It certainly seems that the ZTPRE could well be wired out of phase considering the testing you have made. My DAC has a phase switch so that would be a rather definitive way to test in my system.

I would suggest contacting Steve. Happy holidays!

That's not standard for the ZTPRE though--mine is not phase inverted.

I might do that as well, or just use the phase inversion on my DAC. But I can totally understand wanting to have the component as spec'd, especially when it comes to resale.

I completely agree with CAJames about components being in or out of phase. Even some Recordings are out of phase! The simple answer in this case is to reverse the cable connections at the speakers. Done.

Yes, it would work based on mk60s tests, to get the phase right with the speaker wires "out of phase." Just not my idea of a fix, especially if one ever wanted to sell it. But why not enjoy it that way if not yet clear on what to do about it.

That pic makes it look pretty complicated Lon, especially the way it is shot, and no doubt, there is a lot in there... but my guess is that it is probably on the periphery where things are connected to the attenuators or XLR/RCAs. Steve used those black Mogami cables for moving around  the signal in the past, in my stuff anyway. Can't tell from these pics if Mogami, but you can see the black cables with white shrink on the ends are the ones I am pointing to. I took a screen shot of that manual page, and hope it is sort of legible... a nice page to me describing the design. Could be some other signal connection, but I would look first at these if it were mine, along with the output XLR connections.

Not advocating going in if not comfortable with it and knowing how to do it safely, but if so, these point to point paths are usually pretty easy to follow from within what looks like a lot of stuff.

On the other hand, having Steve fix it is surely a good option! Could likely update the warranty at the time if wanted.

Hi all, thanks for all of your thoughts so far!

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If I'm missing something or misunderstanding here, I will be happy to have that pointed out. But to my understanding this is not what the phase button on a DAC does (or at least isn't what it does on my Denafrips DAC).

We should be careful about terminology here when it comes to talking about phase:

There is *relative* phase, which is the difference in actual phase of the waveforms being generated between the two channels. The problem that I am seeing here with the ZTPRE is that the relative phase of the two channels is 180 degrees, i.e., while one driver on one speaker is pushing outward, the same driver on the other speaker is sucking inward. They are completely out of phase and have no coherence, and are causing frequency cancellations not intended by any recording.

There is *absolute* phase of the channels, which is the overall phase of the signal being fed to both channels (assuming they are the same, which I believe is the usual intent, so that the sound from both speakers sum coherently). Changing absolute phase will invert the phase of *both* channels, so, if they were out of relative phase to begin with, they will still be out of relative phase after inverting the absolute phase.

So, to flip absolute phase, the phase of both channels are inverted, while to flip relative the phase of only one channel should be inverted.

On my DAC, the phase button inverts absolute phase: it flips the phase of both channels and leaves relative phase unchanged. From some quick google searching, this seems to be standard for DACs. My understanding as to why this function exists is, as CAJames mentioned, some recordings are made with an inverted absolute phase, and although this is subtle, some people can detect it and prefer a different absolute phase, and they can use this button to change it. This button however will do nothing to correct relative phase errors.

Here is the .flac file that I use for relative phase tests https://drive.google.com/file/d/1UasX5tZ_BWRkDiJ1wSPe5pjQ7pctQGEx/view?usp=drive....

When the voice says "my voice is in phase", the relative phase between the two channels is zero, and when it says "my voice is out of phase", the relative phase between the two channels is 180, and you can hear the difference. Hitting the phase button on my DAC doesn't change how this test sounds, because the DAC is inverting absolute phase of both channels, and thus has no effect on relative.

Is my understanding of relative and absolute phase here correct?

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What the DAC phase button does is also my understanding of what it means to have a pre-amp or other component that inverts phase -- the absolute phase is inverted, not the relative phase. Inverting absolute phase is a feature, but inverting relative phase would appear to be a bug. Would you agree, or am I misunderstanding? I'm assuming the same is true for what 4krow said about recordings/masterings: some might have an inverted absolute phase, but the relative phase should still be correct no matter what.

