Flipping the phase of 2 XLR outs on a DAC?

[adamlloyd]

Hi, I have a Mytek DAC that I have discovered is flipping the polarity of signals at the XLR stereo output stages, but not the headphone output. Have no idea how this happened because I got it used on ebay.

Is this easy to fix? I have someone here in L.A. who has offered to fix it for $100 bucks, I just have no idea if that's a good deal or not because I don't know what's required. Anyone here willing to do it for cheaper? Any advice? Thanks dudes.

[Studerfreak]

Do you use a Mytek cable with the 25pole Dconnector to XLR's ?
Or any other snake ?

Which Mytek are you using ?
Maybe you just can rewire the XLR's and reverse pins 2 and 3.

[adamlloyd]

Umm... Mytek 25pole Dconnector? I have no idea what that is. No snakes or anything. Just 2 XLR cables that either go to my KRK monitors or for printing stems, re-amping etc.

It's a Mytek Stereo96 DAC, older version. 2005 I think?

I would have no idea how to reverse the pins...

[Studerfreak]

Sorry ! My mistake ! I thought you had a multichannel unit...
What XLR cable do you use ?
Where is that XLR cable going to ?
Do you use an unbalanced input you connect your 96DAC to ?

[adamlloyd]

Errr...

It's a Digital-to-Analog converter. The input is Spdif, no unbalanced connections involved. The outputs are 2 XLR outs, and the headphones jack (so yes, 2 channels, stereo). The headphones jack does not flip the phase. The XLR outputs do.

I have tried all different cables, mogami 2549s and monster cables. Every test I run shows that the signal is being inverted when it leaves the DAC channels.

When I run the same audio using the same cables through the output of my digi 002 and into my ADC unit to compare, the signal phase remains the same as the source.

[DrFrankencopter]

Wire up some new XLR cables, with Pin 2 on one end connected to Pin 3 on the other, and vice versa.

If that's out of your league, then buy a couple of these: Calrad 35-464: AVCable.com

IMO $100 to do it is out to lunch.

Cheers

Kris

[Rick Sanchez]

Originally Posted by DrFrankencopter

Wire up some new XLR cables, with Pin 2 on one end connected to Pin 3 on the other, and vice versa.

If that's out of your league, then buy a couple of these: Calrad 35-464: AVCable.com

IMO $100 to do it is out to lunch.

Cheers

Kris

I recently bought some pre-wired XLR to TT cables at Electronic City in Burbank and they came wired XLR pin 2 to TT ring...so by today's standards, they were phase reversal cables, though they were not supposed to be. Always a nice treat to find out during a session.

They told me, "Sh*t Happens"

So I recommend checking phase on ANY cabling or piece of gear you purchase before using it.

[adamlloyd]

ahh, thanks guys.

That looks like a good idea Kris. I wonder if it would color the sound weird though. I've had issues with cable adapters coloring the sound.

ive definitely learned the importance of phase. .

[JohnRoberts]

For the record it's called polarity and subtle but audible on asymmetrical waveforms like brass and vocals.

JR

[adamlloyd]

Originally Posted by DrFrankencopter

Wire up some new XLR cables, with Pin 2 on one end connected to Pin 3 on the other, and vice versa.

If that's out of your league, then buy a couple of these: Calrad 35-464: AVCable.com

IMO $100 to do it is out to lunch.

Cheers

Kris

Okay, what the F am I missing?

I just got 2 of these adapters that I ordered, today. With or without them, the waveform is still flipped. I don't understand. How is that possible?

All I want is to maintain correct polarity throughout my system.

[DeeDrive]

Originally Posted by adamlloyd83

Okay, what the F am I missing?

I just got 2 of these adapters that I ordered, today. With or without them, the waveform is still flipped. I don't understand. How is that possible?

All I want is to maintain correct polarity throughout my system.

What method are you using to test that your polarity is out? I find it REALLY hard to believe that the Mytek is reversing the polarity on your XLR inputs but not your headphone jack, that would be a pretty huge design flaw. If you're getting the same result with and without polarity reversing adapters, you're definitely doing something wrong. What kind of a signal are you using to test? If you're using a sine wave, is it possible you're getting your peaks and valleys confused? Because a 1KHz sine wave that is delayed 1/2000 of a second will look 180 degree outs when compared with the original.

