[fsimms]

No, I said PS ground is not tied to chassis (and therefore to the IEC ground tag).

Sorry, I corrected my comment but I see you read it 3 minutes after I posted it and didn't get my corrected copy.

Bob

[richidoo]

andyr, sorry for delay. I use Equitech 1.5Q - couldn't be happier. Lots of info on their site.

[Occam]

Of course you would have to tie the CDP player to the preamp through an optical cable to isolate the preamp and the amp.
I don't understand what you  mean. Would you elaborate?

Cables that go from the CDP player to a preamp have grounds running in the cable unless it is an optical cable.   This ground would cause a ground loop through the power cable grounds and cause RF ringing.   Some power cables are designed to dampen out that ringing.   To dampen out all the ringing, you would need one of those power cables to all but one of the boxes in the system that were connected by interconnects with grounds in the cables.

Bob

Bob,

You've really lost me..... I assume you mean that an electrical (coax,AES...) connection between an digital source (transport, server) and a dac, is prone to ground loops because it offers a ground path in addition to the one established via the mains safety ground, and that this establishes a ground loop. And furthermore, using a toslink optical link will break this loop. But please remember the context from which this discussion grew - changing a captive 2 prong cord on an AVA dac to either an IEC to allow use of an IEC terminated cord or simply hardwiring a different captive cord. One of the hard and fast lessons of anyone who has actually done this is to never ever add a mains ground connection to a component that previously lacked one; it is a guaranteed way of getting ground loop hum/noise. The component with a 2 prong mains connection certainly has a ground, but is relative and unreferenced until a connection is made to an actual mains ground by whatever circuitous route, and hence typically does not cause ground loops/noise.
For those using a cd or dvd player as a transport, typically these are 2 prong Class II appliance, with the requisite double insulation and creepage requirements to be certified as Class II appliances by an ETL and not require a mains ground for safety purposes. And that usually means that the internal grounding schemes are not optimized for the situation where someone would foolishly add a mains ground reference internally.

For an excellent discussion of ground loop issues in consumer products, Dan Banquer's polemic is an great reference -
http://www.audiocircle.com/index.php?topic=8780.0
and from the Jensen site
http://www.jensen-transformers.com/an/an004.pdf

In your post here -
http://www.audiocircle.com/index.php?topic=61224.msg548727#msg548727
you conclude that the benefits of powercords are the minimization of ground ringing that you've discovered on your VD3 powercords. Indeed, the magnets on the VD3 might fortuitously provide enough inductance to attenuate ground crap from components with less than ideal ground currents. Lucky you. Nevertheless, the subjective benefits of some replacement cords are there even if the cord does not have a mains ground connection or not.... Post hoc ergo propter hoc.

FWIW,
Paul

[JimJ]

mfsoa

I believe that while you may have a point, two Vodkas of the exact same composition should taste the same. Otherwise you are basically saying that two 100Hz sine waves don't sound the same. That two of the same pieces of music don't sound the same. So while measurements can only go so far, I think tha twe have taken them far enough that if two things have the exact same composition, they are the same. Relating to audio, I would say that two cables of the same material and the same contruction are the same.

-West

If someone's going to bring up the state of current science and what discoveries might be made in molecular or quantum physics, I'm always amazed that the current state of manufacturing doesn't play a larger role in this...nevermind what we don't know, we know that no two runs of anything are going to be exactly alike, there's going to be boatloads of common cause variation in a typical power cable...in the wire, in the dimensions of the plug, in the content of the solder...now if the processes are in control, whether that makes a difference or not is the debate, but I think if the current state of science is what's in question here, manufacturing's variation has to be several orders of magnitude larger.

[fsimms]

For those using a cd or dvd player as a transport, typically these are 2 prong Class II appliance, with the requisite double insulation and creepage requirements to be certified as Class II appliances by an ETL and not require a mains ground for safety purposes. And that usually means that the internal grounding schemes are not optimized for the situation where someone would foolishly add a mains ground reference internally.