In my case, the ZTPRE is not inverting absolute phase (which I wouldn't have any problem with), it is inverting the relative phase. Flipping absolute phase is a matter of rewiring BOTH speakers to be inverted (or hitting the Phase button on your DAC). Flipping relative phase is a matter of rewiring ONE speaker to be inverted. The first is not an actual problem and could be seen a a design choice for the component. The second is not -- nothing sounds correct when the relative phase between the channels is out.

As I said, when I rewire just one speaker OR remove the ZTPRE from the chain, it corrects the issue. So, the issue appears to be that the ZTPRE's relative phase is just incorrect.

Anyway, this may actually be something I can fix myself, as pointed out above. It could be as simple as one of the two channels having the +/- wires from the input terminals being mixed up, which should be easy to figure out by comparing both sides.

Nonetheless, I'm hoping that we can all agree that inverted global phase (as in what a component or recording sometimes has) is not the issue here, and that a component whose channels have inverted relative phase is always a mistake. If not, it means I have something to learn!! If I am mistaken in my assertions above, please please do point it out!

In the meantime, I am of course absolutely enjoying the sound with my left speaker rewired to have opposite phase to correct the issue. I'm actually housesitting right now and on unfamiliar speakers (Revel Salon2 Ultima) but really looking forward to getting it home to see how it is with my differential mono UFO25s and la scalas!

I am always confused about this and it may in fact be because whenever I reverse the speaker leads on one end or use the phase button on my DAC I get the same resulting sound. And I had a component that was out of phase and I rewired the plug end and it sounded as if it was in phase.

So anyway and either way and completely I hope this can be worked out so that you are phase correct.

I don't do FLAC stuff.

I am saying the former, not the latter.

Merry Xmas--hope you get this resolved.

Actually I was misreading your question--it's the latter. Reversing the positive and negative on one end of both speaker cables is the same as using the phase button. Sorry I was confused.

I've experienced both the relative and absolute phase being "off" and neither is a comfortable long-term listen. May your phase be correct and right this season!

Funny. I most always like the Phase on my DAC where I think it is "correct," not inverted. I am using a older modified Gustard x20pro and it is hard for me to tell from the wording what is officially on or off with the phase adjustment. One way says Disable, and the other Enable. But listening, I think Disabled and Enabled might be what was meant.

Disable has more focus, macro dynamic power, more body, more density and push. Enable is softer, less hard, more relaxed and clearer...a more obvious sense of harmonic complexity due to enhanced space and being a little less forceful. Cleaner from a little less push and body, finer, nuanced information is more apparent, with more sense of articulation all the way down...more spatially "alive"...

It has been a lot of years since I left it inverted for a time. Every so often I will flip it and usually go back, preferring Disable... which I am thinking is "off." There have been times where I like it better inverted on first impressions, but most always go back to Disable.

But from listening today, I so far like both, and maybe Enable more. The reason I wanted to try it again was stimulated by how this conversation developed, but also, I am slowly modifying a 300B/845 amp. And like any nice amp I have gotten so far, I crave speeding it up and carefully/musically increase resolution in more clear space.

With this amp at ±250 hours, thinking the bulk of more obvious burnin issues were probably sort of done, I started bypassing signal and power supply caps. Out of the box, it was nicely resolving, presumably a lot because of these big triodes implemented with a relatively "modern" sound," having the 300B/845 characters, but not too obviously syrupy and intensely warm. Still, for me, even after 250 hours, it was a little slow, a little too dense/smooth, and showing enough dark to sound a little too colored... all in all I guess a little too what I imagine some folks mean when they say "tubey." So I am bringing up resolution in space with more immediacy and speed across the spectrum. So far successful, it is faster and clearer without being hard, good warmth and smoothness factors still there, but also more articulation with more complexity, not hard, showing the warmth more subtly with the smoothness, sweetness and complexity of these tubes, but sounding pretty alive. More to come, but a nice shift in the right direction.

Anyway, the modification caps are still a little green, and the sound still just a little too dense and forceful for me overall, especially since "across recording" sound is important to me in tuning... So I thought maybe now could be a good time to flip the DAC phase, hoping it might make the time still needed for modification caps to find their sound more exciting and funner. And this could easily change by tomorrow, or not... but so far this morning, I prefer the phase inverted....

Just one of the many tuning tools I often forget to check out now and then to see if there might be a little more I can pull from the system and room as it evolves.