[adamlloyd]

Originally Posted by DeeDrive

What method are you using to test that your polarity is out? I find it REALLY hard to believe that the Mytek is reversing the polarity on your XLR inputs but not your headphone jack, that would be a pretty huge design flaw. If you're getting the same result with and without polarity reversing adapters, you're definitely doing something wrong. What kind of a signal are you using to test? If you're using a sine wave, is it possible you're getting your peaks and valleys confused? Because a 1KHz sine wave that is delayed 1/2000 of a second will look 180 degree outs when compared with the original.

ok....I'm really not THAT dumb...

I send a track out of the DAC...a mix, or and instrument, I've used both, but not a sine wave...and back into the ADC...zoom into the very first part of the wave...and bam...it's flipped...delayed, too, but that is nothing new, I know how to line stuff up and I don't get peaks and valleys confused... If it was on the same computer I'd take a snapshot and show you, it's very obvious that the waveform is being flipped.

When I do the same thing using the main out of the 002 and into the ADC, the polarity remains the same as the source. I've tried this with all my cables to ensure that the only variable is the DAC.

In terms of the headphone jack not being flipped, I haven't exactly tested that visually but I can tell by listening. When the polarity is flipped, the mix sounds a little socked in, when it's natural/correct polarity, the instruments all sound natural and pleasing (this is the same for headphones or monitors). I simply noticed that it was opposite, monitors vs. headphones...when I inverted everything ITB to make it correct on the monitors, etc.

But I've recently started using the headphone amp on my M-Patch so forget I even mentioned this. I'm just interested in getting the main XLR outputs of the DAC not flipping the polarity.

[DeeDrive]

Well the adapters are switching pins 2 and 3 on the XLRs, so as long as the outputs on your Mytek are balanced, your cables are balanced, and your inputs are balanced, you should see a polarity shift when you insert those adapters. Are you using anything funky like XLR to 1/4" TRS cables or anything that could be wired up wrong, or maybe a 1/4" TS that could be dropping the pin 3 signal somewhere? Kinda shooting in the dark, but this is a pretty strange problem, and if the adapters aren't fixing it, it sounds like something is wired wrong or your testing is somehow flawed.

[adamlloyd]

Ugh. Well. I guess I have no choice but to take it to the expensive tech dude then.

My cables are all balanced. All XLR to XLR. Bloody headache this is...blah...

I guess I should look and see if there's some kind of cable-tester for quick testing all the cables, just to make extra damn sure. I'm sure there is. I'll have to research later, I am spent at the moment.

thanks for your input though.

[SP2016]

It all is a mystery to me as well, so there will we a simple cause.....
Try to check your cables first with a so handy tool like the Behringer CT100.
I could hardly do without it.
Quite cheap.

Have fun !

[mbrebes]

There is a major flaw in your testing. With your test setup, it could be the output, the cable between the out and in, or the input that is causing the phase reversal. And listening to the headphone out is not a reliable test.

[adamlloyd]

Yes. Thanks dude, I know that listening to headphones is not a reliable test, but as I explained it's completely irrelevant to the problem I'm trying to solve. I guess I shouldn't have mentioned it, but everyone on this forum is always preaching to "USE YOUR F-ING EARS" and I was merely reporting what I observed, with my ears. If people can't distinguish correct polarity with their ears, then that's not my issue. We're only talking about the natural physics of audio.

Mytek DAC >> Mytek ADC = Polarity Flipped in DAW
Mytek DAC >> Digi 002 ADC = Polarity Flipped DAW
Digi 002 DAC >> Mytek ADC = Polarity Remains Same as Source, in DAW
Digi 002 DAC >> Digi 002 ADC = Polarity Remains Same

All using same cables.

And then, weird fact, the polarity flipping adapters on the XLR outs of the Mytek DAC don't do anything to the polarity...it remains flipped in the DAW...which makes no sense to me...because obviously with the adapters, it should be the inverse of whatever the DAC is outputting.