I was thinking about 3 prong plugs and you are right that most CDP’s are two prong.   That is my fault.  Just my own fuzzy thinking.   Two prong plugs do have a neutral that is tied to ground.   That is why the two pins of the plug are of different sizes so the hot side can’t be connected to safety ground.

I love the posts that you gave.   The first post by Dan Banquer seems to be consistent to what I was saying.  He is just stating a solution to the problems that I was addressing.  He is talking about lifting grounds at all points except for the preamp.   He does say that he doesn’t recommend it.  He just says that it works.

The second one will take more time to absorb, but it also doesn’t seem to be inconsistent than what I was saying.


Bob

[Occam]

Hey Bob,

If you reread Dan's missive, you'll see that he advocates lifting the the signal grounds from the Safety (mains) grounds at all places but one, typically the preamp. This goes a long way towards minimizing the potential for grould loops/noise, as does limiting oneself to a single dedicated line to power your system. Other techniques to 'stand off' the signal ground from the mains ground are also applicable -
http://sound.westhost.com/earthing.htm

These techniques, and others that may 'stand off' the the signal or even the power supply grounds from the mains, safety ground are fine, as they do not impair the efficacy of a solid saftey earth ground to a conductive chassis.

Regards,
Paul

[fsimms]

http://sound.westhost.com/earthing.htm

Nice link!  The dashed line shows the ground loop I was talking about.

Bob

[Bill Baker]

The one thing captive cords have going for them is a secure connection. You know you will always have a good contact. The problem with [some] components out there is the $0.89 EIC unit that can't grab hold of the plug at the end of that $5,000 power cord.

 Most of the gear I have built to be used in my showroom utilizes the Power-Con connector. If I have my way, all my products will be build with Power-Con connectors and provided with a decent power cord. You can be assured of a good contact at all times and not have to worry about your power cord falling out of the component. It's too bad the industry has not yet accepted these on a larger scale.

[avahifi]

Alas, nobody has answered my basic question yet.

If I was to design a great sounding power cord, what electrical and engineering characteristics should it have?

I will ask all of you a simple question - - - what is a preamplifier supposed to do?  What is its basic job in the system other than providing audio level adjustment and source switching?

If you don't know the answers, makes it kind of hard to design a good product, doesn't it.  "Sounds really good" is not an objective answer.

Regards,

Frank Van Alstine

P.S.  We think we have some of the basic answers to my preamp question above and I will be happy to explain in detail herein in general terms (if anyone wants to hear my ideas), not just specific brand or model verbage.

[andyr]

Alas, nobody has answered my basic question yet.

If I was to design a great sounding power cord, what electrical and engineering characteristics should it have?

Regards,

Frank Van Alstine

Frank,

In terms of your basic question ... shirley the ideal power cord should have:
* zero R (so it doesn't create any "friction" to the flow of electricity  )
* zero C (I don't know what high C does to AC power transmission but I'm sure it must do something bad!  )
* zero L (as inductance acts as a brake on current flow)?

The above is simply to provide "undamaged" power assuming a clean supply.  But since most power is not "clean", it should also ideally:
* be able to filter out "nasties" which are present in the mains wiring in the wall, and
* be shielded, so as to not interfere with adjacent interconnects.

Engineering-wise, it should:
* have plugs/sockets which make a firm, close contact to the wall-socket and the IEC socket, and
* be suffciently robust not to break or become unsafe with repeated handling.

Regards,

Andy

[Occam]

Alas, nobody has answered my basic question yet.

If I was to design a great sounding power cord, what electrical and engineering characteristics should it have?

I will ask all of you a simple question - - - what is a preamplifier supposed to do?  What is its basic job in the system other than providing audio level adjustment and source switching?

If you don't know the answers, makes it kind of hard to design a good product, doesn't it.  "Sounds really good" is not an objective answer.

Regards,

Frank Van Alstine

P.S.  We think we have some of the basic answers to my preamp question above and I will be happy to explain in detail herein in general terms (if anyone wants to hear my ideas), not just specific brand or model verbage.

Oh goodie, a quiz!!!!!