Yeah, absolute phase is one of those things that I'm not sure where I stand with it -- I actually kind of wish that my DAC didn't have a phase button, because I always wonder if what I'm listening to would sound better if I hit the phase button, and every time I try it I'm not sure lol. If it's true that some recordings were meant to be listened to with inverted absolute phase, I really wish that you could tell Roon to figure it out and invert whenever that's the case. But I can see how for others it's a nice extra flavoring they can use when the mood strikes!

Lon, I do have continuing challenges with Dyslexia, and I get confused by some of this stuff. But what you are calling your phase "On" sounds like what I gather is "In" on Direct Stream Settings..or "normal" phase, right?

Do you think from my descriptions with my DAC I am identifying "normal" phase and inverted correctly? Lots of conditions playing into our setups and resulting sound, and my soundstage is pretty good, with good depth, width, and saturation of player locations. With quite a dense signal anyway, the soundstage sonic shifts between phase settings are notable, but usually not in terms of player placement wandering.... It moves them some on many recordings, but usually not a whole lot, and though less dense, they are still pretty nicely saturated in focus and location. "Better" or "worse" in terms of natural sound, not sure... both have different advantages in early tests.

In what I am thinking is inverted, the sound and soundstage do have a more expansive and diffuse vibe...but so far not badly diffuse...the direct note sounds are less dense/full, shifting emphasis toward the atmospheric information taking more of the sonic landscape, but the players are still pretty convincing in placement and dynamic hit, just less-so... And by increasing the feel of spatial information density and presence, it is seductive, the decays filling my space and world more apparently. Soundstage always goes beyond walls here, players and atmospheric information, but this way, in the current configuration anyway, the decays are fuller and more limitless. I particularly like it when decays wrap around me more, more clearly out beyond the room in back of me.

Well, I will repeat that soundstage is a challenge in my system and room, and that I go for frequency balance over soundstage as far as tuning goes, so with a less defined and expansive soundstage I will have a less specific answer to that question regarding phase.

My PS Audio DSD DAC Mk II has a "Normal" and "Inverted" choice in a Phase button, with "Normal" as the default. And in the case of my system and room the two are differentiated by tonal balance and some dimensional and positional factors. "Normal," if the recording is not somewhat "inverted" from the engineering or mastering, the tonal balance is just that, and in my system it's more specific imaging and a focused sound stage. "Inverted" if on the recording or mastered disc the sound is leaner, a bit less focused, and though imaging is good, it is less focused, looser sounding instrumental body and there is a bit more expansive but less specific soundstage. The latter is corrected for the most part by engaging the "Inverted" choice of the phase switch.

So you may right now be preferring the "Inverted" nature of the sound? Hard for me to say sitting here.

Last century I was vigorously exploring the "24 Bit by RVG" series of discs from Blue Note Japan, then a new thing and discussed a lot among jazzers on bulletin boards. I loved the overall "LP like" sound of these and their awesome packaging, but I did find a good portion of them to sound lean and a bit tilted up. Another bulletin board denizen pointed out to me that when he reversed the speaker cabling positive and negative at either amp or speaker but not both, the bass was better and the treble tamer. Which it was on these discs. And that effectively was "inverting" the absolute phase I think. At that time neither of us had DACs with a phase button. I also found that Verve was putting out a series of discs with the same sonic symptoms and these were bettered with inverted phase. I became a student of the sound differences and when I had a phase button on my first PS Audio DAC I would occasionally implement the phase button on a disc if I heard what I perceived as the inverted phase characteristics of a recording. More than 99 percent (outside releases in those two series) the phase is perceived as "Normal" in disc playback.

That may well be. There are certainly phase manipulations on recordings. Some instrumentalists also use it in their own sound; one of my favorite Stratocasters has a phase switch that really does alter the sound especially of a bridge pickup, I don't use it but session players might and likely do. There's also the famous QSound used in some recordings (Roger Waters is famous for its use) and though I am not sure that phase manipulation is a component of its "manufacture," phasey characteristics I think are heard within it.

I'm not a Barber fan and not much of a Krall fan so haven't really heard their recordings enough, but I would not be surprised that some phase manipulation was there in the tracks.