I don't understand how there's a flaw in my testing. It's a simple elimination of variables. We do this all the time when it comes to music technology. ALLLL the TIMMMMME....

[adamlloyd]

Originally Posted by SP2016

It all is a mystery to me as well, so there will we a simple cause.....
Try to check your cables first with a so handy tool like the Behringer CT100.
I could hardly do without it.
Quite cheap.

Have fun !

Thanks man, I'm gonna pick one of these up. Good call.

[Studerfreak]

What happens when you switch from SUPERLOCK to EXTERNAL clock ?

[ulysses]

What happens if you use your polarity-flipping adapters on the output of the 002? If this does NOT cause the polarity to become inverted, then the simple and obvious problem is that your polarity-flipping adapters are not polarity-flipping.

If the adapters DO flip the polarity on the 002, then they aren't the problem.

Based on everything you've told us here, I'm confident there are only two possible explanations:

1. Both Mytek and Calrad sold you equipment that is wired with polarity that's different from what it's supposed to be.

2. Operator error. That's you. It sounds like you know what you're doing, but there's just no other legitimate possibility based on the info you've provided us.

3. The third hypothetical which is NOT a legitimate possibility is that the Mytek manages to produce a different polarity when you use the Calrad adapters than it does when you don't use the adatpers.

Besides using the adapters to route the 002's outputs back into an ADC, the other thing you can do to get to the bottom of this is to use a multimeter to check the connections on your polarity adapters. Look carefully to be sure you're connecting your test probes to the pins you think you're connecting them to at each end of the adapter. Use the "continuity" setting of the meter for an easy "Go/No-Go" beep. Or just open them up and look inside.

Seems odd that Calrec would miswire two adatpers and ship them both to the same guy who got a miswired Mytek converter.

Also seems odd that Mytek would build a converter with connectors installed with wire, the only possible way to get an accidental inversion on one unit. If that's the case, an assembler would have had to miswire both channels. More likely would be that they used PC-mount XLR connectors, which cannot be accidentally miswired. It would have to be a design flaw, one that surely would have been noticed by other users of the same product sometime in the past 5 years.

It kind of sounds like I'm piling on and saying this has to be your error, but I'm really just trying to help you work through the variables. Believe me, I've made far sillier mistakes than this.
But while I'm being pedantic and thorough, I have to say that I doubt your assertions that you've heard adapter cables color your audio, or that you can identify an absolute polarity inversion by ear. Relative polarity inversion (such as right-vs-left or two mikes on a single source) is very easy to hear. Absolute inversion (everything flipped together) is nearly impossible on a very few sources under ideal conditions, and totally impossible on everything else.

[dietrich10]

adam-what happened in the end?

[adamlloyd]

Originally Posted by ulysses

What happens if you use your polarity-flipping adapters on the output of the 002? If this does NOT cause the polarity to become inverted, then the simple and obvious problem is that your polarity-flipping adapters are not polarity-flipping.

If the adapters DO flip the polarity on the 002, then they aren't the problem.

Based on everything you've told us here, I'm confident there are only two possible explanations:

1. Both Mytek and Calrad sold you equipment that is wired with polarity that's different from what it's supposed to be.

2. Operator error. That's you. It sounds like you know what you're doing, but there's just no other legitimate possibility based on the info you've provided us.

3. The third hypothetical which is NOT a legitimate possibility is that the Mytek manages to produce a different polarity when you use the Calrad adapters than it does when you don't use the adapters.

Besides using the adapters to route the 002's outputs back into an ADC, the other thing you can do to get to the bottom of this is to use a multimeter to check the connections on your polarity adapters. Look carefully to be sure you're connecting your test probes to the pins you think you're connecting them to at each end of the adapter. Use the "continuity" setting of the meter for an easy "Go/No-Go" beep. Or just open them up and look inside.

Seems odd that Calrec would miswire two adatpers and ship them both to the same guy who got a miswired Mytek converter.

Also seems odd that Mytek would build a converter with connectors installed with wire, the only possible way to get an accidental inversion on one unit. If that's the case, an assembler would have had to miswire both channels. More likely would be that they used PC-mount XLR connectors, which cannot be accidentally miswired. It would have to be a design flaw, one that surely would have been noticed by other users of the same product sometime in the past 5 years.