Howzabout impedance matching? One would like, at minimum, the input impedance of the preamp to be 10x greater than the source impedance of whatever source(s) its connected to. Similarly, one would like the output impedance of the preamp to be a minimum of 10x smaller than the impedance of the amp, etc... its feeding. Or whatever ratio of impedances that pulls your pizzle string.......

Now that I've answered your patronizing question (I certainly don't need YOUR validation of my answer) howzabout you answer a question of mine?
So why do you provide a 2 prong non-safety grounded cord on your products when they are obviously not ETL certified as Class II appliances, which by current standards require a safety grounded chassis? I respect your products and don't think they represent a serious risk to the user, but a simple glance at the innards of your dac make it quite obvious that it is not built to Class II standards. The real risk to your customers is that they have a fire (your products don't have to be the cause) and an adjuster realizes what you've done and denies the claim, just like they would if they found a cheater plug. You've simple built that 'cheater plug' into your products.
Whats the problem Frank? Can't you build a product that doesn't hummmmmmm when properly connected to the mains? Oops, sorry, that's 2 questions......

So maybe you could also share the engineering beyond 'gud enuf' (UL/CSA certified to the load and use) that made you choose your zip cord.

A favor please? If you do choose to pontificate on preamps, start a new thread.

Warmest regards,
Paul

[fsimms]

P.S.  We think we have some of the basic answers to my preamp question above and I will be happy to explain in detail herein in general terms (if anyone wants to hear my ideas), not just specific brand or model verbage.

Frank, it would be fantastic to hear your views.  The preamp is the key element in a system in that all the other elements have to operate properly through it.  Not an easy task, I am sure.

Bob

[jhm731]

Alas, nobody has answered my basic question yet.

If I was to design a great sounding power cord, what electrical and engineering characteristics should it have?

I will ask all of you a simple question - - - what is a preamplifier supposed to do?  What is its basic job in the system other than providing audio level adjustment and source switching?

If you don't know the answers, makes it kind of hard to design a good product, doesn't it.  "Sounds really good" is not an objective answer.

Regards,

Frank Van Alstine

P.S.  We think we have some of the basic answers to my preamp question above and I will be happy to explain in detail herein in general terms (if anyone wants to hear my ideas), not just specific brand or model verbage.

I don't think a power cord's job is to filter out "nasties" which are present on the mains. External power conditioners and proper power supply design
is a better way to deal with AC issues than fancy power cords.

[satfrat]

Alas, nobody has answered my basic question yet.

If I was to design a great sounding power cord, what electrical and engineering characteristics should it have?

I will ask all of you a simple question - - - what is a preamplifier supposed to do?  What is its basic job in the system other than providing audio level adjustment and source switching?

If you don't know the answers, makes it kind of hard to design a good product, doesn't it.  "Sounds really good" is not an objective answer.

Regards,

Frank Van Alstine

P.S.  We think we have some of the basic answers to my preamp question above and I will be happy to explain in detail herein in general terms (if anyone wants to hear my ideas), not just specific brand or model verbage.

miklorsmith wrote:

I like being able to swap cables but it does feed the nervosa and wallet drain.  What do you think?

Alas Frank,  but I thought this was the basic question in this thread and it was asked by miklorsmith, not you.

Cheers,
Robin

[Brown]

Well has anyone actually taken a cord they like with their preamp and hardwired it in as opposed to the IEC connection ? Has one heard a difference ? Has anyone measured a difference. Both CJ and AR for years resisted the IEC. Why I wonder. No engineer here just a potato head with ears.
   What would one measure that would confirm the advantages if any ? Different powercords affect the sonics so what are they doing ? Managing RFI ? EMI? increasing current ? Adding or subtracting inductance ? WHAT ?

[satfrat]

Well has anyone actually taken a cord they like with their preamp and hardwired it in as opposed to the IEC connection ? Has one heard a difference ? Has anyone measured a difference. Both CJ and AR for years resisted the IEC. Why I wonder. No engineer here just a potato head with ears.
   What would one measure that would confirm the advantages if any ? Different powercords affect the sonics so what are they doing ? Managing RFI ? EMI? increasing current ? Adding or subtracting inductance ? WHAT ?

