier to build this way than to trouble-shoot a failed cable later on. It is very much over-kill as the connectors we're using here already have pretty-much-heroic levels of strain/-relief as it is!

    But ... since I'm "affected" this way, I also add an additional level of strain/relief ... which, in this case, is also necessary to keep the paracord sleeving in place. This is, again, a piece of 3:1 heat shrink tubing, butted up against the individual wires, though this time over the female end of the cable:

    12 - Female End.jpg

    A few notes before you go building this thing:

    You can FULLY assemble either the male or female ends of the cable without regard to final heat shrink or cable boots. But, once you have one end on, make sure to add both pieces of heat shrink and the two necessary cable boots prior to soldering the final connector in place, otherwise you're going to have a very wonky looking cable!

    Anyway, when everything is all soldered up ... and you have screwed your connectors together, you'll wind up with something that looks like this:

    13 - Finished.jpg

    A note on my color-scheme:

    The paracord uses a reverse purple-X on solid-black theme compared to the HD650 cable I built in another thread. This is intended to indicate the "inverted" nature of this cable (it's not the only "phase reversal cable" I have built). Additionally I've used the red-boot/black-collar and /black-boot/red-collar motif on the connectors to also indicate the signal inversion this cable applies.

    And that, as they say, is "that" ...

    Holler if you have questions ... and I'll try and complete the software/config piece either tomorrow or on Thursday (I'm afraid I'm traveling Tuesday and Wednesday ... I lead such a hard life ... ;) )
     
    Last edited: Oct 3, 2016
  4. Torq

    Torq Last Remaining Good HF Poster

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    Playback Software & Settings:

    To make use of this tweak, beyond having built/acquired the necessary adapter cable, you need to feed your DAC/amplifier with a signal that also has the polarity/phase inverted on the appropriate channel (that'll be the right-hand channel if you built the cable in the same configuration as described above).

    Exactly how you do this depends on what you use to play your music, and there are myriad options there, but I'll cover a couple of the most common ones here.

    For most players you either take advantage of built-in output configuration options and/or DSP settings, or you use a third-party plug-in to achieve the same thing (at the end of this post, I'll include references/links to some such plug-ins). Often, when using plug-ins, the polarity/phase reversal options are combined with other functionality. For example, it's very common for EQ software, especially that intended for studio/DAW use, to include phase-control settings.

    We'll start simply, however; I'll add to this post a bit over the next few days to cover a broader array of options.

    For macOS/Windows:

    If you use a recent version of JRiver's Media Center on either Mac or Windows computers, then it already includes the ability to do the necessary phase/polarity inversion. This is handled using JRMC's DSP functionality, and you can access that by either:
    • Selecting "Player" from the menu and then choose "DSP Studio".
    or
    • Clicking the "DSP" button (looks like a three-band graphic equalizer) in the player.
    That should take you to the DSP Studio screen:

    [​IMG]

    And from there, make sure "Room Correction" is checked, and then select the "Room Correction" entry to bring up the settings for it. That should bring you to a screen that looks like this (it'll vary based on your chosen output device and speaker selections):

    [​IMG]

    Here, again assuming you're using a cable wired like the one I described in the first post, you'll want to click on the button for the "Right" speaker, at the top of the dialog box.

    Then, towards the bottom of this window, check the box for "Polarity" (Reverse the polarity of this speaker ...).

    Leave everything else as it is (unless you want to/have already tweaked them for other purposes).

    And then you can play your music and it'll appear at the headphone in the correct phase/polarity, while exercising the DAC and amp in reverse polarity for one channel.

    --

    macOS/OS X:

    Players:


    Plug-ins:

    Some of these plug-ins are paid, some are free, and most have at least a free trial so that you can experiment with them and see if they're going to do what you want (or if this little tweak is something you want to persevere with).
    Personally I use EQuilibrium, but it's rather expensive unless you actually need a full-blown, professional-grade, multi-channel, EQ solution. I run it in my studio setup as well, so I didn't have to buy a separate license just for this sort of thing, those to date it is my favorite EQ tool. To use it properly there's a lot more to it, but it's simple to setup as a trial for this particular tweak.

    Example Configuration:

    The actual configuration required in most cases is very simple, particularly if you are already familiar with Audio Units in macOS applications. All we are looking to do is switch the polarity or phase on the right hand channel. In this case I'll provide a simple illustration of how to do that using EQuilibirum in Audirvana+.

    I'm going to assume you have installed both of those packages (they follow normal macOS installation practices).

