Reverse AC Polarity with DSD


#1

Did anybody test the DSD with reverse polarity? My unit is fairly new at c. 150 hours so I am not testing it yet but I am a big believer in power cable orientation. For instance my Ayre amps (230v European version) benefited immensely from it. Listening impressions as well as actual measurements will be useful. I would not be surprised if the change wrought by correct polarity is greater than 1.2.1 vs pikes peak


#2

Just in case it’s not obvious audio polarity has nothing to do with the direction of the power cables which has nothing to do with which blade of the plug is in which slot in the socket. Each of these three separate “tweaks” has vocal adherents… (as do interconnect orientation, speaker cable orientation, …)

Correct AC polarity? Tho some power transformers have different leakages relative to the safety ground, which polarity sounds best still may well depend on what the AC power signal looks like in your system. But some claim that the difference in noise floor is measureable in some equipment. I suspect not so much in the DS, but who knows? It’s not something that’s safe to experiment with in the DS.

“Correct” direction of power cords, interconnects, etc. may depend on the manufacturing process(es) and/or which direction they were last most used in…

Correct audio polarity? That depends on the recording (sometime the track on a disc). And some recordings have some elements of the recording in one polarity and other elements in the opposite polarity and then they are mixed together: there is no technically correct polarity, you have to pick your poison. Some people I know mark their favorite polarity settings on each disc (and or track.) Personally I’m glad I don’t notice it except on rare occasions, otherwise my OCD tendencies would have me marking discs too.

In any case at least with DSD it is easy to reverse the polarity and with a balanced system you aren’t playing favorites with one polarity or another. Just FYI: with PCM reversing polarity by changing the sign fails on samples that happen to be the maximum negative value. (e.g. -32768 in 16 bit PCM) +32768 isn’t representable in 16 bits so you have to change the signal (at least for those samples) to reverse it’s polarity :)

Which if any is the biggest difference most likely depends critically the specific components and on how your system is set up. In my system the differences with each of those changes in “polarity” pale compared to differences with changes in software.


#3

Just in case you didn’t read thru my longer post: with three pronged plugs (grounded equipment vs, two pronged plugs) reversing the AC polarity can be dangerous. Usually people switch the input or output wires on the power transformer in the unit which may or may not be safe in a given system. I don’t recommend experimenting with this in the DS.


#4

Hi Ted,

Thanks for the detailed explanation but I was referring strictly to AC polarity and two pronged European schuco models where you simply reverse the position of the plug in the wall socket.

And the test is very simple with a multimeter without tweaking the transformer:

1) Turn off all components.

2) Isolate each component by removing all wiring including power cord, interconnects, ground leads, antenna wires, etc.

3) Connect the common probe of the multimeter (black lead) to a ground reference point.

4) Connect the positive probe (red lead) to the chassis or ground terminal of the unit under test.

5) Plug the component into the wall socket and turn on the power switch. Note the A/C voltage reading on the Multimeter.

6) Reverse the position of the plug in the wall socket and repeat step 5.

7) The correct A/C alignment will be the one that gave the lowest reading.


#5

All I was trying to point out was that when safety grounding comes into the picture things are different… I don’t know how that’s handled with Schuko plugs so I can’t comment on safety on equipment using them, but advising people to try things involving the mains when you don’t know everything about their electrical systems is not wise. Careful measurements may keep you from making a mistake when everything is working correctly but they don’t tell you what will happen if something fails later. I can say that, in the case of the DS, reversing the wires at the power transformer is safe, tho I don’t advise it. Similarly I know that people sometimes advise people to lift grounds to get rid of hum, but my brother was electrocuted in our house when I was younger (tho not from a failed consumer device) so I take safety with the mains a little more seriously than some might.


#6

Polarity for power is something I am infested in as well. Although here in the states no such device is allowed due to local and national electrical codes. Lapmizator makes a device that has about 5 duplex or single outlets . Each one has SW allowomg us to change the polarity of each outlet seperetly. The concept is not all tow formers are wound in the same way . Meaning left to right or vice versa . This means the output voltage AC is not the same polarity for all of our devices. Now of course it’s them filters to dc . But the small ripple is reflective of the Ac polirty. This is where he claims his effect from. I do Plan on getting a loaner of one to try just to try and hear it.

Again as it is not ok to use this here I wonder of its effects. After all we spend big bucks ON cords and the like . And people swear by this .

al


#7
Ted Smith said All I was trying to point out was that when safety grounding comes into the picture things are different... I don't know how that's handled with Schuko plugs so I can't comment on safety on equipment using them, but advising people to try things involving the mains when you don't know everything about their electrical systems is not wise. Careful measurements may keep you from making a mistake when everything is working correctly but they don't tell you what will happen if something fails later. I can say that, in the case of the DS, reversing the wires at the power transformer is safe, tho I don't advise it. Similarly I know that people sometimes advise people to lift grounds to get rid of hum, but my brother was electrocuted in our house when I was younger (tho not from a failed consumer device) so I take safety with the mains a little more seriously than some might.
Good advise ted. I have done ground lifting and ISO outllets to remove hum. Until I could get the input ISO devices . They do work and can be bought in both SE and in BAL .