I have a novel idea. Why don't you try doing & listening to some of your ideas of yours and then get back to us on what you are hearing.
Why do you need someone to tell you what you should or should not hear? Experimentation is a huge part of this hobby ya'know. People telling people what they can and can not hear is also a big part of this hobby.

Cheers,
Robin

[Brown]

Well has anyone actually taken a cord they like with their preamp and hardwired it in as opposed to the IEC connection ? Has one heard a difference ? Has anyone measured a difference. Both CJ and AR for years resisted the IEC. Why I wonder. No engineer here just a potato head with ears.
   What would one measure that would confirm the advantages if any ? Different powercords affect the sonics so what are they doing ? Managing RFI ? EMI? increasing current ? Adding or subtracting inductance ? WHAT ?

I have a novel idea. Why don't you try doing & listening to some of your ideas of yours and then get back to us on what you are hearing.
Why do you need someone to tell you what you should or should not hear? Experimentation is a huge part of this hobby ya'know. People telling people what they can and can not hear is also a big part of this hobby.

Cheers,
Robin

Geez get up on the wrong side of the rock ? I was posing a legitimate question not being cute. I have conducted this experiment but was hesitant to suggest anything to avoid answers like yours. Your sarcasm is NOT appreciated. IMO it sounds better without the IEC connection. I just do not know why. Again no engineer here.
 My question was directed to those in the know like frank and Occam. Trying to learn something here. I do not need anyone to tell me what I hear or what to do either, thankyou. Peace dude.

[*Scotty*]

Brown, I am hypothesizing here, but it may be due to the contact resistance in the IEC connection as well as the resistance in the IEC cord cap which is also another non-soldered connection. If I a was betting man I would reasonably expect a good sounding well designed power cord to sound better when hardwired. 
Scotty

[satfrat]

Well has anyone actually taken a cord they like with their preamp and hardwired it in as opposed to the IEC connection ? Has one heard a difference ? Has anyone measured a difference. Both CJ and AR for years resisted the IEC. Why I wonder. No engineer here just a potato head with ears.
   What would one measure that would confirm the advantages if any ? Different powercords affect the sonics so what are they doing ? Managing RFI ? EMI? increasing current ? Adding or subtracting inductance ? WHAT ?

I have a novel idea. Why don't you try doing & listening to some of your ideas of yours and then get back to us on what you are hearing.
Why do you need someone to tell you what you should or should not hear? Experimentation is a huge part of this hobby ya'know. People telling people what they can and can not hear is also a big part of this hobby.

Cheers,
Robin

Geez get up on the wrong side of the rock ? I was posing a legitimate question not being cute. I have conducted this experiment but was hesitant to suggest anything to avoid answers like yours. Your sarcasm is NOT appreciated. IMO it sounds better without the IEC connection. I just do not know why. Again no engineer here.
 My question was directed to those in the know like frank and Occam. Trying to learn something here. I do not need anyone to tell me what I hear or what to do either, thankyou. Peace dude.

Hey, I'm just trying to be honest with ya guy about all your (what do I hear) questions. I know where you were coming from and I wasn't trying to be smart(I wouldn't be any good at it anyways ). I am telling you what most of us do, we try things and then we state our opinion on what we hear. Nothing smart about it at all. I don't make smartass answers to what other folks hear or don't hear,, period dude! But I would sincerely be interested in what you have to say after formulating an opinion. But asking questions on what you're supose to hear*(sonics of different power cords?) don't mean squat. FIND OUT FOR YOUSELF DUDE,,,, then you will know and then just maybe you'll have something to share. 

Cheers,
Robin

[JerryM]

I like being able to swap cables but it does feed the nervosa and wallet drain.  What do you think?

Aside from an extremely well respected manufacturer telling me not to waste my time or money on PCs, I scored a pair of NOS Telefunken ECC801S valves for less than I could have experimented with cords. I am more than certain that the sonic benefit, and life span, they are providing is more significant than any possible PC swap.

JMHO,
Jerry