    Launch Audirvana+, go to the "Audirvana Plus" menu, click it and choose "Preferences ...":
    Screen Shot 2016-10-14 at 5.21.45 PM.png
    Choose the "AudioUnits" tab and check the "Use AudioUnits effects" box. That'll enable the selectors for the various Audio Units that you have installed. Drop down the first of these that you haven't got anything assigned to (which is probably the first once) and select "DMGAudio: EQuilibrium".

    Now we need to actually use EQuilibrium to invert the phase of one channel. To do this, simply click the "Configure" button (as shown in the dialog, above) and you'll get something like this:

    Screen Shot 2016-10-14 at 5.22.19 PM.png
    Now this screen lets you fully configure the plug-in, but we're only interested in one setting. The phase or polarity toggles are found at the bottom of each of the "Left" and "Right" channel gain sliders (bottom right side of the overall window):

    These are the buttons marked as [∅].

    This is a standard symbol in audio tools that indicates a phase setting. In our case we want to invert the phase (default is standard phase), which you do simply by clicking on the right hand phase button - it'll light up orange to show it is enabled.

    Hit "Apply", close out of "Preferences" and you're ready to play.

    --

    Windows:

    Players:

    List of suitable Windows players to follow:

    Plug-ins:

    Instructions for setting up various .VST plug-ins for this will follow.






     
    Last edited: Oct 14, 2016
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  5. Torq

    Torq Last Remaining Good HF Poster

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    Cable build post complete ... software/config will follow as I have connectivity/am back in in town ...
     
    Last edited: Oct 4, 2016
  6. Torq

    Torq Last Remaining Good HF Poster

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    Anywhere it says "paranoid*" it means "paracord".

    Auto-correct will be the death of me ... or the git that dreamt it up ... one of the two ...

    (*Goddamn Jeff Bridges** ... bastard ... even if you don't know what the hell I'm on about).

    (**Potential bonus*** if you DO know what I'm on about here ...)

    (***Bonus might include one, or more, of my particularly "affectionate****" cats coming to live with you for an, as yet, undetermined period).

    (****"Affectionate" might mean "basting you with an intent to nom", with a strict "no-return-you're-stuck-with-the-bugger" policy).

    I might be un-"hinged". Or bracket. @Thad E Ginathom might know what I'm babbling about here, but if he doesn't, the rest of y'all are probably buggered.
     
    Last edited: Oct 4, 2016
  7. bazelio

    bazelio Friend

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    That's correct, and I believe the so-called "preferred solder joint" to aerospace standard specifically calls for exposed joints. There are guidelines for distance between the joint and the insulator, and no insulator or heat shrink is to touch the joint.
     
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  8. Torq

    Torq Last Remaining Good HF Poster

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    Nicely caught, and YES!

    Are you in that field? I'm not (official, at least ... but that doesn't mean there aren't things in orbit with my mitts on them ...) ...

    Holy ellipsis!

    Back to your original point ... often not for the commonly anticipated reasons ... ;)

    Fun stuff like 14 CRF/Part 25 craft specs comes up here.

    At the voltages and currents we're dealing with in audio, it's not super relevant. Joint contamination is largely irrelevant (and mitigated by proper cooling/assembly offset limits), and insulation flash-over isn't much of a worry with a dielectric strength about an order of magnitude over our highest working voltages).

    That is, of course, assuming I'm picking up on the things you're specifically referring to.

    I do know that the stuff I have in orbit was far more constrained by weight/mass factors than anything else! ;)
     
  9. johnjen

    johnjen Friend

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    WAY KEWL!!!! :)
    This project finally made it to the top of your list…!
    I'll be interested to hear what the differences you hear, are.

    I used to cover the soldered ends of the wire with short pieces of heat shrink as well.
    But I got over it when I discovered 2 aspects that make it better for me to NOT do so.

    #1 I take connections apart and fuss with the connects all to frequently.
    This means I have to strip the heat shrink off first before I can get to the soldered ends.
    And then putting a piece of heat shrink back on again is usually neglected, especially if I know I'm going to go back in and fuss a bit more.
    This makes for a 'messy' looking end result.

    #2 I can make the ends of the wires shorter after they leave the cable and then are soldered in the connector.
    I've found that when they are short(er) there is less chance of wires 'misbehaving', especially when yanked or tugged upon.

    And this is but one of 3 tweaks that dovetail well together.
    And another one of them, the SSBB (SubSonic Bass Boost) is greatly enhanced with this PRT (Phase Reversal Tweak).
    And the third tweak, judiciously applied EQ, also helps bring out more net gains along with these other 2.

    Also it is note worthy that applying this PRT is more noticeable using tubes.
    My theory runs that in cases where the left and right channels are present in the same tube, then crosstalk and the common signal influence of these 2 active channels will tend to cancel each other out.
    IOW the 2 channels will have less effect upon each other while being amplified inside the tube itself.