It kind of sounds like I'm piling on and saying this has to be your error, but I'm really just trying to help you work through the variables. Believe me, I've made far sillier mistakes than this.
But while I'm being pedantic and thorough, I have to say that I doubt your assertions that you've heard adapter cables color your audio, or that you can identify an absolute polarity inversion by ear. Relative polarity inversion (such as right-vs-left or two mikes on a single source) is very easy to hear. Absolute inversion (everything flipped together) is nearly impossible on a very few sources under ideal conditions, and totally impossible on everything else.

I kind of just had to walk away from this mess for a couple days. It was going to give me a serious complex if I don't have one already. I ordered the CT100 cable tester and I'm waiting for that just to make absolutely sure it's not something weird with my cables.

"Seems odd that Calrec would miswire two adatpers and ship them both to the same guy who got a miswired Mytek converter." Indeed my friend, it does. I don't know what to tell you. I wouldn't post on this forum if I'd tried absolutely everything I could think of because I know y'all would rip me a new one and say I'm a lunatic. But, that's just the price I pay to having access to this great resource of people with experience far beyond my years and having the opportunity to get feedback from a high end forum.

The calrads, although not flipping the polarity on the mytek, didn't impart any color or change in sound that I noticed. But with all do respect, I have found that anything you place in the line of a signal has the potential to change ("color") the sound. I have noticed this with other adapters, namely TRS to XLR adapters. I am not an electrician, but I would assume from my knowledge it's simply due to the fact that different metals have different conductivity, for the same reason a lot of people prefer gold plated terminals on their cables, etc.

In terms of being able to hear absolute polarity, I also don't know what to tell you. Maybe it's just as much a systemic reaction to music as it is an audible one. Inverted polarity doesn't sound/feel natural to me. Maybe I'm nuts. But I can tell you I've been hired for many a project simply based on the fact that I seem to be able to hear things that other people don't. I think I'm better at just hearing things and pinpointing what I hear than I am at mixing material. I seriously don't even like saying any of this because I'm a very humble person and believe that humility is very important in life and that no one is ever always right. But I can just tell you that I've learned to trust my ears (and systemic reactions to music), in most scenarios, over the years.

Obviously the polarity issue got by me for a while, because I've had this unit for a while. I could just tell something was sounding/feeling weird and it wasn't until I realized that anything I sent out of Pro Tools for outboard processing came back in upside down that I was able to soon pinpoint the issue. I went on to discover that because of this, stuff I had been working on had certain things flipped, other things not flipped, so drums were inverted, synths not, etc, it was a mess.

But in my defense, I went from doing all my editing and mixing on an MBox, where these variables were never an issue, to buying some decent outboard gear to up my game a bit. When I was working with the MBox, I was able to do some really solid work. But when working with this updated gear, I kept noticing something didn't feel right, and couldn't figure out what the heck it was, because SO many things had been improved with the updates...I mean, c'mon, mytek conversion compared to MBox conversion? LA-610 with NOS tubes compared to the generation 1 mbox focusrite pres? There's no f-ing comparison. Anyway, there were several other issues I had to resolve, but once those were out of the way, I was able to pinpoint the polarity issue.

I appreciate all your input and if this is truly error on my behalf I apologize for wasting your time with this thread. I will try using the polarity flippers on the 002 and maybe my 610 just to see if they flip the signal in those applications. I'm also going to wait for the cable tester to make sure there is nothing weird going on with my cables. They were all made by the same guy with a good track record, so I would find it weird if there was an issue, but it definitely is a good thing to check. Right now, I'm sick and I need to rest. I'll report back after I've tried these things. Take care.

[SP2016]

Did you try switching from SUPERLOCK to EXTERNAL clock already ?

[adamlloyd]

Yep yep... Didn't change anything. But thanks for the suggestion

[adamlloyd]

Okay, so, got the CT100, can someone please explain to me if I'm missing something. All of my cables show a left to right, down to up horizontal light-up of the 3 LEDS. So all of the labels match up on top and the side.

But, I tried with the "polarity flipping adapters," and they give me the exact same result.

I attached pics of it.