AL


#8

I just tried to edit my mispelled post and I cannot. There is a 6 where the edit button is.


#9

Ted,

Truly sorry about your brother. I did not know about this. I also appreciate the safety warning but what I am suggesting is not something risky or controversial with a schuko plug. You can plug both ways and you are always grounded (see pic). Germans invented it so it works :-). Many people realize there is a significant sonic advantage of plugging one way over the other and I meant to ask whether anyone tried this with good results.

electricity - type F (socket)


#10

http://www.lampizator.eu/Fikus/SILK_AC_FILTER.html

this is the device . And in Europe there is no ground . It’s all 230 volts and non grounded for some devices hence ots only two progs. Paul shroud know why I do not .

al


#11

no there is grounding. see the top and the bottom of the plug in the picture above


#12

Yes I see it. But nit all euro outlets have them. Thanks


#13

http://www.worldstandards.eu/electricity/plugs-and-sockets/


#14
mcduman said Ted,

Truly sorry about your brother. I did not know about this. I also appreciate the safety warning but what I am suggesting is not something risky or controversial with a schuko plug. You can plug both ways and you are always grounded (see pic). Germans invented it so it works :-). Many people realize there is a significant sonic advantage of plugging one way over the other and I meant to ask whether anyone tried this with good results.

electricity - type F (socket)

It does seem to make a difference, I did not know this until a friend suggested it to me.
Since as Ted says it does not matter which way the power cord is plugged into the socket then the thing to do is to make sure that all components are plugged into the sockets in the same way so that they all have the same polarity.

The best way to do this is to check each of the two sockets on the wall (or the socket you want to check/use) to find which of the two sockets is live, you can safely do this with an electrical testing screwdriver.
Then plug your power cord into to the outlet socket and then check the ends of the power cord that will plug into the unit to see which end is live.
I make sure that all the right pins are live, if it’s not then just plug the power cord the other way around into the wall socket. You do this with all power cords for all components.


#15

That’s not the point here. It’s not about polarity of outlets or cords it’s what’s going inside that may matters

so the device I. Put a link up for does this In a simple easy safe method

maintaining a ground potential at all times.

The reason for the polarity to begin with in all of our devices that are made to USA standards is easy. It takes the actual live wire and keeps It away from you for the most part

it also maintains the power SW is indeed the hot leg

In a simple light socket it’s the small middle pin not the outside spiral one.

The reasons for better sound? who knows? this is audio nothing or very little makes any sense here.

enjoy trying it, as it does seem to matter

but for me a power plant had the same level of improvement. But it did not improve my msb dac weather it’s polarity or my power plants who knows?

Al


#16

Ted did your brother die from the shock ?? Sorry to here if he did or was hurt

as some of my companies are electrical in nature it’s tough to keep things safe at all times

but for me it’s the explosiion I worry about not the shock.

Al


#17

We didn’t see it happen (even tho we were only 10ft away around a corner.) He was wet after a shower with only his underwear on, fell and got tangled in some wires and was grounded thru his feet, we speculate he was trying to free himself and got a zap across the chest - we don’t know for sure.

Still I and my other family members think nothing about getting 120VAC across our chests, 240 isn’t so pleasant. It’s the unexpected things that get you.

Re what’s happening with reversing polarity of the AC input: it’s the leakage current from the powers supply/power transformer to the safety ground (or the interconnects, etc.) - that’s a ground loop and minimizing the voltage difference minimizes the leakage current - hence lowers the induced noise in the system. Another possible effect is with half wave rectified power supplies - if you get the noisy power supplies out of phase with the sensitive power supplies you can minimize the noise transfer from the noisy components to the sensitive components. Obviously this depends greatly on the particular power supply topologies in your system and how much crap is on the lines from the system and everything else in your house.


#18

Ted sorry to here about your brother wow

as as for the topic at hand. Why then does ps audio and many other companies not put a simple SW to do this internally. It’s the only safe and legal way to do it here.


#19

You don’t need one if you build things consistently and right. Some designers (and/or manufacturing lines) don’t care or don’t pay attention. The PerfectWave and DirectStream power supplies are all wired the same and the loads on the transformer outputs are symmetric (and there are big caps) so this “tweak” probably isn’t as effective on them as it is for some devices. Defeating the safety ground and swapping the live and neutral lines outside of the box on a US wired device will put the power switch on the neutral side of the house wiring, and won’t give a lower reading, so it doesn’t make sense to try, let alone having a live box if something goes wrong (even if powered off!) Just say NO.


#20

Ted it was just a question not asking to have it. Your answer as it does make sense and the SW would be on neutral is why it’s not code compliant as is the shielding of the case is as well.

Its just a thought and to me has more merit than fuses or power cords

but of course they both have merit too