    We (an audiophool friend and I) stumbled upon the use of this PRT quite by accident back in 1972.
    And I have since learned that others are aware of this tweak, although no one that I'm aware of, uses it quite this way (for the entire audio chain, from source to drivers).

    It is also very easy to apply to (no soldering required) vinyl/speaker systems, just reverse the right (or left) channel connections on the cartridge, and again on the speaker wires at the power amp for the channel that was reversed at the cartridge.
    Doing it this way keeps the polarity of the speaker wires the same, which can take some time to 'settle in' after having their polarity reversed.


    JJ
     
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  10. landroni

    landroni Friend

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    One of the reasons I use tactile phones for barely uttering mono-syllables, and that only when hard-pressed. Compared to good ol' buttonful phones, buttonless ones are a nightmare... Not sure why people are so fond of writing emails on smartphones while driving... :)
     
  11. wormcycle

    wormcycle Facebook Friend

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    Do not understand why this has to include a DAC.
    If the purpose is ti use the full power of the amp I should get the same results with two XLR polarity reversing adapters: one between the DAC and the amp, and one on the right channel of balanced headphones. In my main setup I use Sony HAP-Z1ES and cannot reverse polarity from the player.

    Not that I am really convinced that it would have any audible benefits.
     
  12. Torq

    Torq Last Remaining Good HF Poster

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    You need a balanced source/amp. What it is doesn't really matter. Most people here are using DACs as their sources driven off a computer. This was the simplest way to set it up without requiring people to make two cables (rather than one).

    That would work (there's still a DAC involved in your example, though).

    You'd have to try it to know. Whether you want to do that is up to you.
     
  13. PoochZag

    PoochZag The Shadow knows - Friend

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    @Torq Minor question, but where do you get the colored neutrik pieces? I've used so many of those and have never seen anything other than black, but seen you and others use them.

    Also, can the ring one be swapped out on an already made cable? (I know the twisty boot one couldn't)
     
  14. No_One411

    No_One411 Fired by Jude

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    PoochZag and Dino like this.
  15. Torq

    Torq Last Remaining Good HF Poster

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    I usually buy mine from Redco, but any Neutrik dealer should have them.

    For the -XX series connectors these are the boots and these are the rings.

    Yes, you can swap the rings at any time.

    I tend to make up cables in advance with the included black/dark-grey rings/boots, and just swap the rings as needed when someone wants a different color. In fact I've largely stopped using the colored-boots as I think the rings look a bit nicer.
     
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  16. wormcycle

    wormcycle Facebook Friend

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    Thank you, I think I will.
    I found HOSA XLR phase reversal adapters for around $7
    https://www.bhphotovideo.com/c/prod...hnology_GXX_195_Audio_Adapter_XLR_Female.html.
    They will only work on dual 3 pin XLR but that's enough for test using my DIY balanced cable for HE500. I will put one adapter on balanced input to BHA-1 from HAP-Z1ES to, and another one the right channel hp out. If it works then I follow you instructions and make two 4 pin polarity reversal adapters with Neutrik and Mogami for HD800S, that will cost a lot more than Hosa. Unless I find 4 pin, single channel phase reversal adapter, but that's unlikely.
     
  17. cskippy

    cskippy Friend

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    So has anyone else tried this? I'm having a weird problem. The cable inverts the polarity between channels as it's supposed to do but also reverses Left and Right audio. It doesn't make a difference which side I select for reverse polarity in JRiver, and I even tried it in Reaper with some audio to bypass JRiver just in case.

    My pinout is 4pin XLR female to 4pin XLR male:

    1->1
    2->2
    3->4
    4->3

    I'm not sure if it's something Gumby is doing, as I've tried different amps, both balanced and unbalanced from Gumby.
     
  18. Torq

    Torq Last Remaining Good HF Poster

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    It sounds to me like you've accidentally reversed which pins you think are which on one of the connectors. Easy to do ... especially if you're not reading the pin numbers on the connector and are, instead, translating them positionally from pictures.
     
  19. cskippy

    cskippy Friend

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    Aren't they grouped + - on 1 and 2, 3 and 4? Even if I read it backwards it would still be "correct" just the left side would be reversed not the right?
     
  20. Torq

    Torq Last Remaining Good HF Poster

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    If you read the pins from the wrong side on one end and soldered it up that way, you'd have swapped the left and right channels AND inverted the polarity on the left one.

    If you connect it correctly, it'll just invert the right channel - however, if it's not that, then you've got something else weird going on. Hard to say what. Across a number of amps and sources, I've never had the channels swapped except for the one time I wasn't paying attention and did things positionally from the wrong side instead of actually reading the pin numbers (I will blame a healthy does of Scotch for that one).
     

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