If the adapters were working, wouldn't they show a different pattern because the pins wouldn't line up? I'm confused.

And yes, I tried both adapters, they both have the same result.

[ulysses]

It would appear your adapters are not adapting anything.

[adamlloyd]

Okay...So I wasn't imagining it or doing anything wrong when I was testing them before...Good...Point for me :-D

So....this all still points to the DAC inverting the polarity, just as I suspected before. All of my cables give the exact same reading as the photos I've posted.

I'm going to test a few more things after I eat something and I'll report back, with photos, so no one can say I'm crazy.

[adamlloyd]

Okay folks. It is the DAC. There is no other way. All of my cables are fine.

I've attached two photos. The 1st is the 002R DAC looped directly to the Mytek ADC. As you can see, the polarity of the looped signal is the same as the source. I also tried inserting the "polarity flipping" calrad adapter, it yielded the same result, which makes sense considering what the aforementioned CT100 test showed.

The 2nd photo is the Mytek DAC to the Mytek ADC. As you can see, the polarity is flipped, and I'm not confusing "crests for troughs." THE POLARITY IS FLIPPED. I've tried with External Sync vs. XTal96, it makes no difference.

This unit was obviously messed with by one of its previous owners, before I bought it. Michal had replaced the spdif jack after it was damaged in shipping, when I first received it, but I spoke to a tech here in L.A. and he said that this repair would have no effect on the polarity. Besides, I think after all these years, that Michal knows what he's doing!!

When I got this thing I didn't even know this could be an issue. I have definitely learned a lesson and will check polarity on EVERY PIECE OF GEAR OR CABLE I ever get in the future. As it stands, I have to go back and re-address months of work that had only certain tracks reamped or processed with outboard gear, some multiple times. It's an F-ing nightmare considering these projects have stems and 40-60 tracks.

And that's once I have a DAC that works properly. I think I'm just going to get rid of this one and buy a brand new one, I've wasted enough time and energy trying to remedy this situation.

P.S. I dont know why the pics are posting vertical, they're not on my computer...

[SP2016]

Originally Posted by adamlloyd83

Okay, so, got the CT100, can someone please explain to me if I'm missing something. All of my cables show a left to right, down to up horizontal light-up of the 3 LEDS. So all of the labels match up on top and the side.

But, I tried with the "polarity flipping adapters," and they give me the exact same result.

You DID push the reset button everytime you connected other cables ?

Yes: With an adapter you would have to see a different pattern (namely 2 and 3 reversed) after pushing the reset switch.

And for the adapters: These then may be just straight Male to Female adapters, wired straight p1 to p1, p2 to p2 and p3 to p3. (P meaning Pin...)
Did these have a label or something when you bought them, with some marking like "PHASE REVERSED" ?

Is it the Calred 35-464
Phase Adapter3 Pin XLR Female Jack to 3 Pin XLR male plug.Crossing Wire for pins 2 & 3.

Then it seems to me that you have to do something with that "crossing wire" to actually reverse pin 2 and 3.
Was there no instruction leaflet with the Calred ? If so: Did you read it ?

[adamlloyd]

Originally Posted by SP2016

You DID push the reset button everytime you connected other cables ?

Yes: With an adapter you would have to see a different pattern (namely 2 and 3 reversed) after pushing the reset switch.

And for the adapters: These then may be just straight Male to Female adapters, wired straight p1 to p1, p2 to p2 and p3 to p3. (P meaning Pin...)
Did these have a label or something when you bought them, with some marking like "PHASE REVERSED" ?

Is it the Calred 35-464
Phase Adapter3 Pin XLR Female Jack to 3 Pin XLR male plug.Crossing Wire for pins 2 & 3.

Then it seems to me that you have to do something with that "crossing wire" to actually reverse pin 2 and 3.
Was there no instruction leaflet with the Calred ? If so: Did you read it ?

Yes sir, I did press the reset every time I connected new cables.

As for the calrads, there was no instruction leaflet. I bought them from avcable.com, and they came in a baggy that has a label with "Calred 35-464" printed on it. The individual adapters, however, have no such identifying marks. They look like the adapters in the picture on the website, where they are said to be polarity flipping adapters.